Dipartimento di ricerca traslazionale e delle nuove tecnologie in Medicina
e Chirurgia
CORSO DI LAUREA MAGISTRALE IN MEDICINA E CHIRURGIA
Tesi di laurea
Transvenous Lead Extraction: outcome in patients with and without
abandoned leads
Relatore:
Dott.ssa M.G. Bongiorni
Candidato:
Federico Fiorentini
Co-Relatore:
Index
1 Introduction ... 1
1.1 CIED Definition1 ... 1
1.2 Pacemaker and ICD1 ... 1
1.2.1 Electrical Components2 ... 2
1.2.2 Evolution, Function and Types of Pacemaker1,2 ... 4
1.2.3 Functioning of ICD2 ... 6
1.3 CIED Implantation3 ... 6
1.4 Electrical Therapy Indications ... 8
1.4.1 Indications for Pacing Therapy ... 8
1.4.2 Cardiac Resyncronization Therapy (CRT) Indications ... 14
1.5 Indications for ICD (Implantable Cardioverter Defibrillator) therapy ... 19
1.5.1 Subcutaneous implantable cardioverter defibrillator (s-ICD) ... 20
2 Device Extraction ... 22
2.1 Indications for extraction ... 22
2.1.1 Infection ... 22
2.1.2 Non-infective Indications ... 28
3 Transvenous Lead Extraction (TLE) ... 35
3.1 Approaches, tools and techniques ... 36
3.1.1 Approaches ... 36
3.2 Procedures’ definitions5 ... 39
3.2.1 Definition of procedures’s type ... 39
3.2.2 Definition of success ... 40
3.3 Definition of complications ... 42
3.4 Outcome predictive indicators ... 43
3.4.1 LED index score ... 44
3.4.2 30-Day all-cause mortality Risk Score ... 44
3.4.3 IKAR Risk Score ... 45
3.5 Extraction procedures... 46
3.5.1 TLE using single sheath mechanical dilatation and multiple venous approaches ... 46
3.6 New hybrid techniques ... 52
3.6.1 Hybrids minimally invasive approach for TLE54 ... 52
3.6.2 Modified hybrid TLE with the bidirectional rotational Evolution® mechanical sheath 55 ... 53
4 Abandoned Leads: Background and Goals ... 54
5 Methods ... 57
6 Statistical Analysis ... 60
7 Results ... 61
7.1 General population ... 61
7.1.2 Indications for Lead Extraction ... 61
7.1.3 Procedural characteristics and outcomes ... 62
7.1.4 Leads: Baseline and Procedural Characteristics ... 62
7.2 Comparison among Group 1 and Group 2 ... 63
7.2.1 Baseline Characteristics ... 63
7.2.2 Indications for Lead Extraction ... 63
7.2.3 Procedural characteristics and outcomes ... 64
7.2.4 Leads: Baseline and Procedural Characteristics ... 64
8 Discussion ... 75
9 Conclusions ... 79
Preface
In the last decades, the use of Cardiac Implantable Electric Devices (CIEDs, i.e. pacemaker or implantable cardioverter defibrillator) is highly augmented, as for CIEDs’ safety and efficacy as well. The increase in their use has inevitably led to an increase in the associated complications, such as malfunction, breakdown of the various components and the establishment of infectious processes on the components themselves.
The occurrence of these complications has led to the development of extraction techniques for the devices, since, due to adhesion and fibrotic processes of the adjacent tissues, the extraction of the leads (components that carries electric signals from the generator up to the heart) is a procedure much more complex than the implantation, especially if such leads have been inside blood vessels for a long time.
The evolution of extraction techniques has allowed excellent results, with very high success rates and low rates of complications and deaths; however, some debates on the management of the devices still remain open.
One of these debates concerns those lead who undergo to malfunctions but, if disconnected from generator and left inside (thus, without extracting it), they do not represent neither an imminent threat to the patient’s health nor a cause of malfunction for the device itself: therefore, there’s the option to abandon or to extract these leads; currently in the literature, it is still not clear which is the best solution, so it is necessary to keep on studying to ensure the best quality of management for these patients.
This study aims to investigate, inside the examined population, how the presence of these “abandoned leads” modifies the results of the extractions.
This paper is divided into several chapters: in chapter one CIEDs will be introduced, with a description of the various types, their components, functions and the main indications for their use; in chapter two, the indications that lead to the device’s extraction will be described; chapter 3 will be dedicated to the extraction procedures, where will be described the main tools and techniques that has been utilized in these years; particularly emphasis will be devoted to the description of the procedure performed by Arrhytmology Operative Unit of University Hospital of Pisa in these years.
In chapter 4 will be described in detail the current state of the art on abandoned leads’ management and the purposes of this study; in chapter 5 the methods used in the study will be described; in chapter 6 the statistical analysis used will be described, while in chapter 7 the results obtained will be shown. Chapter 8 contains the discussion of the results, in chapter 9 the conclusions of the study will be presented.
1 Introduction
1.1 CIED Definition
1CIED is an acronym for implantable electronic device and it is used for checking electrical cardiac activity and also, if necessary, to deliver electrical stimuli. The electrical pulses are generated by the pulse generator, usually powered with a lithium-ions battery; then, electrical signals are delivered by leads, isolated wires with their tips directly connected to the heart walls. The main types of CIEDs are pacemakers (PM) and Implantable Cardioverter-Defibrillator (ICD).
1.2 Pacemaker and ICD
1A Pacemaker (PM), is a therapeutic device, which is designed to rectify some heart problems arising from irregular heart rhythms. In a healthy heart, the natural pacemaker is represented by sinoatrial (SA) node, located in the atrium near the superior vena cava. This structure generates an electrical impulse that is delivered to atrioventricular (AV) node, located in the septal wall of the right atrium, then to the Bundle of His and the Purkinje fibres, from which structures the impulses arrive on all ventricular myocardium, causing the ventricles to contract.
When natural pacemaker is unhealthy, or any other conduction structure is altered, artificial pacemaker can maintain an effective cardiac rhythm and, at the same time,
Instead, ICD is used to recognize and interrupt life-threatening arrhythmias, such as ventricular tachycardia (VT) and ventricular fibrillation (VF), restoring sinus rhythm (SR). This device is used in patients with high-risk of sudden cardiac death (SCD), as a primary prevention, or in patients who have already underwent an aborted SCD.
1.2.1 Electrical Components2
CIEDs consist in three main components: pulse generator, battery and leads (Figure 3). The main component is the pulse generator, which uses the battery’s energy and leads to provide the right electrical stimuli at myocardium tissue. In fact, the electrical signal conventionally flows from the positive electrode (cathode), located on the generator “can” (or pocket), to the negative electrode (anode), which is located on the leads’ tip.
Leads: pacemaker leads’ system serves two functions. The first is to transmit pacing pulses from the pulse generator to the heart. The second is to pick up electrical activities of the heart to modify the pacing sequence. Leads are insulated with non-conductive material (for example, silicon) except at the tip electrode and the connector to the generator. The conductor is made of corrosion-resistive wire, which is coiled to increase flexibility. The electrode (tip of the lead wire) may be attached to the surface of the heart or inserted through a vein into the chambers of the heart. There are many kinds of lead, which differ according to their purposes, PM-related or ICD-related; although, leads’ choice depends on patient’s features and application type, too. Here are listed the main types:
• Unipolar leads: these leads have their cathode on generator pocket (or metal housing), while their anode is inside the heart. Thus, they sense and stimulate in
the space between these two electrodes: the metal housing of the pacemaker also serves as the return electrode.
• Bipolar leads: they both have anode and cathode inside the heart; usually, the anode is located on the lead’s tip, while cathode is represented by a dedicated ring proximally on the lead (compared to the tip). Bipolar sensing is considered more precise and less susceptible from external electromagnetic interferences than unipolar sensing. With bipolar leads, it is also possible to program stimulation on unipolar mode.
• Integrated Leads (false bipolar): these leads are utilized for ICD systems; there are three or four electrodes: the first is on the lead’s tip and has sensing and pacing functions; another is represented by a coil, used for defibrillation (as the anode) and located in right ventricle (RV pacing). Integrated leads often have a second coil, proximally to the first and designed to be located in superior vena cava; this coil is important for widening the lead’s surface for defibrillation. Defibrillation is obtained by delivering shock from the RV’s coil to the generator pocket, then shock returns to the SVC’s coil, obtaining biphasic shock1.
Generator’s components: all generators obtain power from a battery, which can be lithium-iodine (for PM) or lithium-silver (for ICD). Next to the battery is located a
1 Defibrillators were only monophasic at the very beginning; the shock was only delivered from the generator to the heart and the power requested was very high. Modern biphasic defibrillator, both external and internal, need less power to deliver effective shocks.
computer that can process input/output signals (need of programming) and memorizes information from cardiac electrical activity, that can be recovered by an operator. ICD also contains ad high voltage transformer and a compact capacitors system for storing and developing adequate shocks for defibrillation.
1.2.2 Evolution, Function and Types of Pacemaker1,2
During last century, many types of PM have been developed: the first type was called fixed-rate (also known as asynchronous) and it used to be involved in complete atrioventricular block (AVB) treatment; the treatment consisted in a constantly fixed-rated-frequency (60 bpm) stimulation. This device wasn’t unable to sense spontaneous electrical heart activity, and this led to a dangerous competition between heart rhythm and pacemaker rhythm, since this could evolve in life-threatening arrhythmias (VT or VF).
Given possible life-threatening complications, another type of pacemaker was developed by Berkovits in 1964 and called demand pacemaker (all modern pacemaker refers to this for main operation): this device is able to sense heart activity and to pace only if requested (when no intrinsic heart activity is sensed), deleting the competition’s problem. Furthermore, demand pacemakers request minor amount of energy, since they’re not always active; this should lead to a longer battery life.
Thus, the two function of sensing and pacing are carried out by leads’ electrodes: • Pacing: stimulation of heart’s walls from distal electrode (which is adherent to
walls itself);
• Sensing: registration of intrinsic electrical heart activity from the distal-tip electrode. This record is then computed by pulse generator. Demand pacemakers’
pulse generator have complex structure, consisting in three components: (i) sense amplifier (it amplifies and filters incoming signal), (ii) time control circuit
(inhibits stimulation when an intrinsic heart activity is sensed) and (iii) output
driver (delivers signal to leads); this is also called demand-inhibited pacemaker.
A variant of demand-inhibited pacemaker is the demand-triggered pacemaker that sense and pace even with an intrinsic electrical heart activity, synchronously with sinus rhythm (e.g. in a unipolar-one-chamber ventricular pacemaker, pace-activity is detected just before QRS wave, while in bipolar double-chamber pacemaker also before P wave). When no intrinsic activity in sensed, PM will pace in predetermined time intervals. In 1970, Dual-Chambers pacemakers were developed: they can sense heart activity both in atrium and ventricle. If a pace is requested, atrial and ventricular impulses are synchronized by timing control circuit and physiological heart activity can be reproduced in this way. Obviously, this device needs two leads to operate (one in right atrium, the other in right ventricle) and three electrodes (one in right atrium, one in right ventricle, one neutral). This system is usually used to treat SA node pathologies. Despite their great technology, demand pacemakers cannot change heart rate as the metabolic demands vary, such as in exercise situations (this could eventually lead to exercise-related syncope due to the decrease of peripheral resistance with no adequate chronotropic compensation). For these reasons, in recent years new type of pacemakers have been developed: they’re able to adjust stimulation rate with several physiological parameters (such as body movement, heart rate, pH, QT interval, blood temperature, etc.), detected from generator and leads sensors. After that, with an algorithm generator computer-associated system can estimate adequate stimulation rate.
1.2.3 Functioning of ICD2
The main difference between ICD and PM is the ICD ability to generate high-voltage shocks, while maintaining basic functioning of pacing (at least among the 30-seconds after defibrillation period). ICD continuously sense for intrinsic activity: when a potential life-threatening arrhythmia is found (VT or VF, also called shockable rhythms), capacitors are charged at 750 V, then released towards the heart; more shocks might be requested (usually a maximum of 6 shocks are delivered). At the end of the shock therapy, ICD algorithm is used for a new detection: this could refer the SR restoration, VT/FT persistence or eventually VT/FT modification without disappearance.
1.3 CIED Implantation
3PM permanent implantation is performed in a cardiac catheterization laboratory under local or, less common, general anaesthesia, and is considered to be a minimally invasive procedure, as for ICD implantation. Transvenous access to the heart chambers is the preferable technique, commonly via a percutaneous approach of the subclavian vein, the cephalic vein (cut down-technique), or, rarely, the axillary vein, the internal jugular vein or the femoral vein. In some cases, both subclavian vein and cephalic vein are punctured. The most common route is the left or right subclavian vein, entered at the junction of the middle and inner thirds, where the first rib and the clavicle are joined. The vein is usually blindly punctured, unless there are certain anatomical abnormalities, such as chest wall or clavicle deformation. In these cases, an initial brief intravenous contrast injection-venography is attempted in the peripheral arm vein. After the puncture, a small incision
the generator will be placed. After successful vein access, a guide wire is advanced and placed on the right atrium or the vena cava area under fluoroscopy. A second guide wire can be positioned, if necessary, via the same route either by a second puncture or by a double-wire technique in which two guide wires are inserted through the first sheath. A sheath and dilator are advanced, and, when sheath is set in the right place, the guide wire and dilator are retracted. Then, the lead is inserted into the sheath and advanced under fluoroscopy to the appropriate heart chamber, where it is attached to the endocardium either passively with tines or actively via screw in-leads. When implanting a double chamber-PM, the ventricular lead is the first to be placed. When leads are securely placed to the pocket, the sheath can be removed. Specifics tests for sensing and pacing are held and to avoid stimulation of the diaphragm, pacing is set at 10 V. The lead is sewn with a nonabsorbable suture to the underlying tissue and afterwards, the generator is placed to the pocket and connected to the lead. Last, the incision is closed with absorbable sutures and on arm immobilizer is applied for 12-24 hours. The cut-down technique of the cephalic vein demands extensive skin and muscle dissection to visualize the vein. Occasionally, PM/ICD can be implanted surgically via a thoracotomy and the generator is placed in the abdominal area.
In patients with a cardiac resynchronization therapy indication, another lead has to be implanted in left ventricle. This is obtained passing through a tributary vein of coronary sinus (an epicardial left ventricle venous structure).
1.4 Electrical Therapy Indications
Here there’s a list of main indications for the pacing, resynchronization and defibrillation therapy, useful for the treatment’s choice with CIED4.
1.4.1 Indications for Pacing Therapy4
Bradyarrhythmia requesting for pacing therapy can be caused by vary different aetiologies; some of this, can be potentially reversible, thus it is necessary their exclusion as first diagnostic-therapeutic step. Therefore, it has been discovered, in a report of 277 patients with severe bradyarrhythmia in a DEA ward, acute potentially reversible causes such as (i) adverse drug reactions (21%), (ii) acute myocardial infarction (14%), (iii) intoxication (6%) and (iv) electrolyte disorders (4%)5.
In general, when a transient or reversible cause is excluded, the indication for cardiac pacing is determined by the severity of bradycardia, rather than its aetiology. As a severity index, patient’s clinical features are principally used.
1.4.1.1 Physiopathology and Clinical Features4
The main bradycardia’s physiological effect is to decrease cardiac output. As long as changes in stroke volume compensate for the decrease in heart rate, patients with profound bradycardia can remain completely asymptomatic. This usually occurs in young, healthy patients or during sleep, though bradyarrhythmia introduce itself with easy fatigability, reduced exercise capacity, syncope (for a sudden global cerebral hypoperfusion) and symptoms of HF.
1.4.1.2 Persistent Bradycardia Indications4
First indication is persistent bradycardia (Figure 1), considering adult patients. Persistent bradycardia usually refers to two not-potentially reversible pathologies:
• Sinus Node disease
(recommendations 1,2 and 3). Although LoE (level of evidence) isn’t very high, pacing therapy in patients with symptomatic bradyarrhythmia is indicated, while there’s still no evidence for a survival’s impact. Thus, pacing therapy is not indicated in asymptomatic patients, as well in bradyarrhythmia for reversible causes;
• Acquired AVB (atrium-ventricular block): in contrast to SB (sinus bradycardia), AV block may require
PM therapy for prognostic reasons and pacing may be indicated in asymptomatic patients.
Particularly, several observational studies in patients with third- or second-degree type 2 AV block were performed and suggested that pacing prevents recurrence of syncope and improves survival in adults, although formal RCTs (randomized controlled trial) have yet not been performed. In second-degree type 1 AV block,
Figure 1: ESC Clinical Guidelines for pacing therapy in patients with persistent bradycardia
pacing therapy’s indication is controversial, unless AV block causes symptoms or the conduction delay occurs at intra- or intra-His levels. In these cases, for the choice of therapy are therefore evaluated (i) symptoms severity and (ii) risk of progression to complete AV block (higher in patients with wide QRS).
1.4.1.3 Intermittent (documented) Bradycardia4
For intermittent bradycardia (Figure 2), three conditions have been considered: • Sinus node disease, including
brady-tachy form
(recommendations 1 and 4): pacing therapy is indicated when there are at least one of two clinical features in patients affected by intrinsic sinus node disease: (i.) documented symptomatic intermittent sinus arrest or sino-atrial block in patients with asymptomatic, permanent, mild SB (heart rate 40-50 bpm) and (ii.) prolonged sinus pause following the termination of tachycardia in the brady-tachy syndrome. In both, pathological mechanism is
represented by a prolonged recovery of automaticity of sinus node. Therefore, when
a close correlation between symptoms and EKG (electrocardiogram)
Figure 2: ESC Clinical Guidelines for pacing therapy in patients with intermittent bradycardia
documentation is demonstrated, there is general consensus that cardiac pacing is effective and useful for symptoms relief.
• Intermittent/Paroxysmal atrioventricular block, including atrial fibrillation with slow ventricular conduction (recommendations 2 and 4): indications are similar to the ones aforementioned on persistent blocks: symptomatology-ECG correlation is less important than in sinus node disease, because there is general consensus that pacing prevents recurrence of syncope and may improve survival. Thus, pacing therapy is generally indicated in every patient with intermittent
intrinsic (AV-conduction myocardial-proper disease) AV-block, even without a
symptomatology-ECG correlation.
• Intermittent bradycardia and asystole in patients with reflex syncope (recommendations 3 and 4): enough severe bradycardias can cause an effective asystole with global cerebral hypoperfusion and syncope. In an observational study, pacing therapy has shown it can effectively reduce syncope relapse-rate, but not to prevent all of them. (5,18) In another important RCT study (PM-ON vs. PM-OFF), called ISSUE 3 (19), pacing therapy realized to obtain a 57% reduction of syncope-relapses versus control patients. Therefore, when the correlation between symptoms and ECG is established, there is sufficient evidence that (dual-chamber) cardiac pacing is effective and useful for prevention of syncopal recurrences and reduction of syncope burden in patients ≥ 40 years with the
clinical features of those used in the ISSUE studies. Instead, in patients with a clinical diagnosis of reflex syncope and asymptomatic pause > 6 sec, there is weak evidence that cardiac pacing may be effective and useful for reduction of syncopal recurrences.
1.4.1.4 Suspected (undocumented) Bradycardia Indications
Conditions in which were not possible to associate a syncopal event with a cardiac cause, but there are clinical conditions that may rise suspects:
• Bundle Branch Block (BBB): presence of BBB suggests that the cause of syncope may be complete heart block. Nevertheless, less than half of patients with BBB and syncope have a final diagnosis of reflex syncope. a similar percentage have a final diagnosis of reflex syncope and, in about 15%, the cause remains unexplained at the end of a complete diagnostic work-up. ESC Clinical Guidelines for cardiac pacing in patients with BBB are listed in Figure 3.
• Reflex Syncope: reflex syncope has an atypical presentation, used to describe those situations in which reflex syncope occurs with uncertain, or even apparently absent, triggers (prodromes). The diagnosis then relies less on history-taking alone and more on the exclusion of other causes of syncope (for example,
Figure 3: ESC Clinical Guidelines for cardiac pacing therapy in patients with BBB
morphologic heart structure’s valuation) and on reproducing similar symptoms with carotid sinus massage and tilt-table testing. ESC Clinical Guidelines for cardiac pacing in patients with atypical reflex syncope are listed in Figure 4.
Figure 4: ESC Clinical Guidelines for pacing therapy in patients with undocumented reflex syncope
• Unexplained Syncope: syncope with no diagnosis at the end of a complete diagnostic work-up. ESC Clinical Guidelines for cardiac pacing are listed in
Figure 5.
1.4.2 Cardiac Resyncronization Therapy (CRT) Indications4
1.4.2.1 Asynchronous Cardiac Physiopathology
Cardiac asynchrony is a pathological condition that occurs in 5-10% of chronic heart-failure affected patients. Its physiopathology is complex: prolongation of the AV interval delays systolic contraction, which might then encroach on early diastolic filling. Atrial pressure falls as the atria relax. If ventricular contraction is delayed, then LV diastolic pressures will exceed atrial pressure causing diastolic mitral regurgitation. The loss of ventricular pre-load then leads to a reduction in LV contractility, due to loss of the Starling mechanism. Both inter- and intra-ventricular conduction delays lead to
Figure 5: ESC Clinical Guidelines for pacing therapy in patients with unexplained syncope
asynchronous contraction of LV walls regions (ventricular desynchrony), impairing cardiac efficiency and reducing stroke volume and systolic blood pressure. Poorly coordinated
papillary muscle function may cause or aggravate functional systolic mitral regurgitation. Impaired performances promote adverse LV remodelling. CRT helps to restore AV, inter- and intra-ventricular synchrony, improving LV function, reducing functional mitral regurgitation and inducing LV reverse remodelling, as evidenced by increases in LV filling time and LVEF, and decreases in LV end-diastolic- and end-systolic volumes, mitral regurgitation and septal dyskinesis. The dominant mechanism of benefit is likely to vary from one patient to the next and within an individual patient over time. It is possible that no single measure will accurately predict the response to CRT, since the mechanism of benefit is so heterogeneous (see Figure 6).
Following indications vary with patients’ clinical features.
1.4.2.2 CRT therapy indications in Sinus Rhythm Patients
There is evidence that CRT reduces mortality and hospitalization, improves cardiac function and structure in symptomatic HF-patients with sinus rhythm (SR) and following inclusion criteria: (i) optimal medical treatment, (ii) severely depressed LVEF (e.g. ≤ 35%) and complete LBBB. In these patients, CRT therapy is superior either to optimal
medical therapy or to ICD alone. Regarding severity symptoms’ class, no differences between NYHA II-IV were evaluated.
Instead, patients who don’t meet all the above criteria have weak evidence of efficacy; this lead to the necessity of further research, especially for those in NYHA Class I and IV and those with non-LBBB morphology with QRS duration < 150 ms. ESC Clinical Guidelines are summarized in Figure 7.
Figure 7: CRT indications in patients with sinus rhythm
1.4.2.3 CRT Indications in patients with Atrial Fibrillation AF patients differ from whom in SR because of
arrhythmic and faster ventricular rate. Thus, they are generally older, with more co-morbidities and a worse prognosis. CRT should be considered in AF (permanent or long persistent) patients in two ways, (i) AF patients with moderate-to-severe HF with a hemodynamic indication for CRT and (ii) patients with a fast-ventricular rate with HF or LV dysfunction justifying a strong rate control strategy with an AV junction ablation (Figure 8).
1.4.2.4 Patients with heart failure and conventional pacemakers’ indications
• Upgrade from conventional pacemaker or implantable cardioverter defibrillator
to cardiac resynchronization therapy devices (Figure 14): despite the lack of large
randomize trials, there is sufficient evidence and general consensus that, in patients paced for conventional bradycardia indications who, during follow-up, develop severe symptoms of HF and have depressed EF, an upgrading to CRT pacing is likely to reduce hospitalization and improve their symptoms and cardiac performance. However, the quality of evidence is still moderate. Moreover, the risk of complications is higher in upgrading procedures than in primary implantation procedures.
Figure 8: Indications for CRT in patients with permanent atrial fibrillation
• De novo cardiac resynchronization therapy pacing in patients with conventional
indication for anti-bradycardia pacing (Figure 9): there is emerging evidence that de novo CRT implantation may
reduce HF hospitalization, improve quality of life and reduce symptoms of HF in patients with history of HF, depressed cardiac function and a bradycardia indication for pacing. The benefit should be weighed against the added complication rate and costs of CRT devices and their shorter service life. However, the quality of evidence is still low.
1.4.2.5 Back-up implantable cardioverter defibrillator in patients indicated for cardiac resynchronization
i. Benefit of adding CRT in patients with indications for implantable cardioverter defibrillator: in patients who have ICD for primary or secondary
prevention and are included in criteria for CRT (symptomatic heart failure, optimal medical treatment, LVEF ≤ 35%, complete LBBB), a device upgrade it is recommended;
ii. Benefits of adding ICD in patients with indications for CRT: the addition of
ICD therapy in patients with CRT indications correlates with an improvement of mortality SCD-related; therefore, combination therapy should be considered. To help clinicians in the choice of the right treatment, clinical guidance has been released (Figure 10).
1.5 Indications for ICD (Implantable Cardioverter Defibrillator)
therapy
6ICD have been used in clinical practice for more than 30 years; while in the past, their implantation required a thoracotomy surgery, actually it is implanted by a transvenous procedure, with leads located inside right heart for both pacing and defibrillation. Shock is delivered between right heart coil(s) and/or the generator can.
At the very beginning, ICD used to be implanted only in patients requesting it for secondary prevention, who underwent an aborted SCD (cardiac arrest or VF); then, it was recommended in patients at high risk of SCD, as a primary prevention.
Actually, implantation is indicated in patients with documented VF or hemodynamically not tolerated VT (that cannot be related to a reversible cause or within 48 hours after myocardial infarction), with optimal chronic medical therapy and a reasonable expectation of survival with a good functional status > 1 year.
Figure 10: Clinical guidance to the choice of CRT-P or CRT-D in primary prevention
ICD implantation should therefore be considered in patients with recurrent sustained VT, with same indications as above (plus normal LVEF).
Finally, when ICD treatment is unavailable, medical therapy with amiodarone should be considered, contraindicated for concurrent medical reasons or refused by the patient.
1.5.1 Subcutaneous implantable cardioverter defibrillator (s-ICD)6
Problems with access to the heart via vascular system and recurring problems with transvenous leads prompted the development of s-ICD: they have an entirely subcutaneous system of electrodes. System consist of three electrodes: one inside the device’s pocket, the other two on the lead, one is located on the lead’s tip, the other proximally, 8 cm from the tip. Between the tip and the proximal electrode there’s a coil, used for defibrillation against the defibrillator’s pocket. The electrode is positioned so that the distal part of the lead is placed at the left parasternal edge and the device is placed over the fifth intercostal space between the left anterior and mid-axillary line.
S-ICD can deliver effective defibrillation shocks with an output of 80 J.
Available data on this device are confirming the effectiveness in preventing sudden cardiac death. Nonetheless, data on tolerance and long-term safety are still missing. This device can be useful in whom a venous access is difficult, after the removal of a transvenous ICD for infections or in young patients with a long-term need for ICD therapy.
1.5.1.1 S-ICD Contraindications
- Device is not suitable for patients who require bradycardia pacing unless this need is confined to the period immediately following delivery of a shock (transcutaneous pacing can be delivered for 30 seconds after the shock).
- Patient who need cardiac resynchronization therapy are also unsuitable for treatment with the subcutaneous ICD.
- S-ICD is not suitable for patients who suffer from tachyarrhythmia that can be easily terminated by anti-tachyarrhythmia pacing.
2 Device Extraction
Many times, in recent years, list of indications for extraction has been changed. In this chapter, the main device-related complications leading to the need of device’s extraction will be evaluated, following the latest update guidelines published in 2018 EHRA expert consensus statement on lead extraction by Bongiorni MG el al.7
Indications will be followed by an extraction procedures’ description, considering various technique including the one used in MCV2.
2.1 Indications for extraction
• Infection;
• Lead dysfunction;
• Abandoned functional leads; • Lead-related complications; • Venous access issues;
• Access to magnetic resonance imaging (MRI); • Chronic pain;
• Other indications.
2.1.1 Infection
With the increase in CIED clinical applications (as seen in the previous chapter), CIED-related infections have become increasingly prevalent (the prevalence of cardiac device infections increased from 0.94 to 2.11 per 1000 beneficiaries between 1990 and 1999, a 124% increase during the study period).8 Considering the National (Nationwide) Inpatient
Sample (NIS) discharge records, in the period between 1993 and 2008, the incidence of CIED infection was 1.61%; the annual rate of infections remained constant until 2004, when a marked increase was observed, coinciding with an increase in the incidence of major comorbidities in patients undergoing CIED procedures. Furthermore, another report extracted from NIS registry observed an increase in the percentage of CIED extraction for infections, from 30% in 2006 to 50% in 2012.9 In ELECTRa registry,
infection was the most frequent indications for transvenous lead extraction (TLE), amounting to 52,8% (of which approximately two-thirds were local infections).10
Although several entities exist, it is necessary to specify the various types of CIED-related infections.
2.1.1.1 Clinical Presentation
Generator pocket can become infected during the implantation procedure, during battery replacement or during subsequent surgical manipulation of the pocket.
Pocket infection, either primary or secondary infection source (disseminated from bloodstream infections) manifests with local signs of inflammation, such as local erythema (41%), swelling (38%), pain and tenderness (28%), warmth (18%), drainage (38%) and device exposure (21%).11 Once device is exposed through the skin, it is
automatically considered as infected, due to the contact with local bacterial pathogens.12
Primary pocket infections can follow leads’ path (inside the subcutaneous channel), reaching the CIED’s intravascular and intracardiac portion. Therefore, patients presenting this situation can have systemic symptoms, such as fever, chills, malaise, fatigue, anorexia, similarly to those patients who present with primary bloodstream infection. Severity and timing of symptoms and signs depend directly on patient’s clinical features
and on involved microorganism. Staphylococcal species are responsible for 60-80% of CIED infections;13,14,15 particularly, S. aureus alone is responsible for about 25%
CIED-infections and usually causes rapid onset fever, while coagulase-negative staphylococcus frequently infects generator pocket but is less virulent and has fewer systemic symptoms. Generally, Staphylococcal pathogens can be resistant to antimicrobial therapies and host defence system, due to a protective biofilm2 they form16,17: in these cases, extraction
procedure is the only solution. Non-staphylococcal CIED-related infections are prevalent and diverse, with a low virulence and mortality rate.
S-ICD devices as well are involved in infective complications: pocket infection is the main type, while no systemic infections have been documented (data from EFFORTLESS registry).18
2.1.1.2 Types of Infection
CIED infections can be classified (as in EHRA7 and Kusumoto et al.19 consensus
conference) in:
• Isolated pocket infection: an infection limited to the generator pocket or along the lead course. It is associated with clinical features aforementioned, with negative blood cultures; this entity should be differentiated from superficial incisional infection (mentioned below);
2 Biofilm: a biofilm is defined as a device surface-associated community of 1 or more microbial species that are layered together by the product of polysaccaride intercellular adhesion, firmly attached to one together and encased in an extracellular polymeric matrix that holds the biofilm together.
• Isolated Pocket Erosion: chronic process in which device and/or leads are exposed through the skin, with or without local symptoms and signs of infection. In any case, device should be considered as infected, whatever the mechanism or the presentation of erosion. Very often, erosion is preceded by the adherence of the skin on the device with a concomitant browning and thinning of the skin. Haemocultures are generally negative, while patient can be either symptomatic (local pain) or asymptomatic;
• Bacteraemia: positive blood cultures with or without systemic infection symptoms or signs;
• Pocket infection with lead/valvular endocarditis: local signs of pocket infection and positive blood cultures and lead or valvular vegetation(s). 2015 modified Duke Criteria have been used to define endocarditis20. For CIED-related
endocarditis, other criteria, such as:
o Positive cultures of the extracted lead with negative haemocultures; o Presence of lead vegetations;
o Altered metabolic activity around CIED generator and/or leads detected by 18F-fluorodeoxyglucose (FDG)-PET/CT or radiolabelled
leucocytes-PET/CT.
• Pocket infection with bacteraemia: local signs of infection and positive blood cultures, without lead or valvular vegetation(s);
• CIED-related endocarditis without pocket infection: bacteraemia with or without lead or valvular vegetation(s) and without local signs or symptoms of pocket infection;
• Occult bacteraemia with probable device infection: bacteraemia without a known source of infection other than the CIED itself. Resolution (disappearance of bacteraemia) after extraction is expected;
• Superficial incisional infection: infection involve only superficial tissues, skin and subcutaneous tissues, without communication with pocket.
2.1.1.3 Diagnosis of infection Diagnosis must be achieved using:
- Blood Tests: research for signs of systemic infection, first of all leucocytosis; - 2 sets of blood cultures should be obtained before beginning of antimicrobial
therapy;
- Swab cultures from pocket and tissue must be obtained at the time of device removal; tissue’s culture has more sensibility;
- Leads’ tip or entire tip should be controlled with a culture, although lead contamination might occur when leads are extracted through generator pocket; - Imaging:
o TEE (transoesophageal echocardiogram), thanks to its high sensibility and specificity, is the most useful technique to investigate for leads or valvular endocarditis (intravascular infections);21
o PET/CT with 18F-FDG should be considered when a pocket infection is
suspected (sensibility 87%, specificity 100%), although its utility decreases in suspected systemic infections (sensibility 31%, specificity 62%).22 one prospective study demonstrated that18F-FDG activity was
compared with those who didn’t have infection (1.40 [0.88 – 1.73]) and compared with controls (1.10 [0.98 – 1-40]).23,24,25
2.1.1.4 Predictors of CIED infection and Prognosis
Patient’s age and his comorbidities are the main factors associated with CIED infections. In fact, almost 70% of CIED-treated patients has 65 years of age or older and 75% have at least 1 coexisting medical conditions26,27. A meta-analysis of 180.004 patients from 60
prospective and retrospective studies concluded that the main patient-related significative risk factors for CIED infections was:
• Diabetes mellitus (OR);
• End Stage Renal Disease (ESRD): in a cohort of 1440 patients, Tompkins et al found that CIED infection rate was significantly higher in patients with ESRD compared with those without it (12.6% vs 0,2%). Patients with ESRD and infected CIED usually have a poor prognosis28;
• COPD;
• Corticosteroids use;
• History of previous device infection;
• Renal insufficiency: one of the most risk factors, because very frequently patients with CIED has chronic renal diseases. In a 504 patients’ cohort who underwent lead extraction, mainly for infection, 54% had class III-IV chronic renal disease;29
• Malignancy; • Heart failure;
• Preprocedural fever; • Anticoagulant drug use; • Skin disorders.
Once infection has been diagnosed, women have higher risk of death than men.30,31
2.1.2 Non-infective Indications
2.1.2.1 Lead Dysfunction
In case of lead dysfunction, clinicians have to choose if abandoning or extracting it (to reduce intravascular lead burden or regain venous access in presence of venous occlusion).
In the ELECTRa registry, lead dysfunction was the second most frequent indication after infection, representing about 38.1% of all cases.10
Causes of dysfunction are related to lead fracture or isolation failure, resulting in issues with lead impedance, sensing or capture. In some cases, electrical parameters may look normal, but lead’s integrity is clearly compromised (e.g. inside out cable externalization of Riata leads, radiological evidence of subclavian rush etc.).7
2.1.2.2 Abandoned Functional Leads
In some cases, functional leads can be considered as no longer required; thus, there’s the option for either abandoning or extracting it. Examples of these situation may be:
• Upgrade from PM-device to ICD;
• Lead recall3 with prophylactic revision;
• System re-location for radiotherapy; • Lack of device indication;
• Etc.
To avoid future situations, related to fibrotic processes among leads and their burden, their extraction should be considered. Although, lead fragility is proportional to its dwell time, so abandoned lead’s extraction is a high-risk procedure and more frequently a partial success procedure (see below in same chapter). Thus, in patients with abandoned leads who need a Lead Transvenous Extraction (LTE), Risk/Benefit rate is more difficult to calculate: in these cases, assessing of risk procedure-related (including operator experience) and patient’s clinical features should be considered.32,33,34 Nonetheless,
abandoned lead is one of the most frequent indication for extraction; a study have been demonstrated that abandoned lead represent 38% of all lead extraction’s indications .35,36
2.1.2.3 Lead-related complications
Leads may be functional but cause complications for which extraction may be indicated, such as:
• Thromboembolic events; • Superior vena cava syndrome; • Arrhythmias;
3 According to the U.S Food and Drug Administration (FDA), a recall is an action taken to address a problem with a medical device that violates FDA law. Recalls are classified by the FDA to indicate the relative degree of health hazard presented by the product being recalled.
• Perforation;
• Lead-lead interaction; • Etc.
If stenting is planned for treating stenosis in a vein with a transvenous lead, extraction is usually performed to avoid entrapment of the lead.
2.1.2.4 Venous access issues
Up to 25% of patients with transvenous leads can develop a certain degree of stenosis37,
which may later hinder additional lead implantation (for example, when the need of an upgrade occurs). There are a number of different management strategies38, which include
tunnelling a contra-lateral lead across the chest, venoplasty or lead extraction to provide a channel through which new leads can be implanted.
2.1.2.5 Chronic pain
Chronic pain is an infrequent indication, representing about 1-3% of total. Pain is usually located on device pocket or shoulder, and recognizes vary causes:
i. Sub-clinical pocket infection: direct correlation between pain and infection is not already demonstrated, but in case of pain on the device pocket, the possibility of infection may always be assessed;
ii. CIED contact dermatitis: this condition has been confirmed by some reports, with a wide spectrum of possible symptoms, ranging from pain and tenderness to dermatological manifestations;39,40
iii. ICD have been associated with postoperative discomfort and pain;41 chronic
years after implantation (number of implanted leads is the only predictor for chronic shoulder pain);42
iv. Thoracic outlet syndrome: in this case, pain is associated with brachial plexus and subclavian vessels compression;
v. Some patients may have severe chronic pain attributed to lead insertion (e.g. due to a periosteal reaction) for which lead extraction may be performed.
2.1.2.6 Access to Magnetic Resonance Imaging (MRI)
There is evidence that MRI can be safely performed in patients implanted with non-conditional CIEDs, but abandoned or dysfunctional leads are considered to be contraindications (even if an MRI-conditional device is implanted). Nonetheless, extraction may be considered only in selected cases, considering risk/benefit assessment between procedural risks and necessity of MRI, when no other diagnostic alternatives to MRI are available.
2.1.2.7 Other indications
- Recalled Leads19: firm’s removal or correction of a marketed product that the
FDA or the European Medicines Agency (EMA) consider to be in violation of the laws it administers and against, which the agency would initiate a legal action. Recall does not include a market withdrawal or a stock recovery. Although, the potential for adverse events associated with extraction also exists43. There should
be therefore an additional clinical indication for opening the pocket when there is a safety alert for the lead while the lead is still functional and therefore does not pose a manifest risk to the patient.
- Lead Perforation: although lead perforation usually is an acute complication, some delayed episodes have been reported even years after implantation.44 many
leads can have some degree of micro-perforation (demonstrated by imaging findings), but they’re usually not clinically significant. If the perforation causes pain, bleeding, or other complications, extraction will be an important component for the patient’s overall management strategy.
- Severe Tricuspid Regurgitation: with RV pacing and defibrillation leads frequently occurs some degree of tricuspid regurgitation (TR). Although usually this condition is clinically silent, it may result when leaflets fail to coapt, for example due to:
o Too many lead’s loop traversing valve orifice; o Septal leaflet’s retraction by lead;
o Lead impingement on the valve apparatus.45
The severity of TR due to lead implantation varies among studies; risk factors associated with TR include:
i. Elderly;
ii. Defibrillator leads;
iii. Leads’ position (next to posterior and septal leaflets); iv. Leads passing between chordae.46
2.1.2.8 Arrhythmias
It’s been observed that LV leads, associated with an increase in premature ventricular contractions (usually refractory from therapies), might be predictive of lead’s proarrhythmic. It is therefore supported by the evidence of arrhythmias’ resolution after extraction.47
2.1.2.9 Radiotherapy
There’s an issue with radiotherapy when the CIED is situated in the path of the planned radiation beam and might interfere with adequate tumour treatment. In these cases, a CIED relocation it is recommended.48 Options for relocation are the following:
i. Device placement on the contralateral side, with tunnelling of existing leads using adapters/lead extenders;
ii. Placement of a new device system on the contralateral side while abandoning the existing leads;
iii. Placement of a new device system on the contralateral side, while extracting the existing leads.
There are potential risks and benefits with all the approaches. During the shared (between patient and the treating physicians) decision’s process, patient’s clinical features, his ability to tolerate the procedure and his prognosis should be considered. There’s a weak evidence it seems to validate relocation and extraction procedure (iii), for minimizing radiation exposure of the device48,49,50.
Same studies have documented tolerance of the CIED generator well above the recommended 2 Gy threshold and have established that the strongest predictor of CIED malfunction is exposure to neutron-producing beam energies > 10 MV, not cumulative
doses to the device. Enhanced CIED monitoring without invasive measures is appropriate under these circumstances and should again involve an informed discussion between the patient and the treating physicians.
3 Transvenous Lead Extraction (TLE)
In the previous chapter was listed all indications for device extraction; in recent years, the increased indication for device therapy has led to a greater number of complications and, simultaneously, to a higher necessity of device extraction.
Today, in most cases, extraction is performed by a percutaneous transvenous approach, even if some patients, considered at high risk for procedure, sometimes can be still treated with an open extraction with sternotomy and cardiopulmonary by-pass. In last decades, transvenous procedures have evolved from simple lead traction to extraction with dilators and powered sheaths reaching a success rate over 95%; nonetheless, there still is a small but significative number of procedural failures, morbidity and mortality. In fact, fibrotic tissue develops over time and entraps the implanted lead in the veins and in the cardiac chambers, making extraction more difficult and riskier: thus, the use of modern and specialized extracting tools is sometimes not able to overcome these procedural situations, causing failure and/or complications. Actually, to reduce these problems, the main european and international centres are working to develop new techniques, trying to increase even more procedure efficacy.51
In Pisa’s centre, cardiologists are using a modified transvenous technique for lead extraction, which is the procedure wherewith this study was performed. To better understand this specific procedure and other new techniques, explained below, here are some information about the most utilized tools, techniques and approaches. Next, will be listed in this chapter the procedure’s definition for success, outcome and its main complications.
3.1 Approaches, tools and techniques
Lead removal can be performed by a wide spectrum of tools and techniques, from simple manual traction to multiple procedures and combined approaches7.
3.1.1 Approaches
Most lead extraction are performed by percutaneous approach, as aforementioned. Nonetheless, some centres perform hybrid approaches that combine percutaneous extraction with minimally invasive surgery or thoracoscopy. The various approaches are detailed below.
3.1.1.1 Superior Approach
Usually, extraction procedure begins via the same route whereby leads have been implanted at the very beginning; this approach is called venous entry access (VEA) or implant vein approach. If this approach fails, or in the presence of free-floating leads, an internal jugular venous approach can be used, combining superior and femoral accesses.
3.1.1.2 Inferior/Femoral Approach
Extraction can be performed with a femoral venous access, either as the first used technique or as bailout procedure; specialized tools are needed when this approach is used.
3.1.2 Tools and techniques
The use of different tools and techniques can highly modify procedure’s outcome and costs; therefore, when a procedure is described, it is important specify which tools and techniques have been used.
In an extraction procedure, frequently many tools and techniques have to be used, even for the same lead. For this reason, a “stepwise” approach is always suggested, beginning from simpler techniques, like simple lead traction, to more complex ones.
3.1.2.1 Simple traction
This technique consists in a mild pulling force, which is applied on the lead, with no specialized tools (other than a stylet). This kind of extraction was used in 27% of patients in the ELECTRa registry and may be effective for leads with short dwell time (e.g. time since implant less than 1-2 years).
3.1.2.2 Locking Stylets
These stylets are designed to improve tensile strength, to facilitate traction and to stabilize leads during the extraction. They can be used alone or with other specialized tools.
3.1.2.3 Mechanical non-powered telescoping sheaths
These bevelled sheaths were developed to improve the dissection of leads’ fibrotic binding sites to vascular/cardiac walls; dissection is obtained by simple manual pushing/rotational force. They are most often composed by polypropylene, but metallic and Teflon (PTFE) sheaths are also available. They may be used alone or with other tools that can ease their rotation, for example locking stylets.
3.1.2.4 Powered sheaths
There are many kinds of powered sheaths, everyone with its specific mechanism, efficacy and risk profile. Usually, a powered sheath is used with a locking stylet that is inserted into the lead, which builds a rail upon which the sheath is advanced. The main types of powered sheaths are:
- Rotational mechanical sheaths: these are currently hand powered and have a threaded tip which dissects adherent tissue;
- Electrosurgical sheaths: these use radiofrequency energy for dissecting adherence; this type is now seldom used.
- Laser sheaths: laser energy is released circumferentially along the lead’s sheath
3.1.2.5 Snares
These tools are usually used in femoral approaches; they consist in a single or double loop and are used for grabbing a free-floating lead extremity (a single loop snare can be used) or lead’s body (a double loop snare is required).
3.1.2.6 Baskets
Although their function is the same as for snares, baskets are seldomly used today.
3.1.2.7 Lead Extenders
This wire has been developed for grasping conductor cables or lumen-less leads. Thanks to the lead extender, it is possible to use an extraction sheath in conditions in which it wasn’t possible before.
3.1.2.8 Compression coils
These tools allow secure binding of locking stylets and the proximal components of the lead to facilitate extraction.
3.1.2.9 Occlusion Balloons
Occlusion balloon is a highly compliant balloon; when a vascular tear occurs, this tool can be introduced in the vessel and filled with diluted contrast agents to stem bleeding, while waiting for surgical bailout.
3.2 Procedures’ definitions
73.2.1 Definition of procedures’ type
Definition of “lead extraction” has changed several times over last years: this has made it difficult to compare studies that reported data on utility, safety and effectiveness of procedures. In fact, it is not possible to compare the removal of a 3-month implanted lead with a 20-years implanted one.
To cope with this problem, various consensus19,52 have created distinctions between what
is and what is not a lead extraction procedure; following definitions classify the various types of procedures:
• Lead Removal: removal of a pacing lead or defibrillator lead using any technique. This entity includes removal of subcutaneous ICD leads.
• Lead Explant: a lead removal using simple traction techniques (no locking stylets, telescoping sheaths, or femoral extraction tools) and all removed leads were implanted within 1 year.
• Lead Extraction: intervention with removal of at least one lead that has been implanted for more than 1 year, or a lead regardless of duration of implant requiring the assistance of specialized equipment that is not included as part of the typical implant package, and/or removal of a lead from a route other than the implant vein. Percutaneous removal of leadless pacemakers may be considered as extraction procedures.
3.2.2 Definition of success
Regarding the success of a TLE procedure, it is also important to evaluate the follow-up, as well as the procedure itself: if follow-up is limited, success can only be supposed and not validated. Success’ definition also correlates with indications to it: in case of an CIED-related infection, the extraction of all the material is warranted, despite a partial success, with a < 4 cm remnant material may be accepted according to consensus of opinion. Instead, in case of non-infected leads, clinical success can still be obtained even with persistence of residual tip on imaging. The definitions for TLE outcomes are as follows:
1. Complete procedural success: removal of all targeted leads and material, with the
2. Complete Procedural Success Rate: procedures where there is complete success,
divided by the total number of procedures;
3. Clinical Procedural Success: retention of a small portion of a lead that does not
negatively impact the outcome goals of the procedure. This may be the tip or a small part (< 4 cm) of the lead (conductor coil, insulation, or the two combined) when the residual part does not increase the risk of perforation, embolic events, perpetuation of infection, or cause any undesired outcome. Absence of any permanently disabling complication or procedure-related death;
4. Procedural clinical success rate: procedures where there is clinical success
divided by the total number of extractions;
5. Procedural Failure: inability to achieve either complete procedural or clinical
success, or the development of any permanently disabling complication or procedural-related death;
6. Procedural failure rate: extraction procedures that failed divided by the total
number of procedures;
7. Complete lead removal: lead explant or extraction with removal of all targeted
lead material;
8. Incomplete lead removal: lead explant or extraction where part of the lead remains
3.3 Definition of complications
Procedural complications are defined by the timing (related to the procedure) and their severity. Very often, the attribution of a complication to the procedure is not easy, due to contemporary situations, such as reimplantation, or pre-existing condition (for example, sepsis that was the indication for the extraction).
Temporally, complications can be divided into:
• Intra-procedural complication: any event related to the performance of a procedure that occurs or becomes evident from the time patient enters the operating room until the patient leaves the operation room;
• Early post-procedure complications: any event related to the procedure that occurs or becomes evident within 30 days following the intra-procedural period;
• Late post-procedural complications: any event related to the procedure that occurs or becomes evident after 30 days following the intra-procedural period and during the first year.
According to severity (and reversibility), complications can also be divided into:
• Major complications/serious adverse events: any of the outcomes related to the procedure which is life-threatening or results in death (cardiac or non-cardiac). In
requires inpatient hospitalization or prolongation of existing hospitalization, or any event that requires significant surgical intervention to prevent any of the outcomes listed above;
• Minor complications: any undesired event related to the procedure that requires medical intervention or minor procedural intervention to remedy and does not limit persistently or significantly the patient’s function, nor does it threaten life or cause death.
Patients should be monitored for early complications with close follow-up for at least the first 30 days, although the optimal target would be 1 year, since it was observed that patients who underwent TLE for systemic infection have a 1-year mortality close to 25%, regardless of the success of the extraction (anywhere, some preliminary data suggests early extraction of an infected device can improve survival by 1 year). A list of the main complication is showed in Figure 117.
3.4 Outcome predictive indicators
During last years, some studies focused on the research of predictive risk scores about results and potential complications of TLE procedures have been performed.
These studies weighed up many features, either patient’s and device’s and the indication
3.4.1 LED index score
In 201453, Bontempi et al have developed (with the analysis of a high volume centre
database) a score called LED index, which is focused on predicting the difficulties of an extraction procedure. Thus, this score can be helpful to stratify patients, selecting those who should be referred to a high-volume centre.
LED index score is defined by:
• Number of leads extracted within a procedure; • Lead age (years from implant);
• +1 in patients with a double-coil lead (integrated bipolar leads, see chapter 1); • - 1 in patients with vegetation(s).
A LED score > 10 could predict a complex procedure, with a fluoroscopy time beyond 90th percentile (sensibility 78,3%, specificity 76,7%).
3.4.2 30-Day all-cause mortality Risk Score
In 201354, Brunner et al. developed an indicator that could be able to predict major
adverse events and 30-day all-cause mortality in patients undergoing transvenous lead extraction. This study considered 3000 TLE procedures, during which occurred 45 (1,5%) major complications; with a multivariable regression model, they verified 4 independent variables:
• Age;
• Combined age of leads;
• End-Stage Renal Disease (ESRD).
Therefore, considering 30-day all-cause mortality, death occurred in 61 (2%) patients and they verified, with same methods, 8 independent variables:
• Age;
• Body Mass Index (BMI); • Platelet count;
• INR (international normalized ratio); • ESRD;
• NYHA (New York Heart Association) functional class; • Valvopathy;
• Indication for lead extraction.
3.4.3 IKAR Risk Score
Since 2006 to 201455, Lubin’s cardiology centre led a follow-up on 130 patient underwent
LTE procedures; with this, they realized to find a simple predictive score for 1-year mortality from the procedure. Score consist of elements that form the acronym IKAR (I= Infective indications for TLE, 1 point; K= Kidney disfunction, 2 points; A= Age ≥ 56, 1 point, R= Removal of defibrillation lead, 1 point).
From the study, it results that no patients with score = 0 died during 1-year follow-up, while patients with a score ≥ 4 had a 94% 1-year mortality; intermediate scores have increasing mortalities (Figure 12). Therefore, it appears from this study that only clinical
features (and not procedural features, such as intra- or post-procedural complications) would have determined a long-term survival after TLE and that these clinical factors would not have had
an influence on the outcome of the procedure.
3.5 Extraction procedures
In this part will be describe some lead transvenous extraction procedures, among which the modified dilatation technique used in Pisa arrhythmology’s centre (which is the technique studied in this research) and some other newest techniques which use a hybrid transvenous and minimally invasive approach.
3.5.1 TLE using single sheath mechanical dilatation and multiple venous approaches
In the Arrhythmology Division of the University Hospital of Pisa, since 199751, a
modified transvenous extraction using single sheath mechanical dilatation and multiple venous approaches was used in order to perform transvenous lead extraction. Since its introduction, it has proven to be very effective and safe; in addition to reducing the complications, especially serious ones, the use of a single dilator and the ITA (see below) has increased the effectiveness of mechanical dilatation, avoiding the costs and the risks
