26 Guidelines for the Prevention of Thromboembolism

26 Guidelines for the Prevention

of Thromboembolism

Melvin A. Shiffman

26.1

Introduction

Patients who undergo surgery are at risk from venous thromboembolic complications. This is especially criti- cal in the abdominoplasty or liposuction patient who, having an elective procedure, would not expect to have the morbidity or mortality associated with thrombo- embolic disease. The cosmetic surgeon must be aware of the possibility of thromboembolism in every patient and should take a careful history to disclose predispo- sing risk factors. The surgeon should also be aware of the clinical manifestations of pulmonary embolus in order to make a timely diagnosis.

26.2 Risk Factors

Minor surgery < 30 min in patients over 40 years of age without additional risk factors and uncomplicated sur- gery in patients less than 40 years of age without addi- tional risk factors are in the low risk category. General surgery in patients over 40 years of age lasting > 30 min and patients under 40 years on oral contraceptives are in the moderate risk category [1]. High risk category would be major surgery in patients over 40 years of age with recent history of deep vein thrombosis or pulmo- nary embolism, extensive pelvic or abdominal surgery for malignancy, and major orthopedic surgery of the lower extremities.

Predisposing risk factors include age over 40 years, malignancy, obesity, prior history of thromboembo- lism, varicose veins, recent operative procedures, and thrombophilia. These risks are further modified by duration and type of anesthesia, preoperative and postoperative immobilization, level of hydration, and the presence of sepsis [2]. Medical problems associated with increased risk include acute myocardial infarc- tion, stroke, and immobilization [3]. Estrogen therapy and pregnancy are common risk factors while uncom- mon factors include lupus anticoagulant, nephrotic syndrome, inflammatory bowel disease, polycythemia vera, persistent thrombocytosis, paroxysmal noctur-

Table 26.1. Risk categories and associated thromboembolism Risk Calf vein

thrombosis

Proximal vein thrombosis

Fatal pulmo- nary embolism Low < – 10 % < – 1 % < – 0.01 % Moderate 10 % – 40 % 2 % – 10 % 0.1 % – 0.7 % High 40 % – 80 % 10 % – 30 % 1 % – 5 %

nal hemoglobinuria, and inherited factors such as anti- thrombin III deficiency, protein C deficiency, protein S deficiency, plasminogen activator deficiency, elevated plasminogen activator inhibitor, and homocystinuria [4].

Superficial calf vein thrombosis, proximal deep vein thrombosis, and fatal pulmonary embolus increase in incidence as the risk category increases from low to high (Table 26.1).

26.3

Clinical Manifestations

Superficial thrombophlebitis (an inflamed vein) ap- pears as a red, tender cord. Deep-vein thrombosis may be associated with pain at rest or only during exercise with edema distal to the obstructed vein. The first man- ifestation can be pulmonary embolism. There may be tenderness in the extremity and the temperature of the skin may be increased. Increased resistance or pain on voluntary dorsiflexion of the foot (Homan’s sign) and/

or tenderness of the calf on palpation are useful diag- nostic criteria.

Pulmonary embolism is usually manifested by one of three clinical patterns: (1) onset of sudden dyspnea with tachypnea and no other symptoms; (2) sudden pleuritic chest pain and dyspnea associated with find- ings of pleural effusion or lung consolidation; and (3) sudden apprehension, chest discomfort, and dyspnea with findings of cor pulmonale and systemic hypoten- sion. The symptoms occasionally consist of fever, ar- rhythmias, or refractory congestive heart failure.

Chapter 26

26.4 Diagnosis

Deep-vein thrombosis is best diagnosed with duplex ultrasonography, which combines pulsed gated Dopp- ler evaluation of blood flow with real-time ultrasound imaging. Other diagnostic tests include X-ray venogra- phy, radionuclide venography, radioisotope-labeled fi- brinogen, ultrasonography, and impedance plethys- mography. Liquid crystal thermography detects in- creases in skin temperature and is a useful adjunct to ultrasonography or impedance plethysmography.

Ventilation-perfusion (VP scan) lung scan is a safe, sensitive means of diagnosing pulmonary embolism.

Isotope pulmonary perfusion scan (Q scan) is more specific with inclusion of the isotope ventilation scan (V scan). The definitive diagnosis can be made by pul- monary arteriography but VP scan can give a high de- gree of certainty. Arterial blood gas typically shows re- duction in PaO

and PaCO

while the electrocardio- gram will show tachycardia but is best used for ruling out myocardial infarction. Chest X-ray may show basi- lar atelectasis, infiltrates, pleural effusion, or cardiac dilatation.

26.5

Prophylactic Treatment

Low risk general surgical patients may be treated with graduated compression stockings applied during sur- gery, early ambulation, and adequate hydration [5].

Keeping the knees flexed on pillows during surgery and avoiding local compression on any areas of the legs are helpful. All patients are treated the same if there are any low risk factors. The type of surgery does not matter as long as general anesthesia or intravenous sedation is given. Compression stockings (20 – 30 mm support hose is adequate) are applied in the operating room and ambulation is begun when the patient is awake and ca- pable of ambulating with assistance. When the patient is ambulating on a regular basis during the day, the compression stockings can be removed.

For moderate risk patients, low-dose heparin (5,000 units 2 h before surgery and then every 8 – 12 h until ambulatory), low molecular weight heparin (LMWH), dextran, or aspirin is recommended. Alter- natively, graduated compression stockings or intermit- tent pneumatic compression started at the onset of sur- gery, used continuously until ambulatory, or a combi-

nation of both is recommended [2]. Intermittent com- pression garments are better protection than the grad- uated compression stockings.

All high-risk patients should be treated with low- dose heparin or LMWH, and combined pharmacologic and mechanical methods.

Dextran can result in cardiac overload, and high dose aspirin (1,000 – 1,500 mg/day) has limited efficacy in preventing deep-vein thrombosis. In cosmetic sur- gery, use of aspirin or heparin may result in postopera- tive bleeding

26.6 Discussion

The best prophylaxis for low risk cosmetic surgery pa- tients would appear to be mechanical methods includ- ing knee compression stockings and early ambulation.

For low risk patients the knees should be slightly flexed and extremity compression avoided [6].

The risk of thromboembolism increases when lipo- suction is combined with abdominoplasty. This should be taken into consideration when planning therapy for abdominal lipodystrophy and abdominal wall derma- tochalasis. Estrogen, as birth control pills and replace- ment therapy, increase the risk of thromboembolism and should be avoided from 3 weeks before surgery un- til 2 weeks after surgery. Precautions should be taken during surgery when the procedure has moderate risk for thromboembolism.

References

1. European Consensus Statement of the Prevention of Venous Thromboembolism (1992) Int Angiol 11:151

2. Bick RL, Haas SK (1998) International Consensus Recom- mendations: Summary statement and additional suggested guidelines. Med Clin N Am 82:613 – 633

3. Clement DI, Gheeraert P, Buysere M, et al (1994) Medical patients. In: Bergquist D, Comerota AJ, Nicolaides AN, et al (eds) Prevention of venous thromboembolism. Med-Orion, London, p 319

4. Senior RM (1992) Pulmonary embolism. In: Wyngaarden JB, Smith LH Jr, Bennett JC (eds) Cecil textbook of medi- cine. WB Saunders, Philadelphia, pp 421 – 428

5. Nicolaides AN, Breddin HK, Fareed J, et al (1997) Preven- tion of venous thromboembolism. International Consensus Statement. Guideline according to scientific evidence. Int Angiol 16:3

6. McDevitt NB (1999) Deep vein thrombosis prophylaxis.

Plast Reconstr Surg 104:1923 – 1928

222 26 Guidelines for the Prevention of Thromboembolism