22. Prophylaxis Against Deep Venous Thrombosis
James H. Holmes IV, M.D.
Thomas R. Biehl, M.D.
A. Incidence of Deep Vein Thrombosis
1. Up to 40% of major operations performed by laparotomy are compli- cated by postoperative deep vein thrombosis (DVT) if no method of prophylaxis is utilized, as determined by screening with the labeled fibrinogen uptake test (FUT). The majority of DVTs are asymptomatic, and the reported incidence of DVT would be less if duplex ultrasound or symptoms were used as the screening modality, given their lower sensitivities relative to FUT.
2. The true incidence of DVT following laparoscopic operations is diffi- cult to determine for a number of reasons:
a. Clinically evident DVT is an uncommon complication following laparoscopic procedures.
b. DVT typically presents in a delayed fashion, and symptoms may be disregarded by patients following discharge from the hospital.
c. No systematic surveillance of venous thromboembolic compli- cations has been carried out and reported in any large laparo- scopic series.
d. The use of DVT prophylaxis has been inconsistently reported.
e. FUT may lead to infectious complications and, thus, is no longer clinically acceptable as a screening modality for DVT.
f. The demographics of patients undergoing laparoscopic opera- tions are constantly changing.
3. The reported incidence of DVT following laparoscopic cholecystec- tomy is approximately 0.03%–0.4%. However, this figure should be viewed as a minimum value given the aforementioned difficulties with establishing an accurate incidence.
4. The true incidence of DVT following other laparoscopic operations is unknown. Minimum estimates may be inferred from the reported inci- dences of pulmonary embolism listed below.
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264 J H Holmes and T R Biehl
B. Incidence of Pulmonary Embolism
1. Clinically evident pulmonary embolism (PE) is a complication in ~2%
of major open operations when no method of DVT prophylaxis is employed.
2. The true rate of PE following laparoscopic procedures is unknown for reasons similar to those mentioned in the DVT section above.
3. The reported incidences of PE after laparoscopic procedures are as follows:
a. Cholecystectomy: ~0.02%–0.4%
b. Antireflux procedures: ~1.8%
c. Colorectal operations: ~0.7%
C. Risk Factors for DVT/PE
1. Virchow’s triad:
a. Venous stasis b. Endothelial injury c. Hypercoagulability 2. Surgical risk factors:
a. Abdominopelvic or lower extremity operations b. Operative time >1 hour
c. General anesthesia
d. Reverse Trendelenburg position 3. Patient risk factors:
a. Age >40 years
b. Prolonged immobility/paralysis c. Prior venous thromboembolic event d. Malignancy
e. Obesity f. Varicose veins
g. Congestive heart failure h. Myocardial infarction
i. Inflammatory bowel disease j. Nephrotic syndrome k. Estrogen use
l. Hypercoagulable states
4. Most surgical patients have at least two of the risk factors listed above.
5. Laparoscopy-related risk factors:
a. The reverse Trendelenburg position causes decreased common femoral vein (CFV) flow velocity and increased CFV diameter, promoting venous stasis and potential endothelial injury.
b. Pneumoperitoneum has been consistently shown to decrease CFV flow velocity and pulsatility while increasing CFV pressure and diameter; these changes promote venous stasis.
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D. DVT Prophylaxis for Open, Major Operations
1. Prophylaxis decreases the incidence of DVT by more than 50%. Fol- lowing is a list of the methods used for prophylaxis for open opera- tions and the incidence of DVT associated with each method.
a. Low-dose unfractionated heparin (LDUH), usual dose 5000 units via subcutaneous injection q 12 hours: ~8%
b. Low molecular weight heparin (LMWH): ~7%
c. Sequential compression devices (SCD)/intermittent pneumatic compression (IPC): ~10%
d. Graded compression elastic stockings (ES): ~9%
e. Combining pharmacologic and mechanical modalities of pro- phylaxis may have additive effects.
2. Prophylaxis with LDUH lowers the rate of fatal PE by approximately 50% following open operations for malignant disease.
3. There are few complications of DVT prophylaxis. Low-dose heparin is associated with minor bleeding but no significant increased risk of major hemorrhage. LDUH carries a 3% risk of heparin-induced throm- bocytopenia. Mechanical prophylaxis has not been associated with complications.
E. DVT Prophylaxis for Laparoscopic Operations
1. There are no prospective, randomized, clinical trials evaluating DVT prophylaxis for laparoscopic operations.
2. Multiple prospective, randomized studies have analyzed the effect of mechanical DVT prophylaxis modalities on lower extremity venous hemodynamics as a surrogate marker for venous thromboembolism.
From the available data, the following may be concluded:
a. SCD/IPC of any style, either with or without ES, effectively over- comes the lower extremity venous stasis induced by the pneu- moperitoneum and reverse Trendelenburg position.
b. There are conflicting reports regarding the efficacy of ES alone in overcoming lower extremity venous stasis.
3. Recommendations:
a. Based on the aforementioned data and established recommenda- tions for open operations, all patients undergoing laparoscopic operations should receive DVT prophylaxis in the form of SCD/IPC with or without ES until further data are available.
b. The substitution/addition of pharmacologic DVT prophylaxis should be at the discretion of the operating surgeon based upon established recommendations and risk assessment for the partic- ular operation to be performed (open data).
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F. Selected References
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Clagett GP, Anderson FA, Geerts W, et al. Prevention of venous thromboembolism. Chest 1998;114:531S–560S.
Ido K, Suzuki T, Kimura K, et al. Lower extremity venous stasis during laparoscopic cholecystectomy as assessed using color Doppler ultrasound. Surg Endosc 1995;9:
310–313.
Jorgensen JO, Lalak NJ, North L, et al. Venous stasis during laparoscopic cholecystec- tomy. Surg Laparosc Endosc 1994;4:128–133.
Lindberg F, Bergqvist D, Rasmussen I. Incidence of thromboembolic complications after laparoscopic cholecystectomy: review of the literature. Surg Laparosc Endosc 1997;7:324–331.
Millard JA, Hill BB, Cook PS, et al. Intermittent sequential pneumatic compression in pre- vention of venous stasis associated with pneumoperitoneum during laparoscopic cholecystectomy. Arch Surg 1993;128:914–919.
Moneta GL, Bedford G, Beach K, et al. Duplex ultrasound assessment of venous diame- ters, peak velocities, and flow patterns. J Vasc Surg 1988;8:286–291.
Nguyen NT, Luketich JD, Friedman DM, et al. Pulmonary embolism following laparo- scopic antireflux surgery: a case report and review of the literature. J Soc Laparosc Surg 1999;3:149–153.
SAGES. Global statement on deep venous thrombosis prophylaxis during laparoscopic surgery. Surg Endosc 1999;13:200.
Schwenk W, Bohm B, Fugener A, et al. Intermittent pneumatic sequential compression (ISC) of the lower extremities prevents venous stasis during laparoscopic cholecys- tectomy. Surg Endosc 1998;12:7–11.
Wilson YG, Allen PE, Skidmore R, et al. Influence of compression stockings on lower- limb venous haemodynamics during laparoscopic cholecystectomy. Br J Surg 1994;
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