Lower extremity compartment syndrome after off-pump aortocoronary bypass

Abstract

Lower extremity compartment syndrome is a rare complication after on-pump coronary artery bypass grafting (CABG). It is associated with fasciotomy wound-related morbidity, occasional amputation, and universal occurrence of permanent foot drop. Compartment syndrome after off-pump CABG has not been reported so far. We report a case of lower limb compartment syndrome after off-pump CABG. A 54-year-old diabetic, hypertensive, nonsmoking man was detected to have echocardiographic changes of an old inferior wall myocardial infarct on routine cardiac evaluation. Treadmill test result was positive, and a subsequent coronary angiogram showed proximal triple vessel disease. His left ventricular function was normal with an ejection fraction of 65%. He had no other comorbidities. His renal and liver functions were normal. The patient underwent off-pump CABG with the left internal thoracic artery grafted to the left anterior descending artery, and saphenous vein grafts to OM2 and right coronary artery. The saphenous vein was harvested from his left leg with the thigh abducted and externally rotated and a pillow kept under the knee. The intraoperative course was uneventful with no episodes of hypotension (mean arterial pressure maintained at ∼65 mm Hg), and the patient was transferred to the intensive are unit with stable hemodynamics and minimal inotropes (dopamine 5 micrograms/kg/min). He was extubated successfully the morning after surgery. Approximately 24 hours after the procedure, the patient experienced severe pain in his left leg. Examination revealed blisters over his left leg with tense swelling of the calf. Peripheral left lower limb pulses were palpable. Venous and arterial Doppler of the left lower limb showed patent flow in the tibial, femoral, and iliac vessels. Because of the increasing pain and swelling, 3-compartment fasciotomy was performed to reduce compartmental pressures. Postfasciotomy, necrosis of the lateral compartment muscles developed, necessitating regular debridement. Foot drop also developed in the patient. Delayed primary closure was not feasible, and after 1 month of daily dressings, a split-skin graft was applied successfully to the well-granulated wound. Compartment syndrome is a rare but known complication after on-pump CABG.1James T. Friedman S.G. Scher L. Hall M. Lower extremity compartment syndrome after coronary artery bypass.J Vasc Surg. 2002; 36: 1069-1070Abstract Full Text PDF PubMed Scopus (13) Google Scholar, 2van den Wildenberg F.A. Houben P.F. Maessen J.G. Compartment-syndrome of the lower extremity after CABG.J Cardiovasc Surg (Torino). 1996; 37: 237-241PubMed Google Scholar, 3Pasic M. Carrel T. Tonz M. Vogt P. von Segesser L. Turina M. Acute compartment syndrome after aortocoronary bypass.Lancet. 1993; 341: 897Abstract PubMed Scopus (11) Google Scholar Generalized vasoconstriction and increased microvascular permeability induced by cardiopulmonary bypass are factors held responsible for the pathogenesis of increased interstitial pressures.1James T. Friedman S.G. Scher L. Hall M. Lower extremity compartment syndrome after coronary artery bypass.J Vasc Surg. 2002; 36: 1069-1070Abstract Full Text PDF PubMed Scopus (13) Google Scholar Hypotension and hypoxemia during cardiopulmonary bypass may cause ischemia that predisposes to inflammatory injury of the lower extremity after reperfusion.4Scott J.R. Daneker G. Lumsden A.B. Prevention of compartment syndrome associated with dorsal lithotomy position.Am Surg. 1997; 63: 801-806PubMed Google Scholar Thus far, the main culprit implicated in the pathogenesis has been the use of cardiopulmonary bypass. However, our case illustrates that lower limb compartment pressures can increase significantly even after off-pump surgery. This suggests that local factors are probably more important than extracorporeal circuit-induced systemic inflammatory response leading to increased compartmental pressures. This view is strengthened by the fact that the compartment syndrome occurred in the vein donor limb in our patient and in all 9 cases reported thus far. In the case reported by James and colleagues,1James T. Friedman S.G. Scher L. Hall M. Lower extremity compartment syndrome after coronary artery bypass.J Vasc Surg. 2002; 36: 1069-1070Abstract Full Text PDF PubMed Scopus (13) Google Scholar the use of aprotinin (an agent believed to reduce the inflammatory response after cardiopulmonary bypass) did not prevent the occurrence of compartment syndrome. Local factors resulting in compartment syndrome are manifold. Surgical trauma leads to local inflammation and tissue edema. The externally rotated and abducted position of the lower limb during vein harvesting may further contribute to venous stasis and the development of increased microvascular permeability in a manner similar to the effect of lithotomy position on the development of compartment syndrome.4Scott J.R. Daneker G. Lumsden A.B. Prevention of compartment syndrome associated with dorsal lithotomy position.Am Surg. 1997; 63: 801-806PubMed Google Scholar, 5Tuckey J. Bilateral compartment syndrome complicating prolonged lithotomy position.Br J Anaesth. 1996; 77: 546-549Crossref PubMed Scopus (52) Google Scholar Moreover, in our patient, application of tight compression dressings after vein harvesting may have contributed to limb ischemia, which is a definite mechanism of elevated intracompartmental pressures.4Scott J.R. Daneker G. Lumsden A.B. Prevention of compartment syndrome associated with dorsal lithotomy position.Am Surg. 1997; 63: 801-806PubMed Google Scholar Hypoperfusion during surgery, which necessitated the use of dopamine, could also have been a contributory factor. Compartment syndrome has to be detected before vascular compromise begins. Because all cases have occurred within 24 hours of surgery, periodic examination of the vein donor limb for at least 24 hours to detect limb swelling or tenderness on passive dorsiflexion is essential. Avoiding tight compression dressings after vein harvesting may prevent the development of this entity.