Femoro-femoral bypass for repeat open-heart surgery

Abstract

Repeat open-heart operations are becoming more frequent with a patient population at higher risk. Sternal re-entry poses the risk of possible damage to vital structures. These include laceration of the myocardium, especially the right ventricle, tearing of patent grafts and internal mammary grafts in particular, or dislodgement of emboli from patent vein grafts. To minimize the risk associated with sternal re-entry, we adopted the method of establishing femoral artery-femoral vein cardiopulmonary bypass (CPB) in order to achieve cardiac decompression prior to sternotomy. Between June 1994 and October 1997, 94 patients underwent repeat open-heart operations at our institution. Of these, seven were a second time reoperation. Mean age was 62 years (range 31-80 years), and 65 were male. Fifty-nine patients had coronary bypass, 27 had aortic valve replacement, 45 had mitral valve replacement, and nine had other procedures (these numbers include patients having combined procedures). In patients with no known vascular disease, the femoral vessels were exposed, and if found suitable, were cannulated, and the patients connected to CPB. The sternum was opened with an oscillating saw, and on penetration through the posterior table, the heart was drained to allow for decompression. If the femoral vein cannula did not allow full bypass, ventilation was maintained until the right atrium was exposed and cannulated and full bypass was achieved. Femoro-femoral bypass was established in 75 patients. In 19 patients it was not done for the following reasons: eight patients had a diseased femoral artery, in one patient the femoral vein could not be cannulated, nonuse of CPB altogether occured in three patients, and it was because of surgeon's preference in seven patients. In one patient a high pressure developed in the arterial line, requiring conversion to aortic cannulation during the course of CPB, without any negative consequences. There were no problems associated with sternal re-entry, no patient had limb ischemia or venous thrombosis. Two patients (2.6%) had complications related with femoral cannulation, with one having trauma to an atherosclerotic femoral artery requiring repair with vein interposition, and the other a tear of iliac vein requiring laparotomy. Groin wound infection occurred in five patients (6.6%), and groin hematoma in four patients (5.3%). All complications were treated successfully with no permanent damage. Operative mortality was 9% (seven patients). Causes of death included myocardial infarction (2), infection (3), respiratory (1), and cirrhosis (1). We conclude that femoro-femoral bypass prior to sternotomy is a safe and easy method to reduce the risk of sternal re-entry by allowing early decompression of the heart, and in unstable patients it offers better myocardial protection by earlier connection to CPB. Proper selection of patients is important in order to minimize related comorbidity. We recommend this method in redo patients in whom femoral cannulation is feasible.