The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Oct 1995
Determinants of operative mortality in reoperative coronary artery bypass grafting.
Previously suggested risk factors for operative mortality in reoperative coronary artery bypass grafting are contradictory. Therefore, we analyzed our data of 622 patients who underwent reoperative bypass grafting from January 1986 through June 1993. Among these patients, 258 had saphenous vein grafts alone and 364 had internal mammary artery grafting, including unilateral (342 patients) and bilateral (22 patients) mammary artery grafting with or without additional saphenous vein grafting. ⋯ The logistic regressions demonstrate that preoperative variables (low ejection fraction [p = 0.0002], old age [p = 0.003], female gender [p = 0.011], and history of arrhythmia [p = 0.023]), intraoperative variables (emergency operation [p = 0.0001] and long perfusion time [p = 0.0001]), and postoperative variables (complications) are independently associated with higher mortality. Unlike previously described results, aortic crossclamp time, route of cardioplegia, use of internal mammary artery, number of grafts, and year of operation are not associated with operative mortality. The identification of these risk factors may have important implications in further improvement of the results of reoperative coronary artery bypass grafting.
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J. Thorac. Cardiovasc. Surg. · Oct 1995
Cerebral blood flow velocity in pediatric patients is reduced after cardiopulmonary bypass with profound hypothermia.
Transcranial Doppler sonography of the middle cerebral artery was used to determine whether cerebral perfusion was detectable in low flow states during operations with cardiopulmonary bypass in pediatric patients. Quantitative and qualitative differences in cerebral blood flow velocity after rewarming in patients treated with continuous low-flow bypass or deep hypothermic circulatory arrest were assessed. To determine whether the alterations in cerebrovascular resistance pattern observed in our patients undergoing profound hypothermia was more a function of perfusion technique than of minimum temperature during operation, a third group of patients treated with moderate hypothermia was studied. ⋯ Patients treated with profound hypothermia who underwent a period of cold full-flow reperfusion before rewarming did not exhibit this high resistance pattern after rewarming. The present findings indicate that profound hypothermia may evoke changes in the cerebral vasculature that result in decreased mean cerebral blood flow velocity after cardiopulmonary bypass rewarming. A period of cold full-flow reperfusion before rewarming may prevent these alterations and improve cerebral perfusion during rewarming.
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J. Thorac. Cardiovasc. Surg. · Oct 1995
Coronary artery bypass without cardiopulmonary bypass: analysis of short-term and mid-term outcome in 220 patients.
Two hundred twenty patients, preferentially those with high-risk conditions, underwent coronary artery bypass grafting without cardiopulmonary bypass. Early unfavorable outcome events included operative mortality (7 patients, 3.2%), nonfatal perioperative myocardial infarction (6 patients, 2.7%), cerebrovascular accident (1 patient, 0.4%), and sternal infection (3 patients, 1.4%). There were two deaths (13%) among 15 patients with calcified aorta and four (12%) in 33 patients who underwent emergency operation. ⋯ We conclude that coronary artery bypass grafting without cardiopulmonary bypass can be done with relatively low operative mortality, although there seems to be an increased risk for early return of angina. This procedure should therefore be considered for patients with appropriate coronary anatomy, in whom cardiopulmonary bypass poses a high risk. This procedure is still hazardous with calcified aorta or emergency operation.
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J. Thorac. Cardiovasc. Surg. · Oct 1995
Studies of hypoxemic/reoxygenation injury: without aortic clamping. II. Evidence for reoxygenation damage.
This study tested the hypothesis that the developing heart is susceptible to oxygen-mediated damage after reintroduction of molecular oxygen and that this "unintended" reoxygenation injury causes lipid peroxidation and functional depression that may contribute to perioperative cardiac dysfunction. Among 49 Duroc-Yorkshire piglets (2 to 3 weeks old, 3 to 5 kg) 15 control studies were done without hypoxemia to test the effects of the surgical preparation (n = 10) and 60 minutes of cardiopulmonary bypass (n = 5). Twenty-nine piglets underwent up to 2 hours of ventilator hypoxemia (with inspired oxygen fraction reduced to 6% to 7%) to lower arterial oxygen tension to approximately 25 mm Hg. ⋯ Comparable biochemical and functional changes occurred in piglets undergoing ventilator hypoxemia and/or cardiopulmonary bypass hypoxemia and reoxygenation on cardiopulmonary bypass. We conclude that hypoxemia increases vulnerability to reoxygenation damage by reducing antioxidant reserve capacity and that reoxygenation by either ventilator or cardiopulmonary bypass produces oxidant damage with resultant functional depression that is not a result of cardiopulmonary bypass. These findings suggest that initiation of cardiopulmonary bypass in cyanotic immature subjects causes an unintended reoxygenation injury, which may increase vulnerability to subsequent ischemia during surgical repair.