Coronary artery bypass surgery: emerging trends in mortality.

In a consecutive series of 4,697 patients undergoing coronary artery bypass surgery, these risk factors were found to be significant for increased postoperative mortality: age greater than 70, female sex, unstable angina, prior myocardial infarction, hypertension, diabetes mellitus, and ejection fraction less than .40. A comparison by year (1980-1988) revealed a steadily increasing incidence of these risk factors. Future analysis of coronary artery bypass mortality should include risk-factor stratification.

Trends in invasive treatment of single-vessel and double-vessel coronary disease.

We examined our practice of invasive therapy for one- and two-vessel coronary disease to assess the impact of the randomized trials of coronary surgery and the current use of angioplasty. We first reviewed our results with coronary artery bypass graft in equivalent patients in the Coronary Artery Surgery Study with one- and two-vessel disease between 1976 and 1981. Among 1376 patients, hospital mortality was 0.07%, and 5-year survival was 95.2% +/- 0.8%. To define trends in invasive therapy, which have since occurred, we compared 100 patients with one- and two-vessel disease in each of three groups: 1979 coronary artery bypass graft, 1984 coronary artery bypass graft, and 1984 percutaneous transluminal coronary angioplasty. Preoperative characteristics in the average 1979 and 1984 patients were similar; however, in 1984, patients who had a coronary artery bypass graft were older than patients who had percutaneous transluminal coronary angioplasty (61.5 versus 56.7 years, p less than 0.01), they required more heart medications (2.1 versus 1.5, p less than 0.01), had more previous infarctions (0.8 versus 0.5, p less than 0.01), and more patients had an ejection fraction of less than 50% (34% versus 7%, p less than 0.01). Patients who had angioplasty had a shorter postoperative stay (median number of days 7, 7, 2, p less than 0.01). Freedom from major complications was similar among the groups (91%, 87%, 85%). Unstable symptoms were the most frequent indication for invasive therapy (approximately 80%), whereas long-term symptoms, those considered in the randomized trials, occurred in relatively few patients. The number of patients without at least one definite indication for invasive therapy was 13%, 3%, and 11%, p less than 0.05, suggesting that the indications for the 1984 coronary artery bypass graft group have become more restrictive since the 1979 coronary artery bypass graft group. Indications for the 1984 percutaneous transluminal coronary angioplasty group remained less restrictive, being similar to those for the 1979 coronary artery bypass graft group. A continuing trend toward the use of percutaneous transluminal coronary angioplasty was evident, as 56% of the 1979 coronary artery bypass graft group of patients and 32% of the 1984 coronary bypass group of patients would be offered percutaneous transluminal coronary angioplasty rather than coronary artery bypass graft on the basis of 1986 percutaneous transluminal coronary angioplasty criteria. The p values were obtained with analysis of variance or chi 2 test.

Importance of coronary artery anomalies in operations for congenital heart disease.

A congenital coronary artery anomaly influenced operative management of 21 children (34 operations) during a recent 8-year interval. This group represented 1.3% of cardiothoracic operations performed. Survivors included 5 of 10 children having correction of the left coronary artery from the pulmonary artery and 11 children having correction of intracardiac defects associated with major coronary arteries crossing the right ventricular outflow tract. Two children survived primary repair of injured major coronary arteries. Isolated coronary artery anatomy must be considered during management of intracardiac defects. Intraoperative injury to a major coronary artery requires meticulous repair.

Overperfusion, hypoxia, and increased pressure cause only hydrostatic pulmonary edema in anesthetized sheep.

Overperfusion (high pressure and flow through a restricted microvascular bed) has been suggested as the mechanism for both microembolic and high altitude pulmonary edema. In eighteen anesthetized, ventilated sheep, we measured pulmonary hemodynamics, lung lymph flow, and lymph:plasma protein concentration ratio. After a 2-hour stable baseline, we resected 65% of lung mass (right lung and left upper lobe) and gave whole blood transfusions to maintain cardiac output. During overperfusion of the left lower lobe, lymph flow increased moderately (5.8 +/- 2.3 to 7.7 +/- 3.8 ml/hr) and lymph:plasma protein concentration decreased (0.73 +/- 0.08 to 0.64 +/- 0.08). After a 2-hour stable period, we decreased inspired oxygen in 10 sheep (Pao2 = 40 +/- 3 mm Hg). With added alveolar hypoxia, pulmonary artery pressure increased modestly, but lymph flow and the lymph:plasma protein concentration ratio did not change. In eight sheep (four hypoxic, four normoxic), we raised left atrial pressure approximately 12 cm H2O for 2 hours. Lymph flow rose (10.8 +/- 3.8 ml/h) and lymph:plasma protein concentration decreased further (0.52 +/- 0.07). At each step, lymph:plasma protein concentration decreased, as predicted for the calculated rise in microvascular pressure. There was no evidence that overperfusion, with or without alveolar hypoxia, increased lung endothelial barrier protein permeability.