Outcome of acute ST-segment elevation myocardial infarction in patients with prior coronary artery bypass surgery receiving thrombolytic therapy.

BACKGROUND: Patients with prior coronary bypass surgery with acute ST-segment elevation myocardial infarction (MI) pose an increasingly common clinical problem. We assessed the characteristics and outcomes of such patients undergoing thrombolysis for acute MI. METHODS AND RESULTS: We compared the characteristics and outcomes of patients in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries trial (GUSTO-I) who had had prior bypass (n = 1784, 4% of the population) with those without prior coronary artery bypass grafting (CABG), all of whom were randomized to receive one of four thrombolytic strategies. Patients with prior bypass were older with significantly more prior MI and angina. Overall, 30-day mortality was significantly higher in patients with prior bypass (10.7% vs 6.7% for no prior bypass, P <.001); these patients also had significantly more pulmonary edema, sustained hypotension, or cardiogenic shock. Patients with prior bypass showed a 12.5% relative reduction (95% confidence interval, 0% to 41.9%) in 30-day mortality with accelerated alteplase over the streptokinase monotherapies. In the 62% of patients with prior CABG who underwent coronary angiography, the infarct-related vessel was a native coronary artery in 61.9% and a bypass graft in 38.1% of cases. The Thrombolysis in Myocardial Infarction (TIMI) 3 flow rate was 30.5% for culprit native coronary arteries and 31.7% for culprit bypass grafts. Patients with prior bypass had more severe infarct-vessel stenoses (99% [90%, 100%] vs 90% [80%, 99%], P <.001). CONCLUSIONS: The 30-day mortality in patients with prior CABG was significantly higher than that for patients without prior CABG. As in the overall trial, these patients derived an incremental survival benefit from treatment with accelerated alteplase, but mortality remained high (16.7%) at 1 year. These results are at least partially explained by the higher baseline risk of these patients and by the lower rate of patency of the infarct-related artery.

Reduction of coronary atherosclerosis by moderate conditioning exercise in monkeys on an atherogenic diet.

All available evidence that exercise may protect against coronary heart disease is circumstantial, and direct evidence is difficult to obtain in human beings. Therefore, we studied the effect of moderate conditioning with treadmill exercise on developing coronary-artery disease in monkeys on an atherogenic diet. Physical training was demonstrated by slow heart rates. Serum total cholesterol was the same (approximately 600 mg per deciliter or 15.5 mmol per liter) in exercising and non-exercising monkeys, with significantly higher high-density-lipoprotein (HDL) cholesterol and much lower triglyceride and low-density-lipoprotein (LDL) plus very-low-density-lipoprotein (VLDL) triglyceride in the exercise group. Ischemic electrocardiographic changes, angiographic signs of coronary-artery narrowing, and sudden death were observed only in non-conditioned monkeys, in which post-mortem examination revealed marked coronary atherosclerosis and stenoses. Exercise was associated with substantially reduced overall atherosclerotic involvement, lesion size, and collagen accumulation; it also produced much larger hearts and wider coronary arteries, further reducing the degree of luminal narrowing. Our data suggest that moderate exercise may prevent or retard coronary heart disease in primates.