Improved longevity due to reduction of sudden death by aortocoronary bypass in coronary atherosclerosis

Abstract

To evaluate the efficacy of coronary bypass surgery in reduction of sudden death, the prognosis of 286 similar patients with multivessel coronary stenosis was studied prospectively and the results of medical therapy (Group I, 114 patients) were compared with those of surgical therapy (Group II, 172 patients) after cardiac catheterization and coronary arteriography. During 39 months' evaluation of both groups, mortality from congestive heart failure and noncardiac causes did not differ (Group I, 14 percent; Group II, 8 percent) (P greater than 0.05). Sudden was evaluated in the remaining 217 patients (Group I, 96; Group II, 121 patients) who were matched for age (Group I, 52 years; Group II, 51 years); duration of overt coronary disease (Group I, 3.8 years; Group II, 4.0 years); angina pectoris (Group I, 83 percent; Group II, 95 percent); prior myocardial infarction (Group I, 77 percent; Group II, 74 percent); and congestive heart failure (Group I, 30 percent; Group II, 23 percent) (all P greater than 0.05). In addition, the prevalence of coronary risk factors was the same (P greater than 0.05) in both groups (hypertension, cigarette smoking, diabetes mellitus, lipid abnormalities and family history of coronary disease). Importantly, arteriography and catheterization established a similar extent and location of major coronary arterial stenoses and of ventricular dysfunction; two vessel disease (Group I, 32 percent; Group II, 33 percent) and three vessel disease (Group I, 68 percent; Group II, 67 percent); left ventricular end-diastolic pressure (Group I, 13; Group II, 14 mm Hg);cardiac index (Group I, 2.85; Group II, 2.91 liters/min per m2); and coronary collateral vessels (Group I, 58 percent; Group II, 61 percent) (all P greater than 0.05). Fifty-six percent of patients in Group II had multiple bypass grafts and a late patency rate (average 21 months) of 87 percent of one or more grafts. During subsequent prospective evaluation of over 3 years, bypass surgery provided greater symptomatic benefit of improved functional capacity (Group I, 12 percent; Group II, 69 percent) (P less than 0.05) and complete anginal relief (Group I, 30 percent; Group II, 60 percent) (P less than 0.05). Moreover, bypass surgery was associated with marked reduction in sudden death (Group I, 24 percent; Group II, 6 percent) (P less than 0.05). Thus, in patients with multivessel coronary disease carefully matched for clinical factors, hemodynamics, atherogenic precursors and coronary pathoanatomy, effective aortocoronary bypass surgery appeared to prolong survival by decreasing the incidence of sudden death, possibly by a decrease of unexpected fatal arrhythmias.