Hazards in the evaluation of secondary prevention trials.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to K Detre.
Explore the source record for details and available documents.
Recent studies of patients with coronary heart disease (CHD) at baseline have shown that their cholesterol levels are much less predictive of subsequent mortality than in populations free of CHD (FCHD). One previously suggested explanation of this attenuation is that the impact of hyperlipidemia on atherosclerosis or of atherosclerosis on mortality is reduced for post-myocardial infarction patients. In this paper it is shown that an alternative explanation is selection of CHD populations from FCHD populations for higher atherosclerosis levels. Data from all known follow-up studies on patients with baseline coronary angiograms are assembled to yield relations between cholesterol, atherosclerosis and mortality in CHD and FCHD populations. These data show that the selection hypothesis is not only logically possible but is also consistent with presently available epidemiologic information on relations between these three variables. An ethically impracticable large prospective study of a FCHD population with baseline angiograms might, however, be needed to choose definitively between the selection and reduced impact hypotheses.
There is considerable uncertainty about the effects of bypass surgery on the longevity of patients with coronary-artery disease and angina. The Cleveland Clinic has reported improved survival after surgical treatment; the Duke University study indicated improvement in a high-risk subgroup only. The Veterans Administration (V.A.) randomised study initially reported improved survival only for patients with significant left main artery (L.M.) disease. Further analysis of the V.A. study shows that survival in the high-risk subgroup was 87% for the surgically treated patients and 74% for those treated medically--a highly significant difference after four years of follow-up. However, exclusion of the L.M. group reduced the difference to a non-significant one of 84% versus 79%. For patients not in the high-risk subgroup, survival at four years (with L.M. excluded) was 93% for those treated surgically and 96% for those treated medically. For all patients the rates were 85% and 86%, respectively. These findings indicate that in the evaluation of the effects of bypass surgery on longevity the characteristics of the coronary-artery disease are critical.
We evaluated the effect of saphenous-vein-bypass grafting on survival in patients with chronic stable angina by comparing medical and surgical treatment in a large-scale, prospective randomized study. Excluding patients with left-main-coronary-artery disease who have already been reported, a total of 596 patients were entered into this study; when randomized into a medical group (310 patients) and a surgical group (286 patients), entry clinical and angiographic base lines were comparable. Operative mortality at 30 days was 5.6 per cent. At an average of one year after operation, 69 per cent of all grafts were patent, and 88 per cent of the surgical patients had atleast one patent graft. There was no statistically significant difference in survival, at a minimal follow-up interval of 21 months, between patients treated medically and those treated with saphenous-vein-bypass grafting. At 36 months, 87 per cent of the medical group and 88 per cent of the surgical group were alive.
The relation of the risk of sudden death from arteriosclerotic heart disease to psychosocial and biologic factors was studied retrospectively in 64 white women who died suddenly of arteriosclerotic heart disease and in 64 age-related neighborhood control women. All sudden deaths occurred outside the hospital within 24 hours of the onset of symptoms in women who were not incapacitated before death. Women who died suddenly were less often married, exhibited more educational incongruity with their spouses and had fewer children than the control population. Twelve of the 64 women who died suddenly of heart disease and none of the control women had a definite history of psychiatric treatment. The women who died suddenly also smoked more cigarette and consumed greater quantities of alcoholic beverages than age-matched neighborhood control women. Multiple regression analysis revealed that history of psychiatric illness, cigarette smoking, alcohol consumption, educational incongruity and number of children contributed significantly to differences between women who died suddenly of heart disease and control subjects.
Explore the source record for details and available documents.
A large scale, prospective, randomized study of surgical v. medical management of disabling angina pectoris is being conducted as a cooperative study among thirteen Veterans Administration hospitals in the U.S.A. A total of 1015 patients have been entered into the study and follow-up data are currently being evaluated. Patient entry into the study was concluded in December 1974. Patient compliance has been acceptable with only 7% of patients not adhering to their randomization category. Thirty-day operative mortality (1972-1974) in 309 patients was 5-3%. The patient population exhibited a severe degree of coronary disease. There was ECG evidence of prior myocardial infarction in 40%. There were significant obstructive lesions in three major coronary arteries in 51% and significant lesions of the left main coronary artery in 11%. Medical and surgical treatment groups demonstrated no significant differences in objective descriptive characteristics. Mortality in the medical group at 1 year was 8%. Mortality was influenced by several factors including the number of vessels involved, left ventricular function and the presence of left main coronary artery disease. The lowest mortality occurred in patients with single vessel disease and normal LV function who had a 1-year mortality of 3%. Patients with 3-vessel disease and abnormal LV function exhibited a 14% 1-year mortality. Patients with disease of the left main coronary artery and poor LV function had a 1-year mortality of 37%. Analyses of the results of treatment modalities in sub-groups is currently being performed and will be reported in future publications.