PubMed · 5420151
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D I Williams, I Hulme-Moir. 1970. Primary obstructive mega-ureter.. https://doi.org/10.1111/j.1464-410x.1970.tb10013.x
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BACKGROUND: Atrial fibrillation (AF) is associated with an increased risk of stroke. Six randomized studies of the use of oral anticoagulation therapy have demonstrated that the relative risk of stroke is decreased by approximately 68%. Three of these studies also compared aspirin with placebo use in a double-blind design. We pooled individual patient data from these 3 studies. OBJECTIVES: To determine if there were subgroups of patients who were particularly responsive to aspirin use and to determine the efficacy of aspirin compared with placebo use in the broad spectrum of patients with AF. METHODS: There were 1985 patient-years assigned to the aspirin and 1867 patient-years assigned to the placebo groups in the analysis. The daily dose of aspirin was 75 mg in the Atrial Fibrillation, Aspirin, Anticoagulation Study, 325 mg in the Stroke Prevention in Atrial Fibrillation 1 Study, and 300 mg in the European Atrial Fibrillation Trial. The European Atrial Fibrillation Trial was a secondary prevention trial, while the other 2 were primary prevention studies. The primary end point in this analysis was ischemic stroke. RESULTS: At the time of randomization, the patients' mean age was 70 years and the mean blood pressure was 145/83 mm Hg. Sixty-two percent of patients were male, 46% had a history of hypertension, 35% had a previous transient ischemic attack or stroke, and 19% had intermittent AF. Although aspirin use seemed particularly effective in younger patients and in those with hypertension in the Stroke Prevention in Atrial Fibrillation 1 Study, this was not the case in the other studies. No other subgroups particularly responsive to aspirin therapy were identified. When patients from all the studies were combined, the relative risk reduction with aspirin therapy was 21% (95% confidence interval, 0%-38%; P = .05). CONCLUSIONS: A subgroup of patients with AF that has a particularly large reduction in stroke incidence from aspirin therapy was not convincingly identified. The data from the combined analysis of these 3 randomized trials suggest a small effect of aspirin use in preventing stroke in patients with AF.
BACKGROUND: With the expectation that physicians who perform larger numbers of coronary angioplasty procedures will have better outcomes, the American College of Cardiology/ American Heart Association guidelines recommend minimum physician volumes of 75 procedures per year. However, there is little empirical data to support this recommendation. METHODS AND RESULTS: We examined in-hospital bypass surgery and death after angioplasty according to 1992 physician and hospital Medicare procedure volume. In 1992, 6115 physicians performed angioplasty on 97,478 Medicare patients at 984 hospitals. The median numbers of procedures performed per physician and per hospital were 13 (interquartile range, 5 to 25) and 98 (interquartile range, 40 to 181), respectively. With the assumption that Medicare patients composed one half to one third of all patients undergoing angioplasty, these median values are consistent with an overall physician volume of 26 to 39 cases per year and an overall hospital volume of 196 to 294 cases per year. After adjusting for age, sex, race, acute myocardial infarction, and comorbidity, low-volume physicians were associated with higher rates of bypass surgery (P < .001) and low-volume hospitals were associated with higher rates of bypass surgery and death (P < .001). Improving outcomes were seen up to threshold values of 75 Medicare cases per physician and 200 Medicare cases per hospital. CONCLUSIONS: More than 50% of physicians and 25% of hospitals performing coronary angioplasty in 1992 were unlikely to have met the minimum volume guidelines first published in 1988, and these patients had worse outcomes. While more recent data are required to determine whether the same relationships persist after the introduction of newer technologies, this study suggests that adherence to minimum volume standards by physicians and hospitals will lead to better outcomes for elderly patients undergoing coronary angioplasty.