Variation in the use of coronary angiography in patients with unstable angina is related to differences in patient population and availability of angiography facilities, without affecting prognosis

OBJECTIVES: Examination of the difference in management strategies with respect to coronary angiography in patients with unstable angina pectoris, and the consequences of this difference on prognosis. DESIGN: Prospective registration of consecutive patients admitted to two different hospitals. SETTING: University and a large community hospital in Rotterdam, the Netherlands. SUBJECTS: Patients under 80 years, without recent ( <4 weeks) infarction or recent ( <6 months) coronary revascularization procedure, admitted for chest pain suspected to indicate unstable angina pectoris. MAIN OUTCOME MEASURES: Decision to initiate coronary angiography or to continue on medical treatment. At 6 months the occurrence of death and myocardial infarction was measured. RESULTS: Clinical variables associated with the decision to initiate angiography were young age, male gender, progression of angina, multiple pain episodes and use of beta-blocker or calcium antagonists before admission, abnormal ST-T segment on baseline ECG, recurrent pain in hospital, and ECG changes during pain. These associations did not differ between hospitals. Nevertheless, angiography was performed more often in the presence of angiography facilities (university hospital), independent of the variable case-mix. Survival and infarct-free survival were similar in both hospitals, 96% and 90% respectively. CONCLUSION: The difference in angiography rate for unstable angina can be explained in part by differences in patient population and hospital facilities, but no difference was observed in physicians' assessment of patient characteristics. The observed practice variation did not affect prognosis