Incidence, clinical characteristics, and short-term prognosis of angina pectoris

OBJECTIVES--To estimate the clinical incidence and short-term prognosis of patients presenting with typical angina pectoris in the general population. DESIGN--Prospective survey of all patients referred by 117 general practitioners from a random sample of 17 general practices serving a population of 191,677 with a median follow up of 16 months. SETTING--A special open access chest pain clinic, based in the non-invasive cardiology department of a teaching hospital, set up for this study. PATIENTS--110 consecutive patients < or = 70 years age with no history of coronary heart disease presenting for the first time with typical angina. MAIN OUTCOME MEASURES--Age and sex specific incidences, persistence of chest pain, revascularisation procedures, myocardial infarction, and death. RESULTS--The crude annual incidence of angina pectoris (95% confidence interval) was 0.83 (0.66 to 1.0) per thousand population aged 31-70 years; the rates were 1.13 (0.85 to 1.40) for men and 0.53 (0.33 to 0.72) for women. On resting electrocardiography 5% of patients had > or = 1 mm horizontal or downsloping ST depression, 5% had Q/QS patterns, and in one (1%) there was complete left bundle branch block. Among the 103 patients who underwent a Bruce protocol exercise test, 29% had > or = 3 mm ST segment depression induced at a low workload. Of 107 patients at a median (range) follow up of 15.8 (7-30) months, angina remitted spontaneously in 12 patients (11%), 20 (19%) underwent revascularisation, eight (7%) sustained a non-fatal myocardial infarction, and four (4%) died. CONCLUSION--Incidence of new cases of angina pectoris in the United Kingdom is conservatively estimated from this study to be 22,600 patients per annum. Almost one third of these patients will have positive exercise tests at low workload, so the potential for coronary angiography and revascularisation is considerable. With one in 10 patients experiencing a non-fatal myocardial infarction or coronary death within a year of presentation the prognosis of angina is not benign. Further research is required to identify those patients in the general population who would benefit most from coronary revascularisation.