Unstable angina: individualized stratification and prognosis.

ABSTRACT

OBJECTIVE: To analyse the methodology of risk stratification and the prognosis of patients admitted with unstable angina. POPULATION AND METHODS: This retrospective study involved a population of 68 patients (43 males and 25 females with a mean age of 65.8 +/- 9.8 years) consecutively admitted for suspected unstable angina during the year of 1996. Thirty six patients (52.9%) had angina at rest, 13 patients (19.1%) had both exertional and rest angina, 9 patients (13.2%) crescendo angina, 6 patients (8.8%) new onset exertional angina (less than 1 month), and 4 patients (5.8%) post-infarction angina (less than 2 weeks). The risk stratification was individualized. The coronary angiography (35 patients) was only performed when the medical therapy failed in patients with recurrent angina, or with proved ischemia after an exercise test and/or thallium 201 stress scintigraphy. Thirteen patients (19.1%) did not undergo these tests (advanced age and or bad general condition, or refusal). The follow-up of patients with and without ST-T changes was compared, as well as those revascularized versus non-revascularized. It was possible to achieve a mean follow-up of 13.7 +/- 6.2 months (3 to 25 months). RESULTS: The exercise test and/or thallium-201 stress scintigraphy were positive for myocardial ischemia in 28 pts (41.1%) and negative in 7 patients (10.2%). The coronary angiography revealed three-vessel coronary artery disease in 18 patients (26.4%), one vessel disease in 11 patients (16.1%) and two-vessel disease in 5 patients (7.3%). One patient had normal coronary arteries. Medical therapy was the initial approach. Coronary surgery was urgently performed in 3 patients and coronary angioplasty in 5 patients for refractory unstable angina. In the whole group coronary artery surgery was undertaken in 14 patients (20.5%) and coronary angioplasty in 12 patients (17.6%). A mean follow-up of 13.7 +/- 6.2 months was obtained in the 68 patients. During this period 6 patients (8.8%) died due to cardiac causes and 16 patients (23.5%) were readmitted 8 patients (11.7%) for unstable angina, 5 patients (7.3%) for congestive heart failure and 3 patients (4.4%) for myocardial infarction. Fifty two patients (76.4%) remained free of cardiac events. The patients with transitory ST-T changes had more cardiac events (unstable angina, myocardial infarction, mortality) than the patients without ECG changes (13/30 vs 2/30, p = 0.003). When the revascularized patients were compared to the non revascularized no significant differences were observed regarding myocardial infarction and mortality, however revascularized pts had a less significant incidence of rehospitalization for unstable angina (0/26 vs 8/42 p = 0.02). CONCLUSIONS: An individualized strategy can be effective in pts with unstable angina. In this study 76.4% of patients remained free of cardiac events during the follow-up, 23.6% had severe cardiac events and the cardiac mortality was 8.8%. The patients with transitory ST-T changes had more cardiac events and worse prognosis. No patients significant difference was observed in the revascularized versus non revascularized patients for myocardial infarction and mortality; however, the revascularized patients had less significant incidence of rehospitalization for unstable angina.