Objectives: To evaluate the influence of prior medication on mode of presentation and short-term prognosis of acute coronary syndromes (ACS).
Design: Prospective study.
Setting: Coronary intensive care unit in Santa Cruz Hospital.
Population: We included 425 consecutive patients admitted for ACS.
Methods: Prior medication with anti-platelet agents, beta-blockers, nitrates, calcium channel blockers, statins and angiotensin-converting enzyme (ACE) inhibitors was recorded on admission. Medication introduced in the last 7 days was excluded. Using a multivariate analysis model we examined the impact of baseline characteristics and previous medication on mode of presentation of ACS. We also evaluated their influence on short-term prognosis (death or non-fatal myocardial (re)infarction in the first 30 days).
Results: Of the 425 patients studied 228 (53.6%) presented with unstable angina (UA), the remainder with acute myocardial infarction (AMI) (24.7% with ST elevation). Medication prior to admission included anti-platelet agents in 53.7% of patients, beta-blockers in 44.2%, nitrates in 48.2%, calcium channel blockers in 36.9%, statins in 28.9% and ACE inhibitors in 38.6%. During the first 30 days, 14 deaths (3.3%) and 37 (re)infarctions (8.7%) occurred. The combined occurrence of death or (re)infarction was 10.8%. Variables with significant and independent influence on mode of presentation of ACS were male gender, presence of known coronary artery disease and previous medication with anti-platelet agents and beta-blockers. Male gender was a predictor of AMI as mode of presentation, whereas a previous history of coronary artery disease and medication with anti-platelet agents or beta-blockers predicted UA. Short-term prognosis was influenced by heart failure symptoms on admission, but not by previous medication.
Conclusion: Previous medication with anti-platelet agents and beta-blockers was associated with an increased frequency of UA as mode of presentation of ACS. No relation between previous medication and short-term prognosis was observed in the present study.