Prognostic Value of Selected Presenting Features of Acute Coronary Syndrome in Predicting In-Hospital Adverse Events: Insight from the Thai Acute Coronary Syndrome Registry

OBJECTIVE: To evaluate the relationship of the presenting features of acute coronary syndrome (ACS) to in-hospital adverse events (total and cardiac deaths, heart failure and serious dysrhythmia) and the effects of coronary intervention. BACKGROUND: Patients with ACS may present with dyspnea, shock and/or cardiac arrest with or without accompanying chest pain. METHODS: We evaluated 9,373 patients (age 65+/-12 years and 60% males) enrolled in the Thai ACS Registry. Cardiac dyspnea included shortness of breath on exertion, and/or at rest, orthopnea, or paroxysmal nocturnal dyspnea presumed from cardiac sources. Shock was present if systolic blood pressure was <90 mmHg for >30 min with symptoms of end-organ hypoperfusion. Post cardiac arrest was identified if cardiopulmonary resuscitation was required. We calculated the frequencies of these presenting features and assessed their contribution toward in-hospital adverse events (total and cardiac deaths, heart failure and serious arrhythmias) for the whole ACS and each entity of ACS and the effects of in-hospital interventions, both coronary and medicinal. RESULTS: Cardiac dyspnea, shock and post cardiac arrest were seen in 32.7%, 9.3%, and 4.2% of patients, respectively. In-hospital adverse events occurred more frequently in patients with these presenting features than those without (p<0.05). Cardiac dyspnea and shock were independent predictors of heart failure and death, respectively, while post cardiac arrest independently identified patients at risk of arrhythmia, total and cardiac death, regardless of the subgroup of ACS. Coronary revascularization significantly reduced the risk of total and cardiac death. CONCLUSION: These 3 presenting features of ACS portend a poor prognosis, regardless of the subgroup of ACS and should be considered as important early indicators for early intervention.