COMPARISON OF CLINICAL, ANGIOGRAPHIC CHARACTERISTICS AND IN HOSPITAL OUTCOME OF PATIENTS PRESENTING WITHIN 12 HOURS VS. THOSE PRESENTING AFTER 12 HOURS OF SYMPTOMS WITH ST-SEGMENT ELEVATION MI

Abstract

Background: Patients with STEMI arriving > 12 hours after symptoms onset have worse long-term outcomes than those coming within 12 hours of symptoms onset. We compared clinical, angiographic characteristic and in-hospital outcome of patients presenting ≤ 12 hours and > 12 hours of symptoms.

Method: The study was a prospective observational study conducted as a part of ACS registry in  SICVD satellite center and IMC Hospital in Pakistan over 06 months, from November 2025 to April 2026. All patients with STEMI < 48 hours and age > 18 years were included; patients who did not undergo invasive management for any reason were excluded. Data was entered in a structured Performa and analyzed. Patients were further divided into two groups: those within 12 hours (on time) and those >12 hours (late arrival). Comparison was made for the clinical and angiographic characteristics and in-hospital outcome complications (arrhythmias, access site complications) or mortality. 

Results: A total of 627 patients were enrolled, among whom 79% (n=497) arrived within 12 hours and 21% (n=130) arrived late > more than 12 hours. Patients in the early group were younger (<60 years) than those in the Late group (71% vs. 63%. Hypertension (55% vs. 50%) and smoking (40% vs. 35%) were more prevalent as risk factors in the on-time group. More patients in the early group were already on antiplatelet therapy than the late arrivals. Regarding angiographic characteristics, the Incidence of three-vessel disease (26.7 vs. 34.5%) and non-obstructive coronaries (3.0% vs. 1.5%) were, respectively. Access site complication occurred 1.6% in the on-time vs. 0% in the late group, while overall mortality remained the same (3.2% vs. 3.0%).

Conclusion: Despite the difference in clinical and angiographic characteristics, the in-hospital mortality remains the same between patients with STEMI presenting within 12 hours as compared to those presenting > 12 hours of symptoms.