OBJECTIVES: Accurately predicting short-term MACE (major adverse cardiac events) following primary percutaneous coronary intervention (PCI) remains a clinical challenge. This study aims to assess the effectiveness of four established risk scores in predicting short-term MACE after primary PCI. DESIGN: Prospective observational study. SETTING: The National Institute of Cardiovascular Diseases, Karachi, Pakistan. PARTICIPANTS: We enrolled a cohort of consecutive adult patients diagnosed with ST-elevation myocardial infarction undergoing primary PCI over a 6-month period, from 1 January 2022 to 30 June 2022. OUTCOME MEASURES: All the patients were followed at intervals of 3 months up to 12 months, and MACE events were recorded. Thrombolysis in Myocardial Infarction (TIMI), Primary Angioplasty in Myocardial Infarction (PAMI), Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) and Global Registry of Acute Coronary Events (GRACE) scores were obtained. RESULTS: A total of 2839 patients (79.3% male, mean age 55.6±11.2 years) were included. Over a median follow-up of 244 days, the composite MACE rate was 18.4% (521). All-cause mortality was 13.5% (384), reinfarction requiring revascularisation was 4.3% (121), heart failure-related rehospitalisation was 2.7% (76), stent thrombosis occurred in 5.6% (160) and cerebrovascular accident events were documented in 1% (28). The area under the curve for TIMI, PAMI, CADILLAC and GRACE scores was 0.682 (95% CI 0.655 to 0.709), 0.688 (95% CI 0.663 to 0.713), 0.686 (95% CI 0.66 to 0.711) and 0.695 (95% CI 0.669 to 0.72), respectively, for the prediction of MACE. On multivariable Cox regression, high-risk categories based on GRACE score were independent predictors of MACE with adjusted HR of 1.88 (95% CI 1.28 to 2.77
p=0.001). CONCLUSIONS: A significant proportion of patients experienced short-term MACE after primary PCI. While none of the assessed scores demonstrated significant predictive power, the GRACE score exhibited comparatively better predictive ability than the TIMI, PAMI and CADILLAC scores.