In-Hospital Mortality of Cardiogenic Shock After Acute Myocardial Infarction: A Prospective Study

Background and objective Cardiogenic shock (CS) following acute ST-segment elevation myocardial infarction (STEMI) is a life-threatening complication associated with high in-hospital mortality despite advances in reperfusion and critical care. Published evidence from South Asia remains limited, and the independent contribution of time-dependent treatment variables to mortality in this setting is poorly characterized. The objective of this study is to determine the frequency of in-hospital mortality and its independent predictors among patients with CS following acute STEMI. Methodology The study was conducted as a prospective observational cohort study in the Department of Cardiology, Ayub Teaching Hospital, Abbottabad, Pakistan, from April to December 2021. Using consecutive non-probability sampling, 135 patients aged 18-80 years with STEMI and CS were enrolled. A structured proforma was used to gather data on demographic characteristics, comorbidities, reperfusion strategy (primary percutaneous coronary intervention (PPCI), thrombolysis, or conservative medical management), symptom-to-door time, total ischemic time, door-to-balloon time, door-to-needle time, and clinical outcomes. In-hospital mortality was evaluated during the hospital stay. Data were analyzed with IBM SPSS Statistics for Windows, Version 20 (Released 2011; IBM Corp., Armonk, NY, USA). Univariate analysis (chi-square test, Mann-Whitney U test, and logistic regression) was performed to identify associations, and multivariate logistic regression with backward elimination was used to determine independent predictors. A two-sided p-value < 0.05 was considered significant. Results Among 135 patients, the mean age was 55.03 ± 13.06 years, and 68 (50.37%) were male. Diabetes mellitus was present in 81 (60.00%), hypertension in 94 (69.63%), and smoking in 28 (20.74%) patients. PPCI was performed in 80 (59.26%), thrombolytic therapy in 31 (22.96%), and medical therapy only in 24 (17.78%) patients. The median symptom-to-door time was 3.70 hours (IQR 2.63-5.33), and the median total ischemic time was 5.10 hours (IQR 3.86-6.83). In-hospital mortality occurred in 48 patients (35.56%). Multivariate analysis identified four independent predictors of mortality: diabetes mellitus (adjusted OR 37.67, 95% CI 4.94-287.29, p < 0.001), hypertension (adjusted OR 170.50, 95% CI 5.72-5081.40, p = 0.003), anterior wall MI (adjusted OR 27.06, 95% CI 5.17-141.74, p < 0.001), and symptom-to-door time (adjusted OR 1.89 per hour, 95% CI 1.19-2.99, p = 0.007). The crude protective association of smoking (OR 0.05) was fully attenuated after adjustment (aOR 0.19, p = 0.234), consistent with the smoker's paradox. Conclusion CS in STEMI patients is associated with high in-hospital mortality. Diabetes, hypertension, anterior infarct location, and prolonged symptom-to-door time are independent predictors of death. Every hour of pre-hospital delay increases mortality risk by 89% after controlling for comorbidities and reperfusion strategy, underscoring the critical importance of rapid hospital presentation in this high-risk population.