Sex Differences in the Incidence and Predictors of Slow/No-Reflow among STEMI Patients with High Thrombus Burden Undergoing Primary Percutaneous Coronary Intervention

Abstract

Objective: To compare the incidence of slow/no-reflow (SNR) between men and women with high thrombus burden (HTB) undergoing primary percutaneous coronary intervention (PPCI), identify independent predictors of SNR, and evaluate its association with adverse in-hospital clinical outcomes. Methodology: This prospective observational cohort study was conducted at the National Institute of Cardiovascular Diseases (NICVD), Karachi. A total of 370 patients with ST-segment elevation myocardial infarction (STEMI), angiographically confirmed HTB, and treated with PPCI were enrolled. Among the participants, 72.4% were men, and the mean age was 55.2 ± 8.1 years. Slow/no-reflow was defined as the occurrence of post-procedural TIMI flow grade ≤2 at any stage during or immediately following PPCI before completion of the procedure. Results: Slow/no-reflow occurred in 159 patients (43.0%). Although the incidence was numerically higher among men than women (45.5% vs. 36.3%), the difference was not statistically significant (p=0.108). Univariate analysis identified age, diabetes mellitus, hypertension, previous myocardial infarction, congestive cardiac failure, prolonged ischemic time, elevated left ventricular end-diastolic pressure (LVEDP), multivessel disease, lesion length, and infarct vessel diameter as significant predictors of SNR (all p<0.05). After adjustment for confounding factors, age ≥55 years (aOR 2.37, 95% CI: 1.19–4.73), diabetes mellitus (aOR 2.27, 95% CI: 1.02–5.08), congestive cardiac failure (aOR 23.69, 95% CI: 2.46–228.38), LVEDP >18 mmHg (aOR 5.19, 95% CI: 2.61–10.34), multivessel disease (aOR 5.45, 95% CI: 2.31–12.88), lesion length ≥28 mm (aOR 2.22, 95% CI: 1.16–4.25), and infarct vessel diameter ≥3.5 mm (aOR 2.05, 95% CI: 1.07–3.93) remained independent predictors of SNR. Sex was not independently associated with SNR. Patients who developed SNR experienced significantly higher rates of cardiogenic shock, arrhythmias, and in-hospital mortality. Conclusion: Among STEMI patients with high thrombus burden undergoing PPCI, no statistically significant sex-based difference was observed in the incidence of slow/no-reflow. The occurrence of SNR was primarily associated with clinical severity, hemodynamic compromise, and angiographic lesion complexity.