Sex‐Specific Treatment Effects After Primary Percutaneous Intervention: A Study on Coronary Blood Flow and Delay to Hospital Presentation

Background We hypothesized that female sex is a treatment effect modifier of blood flow and related 30‐day mortality after primary percutaneous coronary intervention (PCI) for ST‐segment–elevation myocardial infarction and that the magnitude of the effect on outcomes differs depending on delay to hospital presentation. Methods and Results We identified 2596 patients enrolled in the ISACS‐TC (International Survey of Acute Coronary Syndromes in Transitional Countries) registry from 2010 to 2016. Primary outcome was the occurrence of 30‐day mortality. Key secondary outcome was the rate of suboptimal post‐PCI Thrombolysis in Myocardial Infarction (TIMI; flow grade 0–2). Multivariate logistic regression and inverse probability of treatment weighted models were adjusted for baseline clinical covariates. We characterized patient outcomes associated with a delay from symptom onset to hospital presentation of ≤120 minutes. In multivariable regression models, female sex was associated with postprocedural TIMI flow grade 0 to 2 (odds ratio [OR], 1.68; 95% CI, 1.15–2.44) and higher mortality (OR, 1.72; 95% CI, 1.02–2.90). Using inverse probability of treatment weighting, 30‐day mortality was higher in women compared with men (4.8% versus 2.5%; OR, 2.00; 95% CI, 1.27–3.15). Likewise, we found a significant sex difference in post‐PCI TIMI flow grade 0 to 2 (8.8% versus 5.0%; OR, 1.83; 95% CI, 1.31–2.56). The sex gap in mortality was no longer significant for patients having hospital presentation of ≤120 minutes (OR, 1.28; 95% CI, 0.35–4.69). Sex difference in post‐PCI TIMI flow grade was consistent regardless of time to hospital presentation. Conclusions Delay to hospital presentation and suboptimal post‐PCI TIMI flow grade are variables independently associated with excess mortality in women, suggesting complementary mechanisms of reduced survival. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01218776.