Impact of post-dilatation on post-procedural physiology, microcirculatory resistance, and target vessel failure in STEMI patients undergoing PPCI: A single-center experience

Background: Suboptimal stent deployment is frequently observed in ST -segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PPCI). This study sought to investigate whether these patients could benefit from post-dilatation with respect to post-procedural physiology, microcirculatory resistance, and long-term clinical outcomes. Methods: This was a retrospective study of consecutive STEMI patients who underwent successful stent implantation during PPCI from February 2016 to November 2021. Post-procedural physiology and microcirculatory resistance were assessed by Murray law-based quantitative flow ratio (mu QFR) and angiographic microcirculatory resistance (AMR), respectively. The primary outcome was target vessel failure (TVF), a composite of cardiac death, target vessel-oriented myocardial infarction, and clinically driven target vessel revascularization. Results: A total of 671 patients (671 culprit vessels) were included. Post-dilatation was selectively performed in 430 (64.1%) culprit vessels, resulting in a 0.02 (interquartile range: 0.00-0.05, p < 0.001) increase in postprocedural mu QFR but no significant impact on AMR. During a median follow-up of 2.8 years (interquartile range: 1.4-3.0 years), TVF occurred in 47 (7.0%) patients. Post-dilatation demonstrated a trend toward a reduction in TVF (5.3% vs. 10.0%; adjusted hazard ratio: 0.60, 95% confidence interval: 0.33-1.09, p = 0.094), mainly driven by a lower incidence of clinically driven target vessel revascularization (1.6% vs. 4.1%; adjusted hazard ratio: 0.32, 95% confidence interval: 0.11-0.90, p = 0.030). Conclusions: In STEMI patients undergoing PPCI, selective post-dilatation was associated with improved postprocedural physiological results and a trend toward less TVF events without aggravating microcirculatory resistance.