Changes of coronary blood flow before and after post-dilation following primary percutaneous coronary intervention in patients with STEMI.

This retrospective cohort study aimed to examine changes in coronary blood flow before and after post-dilation following primary percutaneous coronary intervention (PPCI) in patients with ST-segment elevation myocardial infarction (STEMI). 419 eligible patients who underwent PPCI due to STEMI between January 2019 and September 2023 were enrolled. The corrected thrombolysis in myocardial infarction frame count (CTFC), final quantitative coronary angiography, and the incidence of no-reflow and slow-flow during different procedure moments were assayed. The changes in coronary blood flow before and after post-dilation in the post-dilation group were analyzed. Among the 419 patients enrolled, 259 patients underwent post-dilation. The post-dilation procedure was more frequently performed in patients with calcium plaque present, longer stents, bigger-diameter stents, and overlapping stents. The incidence of final no-reflow and slow-flow in the post-dilation group was not significantly higher than that observed in the non-post-dilation group. In contrast post-dilation patients had significantly increased CTFC values by 3.54 ± 10.54 frames (P < .001) and the rate of no-reflow/slow-flow increased on average by 114% (P < .001) in comparison to patients not undergoing post-dilation. The receiver operating characteristic curve showed that if post-dilation was performed in patients when their after-stent CTFC was smaller than 23.25, no-reflow/slow-flow was less likely to occur (63.5% sensitivity, 88.8% specificity, [AUC]: 0.817, 95% CI: 0.749-0.886, P < .001). Post-dilation exacerbates the coronary blood flow and increases the incidence of no-reflow/slow-flow during PPCI for STEMI patients, except where after-stend CTFC values were <23.25.