A Randomized Controlled Clinical Trial of Prolonged Stent Deployment Strategy in Primary Percutaneous Coronary Intervention for ST-segment Elevation Myocardial Infarction: A Pilot study

Abstract

Background Primary percutaneous coronary intervention (PPCI) is the most standard reperfusion strategy for ST-segment elevation myocardial infarction (STEMI), but the no-reflow phenomenon is still common and is associated with adverse outcomes. Little is known about the consequences of different strategies of deploying stents on outcomes in STEMI patients. The aim of this study was to evaluate whether prolonged inflation would decrease the no-reflow phenomenon in PPCI compared with the conventional rapid inflation/deflation strategy. Methods This was a prospective, single-center, blinded, randomized controlled trial. Patients were randomized 1:1 to a prolonged deployment strategy group or a conventional deployment strategy group. A subset of patients was included in a cardiac magnetic resonance (CMR) examination assessment. The primary outcomes were the number of patients with Thrombolysis in Myocardial Infarction (TIMI) flow grade 3, the incidence of intraoperative no-reflow/slow flow, the corrected TIMI frame count, the myocardial blush grade, and the number of patients with ST-segment resolution>50%. The secondary outcome was major cardiovascular adverse events at one month and one year following the index PPCI. Results TIMI flow grade 3 was found in 96.7% of the prolonged deployment strategy group and 63.3% of the conventional deployment group (P=0.005). The prolonged inflation strategy and inflation/deflation strategy group respectively showed the following rates: 0% vs 30% no-reflow or slow flow (P=0.002); 90% vs 66.7% ST-segment resolution ≥50% (P=0.028); 35.6±14.5 frames vs 49.18±25.2 frames on corrected TIMI frame count (P=0.014); and 60% vs 20% myocardial blush grade 3 (P=0.001). The major cardiovascular adverse event rate was 3.3% in both groups at one month and 3.3% for the prolonged inflation strategy group vs 6.7% for the rapid inflation/deflation strategy group at one year (P=1.0). In the CMR subset of cases, the presence of microvascular obstruction (MVO) was detected in 6.7% of patients in the prolonged inflation strategy group and in 50% of patients in the rapid inflation/deflation strategy group (P=0.023). Conclusions In the patients with STEMI who underwent PPCI, the effect of the prolonged inflation strategy could decease the no-reflow phenomenon and improve myocardial microcirculation perfusion, but there were no benefits for the 30-day or one-year clinical outcomes. (ClinicalTrials.gov number: NCT03199014.Registered June 23, 2017,http://https://clinicaltrials.gov/ct2/show/NCT03199014?term=NCT03199014&cntry=CN&draw=2&rank=1)