Effect of prasugrel versus ticagrelor on coronary microcirculation in patients undergoing pharmacoinvasive strategy - acute and short-term results

Introduction Both ticagrelor and prasugrel are class I recommendations for treatment of ST-elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI) [1]. But clinical outcomes with the two drugs are conflicting which might be due to differential effects on coronary microcirculation. No study to date had compared the effects of prasugrel or ticagrelor on coronary microcirculation in patients undergoing pharmacoinvasive PCI (pPCI). Aim and objective To compare the effects of prasugrel and ticagrelor on coronary microcirculation in STEMI patients undergoing pPCI as assessed by Myocardial Blush Grade (MBG). The secondary aim was to assess flow in the infarct-related artery by corrected thrombolysis in myocardial infarction (TIMI) frame count (cTFC) and whether a differential effect if detected on coronary microcirculation translated in improvement in left ventricular ejection fraction assessed at 6 months. Material and methods A total of 240 patients with STEMI were evaluated in this open-label randomized control trial who initially underwent thrombolysis and later PCI (from 24 to 48 h) post-successful thrombolysis. The study subjects were randomized to receive either ticagrelor (n = 120) or prasugrel (n = 120) in 1 : 1 ratio 2 h prior to elective PCI. Patients underwent PCI according to standard protocol and post-procedure cTFC and MBG were compared. Patients were also followed up for 6 months to compare ejection fractions in both groups. We also assessed the effect of the two drugs on bleeding complications during hospitalization and over 6-month follow-up period. Results There were no significant differences between the two groups with respect to baseline characteristics. Prasugrel administration resulted in higher MBG Grade 3 (50.86% vs 33.89%, P = 0.012) and lower cTFC (17.14 +/- 4.08 vs 19.3 +/- 4.06, P < 0.01). Improvement in ejection fraction was significantly higher with prasugrel compared to ticagrelor (10.29% +/- 15.2 vs 4.66% +/- 13.5, P = 0.003). Bleeding events at 6 months follow-up according to TIMI classification were similar in both the groups (11.86% vs 6.9%, P = 0.39). Conclusion Prasugrel produces greater improvement in coronary microcirculation than Ticagrelor resulting in improved myocardial salvage in patients of STEMI undergoing pPCI.