Myocardial blush and microvascular reperfusion following manual thrombectomy during percutaneous coronary intervention for ST elevation myocardial infarction: insights from the TOTAL trial

Abstract

Aims: Thrombectomy during primary percutaneous coronary intervention (PPCI) for ST elevation myocardial infarction (STEMI) has been thought to be an effective therapy to prevent distal embolization and improve microvascular perfusion. The TOTAL trial (N = 10 732), a randomized trial of routine manual thrombectomy vs. PCI alone in STEMI, showed no difference in the primary efficacy outcome. This angiographic sub-study was performed to determine if thrombectomy improved microvascular perfusion as measured by myocardial blush grade (MBG).

Methods and results: Of the 10 732 patients randomized, 1610 randomly selected angiograms were analysable by the angiographic core laboratory. Primary outcomes included MBG and post-PCI thrombolysis in myocardial infarction (TIMI) flow grade. Secondary outcomes included distal embolization, PPCI complications, and each component of the complications. The primary end point of final myocardial blush (221 [28%] 0/1 for thrombectomy vs. 246 {30%} 0/1 for PCI alone group, P = 0.38) and TIMI flow (712 [90%] TIMI 3 for thrombectomy vs. 733 [89.5%] TIMI 3 for PCI alone arm, P = 0.73) was similar in the two groups. Thrombectomy was associated with a significantly reduced incidence of distal embolization compared with PCI alone (56 [7.1%] vs. 87 [10.7%], P = 0.01). In multivariable analysis, distal embolization was an independent predictor of mortality (HR 3.00, 95% CI 1.19-7.58) while MBG was not (HR 2.73, 95% CI 0.94-5.3).

Conclusions: Routine thrombectomy during PPCI did not result in improved MBG or post-PCI TIMI flow grade but did reduce distal embolization compared with PCI alone. Distal embolization and not blush grade is independently associated with mortality.

Keywords: Myocardial Blush Grade; STEMI; Thrombectomy.