To assess the effect of manual thrombectomy (MT) on microvascular obstruction (MVO) using cardiac magnetic resonance (CMR) in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI).
Three hundred and eighty-three patients admitted for STEMI and undergoing CMR fulfilled the inclusion criteria and were categorized into two groups (did or did not undergo MT). The two primary endpoints were the occurrence and extent of MVO, analyzed as a categorical variable and as a semicontinuous variable. Among the 383 patients, 49.1% exhibited MVO. Both the incidence of MVO and the median number of segments presenting with MVO were significantly higher in the MT group than in the no-MT group, (59.5 vs. 38.9%, p < .001) and (1.5 [0;4] vs. 0 [0;2], p < .001). Analysis stratified on coronary thrombus grade showed similar results, only in patients with a high thrombus burden (60.7 vs. 43.5%, p = .004, and 2 [0;4] vs. 0 [0;3], p = .001. When adjusting for baseline differences, MT remained a determinant of MVO occurrence and extent (odds ratio, OR 1.802 [95% confidence interval, CI 1.080-3.009], p = .024) and β = .137, p = .024) in patients with a high thrombus grade.
In STEMI patients, MT was associated with the occurrence and extent of MVO, on CMR, especially in patients with a high thrombus burden.