Manual vs mechanical thrombectomy during PCI for STEMI: a comprehensive direct and adjusted indirect meta-analysis of randomized trials

Thrombus removal by manual thrombectomy improves coronary flow and myocardial perfusion after percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction (STEMI); growing interest is on mechanical devices for thrombectomy which may allow a larger thrombus removal as compared to manual devices. We aimed to perform the first direct and adjusted indirect meta-analysis of studies on manual and mechanical thrombectomy in PCI for STEMI. Methods: The literature was scanned for direct and indirect randomized comparisons between manual and/or mechanical thrombectomy and/or placebo by formal searches of electronic databases from November 1994 to June 2013. Clinical and procedural endpoints were selected. Results: Three studies directly comparing (2 RCTs and 1 non-randomized; N = 513) and 21 RCTs (N = 4514) indirectly comparing the two strategies were included in the meta-analysis. The direct meta-analysis showed comparable rates of survival (p = 0.88), re-infarction (MI)( p = 0.84) and procedural outcomes between the two strategies; direct evidence was however limited in number of enrolled patients. The indirect meta-analysis showed a superior reduction in mortality with manual thrombectomy compared to mechanical thrombectomy in the overall analysis (p = 0.01); by excluding trials with low percentage of patients with intracoronary thrombus (< 50%) at baseline, the two strategies were comparable in survival, but mechanical thrombectomy was associated with a significant reduction in re-MI (p < 0.001) and stroke (p = 0.04). Conclusions: This meta-analysis lends support to mechanical thrombectomy in the population with high thrombus burden only where, compared to manual thrombectomy, it is likely to provide higher benefits in reduction of re-MI and stroke.