Meta-analysis of randomized trials comparing anti-embolic devices with standard PCI for improving myocardial reperfusion in patients with acute myocardial infarction.

Background: Failure to achieve adequate myocardial reperfusion often occurs during PCI in patients with STEMI. This is in part due to atheromatous and thrombotic distal embolization. Several anti-embolic devices have been developed to protect against distal embolization during percutaneous coronary interventions (PCI) to improve myocardial reperfusion and enhance event free survival. Evidence from current studies has not shown a consistent benefit, but anti-embolic devices continue to be used.

Methods: We conducted a systemic overview (meta-analysis) of randomized trials of thrombectomy or distal protection devices versus standard PCI to evaluate the effects of reducing distal embolization during PCI for native vessel acute myocardial infarction (AMI). We identified randomized trials by searching PubMed, OVID, the Cochrane databases, references of articles, and abstracts of conference proceedings (all from September 2000 to October 2005). Each trial tested the hypothesis that anti-embolic therapy would result in better clinical or angiographic results than standard PCI alone.

Results: Fourteen trials (n = 2630) were identified comparing a distal protection device or a thrombectomy device (n = 1320) versus standard PCI (n = 1310). When the studies were combined, primary endpoints of death or reinfarction were not improved by the use of anti-embolic devices (4% [52/1309] vs. 4.5% [59/1303], odds ratio [OR] 0.82 [95% CI 0.55 to 1.24, P= 0.35]). In subgroup analysis, analyzing the class of device separately, use of thrombectomy devices (4.4% [33/758 vs. 4.2% [32/763], OR 0.98 CI 0.53 to 1.83, P = 0.95]), and the use of distal protection device 3.5% [19/551] vs. 5% [27/540], OR 0.68 CI 0.37 to 1.23, P = 0.20]) during PCI for native vessel AMI did not improve the clinical outcome of death or reinfarction. The secondary endpoints of death, reinfarction, and major adverse cardiac events did not improve with the use of anti-embolic devices.

Conclusion: The combined experience from randomized trials suggests that the use of anti-embolic devices does not decrease early mortality or reinfarction during PCI for native vessel AMI. Whether their use improves longer term outcomes is unknown. Further research is needed to clarify the indication and optimal devices for anti-embolic protection.