Original title: A Prospective Randomized Trial of Trombectomy Versus No Thrombectomy in Patients With ST-Segment Elevation Myocardial Infarction and Thrombus-Rich Lesion. MUSTELA (MUltidevice Thrombectomy in Acute ST-Segment ELevation Acute Myocardial Infarction) Trial Reference: Marco De Carlo, et al. J Am Coll Cardiol Intv 2012;5:1223–30

The main objective during primary PCI is myocardial reperfusion, which is limited by distal embolization of thrombi. Several thrombectomy devices have been developed with controversial results since, till now, all studies have included patients with variable thrombus load; therefore whether thrombectomy should be routine or alternative practice to treat high thrombus burden patients remains a question. The aim of this randomized study was to assess the impact of manual or reolytic thrombectomy during primary PCI in patients with high thrombus burden. 208 AMI patients undergoing PCI were included, randomized 1:1 to two groups: thrombus aspiration (TG) and standard (ST), the GT group to manual aspiration or AngiJet Ultra.

Primary end point was ST resolution at 60 minutes and AMI size at 3 months, assessed by MRI. Secondary end point included TIMI flow, myocardial blush, transmurality, microvascular obstruction and one year freedom from mayor cardiac events.

Baseline characteristics were similar, radial approach was used in 95.2% of the population, reolytic thrombectomy was 51.9% and 3.8% required dilation previous to thrombus aspiration. AngioJet Ultra was more effective to achieve complete aspiration of thrombi.

Thrombectomy allowed a significantly greater use of primary stent, lower TIMI 2 flow and a trend to a higher TIMI 3. Primary end point (complete resolution of STEMI) was significantly better in GT (57.4% vs. 37.3%; p=0.004). At 3 months, MRI showed significantly less microvascular obstruction in GT, but there was no difference in infarction size, transmurality, ejection fraction and ventricular volumes, which remained similar. Freedom from mayor cardiac events was also similar in both groups (91.4% vs. 90.2%).

Conclusion 

The use of thrombus aspiration in primary PCI was effective to achieve STEMI resolution, improve TIMI flow and reduce microvascular obstruction but did not reduce infarction size or transmurality.

Editorial Comment:

This randomized study showed that thrombectomy is beneficial to solve STEMI, improve myocardial flow and microvascular obstruction, which leads to infer this technique is indeed beneficial, despite the fact that it has not shown to improve hard events at one year. A larger number of patients may surely show this benefit. 

Courtesy of Dr. Carlos Fava.
Interventional Cardiologist.
Favaloro Foundation. Argentina.

Dr. Carlos Fava para SOLACI.ORG