Thrombectomy Fails to Reduce Microvascular Obstruction in Non-STEMI

San Francisco, CA—In the first multicenter randomized trial in non-STEMI patients with thrombus-containing lesions, aspiration thrombectomy did not reduce the extent of microvascular obstruction or improve outcomes compared with standard PCI alone.

Results of the TATORT-NSTEMI trial were presented Thursday at TCT 2013 by Holger Thiele, MD, of the University of Leipzig Heart Center in Leipzig, Germany.

For the trial, 440 non-STEMI patients intended for early intervention at seven German centers were randomly assigned to manual thrombectomy (Eliminate, Terumo Europe) plus standard PCI or standard PCI alone. All patients experienced ischemic symptoms for longer than 20 minutes with the last symptoms within 72 hours of randomization, elevated troponin T or I levels above the 99th percentile and had an identifiable culprit lesion containing thrombus of TIMI grade 2 to 5. 

Thrombus material was retrieved in 74% of the thrombectomy group, and primary stenting was performed in 61% compared with 45% of the standard PCI group (P<.01). 

The presence and extent of microvascular obstruction as assessed by cardiac MRI between 1 and 4 days after PCI did not differ between the thrombectomy and standard PCI groups (see Figure). The lack of benefit was consistent across prespecified subgroups defined by sex, diabetic status, TIMI thrombus grade (2-4 vs. 5), baseline TIMI flow (0-1 vs. 2-3) and glycoprotein IIb/IIIa inhibitor use. 

The same pattern of similarity between thrombectomy and standard PCI results was seen for median area at risk, infarct size assessed by cardiac MRI, myocardial salvage index, enzymatic infarct size at 48 hours, TIMI flow grade and myocardial blush grade. 

At 6 months, patients who did or did not receive thrombectomy showed comparable rates of  the composite of death, reinfarction, target vessel revascularization and new congestive HF (7.3% vs. 10.1%; HR 0.72; 95% CI 0.37-1.41; P=.34); the rates of the individual endpoints did not differ between the groups. 

In a discussion following the presentation, On Topaz, MD, of the Charles George Veterans Affairs Medical Center in Asheville, N.C., suggested that in cases of significant thrombus burden, manual thrombectomy may be insufficient and that perhaps the finding should serve as an impetus to identify a better tool. 

Robert Byrne, MB, BCh, PhD, of Deutsches Herzzentrum in Munich, observed that in the absence of improvement in microvascular obstruction, thrombectomy may nonetheless enable more precise stenting, potentially resulting in reduced restenosis in the long term. 

Disclosures:

The study was funded by grants from Lilly Germany and Terumo Europe.

Byrne reports receiving consultant fees/honoraria and serving on the speaker’s bureau from Biotronik.

Thiele reports receiving research funding from Eli Lilly, Maquet Cardiovascular, Teleflex Medical, Terumo and The Medicines Company, and speaker’s honoraria from AstraZeneca, Boehringer Ingelhiem, Daiichi Sankyo, Eli Lilly, Maquet Cardiovascular and The Medicines Company.

Topaz reports no relevant conflicts of interest.