MUSTELA: Thrombectomy Use Not Associated with Smaller Infarcts at 1 Year

SAN FRANCISCO, CALIF.—Thrombectomy did not reduce infarct size compared to standard PCI after 3 months in a high-thrombus burden STEMI population in the MUSTELA trial. The procedure was, however, associated with a higher rate of complete ST-segment elevation resolution than PCI alone.

“No significant difference was observed regarding 1-year freedom from MACE,” said Anna Sonia Petronio, MD, of the University of Pisa in Italy. Petronio noted that thrombectomy was associated with less microvascular obstruction at 3-month MRI; thrombectomy patients tended to have viable tissue interspersed with necrotic areas.

The prospective, randomized MUSTELA trial randomized 208 patients to aspiration or no aspiration, with the aspiration patients split between rheolytic and manual methods. All patients had STEMI and a high thrombus burden (TIMI thrombus ≥ grade 3).

Postprocedural TIMI 3 flow was achieved in 90.4% of thrombectomy patients compared with 81.7% of controls (P=.07), ST-segment elevation resolution of greater than 70% at 60 minutes was achieved in 57.4% of the thrombectomy group compared with 37.3% of controls (P=.004).

At 3 months, MRI results showed a delayed enhancement area of 20.4% in thrombectomy patients compared with 19.3% of controls (P=.54). At 1 year, freedom from MACE was 93.9% in control patients vs. 92.3% in thrombectomy patients (P=.57).

In a subanalysis of the thrombectomy patients, angiographic success was more common in those who underwent rheolytic aspiration (n=54) compared with those who underwent manual aspiration (n=50) (P=.02). Overall, rates of success for the rheolytic vs. manual group were 94.4% and 78.0%, respectively (P=.02). At 3-month MRI, however, there were no significant differences with regard to infarct size. Successful delivery of the manual thrombectomy system was 98% compared with 100% for the rheolytic system.

Baseline characteristics were similar between the thrombectomy and control groups. The average age was 61.5 years in the control group and 63 years in the thrombectomy group, and there were equivalent rates of diabetes, hypertension and other risk factors. Although it did not reach significance, there was a trend toward a lower pain-to-balloon time in the control group vs. thrombectomy group (241 minutes vs. 260 minutes; P=.07). There were less control patients with an initial diagnostic TIMI flow of 0-1 (77.9%) than there were thrombectomy patients (91.3%; P=.007).

  • Dr. Petronio reports no relevant conflicts of interest.