Thrombus aspiration in heart attack patients showed no benefit and raised the risk of stroke, according to a pair of studies of percutaneous coronary interventions using Medtronic‘s (NYSE:MDT) Export aspiration catheter, presented today at the annual Transcatheter Cardiovascular Therapies conference in San Francisco.
Early thrombectomy’s promise Totaled?
The 10,064-patient Total study compared PCI alone and PCI with thrombectomy in ST-elevated myocardial infarctions within 12 hours of onset. The primary endpoint (a composite of cardiovascular death, recurrent myocardial infarction, cardiogenic shock, or class IV heart failure) at 1 year was 8% for both arms of the trial (395 of 5,035 thrombectomy patients, 394 of 5,029 PCI-only patients).
Cardiovascular death occurred in 4% for both arms (179 in the thrombectomy arm and 192 in the control arm). The rates of recurrent myocardial infarction, cardiogenic shock, or heart failure, all-cause death, stent thrombosis, definite stent thrombosis, target vessel revascularization and major bleeding were all similar for both arms of the study.
But the thrombectomy arm fared poorly in the main safety endpoint, stroke within 1 year, showing a rate of 1.2% (60 patients) in the thrombectomy arm but only 0.7% (36 patients) for the PCI-alone cohort.
“Routine thrombus aspiration during PCI for STEMI did not reduce cardiovascular death, myocardial infarction, shock, or heart failure after 1 year compared with PCI alone,” lead investigator Dr. Sanjit Jolly, of Canada’s Hamilton Health Sciences and McMaster University, said in prepared remarks.
“A strategy of routine thrombus aspiration may be associated with an increased rate of stroke. The Total trial is the largest trial of thrombus aspiration with significantly more power to detect differences in which stroke was a pre-specified safety outcome. As a result, thrombus aspiration can no longer be recommended as a routine strategy in STEMI,” Jolly said.
Late thrombectomy no better
A much smaller study of thrombectomy 12-48 hours after STEMI onset similarly came up empty on thrombectomy’s benefits versus PCI alone. A 144-patient study randomized patients to PCI with thrombectomy (70 patients) or PCI alone (74 patients), with a primary endpoint of the extent of microvascular obstruction, assessed by cardiac magnetic resonance imaging after 1 to 4 days.
There was no statistically significant difference in the rate of MVO for either group, at 2.5% for the thrombectomy cohort and 3.1% for the control arm. Nor were there significant differences in the secondary endpoints of infarct size, left ventricular ejection fraction, or angiographic and clinical endpoints between groups.
“In patients with subacute STEMI, routine manual thrombus aspiration before PCI failed to show a significant reduction in the primary endpoint of microvascular obstruction assessed by cardiac magnetic imaging compared to conventional PCI alone,” lead investigator Dr. Steffen Desch, of the University of Schleswig-Holstein in Lübeck, Germany, said in prepared remarks. “This finding is further supported by a lack of benefit in angiographic, enzymatic, and clinical secondary endpoints.”