Aspiration Thrombectomy in STEMI PCI Plummets Nationwide

Patrice Wendling

January 16, 2019

A national registry analysis shows that use of aspiration thrombectomy during primary percutaneous coronary intervention (PCI) for ST-segment-elevation myocardial infarction (STEMI) has fallen by more than half, and that even selective use offers no clinical benefits.

"We were impressed to see that the national community of operators really responded to the data and that there was a pretty precipitous drop in the use of this device after the two large trials were presented," study author Eric A. Secemsky, MD, Beth Israel Deaconess Medical Center, Boston, told  | Medscape Cardiology.

Upfront manual aspiration thrombectomy grew rapidly after the 2008 single-center TAPAS study showed that it led to better 30-day myocardial reperfusion and a significant survival benefit at 1 year.

The randomized TOTAL and TASTE trials, however, were unable to confirm this survival benefit, with TOTAL actually reporting a significantly higher stroke risk with aspiration thrombectomy. As a result, the 2015 treatment guidelines for PCI in STEMI downgraded the routine use of aspiration thrombectomy to a class III recommendation.

"I think we always wonder whether evidence changes practice and how long it takes, so I think this was reassuring that the practice does follow the evidence and guidelines," TOTAL principal investigator, Sanjit Jolly, MD, McMaster University, Hamilton, Ontario, Canada, told | Medscape Cardiology.

Interventionalists have continued to use aspiration thrombectomy in select cases with high thrombus burden, with some suggesting that it facilitates direct stenting. Others argue that the heterogeneity of trial operators and mandatory use of thrombectomy, regardless of thrombus burden, could have influenced the negative results, Secemsky explained.

"In our analysis, we're studying operators who used this device in patients they felt would benefit from it; they weren't obligated to use it," he said. "So it's really looking at the selective use of manual aspiration thrombectomy and determining if there's a treatment benefit."

The analysis, published January 9 in JAMA Cardiology, assessed temporal trends and in-hospital outcomes in an unselected cohort of 683,584 patients (mean age, 61.7 years; 71.6% male) undergoing primary PCI for STEMI from July 2009 to June 2016 in the National Cardiovascular Data Registry CathPCI Registry.

Longitudinal outcomes were examined using CathPCI Registry data linked to US Centers for Medicare and Medicaid Services data from June 2009 to December 2014. Instrumental variable analysis was used to compare the safety and effectiveness of selective thrombectomy.

Widely Varying Practice

Individual use of aspiration thrombectomy for STEMI primary PCIs varied over the study period from none to 83.3%, the authors report. Roughly a third (34.1%) of operators did not use thrombectomy during the study, 23.4% used it in up to 5.4% of primary PCIs, and 15.8% used it in 21.6% to 83.3% of PCIs.

There were no clear trends in annual or STEMI PCI volume with increasing thrombectomy use, although a greater proportion of high-thrombectomy users practiced in the Northeast and Midwest, at teaching hospitals, and in urban hospital centers.

"These were not the granular data you need to really understand why operators are different," but "in the community of interventionalists, a lot of us have preconceived notions in terms of these devices and we have our set practices that we believe in. I think some of that reflects in the variation in practice," Secemsky said.

Is 5% Reasonable?

Overall, aspiration thrombectomy use increased by nearly 50% in the 2 years after the publication of TAPAS, reaching 10.0% in 2009 and peaking at 13.8% in late 2011, when thrombectomy received a class IIb designation in the PCI guidelines. Since then, use declined by more than 50%, to just 4.7% in mid-2016.

Asked whether a thrombectomy rate of about 5% is reasonable, Secemsky explained that "there was some signal of harm when this was used routinely, but among operators who use these devices and understand these devices, that might not be the wrong number. Again, that reflects that we're not using it routinely in most PCIs and we're not using it selectively in most PCIs — we're really using it in specific situations."

Jolly pointed out that bailout thrombus aspiration was allowed in the PCI-alone group of TOTAL and used in about 5% of cases. "Based on the trial results, that would make sense where we've landed," he said, adding that use at his institution has fallen from 50% to 60% before TOTAL to somewhere in the range of 5% to 7% today.

High-Risk Patients

A recent patient-level meta-analysis published by Jolly and the Thrombectomy Trialists Collaboration showed no overall benefit with thrombus aspiration, but there was a signal for reduced 30-day cardiovascular death at the cost of a clear increase in stroke in the subgroup of patients with a high thrombus burden.

In the registry's instrumental variable analysis, risk for in-hospital mortality was not significantly different between people treated with thrombus aspiration and those treated without it, but there was a small excess risk for in-hospital stroke among those receiving thrombectomy (adjusted risk difference, 0.14%; = .03).

At 30 and 180 days, risks were similar for death, stroke, heart failure, and hospital readmission in patients treated with and without thrombectomy.

Secemsky said he still uses aspiration thrombectomy (AT) in select cases and that it is useful to have tools to help interventionalists effectively get through a case.

"My take-home isn't to identify the super-selective opportunity for its use but to say we don't have data that say routine aspiration thrombectomy, and probably even in selective cases, is changing your clinical end points," he said.

In an accompanying editorial, Patrick O'Gara, MD, Brigham and Women's Hospital, Boston, and JAMA Cardiology deputy editor writes that "there are limitations to any observational study of this type, despite the use of sophisticated statistical modeling to account for unmeasured confounders. Nevertheless, justification for the use of AT is not forthcoming from this study."

"Whether an adequately powered randomized clinical trial of the use of AT either as a bailout strategy or in a preselected group of patients with high thrombus burden can be executed is uncertain," O'Gara said.

Before a new trial is launched, interventionalists need to work with their biomedical engineering colleagues to address the limitations of current technology, which is "basically a syringe with a tube," Jolly said.

"Patients with high thrombus burden, the people who you'd like to target, have much higher event rates than the rest of the population, so we still have an unmet need," he said.

"Once we've got an improved technology, then I think we need to target the high-risk populations and do a large trial to see if they truly avoid stroke and they can reduce mortality."

The study was funded by the National Cardiovascular Data Registry. Secemsky reports no relevant conflicts of interest. Coauthor Ajay Kirtane is associate editor of JAMA Cardiology but was not involved in any decisions regarding review or acceptance of the manuscript. Jolly reported institutional grant support from Medtronic and Boston Scientific. O'Gara reported no relevant conflicts of interest.

JAMA Cardiol. Published online January 9, 2019. Article, Editor's Note

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