Registry Behind TASTE Reopens Thrombus Aspiration Question With New Analysis of Stent Thrombosis
WASHINGTON, DC—Thrombus aspiration during primary PCI for STEMI may have no impact on mortality, but new data hint that it may, in fact, reduce the risk of stent thrombosis within the first 30 days. What’s more, those insights come from SCAAR, the same large, Swedish registry that helped deliver one of the hardest knocks to thrombectomy in STEMI in the first place.
Importantly, the analysis also showed no increased risk of stroke with thrombus aspiration—a lingering concern from the TOTAL trial, which saw a two-fold risk in stroke among STEMI patients treated with thrombus aspiration plus PCI compared with those who underwent PCI only. In TASTE, by contrast, there was no signal of increased stroke risk, but there was a trend towards reduced stent thrombosis risk when thrombectomy was used.
Elmir Omerovic, MD, PhD, of Sahlgrenska University Hospital (Gothenburg, Sweden), presented the new analysis here at CRT 2016.
As previously reported by TCTMD, TASTE used a unique “randomized-registry” design wherein more than 7,000 patients were randomized to PCI with or without thrombus aspiration within 29 hospitals in Sweden. Participation in the Swedish Coronary Angiography and Angioplasty Registry is mandatory for all Swedish hospitals. (Two additional hospitals, 1 in Iceland and 1 in Denmark, also participated in TASTE). The negative results from TASTE, coupled with those from INFUSE-AMI and TOTAL, were recently used to update US guidance from the major American cardiology professional societies.
“The argument is that there is no mortality benefit of thrombus aspiration in primary PCI, based on 2 recent randomized clinical trials, TASTE and TOTAL, and I think it’s fair to say ‘granted’ to that argument,” Omerovic said here. “However, the question remains, is there a benefit of thrombus aspiration in PCI beyond mortality?”
To answer this, Omerovic and colleagues reviewed the SCAAR database looking at all STEMI procedures between 2005-2014, including those randomized in TASTE as well as those treated outside the trial. In all, 10,653 patients had thrombus aspiration during their PCI procedures, compared with 31,992 treated with PCI only.
As Omerovic showed here, mortality at 30 days and 1 year was no different between groups, reflecting what has also been seen in the major trials. In-hospital stroke rate also was identical between groups. For stent thrombosis, however, investigators saw a nearly three-fold higher relative risk among patients undergoing PCI only as compared with PCI plus thrombus aspiration (0.6% vs 0.4%, RR 2.9, P < .001).
In a landmark analysis, the difference in stent thrombosis was seen in the first 30 days, but not thereafter.
Finally, in what Omerovic characterized as “supporting evidence,” investigators charted thrombectomy use over the 10-year study window and superimposed this graph over rates of stent thrombosis over the same period. That exercise showed that from 2010-2012, when use of thrombus aspiration was at its highest, stent thrombosis rates fell to their lowest of the study period.
This “supports the conclusion that there might be some positive association between thrombectomy and [stent thrombosis],” he said.
Cost and Patient Selection
The findings offer an olive branch to operators who have been reluctant to leave behind visible thrombus during STEMI, something Omerovic acknowledged in his remarks. “I think at the end of the day it will be an issue of cost effectiveness. If the companies who make these devices lower the price, and we actually go into the data and see which patients are actually . . . more prone to benefit, we could find a group of patients who could benefit from this. I would argue that totally saying this has no benefit and it only adds cost and risk, I don’t think that that argument stands, at least in the current state of our knowledge.”
In discussion following the presentation, session co-moderator, Ron Waksman, MD, MedStar Washington Hospital Center (Washington, DC), observed: “This looks like a positive study, to me, of thrombus aspiration.”
Co-moderator Eberhard Grube, MD, University Hospital Bonn (Siegburg, Germany), seemed to agree, admitting that he personally, despite the randomized controlled evidence to the contrary, tends to act on instinct. “When I see someone coming in with an acute infarct, and . . . there is a thrombus, I take it out. I know it’s not supported, but I will still go for it,” he stated.
Asked by TCTMD whether it was worth worrying about stent thrombosis if there were no differences in death, MI, or stroke, Waksman said: “Stent thrombosis is never a wanted event.” He believes the results will make sense, in select cases, to interventionalists who have intuitively resisted the major trial results. “The dust has not yet settled on thrombus aspiration,” he predicted.
Omerovic E. Impact of thrombus aspiration on mortality, stent thrombosis, and stroke in patients with STEMI: a report from the SCAAR registry. Presented at: CRT; February 21, 2016; Washington, DC.
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- The SCAAR registry is 100% funded by Swedish health authorities.
- Omerovic reports institutional grants from AstraZeneca and Abbott and consulting fees/honoraria from AstraZeneca and Medtronic.
- Grube discloses being a consultant and speaker for Biosensors, Boston Scientific, Claret, Cordis, Direct Flow, InSeal Medical, Medtronic, and Mitralign.
- Waksman is the course chairman for CRT; he reports no disclosures.