Coronary Clot Aspiration Provides No MI Survival Benefit

Thrombectomy did not improve outcomes for myocardial infarct (MI) patients presenting after symptom onset, according to a new study.

Researchers at University College London (UCL; United Kingdom), the University of Manchester (United Kingdom), and other institutions conducted a retrospective study based on a UK national registry to examine thrombectomy use in ST-segment elevation MI (STEMI) patients and relationship to overall mortality. In all, 98,176 patients treated via percutaneous coronary intervention (PCI) were grouped on the basis of whether they received thrombectomy or not; subgroups of simple (manual aspiration) and complex (mechanical) thrombectomy were also evaluated.

The results showed no significant mortality difference between the overall thrombectomy group and the no thrombectomy group, either at 30 days or at one year. Likewise, no difference was seen between the simple thrombectomy versus no thrombectomy. The complex thrombectomy group, on the other hand, demonstrated significantly higher mortality at one-year follow-up. The researchers observed that thrombectomy use markedly increased in the United Kingdom between 2008 and 2010, but plateaued thereafter at slightly below 50% of all primary PCI cases. The study was published in the January 2016 issue of JACC: Cardiovascular Interventions.

“Our large observational study does not provide evidence to support the hypothesis that selective thrombectomy in primary PCI is associated with lower mortality,” concluded lead author Alex Sirker, MB BChir, and colleagues. “Our findings are in keeping with other negative clinical outcomes from two recent large randomized controlled trials studying routine thrombectomy use in STEMI.”

“Thrombus removal remains an intuitively valid concept; however, thrombus removal is more complex than initially appreciated,” added Dharam Kumbhani, MD, of the University of Texas Southwestern Medical Center (Dallas, USA) and Anthony Bavry, MD, of the University of Florida, (Gainesville, USA), in a related editorial. “Future studies will need to similarly rigorously evaluate the role of selective thrombectomy versus no thrombectomy, determine more effective thrombectomy devices, and better discriminate appropriate lesions to which this therapy can be applied.”

Thrombectomy with aspiration of thrombus prior to PCI is thought to prevent distal embolization and improve microvascular perfusion. But although electrocardiographic and angiographic outcomes improve with thrombectomy, such as an increased ST-segment resolution and a decreased distal embolization, no clinical benefits have been shown. One recent large study even found that the risk of stroke actually increased by 66%.

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