The ACST-2 was designed to compare long-term outcomes of carotid artery stenting (CAS) vs carotid endarterectomy (CEA) in patients with asymptomatic stenosis.
Prior to this study we had the German registry including 18,000 patients undergoing CAS and 86,000 receiving CEA between 2014 and 2019. At 30 days, disabling stroke rate was 0.7% for both strategies.
The ACST-2 randomized 3,625 patients with severe unilateral or bilateral asymptomatic carotid artery stenosis (60% or more by echocardiography) in 130 centers across 33 countries.
All patients were considered good candidates for both strategies.
All other procedural aspects were left to operator criterion and all patients received optimal medical treatment.
As with prior studies and registries, around 1% presented disabling stroke (modified Rankin scale 3-5) or died in hospital in both arms.
As regards disabling stroke, and also as in prior studies, CAS presented more events (2.7% vs 1.6%; p=0.03). Most disabling strokes scored 0 or 1 in the modified Rankin scale.
After a mean 5 year follow up (excluding periprocedural events) fatal or disabling stroke rate resulted identical in both arms with 2.5% (p=0.91). On the other hand, from index procedure and 5 years after that, figures are quite similar (3.5% for CAE vs 3.4% for CAS).
The rate of any stroke unrelated to the procedure was slightly higher, though not significative, in the angioplasty arm (5.2% vs 4.5%; RR 1.16; CI 95% 0.86 to 1.57).
They are planning to followup patients for 10 years.
The subgroup analysis did not show differences when looking at age, sex or stenosis severity.
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The multidisciplinary approach in this study was essential, seeing as all participating centers, interventionists, surgeons and neurologists, agreed that patients could receive any of the strategies. This might not represent the daily practice in the real world.
Another important message to get from this study is the relatively high global mortality of the population (18% at 5 years). These figures speak of the high stenosis load of patients and the need to adjust treatment accordingly as much as possible.
This new study contributes to other 8 great studies previously published that had shown similar stroke incidence with both strategies, both in asymptomatic and symptomatic patients.
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What the ACST-2 left unanswered is something clinicians are debating. The questions around the need for revascularization. The entire ACST-2 population received one or the other revascularization strategy. The advances recently made in optimal medical treatment require further study for it to be incorporated as a third therapeutic option.
Original Title: Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy.
Reference: Presentado por Halliday A en el ESC 2021 y publicado simultáneamente en Lancet. 2021.
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