Research in context
Evidence before this study
We searched MEDLINE for studies published between Jan 1, 2014, and Jan 1, 2019, using any combination of two of the following search terms with no language restrictions: “stroke”, “thrombectomy”, or “randomized trial”. This search yielded ten randomised trials providing evidence that thrombectomy was superior to medical therapy for treatment of emergent large-vessel stroke. However, all but one study were primarily based upon stent retriever technology; the tenth study, THERAPY, failed to meet its primary endpoint. ASTER is the only reported trial that used aspiration thrombectomy as a first pass approach versus stent retriever as a first line approach, and it failed to meet its primary endpoint of angiographic superiority for aspiration thrombectomy as first pass. As a result, it is unclear whether the benefit of thrombectomy is unique to a single approach–stent retriever as first line or whether alternate approaches to thrombectomy would also confer a clinical benefit. Whether stent retrievers are a necessary component for successful thrombectomy is hotly debated internationally, as most clearly evidenced by the variable language used across multiple society clinical guidelines.
Added value of this study
COMPASS was a North American, prospective, multicentre, masked assessor, randomised trial assessing the non-inferiority of aspiration thrombectomy as first pass versus stent retriever as first line for large vessel occlusion. COMPASS directly addressed whether stent retrievers are necessary for successful thrombectomy, with strongly positive results.
Implications of all the available evidence
COMPASS, with the supportive but non-clinically focused ASTER results, provides level 1 data that an aspiration thrombectomy as first pass approach is non-inferior to a stent retriever as first line approach for the treatment of selected patients with acute large vessel ischaemic stroke. This finding will be of broad interest to all stroke physicians and might directly affect current stroke treatment guideline recommendations. Furthermore, these data have the potential to substantially reduce the cost of thrombectomy procedures worldwide.