Kaustubh Limaye, MD

Mueller-Kronast NH, Zaidat OO, Froehler MT, Jahan R, Aziz-Sultan MA, Klucznik RP, et al. Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke: Primary Results of the STRATIS Registry. Stroke. 2017

It is possible to match “benchmark” workflow timings and clinical outcomes in a community setting for acute stroke patients with large vessel occlusion needing endovascular therapy.

The Systematic Evaluation of Patients Treated with Neurothrombectomy Devices for Acute Ischemic Stroke (STRATIS) registry sought to compare real-world patient workflow and outcome of patients with intracranial large vessel occlusion (LVO) requiring endovascular therapy (EVT). A total of 984 eligible patients with large vessel occlusion were enrolled at 55 different sites with an enrolling cap of 75 patients. Patients with pre-treatment modified Rankin score of 0-1, confirmed LVO, NIHSS≥8 with an intention to be treated with a Medtronic market-released neurothrombectomy device (Solitaire and Mindframe) as an initial device for stent assisted thrombectomy within 8 hours from symptom onset.

Out of 1000 patients enrolled, 16 were deemed to be screen failure resulting in intention to treat analysis of 984 patients. 64% of the patients enrolled received intravenous thrombolysis and mean NIHSS of the enrolled patients was 17. 45.2% of patients were transferred from another facility to the enrolling center. Mean distance from field to the enrolling site was 29 miles with 2/3rd of the patients <25 miles distance from enrolling site. The clinical trials for LVO needing EVT set a few important “benchmarks” for patient workflow: 1) onset to puncture time; 2) door to puncture time (DTP); 3) puncture to reperfusion time (PTR); and 4) the quality of substantial reperfusion (TICI ≥ 2b).

In the STRATIS registry, median onset to puncture time was 208 minutes, which is comparable to that noted in MR CLEAN (208 mins), EXTEND-IA (210 mins), SWIFT-PRIME (224 mins), and REVASCAT (269 mins). Median PTR time in STRATIS was 36 minutes, which is again comparable to ESCAPE (30 mins), EXTAND-IA (43 mins), and REVASCAT (59 mins). Lastly, the quality of reperfusion was also similar to that of clinical trials. In the STRATIS registry, 87.9% of patients had substantial reperfusion (TICI≥2b), which was better than that of MR CLEAN (59%), ESCAPE (72%), EXTEND-IA (86%), and REVASCAT (66%), and only SWIFT-PRIME reported slightly better rates of reperfusion (88%).

Study device–related serious adverse events were reported in 2 patients (2/984 = 0.2%, 1 carotid artery dissection and 1 subarachnoid hemorrhage), and 1.7 % of patients had procedure-related serious adverse events. Symptomatic intracranial hemorrhage was reported in 1.8% of patients in STRATIS, as compared to the intervention arms of MR CLEAN (6%), ESCAPE (4%), and REVASCAT (5%), with only SWIFT-PRIME (1%) and EXTEND-IA (0%) reporting less symptomatic hemorrhage cases.

STRATIS registry investigators were able to demonstrate that improving workflow by reducing delay in care by 60 minutes was associated with 5.5% absolute decline in achieving good outcome. High-volume centers (>30 patients) had significantly lower DTP time as compared to other centers (67 mins vs. 86 mins; P<0.001). They also were able to corroborate the REVASCAT data, which shows similar outcomes in patients treated between 6–8 hours as compared to those treated within 6 hours.

Quick and efficient field triage, prioritization of endovascular-ready stroke centers in transfer of patients with high suspicion of large vessel occlusion, reducing interfacility transfer time, and redesigning neuroangiography suite will hold the key in the future to further reducing workflow times. Furthermore, it should be noted that CT perfusion leads to better selection of patients and better outcomes (as corroborated by STRATIS data, that is despite the addition of 15.7 minutes to workflow times!). It remains to be seen if more inclusive criteria like “clinical – infarct mismatch” on CT ASPECTS is good enough to select patients for EVT with symptom onset < 6 hours and reserve CT-perfusion (with RAPID analysis) imaging only for 6–24 hrs. time window (DAWN Trial window).