Endovascular Thrombectomy Practice Pattern Across The Nihss Spectrum

Background: Endovascular thrombectomy (EVT) after Ischemic Stroke (AIS) has shown to improve outcomes in multiple large clinical trials. However, most guidelines recommend EVT for patients with NIHSS greater than 5 and caution EVT in severe stroke. We analyzed data from a stroke registry to learn about ‘real-world’ use of EVT across stroke serverity. Most clinical trials focus on academic medical centers. Our analysis reports on data from all centers within a region. Methods: The San Diego County EMS Stroke Registry represents data from 10 EVT ready centers. We included all AIS cases with NIHSS between 0 and 42 from July 2016 through December 2018. Patients were grouped into three categories: 1) NIHSS 0-5, 2) 6-25, 3) 26-42. We analyzed frequency of EVT use, last known normal (LKN) to skin puncture time, admission NIHSS in EVT cases, and hospital discharge dispositon of EVT cases. Results: Of 7,050 AIS cases, 662 (9.4%) received EVT from July 2016 to December 2018. Group (G) 1: 80 of 4184 cases received EVT (1.9%), G2: 470 of 2502 cases received EVT (18.8%), G3: 112 of 364 cases received EVT (30.8%). Rate of EVT in all AIS and for each NIHSS group did not change (all AIS: p=.24, G1: p=.59, G2: p=.15, G3: p=.57). Mean (±SD) NIHSS among all AIS was 7.4 (±8.5); among EVT cases it was 17.2 (±8.6). Mean (±SD) LKN to skin puncture (hours) was G1: 9.2 (±12.1), G2: 5.8 (±5.8), G3: 5.5 (±5.3) (p=.000001). Mean (±SD) age (years) of EVT cases was G1: 65.5 (±15.4); G2: 71.9 (±15.6); , G3: 77.1 (±14.0) (p=.00001). Discharge to home among EVT cases was Group 1: 50.0%; 2) 26.5%; 3) 9.8%; to a non-acute health care facility: G1) 28.8%, 2) 39.5%, 3) 44.6%); in-hospital death 1) 10.0%, 2) 13.6%, 3) 25.0%. Conclusion: Patients with mild and severe stroke present a significant subpopulation of patients undergoing EVT in this sample. Overall, one in three stroke patients with NIHSS above 25 underwent EVT; less than one in five stroke patients with low NIHSS underwent EVT. Over time there has been no change in the number of patients receiving EVT and no change in EVT use within NIHSS groups. Half of patients with low NIHSS were discharged home; one in four patients with high NIHSS expired in hospital. As hospitals embraced EVT, the use of the procedure among patients with low or high NIHSS has remained consistent.