Updated estimates of large and medium vessel strokes, mechanical thrombectomy trends, and future projections indicate a relative flattening of the growth curve but highlight opportunities for expanding endovascular stroke care.

BACKGROUND: A study was undertaken to determine the incidence of acute ischemic stroke (AIS) and strokes related to large (LVO) and medium (MVO) vessel occlusions, and to estimate annual mechanical thrombectomy (MT) volume, past trends and future growth. METHODS: A population-based analysis was performed to estimate the rate of AIS, LVOs (internal carotid artery terminus, M1 branch of the middle cerebral artery, basilar artery) and MVOs (M2 and M3 branches of the middle cerebral artery, anterior and posterior cerebral arteries). MT estimates were determined from multiple governmental data sources. Annual US numbers were adjusted for population growth. RESULTS: The incidence of AIS is estimated at 216 (95% CI 199 to 238)/100 000 persons/year or 718 191 (95% CI 661 483 to 791 121) AIS/year in the USA. A vascular occlusion was observed in 21% of patients with AIS (95% CI 15 to 29). The rate of LVO was 24/100 000 persons/year (95% CI 19 to 31) or 80 075 (95% CI 62 457 to 104 375) LVOs/year, and the rate of MVO was 20/100 000 persons/year or 65 798 (95% CI 45 555 to 95 110) MVOs/year. MT estimates for 2021 are 39 164 procedures with a flattening of the growth curve from 2019 (9%, 2020-2021; 4%, 2019-2020) as opposed to initial steep growth from 2015 to 2018. Current MT procedures represent 5% of all AIS, 27% of all vascular occlusions (LVO+MVO) and 38% of all LVO and M2 occlusions. The current trajectory indicates a future growth of 5-10%/year for the next several years. CONCLUSION: A decline in MT growth is observed. The incidence of LVO+MVO is estimated at 44/100 000 persons/year or almost 144 000 large and medium vessel strokes annually. Of these, currently an estimated 27% undergo an MT procedure, indicating an opportunity for growth. Further expansion may require focusing on the elderly, medium vessel strokes and workflow efficiencies from diagnosis to treatment.

Intravenous thrombolysis before endovascular therapy for large vessel strokes can lead to significantly higher hospital costs without improving outcomes.

BACKGROUND: Limited efficacy of IV recombinant tissue plasminogen activator (rt-PA) for large vessel occlusions (LVO) raises doubts about its utility prior to endovascular therapy. PURPOSE: To compare outcomes and hospital costs for anterior circulation LVOs (middle cerebral artery, internal carotid artery terminus (ICA-T)) treated with either primary endovascular therapy alone (EV-Only) or bridging therapy (IV+EV)). METHODS: A single-center retrospective analysis was performed. Clinical and demographic data were collected prospectively and relevant cost data were obtained for each patient in the study. RESULTS: 90 consecutive patients were divided into EV-Only (n=52) and IV+EV (n=38) groups. There was no difference in demographics, stroke severity, or clot distribution. The mean (SD) time to presentation was 5:19 (4:30) hours in the EV-Only group and 1:46 (0:52) hours in the IV+EV group (p<0.0001). Recanalization: EV-Only 35 (67%) versus IV+EV 31 (81.6%) (p=0.12). Favorable outcome: EV-Only 26 (50%) versus IV+EV 22 (58%) (p=0.45). For patients presenting within 4.5 hours (n=64): Recanalization: EV-Only 21/26 (81%) versus IV+EV 31/38 (81.6%) (p=0.93). Favorable outcome: EV-Only 14/26 (54%) versus IV+EV 22/38 (58%) (p=0.75). There was no significant difference in rates of hemorrhage, mortality, home discharge, or length of stay. A stent retriever was used in 67 cases (74.4%), with similar recanalization, outcomes, and number of passes in the EV-Only and IV+EV groups. The mean (SD) total hospital cost was $33 810 (13 505) for the EV-Only group and $40 743 (17 177) for the IV+EV group (p=0.02). The direct cost was $23 034 (8786) for the EV-Only group and $28 711 (11 406) for the IV+EV group (p=0.007). These significantly higher costs persisted for the subgroup presenting in <4.5 hours and the stent retriever subgroup. IV rt-PA administration independently predicted higher hospital costs. CONCLUSIONS: IV rt-PA did not improve recanalization, thrombectomy efficacy, functional outcomes, or length of stay. Combined therapy was associated with significantly higher total and direct hospital costs than endovascular therapy alone.

A population-based incidence of M2 strokes indicates potential expansion of large vessel occlusions amenable to endovascular therapy.

BACKGROUND: M2 occlusions may result in poor outcomes and potentially benefit from endovascular therapy. Data on the rate of M2 strokes is lacking. METHODOLOGY: Patients with acute ischemic stroke discharged over a period of 3 years from a tertiary level hospital in the 'stroke belt' were evaluated for M2 occlusions on baseline vascular imaging. Regional and national incidence was calculated from discharge and multicounty data. RESULTS: There were 2739 ICD-9 based AIS discharges. M2 occlusions in 116 (4%, 95% CI 3.5% to 5%) patients constituted the second most common occlusion site. The median National Institute of Health Stroke Scale (NIHSS) score was 12 (IQR 5-18). Good outcomes were observed in 43% (95% CI 34% to 53%), poor outcomes in 57% (95% CI 47% to 66%), and death occurred in 27% (95% CI 19% to 37%) of patients. Receiver operating characteristics curves showed the NIHSS to be predictive of outcomes (area under the curve 0.829, 95% CI 0.745 to 0.913, p<0.0001). An NIHSS score ≥9 was the optimal cut-off point for predicting poor outcomes (sensitivity 85.7%, specificity 67.4%). 71 (61%) patients had an NIHSS score ≥9 and 45 (39%) an NIHSS score <9. The rate of good-outcome was 22.6% for NIHSS score ≥9 versus 78.4% for NIHSSscore <9 (OR=0.08, 95% CI 0.03 to 0.21, p<0.0001). Mortality was 42% for NIHSS score ≥9 versus 2.7% for NIHSS score <9 (OR=26, 95% CI 3.3 to 202, p<0.0001). Infarct volume was 57 (±55.7) cm3 for NIHSS score ≥9 versus 30 (±34)cm3 for NIHSS score <9 (p=0.003). IV recombinant tissue plasminogen activator (rtPA) administered in 28 (24%) patients did not affect outcomes. The rate of M2 occlusions was 7 (95% CI 5 to 9)/100 000 people/year (3%, 95% CI 2% to 4%), giving an incidence of 21 176 (95% CI 15 282 to 29 247)/year. Combined with M1, internal carotid artery terminus and basilar artery, this yields a 'large vessel occlusion (LVO)+M2' rate of 31 (95% CI 26 to 35)/100 000 people/year and a national incidence of 99 227 (95% CI 84 004 to 112 005) LVO+M2 strokes/year. CONCLUSION: M2 occlusions can present with serious neurological deficits and cause significant morbidity and mortality. Patients with M2 occlusions and higher baseline deficits (NIHSS score ≥9) may benefit from endovascular therapy, thus potentially expanding the category of acute ischemic strokes amenable to intervention.

A population-based incidence of acute large vessel occlusions and thrombectomy eligible patients indicates significant potential for growth of endovascular stroke therapy in the USA.

BACKGROUND: Data on large vessel strokes are important for resource allocation and infrastructure development. OBJECTIVE: To determine an annual incidence of large vessel occlusions (LVOs) and a thrombectomy eligible patient population. METHODS: All patients with acute ischemic stroke discharged over 3 years from a tertiary-level hospital serving a large geographic area were evaluated for an LVO (M1, internal carotid artery terminus, basilar artery). The incidence of LVO was determined for the hospital's 4-county primary service area (PSA, population 210 000) based on each county's discharges and extrapolated to the US population. 'Thrombectomy eligibility' for anterior circulation LVOs was based on time (onset <6 hours) and imaging (Alberta Stroke Program Early CT Score (ASPECTS) ≥6). The number of annual thrombectomy procedures was calculated for Medicare and private payer patients using federally available databases. RESULTS: 1157 patients were discharged from the hospital's PSA, of whom 129 (11.1%, 95% CI 9.5% to 13.1%) had an LVO. This translated into an LVO incidence of 24 per 100 000 people per year (95% CI 20 to 28). 20 per 100 000 people per year had anterior circulation LVOs (95% CI 19 to 22), of whom 10/100 000/year (95% CI 8 to 11) were 'thrombectomy eligible'. An additional 5/100 000/year (95% CI 3 to 6) presented with favorable ASPECTS after 6 hours of symptom onset. Basilar occlusion incidence was estimated at 4/100 000/year (95% CI 2 to 5). These rates yield 77 569 (95% CI 65 835 to 91 091) new LVOs per year in the USA. An estimated 10 284 mechanical thrombectomy procedures were performed in 2015. CONCLUSIONS: This study estimates an LVO incidence of 24 per 100 000 person-years (95% CI 20 to 28). A current estimated annual thrombectomy rate of three procedures per 100 000 people indicates significant potential increase in the volume of endovascular procedures and the need to develop systems of care.