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Bozorgchami, Hormozd

Mayo Clinic

Oregon Health & Science University

Citations 8

EXCELLENT Registry: A Prospective, Multicenter, Global Registry of Endovascular Stroke Treatment With the EMBOTRAP Device
Nogueira, Raul G. , Andersson, Tommy , Haussen, Diogo C , Yoo, Albert J. , Hanel, Ricardó A. , Zaidat, Osama O. , Hacke, Werner , Fiehler, Jens , Brinjikji, Waleed , Doyle, Karen , Kallmes, David F. , Liebeskind, David S. , Kokoszka, Malgosia A., Inoa, Violiza , Humphries, William, Woodward, Keith, Bozorgchami, Hormozd, Boor, Stephan , Cohen, José E. , Taqi, Muhammad , Budzik, Ronald F. , Hussain, M. Shazam , Estrade, Laurent , Puri, Ajit S., Brekenfeld, Caspar , Siddiqui, Adnan H. , Jovin, Tudor G , Fiehler, Jens , De Meyer, Simon F , Brinjikji, Waleed , Doyle, Karen M , Liebeskind, David S. , Virmani, Renu , Inoa, Violiza , Jabbour, Pascal , Levy, Elad I , Boor, Stephan , Cohen, Jose E , Dashti, Shervin R , Schirmer, Clemens M , Estrade, Laurent , De Leacy, Reade , Chitale, Rohan V , Brekenfeld, Caspar , Siddiqui, Adnan H , Andersson, Tommy , Hanel, Ricardo A , Nogueira, Raul G , Yoo, Albert J , Jovin, Tudor G. , Virmani, Renu , Jabbour, Pascal , François, Olivier , Levy, Elad I. , Schirmer, Clemens M. , Leacy, Reade De , Puri, Ajit S

Stroke | November 19, 2024 | Volume: 55 | Issue: 12 | Pages: 2804-2814

10.1161/strokeaha.124.047324 Get It

BACKGROUND: The EXCELLENT registry aimed to evaluate the effectiveness of the EMBOTRAP Revascularization Device in an all-comer population in a real-world setting, with a focus on the composition of retrieved clots. METHODS: EXCELLENT is a prospective, global registry of patients with acute ischemic stroke treated with EMBOTRAP as the first-line mechanical thrombectomy device conducted at 34 sites (25 sites contributing clot) from September 2018 to March 2021, utilizing core imaging and central histology laboratories blinded to clinical data, independent 90-day modified Rankin Scale assessment and Clinical Events Committee. RESULTS: After screening 3799 patients, a total of 997 subjects (mean age, 70.0±14.2 years; 51.8% women; 19.7% non-White) were included. The first-pass modified Treatment in Cerebral Infarction (mTICI) ≥2b rate was 64.5% (623/966), first-pass mTICI ≥2c was 39.1% (378/966), and final mTICI ≥2b was 94.5% (931/985). A total of 427/912 (46.8%) patients achieved a 90-day modified Rankin Scale of 0 to 2 or ≤baseline. Embolization to a new territory occurred in 0.2% (2/984), and symptomatic intracranial hemorrhage at 24 hours in 1.6% (16/997). The 90-day mortality was 19.1% (175/918). Device- and/or procedure-related serious adverse events occurred in 5.9% (54/912) through 90 days. The mean RBC percentage of retrieved clots was 45.62±21.372. Among patients who achieved mTICI ≥2b with the first pass, 15.7% (52/331) and 9.7% (32/331), respectively, had RBC-poor (<25%) and RBC-rich (>75%) clots. Patients with no clot retrieved in any procedural pass had a lower percentage of hyperdense or susceptibility vessel sign on baseline imaging (58.9% versus 74.7%; P <0.001), pointing to a potential preprocedure indicator of challenging clot. CONCLUSIONS: The EXCELLENT registry informs real-world practices in mechanical thrombectomy and sheds light on the range of clots effectively retrieved by current technology. This is the first report of detailed patient characteristics where mechanical thrombectomy maneuvers failed to remove any clot material. Although the composition of nonretrievable clots cannot be assessed histologically, the results support the notion that no retrieval may be correlated with imaging findings suggesting clots lower in RBC. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03685578.
Degree of Stenosis by Angiography Does Not Influence Risk of Endarterectomy or Stenting in Patients with Severe Asymptomatic Carotid Stenosis (P1.236)
Brott, Thomas G. , Lal, Brajesh K. , Voeks, Jenifer H. , Heck, Donald , Brooks, William H. , Bozorgchami, Hormozd, Roubin, Gary S., Brooks, William

Neurology | December 7, 2023 | Volume: 86 | Issue: 16_supplement | Pages: No page available

10.1212/wnl.86.16_supplement.p1.236 Get It

Abstract Number ‐ 7: Final Angiographic, Clinical and Thrombus Composition Results of 1000 Patients in the EXCELLENT Registry
Zaidat, Osama O. , Hacke, Werner, Brinjikji, Waleed , Doyle, Karen, Inoa, Violiza , Humphries, William, Woodward, Keith, Bozorgchami, Hormozd, Boor, Stephan , Cohen, José E. , Taqi, Muhammad , Budzik, Ronald F. , Hussain, Shazam, Estrade, Laurent , Puri, Ajit S , Brekenfeld, Caspar , Nogueira, Raul G. , Andersson, Tommy , Yoo, Albert J. , Hanel, Ricardó A. , Jovin, Tudor G. , Fiehler, Jens , De Meyer, Simon F , Liebeskind, David S. , Haussen, Diogo C , Jabbour, Pascal , François, Olivier , Levy, Elad I. , Dashti, Shervin R , Schirmer, Clemens M. , Leacy, Reade De , Chitale, Rohan V , Siddiqui, Adnan H.

Stroke: Vascular and Interventional Neurology | April 25, 2023 | Volume: 3 | Issue: S1 | Pages: No page available

10.1161/svin.03.suppl_1.007 Get It

Introduction EXCELLENT (NCT03685578; Cerenovus) is a large, prospective, international, real‐world registry of endovascular clot removal in acute ischemic stroke (AIS) with EmboTrap as the first line mechanical thrombectomy (MT) device, which included collection and analysis of the retrieved thrombus material. Methods Between September 2018 and March 2021, 1000 “all‐comer” patients were enrolled at 34 global sites (27 US, 5 EU, 1 UK, 1 Israel) and treated according to standard of care at each center (with Embrotrap as first line). The study employed blind endpoint evaluation, including a core imaging lab and an independent 90‐day mRS assessment. Retrieved clot was collected per each MT maneuver from 538 subjects across 26 sites and clot analysis was performed by independent central labs blinded to clinical data. Results mITT population included 998 subjects. Mean age was 69.9±14.18 years (range 18–102), 51.8% (517/998) subjects were female and 9.9% (97/997) had a pre‐stroke mRS 3–5. Baseline NIHSS was 15.6±6.87 (range 0–36); 10.1% (82/815) subjects had a large core (ASPECTS 0–5); 5.8% (57/990) had posterior stroke; 56.3% (523/929) underwent MT ≤ 6hrs of onset and 38.1% (380/998) received IV‐tPA prior to MT. First pass eTICI 2c‐3 was achieved in 38.3% (377/984) and final 2b‐3 in 94.5 % (930/984; median number of passes = 1) of subjects. 90‐day mRS≤2 or ≤pre‐stroke was 46.9% (429/915) and 90‐day all‐cause mortality was 19.0% (175/921). The univariate analysis of clot components showed high red blood cell and low platelet content were significant predictors of good mRS outcome (p < 0.001 and 0.009) and negative predictors of 90‐day mortality (p < 0.001 and 0.017, respectively). Conclusions This large multi‐center, all‐comer cohort reflects the population undergoing thrombectomy today in a real world‐setting. Final angiographic, clinical and thrombus composition results, along with multivariate analysis of predictors of clinical outcomes, will be presented at the time of the conference.
Abstract 28: First Pass Outcomes And Associated Clot Characteristics: Secondary Analysis Of The Excellent Registry
Zaidat, Osama O. , Hacke, Werner, Jovin, Tudor G. , Brinjikji, Waleed , Doyle, Karen, Inoa, Violiza , Humphries, William, Woodward, Keith, Bozorgchami, Hormozd, Boor, Stephan , Cohen, José E. , Taqi, Muhammad , Budzik, Ronald F. , Hussain, M. Shazam , Estrade, Laurent , Puri, Ajit S , Brekenfeld, Caspar , Jovin, Tudor G , Andersson, Tommy , Nogueira, Raul G. , Yoo, Albert J. , Hanel, Ricardó A. , Fiehler, Jens , De Meyer, Simon F , Liebeskind, David S. , Haussen, Diogo C , Jabbour, Pascal , François, Olivier , Levy, Elad I. , Dashti, Shervin R , Schirmer, Clemens M. , Leacy, Reade De , Chitale, Rohan V , Siddiqui, Adnan H.

Stroke | February 2, 2023 | Volume: 54 | Issue: Suppl_1 | Pages: No page available

10.1161/str.54.suppl_1.28 Get It

Introduction: EXCELLENT (NCT03685578) is a global prospective, multicenter, real-world registry of mechanical thrombectomy for stroke with the EmboTrap device as first line treatment which includes clot collection and analysis. Aim of the study: To report the rates of clinical outcomes and clot characteristics associated with first pass reperfusion in EXCELLENT. Methods: Per pass angiographic outcomes assessed by an independent core lab were available in 984 subjects Analysis of clot from 538 cases was performed by independent central labs blinded to clinical data. 90-day mRS assessment was blinded to subject data. Results: First pass reperfusion of mTICI 2b-3 (63.2%) and 2c-3 (38.3%) was significantly predictive of mRS 0-2 or ≤pre-stroke (p=0.011 and p=0.016) but not all-cause mortality at 90 days (p=0.080 and p=0.123, respectively). Further, mTICI 2c-3 in one pass was associated with a higher rate of mRS 0-2 or ≤pre-stroke vs. mTICI 2c-3 reperfusion in >1 pass, (55.5% and 45.1%, respectively, p=0.013) and a rate of all-cause mortality at 90 days of 14.6% vs. 19.8% (p=0.097). Full patient characteristics and clinical outcomes are shown in Table 1. Notable clot composition findings included: RBC (%, mean±SD): mTICI 2c-3, 1 pass 47.69±22.25, mTICI 2c-3, >1 pass 43.86±19.05, (p=0.088); fibrin: mTICI 2c-3, 1 pass 23.20±13.80, mTICI 2c-3 >1 pass 25.40 ± 13.52 (p=0.131); von Willebrand factor (VWF): mTICI2c-3, 1 pass 16.09±14.62, mTICI 2c-3, >1 pass 19.42±17.15 (p=0.038). Conclusions: First pass reperfusion in the EXCELLENT registry was associated with better clinical outcomes at 90 days. Clots retrieved with first pass reperfusion had higher RBC and lower fibrin and VWF content compared to those who achieved reperfusion at greater than one pass.
Abstract TP131: Degree of Stenosis by Angiography Does not Influence Risk of Endarterectomy or Stenting in Patients With Severe Asymptomatic Carotid Stenosis
Roubin, Gary S., Lal, Brajesh K. , Voeks, Jenifer H. , Heck, Donald , Brooks, William H. , Bozorgchami, Hormozd, Brott, Thomas G. , Investigators, for the CREST, Brooks, William H, Investigators, for the CREST

Stroke | March 20, 2022 | Volume: 47 | Issue: suppl_1 | Pages: No page available

10.1161/str.47.suppl_1.tp131 Get It

Introduction: Increasing stenosis has been questioned as a factor increasing risk of carotid endarterectomy (CEA) or carotid stenting (CAS) in patients with severe asymptomatic carotid stenosis. Hypothesis: Greater severity of carotid stenosis is associated with higher rates of periprocedural stroke and death following revascularization for asymptomatic patients. Methods: Asymptomatic patients with carotid stenosis ≥ 70% by ultrasound or ≥ 60% by angiogram were eligible for the Carotid Revascularization Endarterectomy vs Stenting Trial (CREST). Patients who had a catheter-angiogram were divided into tertiles based on the degree of stenosis. Outcomes were the occurrence of any stroke or death at 30 days. Proportional hazards models adjusting for age and treatment were used to assess risk of 30 day stroke or death by tertile of stenosis. Results: Among 1181 asymptomatic patients, qualifying angiograms were done for 662 patients who had assigned procedure performed within 30 days of randomization. Median % stenosis was 62.6, 73.4, and 83.0 for the tertiles that otherwise differed only for female sex (40% female in tertile 1, 36% in tertile 2, 29% in tertile 3, p=0.01). The 30-day stroke and death rates did not differ significantly by severity of stenosis (Table), but the number of stroke and deaths was only 14 across the tertiles (Table). Similarly meaningful comparison of CEA vs CAS was not possible. Conclusion: This is the largest contemporary study of carotid angiograms performed in patients with severe asymptomatic carotid stenosis. No relationship was detected between severity of stenosis and 30-day stroke and death. The safety of CEA and CAS in asymptomatic patients limits detection of other factors that may increase risk because so few events complicate these procedures.
The Hydrogel Endovascular Aneurysm Treatment Trial (HEAT): A Randomized Controlled Trial of the Second-Generation Hydrogel Coil
Bendok, Bernard R. , Abi-Aad, Karl R., Ward, Jennifer , Kniss, Jason F , Kwasny, Mary , Rahme, Rudy J. , Aoun, Salah G. , Tecle, Najib E. El , Zammar, Samer G. , Aoun, Rami James N. , Patra, Devi Prasad, Raymond, Jean , Woo, Henry H. , Dabus, Guilherme , Milot, Geneviève , Scott, John A. , DeNardo, Andrew , Investigators, HEAT Study, Lavine, Sean D., Bozorgchami, Hormozd, Veznedaroglu, Erol, Albuquerque, Felipe C. , Fiorella, David, Boulos, Alan S. , Cortes, Maria, Kanaan, Hilal, Jindal, Gaurav , Klucznik, Richard , Kalmes, David, Xavier, Andrew, Hussain, Muhammad , Moran, Christopher J. , Adel, Brian van , Milot, Genevieve, Hirsch, Joshua A , Carpenter, Jeffrey , Powers, Ciarán J. , Luh, George, Tummala, Ramanchandra, Evans, Avery J. , Garg, Ankur, James, Roberts, Sauvageau, Eric , Fields, Jeremy D. , Grobelny, Thomas, Hartman, J., Patra, Devi P. , Bendok, Bernard R , Ward, Jennifer D, Ahmadieh, Tarek Y. El , Ansari, Sameer A. , Fiorella, David , Dabus, Guilherme C. , Almandoz, Josser E Delgado , Dashti, Shervin R , Investigators, HEAT Study, Deshaies, Eric Michael , Fiorella, David, Tawk, Rabih G. , Romero, Charles, Kelly, Michael , Chaudry, Imran , Pandey, Aditya S , Wang, Dennis Y.Q. , Milot, Genevieve, Jabbour, Pascal , Shankar, Jai , Patsalides, Athos T , Lee, Sung , James, Robert F. , Jayaraman, Mahesh V. , Satti, Sudhakar R

Neurosurgery | February 10, 2020 | Volume: 86 | Issue: 5 | Pages: 615-624

10.1093/neuros/nyaa006 Get It

Abstract BACKGROUND Aneurysm recurrence after coiling has been associated with aneurysm growth, (re)hemorrhage, and a greater need for follow-up. The second-generation HydroCoil Embolic System (HES; MicroVention, Inc) consists of a platinum core with integrated hydrogel and was developed to reduce recurrence through enhancing packing density and healing within the aneurysm. OBJECTIVE To compare recurrence between the second-generation HES and bare platinum coil (BPC) in the new-generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT). METHODS HEAT is a randomized, controlled trial that enrolled subjects with ruptured or unruptured 3- to 14-mm intracranial aneurysms amenable to coiling. The primary endpoint was aneurysm recurrence using the Raymond-Roy scale. Secondary endpoints included minor and major recurrence, packing density, adverse events related to the procedure and/or device, mortality, initial complete occlusion, aneurysm retreatment, hemorrhage from target aneurysm during follow-up, aneurysm occlusion stability, and clinical outcome at final follow-up. RESULTS A total of 600 patients were randomized (HES, n = 297 and BPC, n = 303), including 28% with ruptured aneurysms. Recurrence occurred in 11 (4.4%) subjects in the HES arm and 44 (15.4%) subjects in the BPC arm ( P = .002). While the initial occlusion rate was higher with BPC, the packing density and both major and minor recurrence rates were in favor of HES. Secondary endpoints including adverse events, retreatment, hemorrhage, mortality, and clinical outcome did not differ between arms. CONCLUSION Coiling of small-to-medium aneurysms with second-generation HES resulted in less recurrence when compared to BPC, without increased harm. These data further support the use of the second-generation HES for the embolization of intracranial aneurysms. Video Abstract
Impact of Balloon Guide Catheter Use on Clinical and Angiographic Outcomes in the STRATIS Stroke Thrombectomy Registry
Zaidat, Osama O. , Mueller‐Kronast, Nils , Hassan, Ameer E , Jadhav, Ashutosh P. , Froehler, Michael T. , Aziz‐Sultan, Mohammad Ali , Klucznik, Richard , Hellinger, Frank R, Yavagal, Dileep R. , Yao, Tom L., Gupta, Rishi , Martin, Coleman, Bozorgchami, Hormozd, Kaushal, Ritesh , Gandhi, Ravi H. , Peterson, Eric C. , Given, Curtis A., Mehta, Brijesh , Deshmukh, Vivek R., Starkman, Sidney , Linfante, Italo , McPherson, Scott H., Kvamme, Peter , Grobelny, Thomas, Hussain, Muhammad Shazam , Thacker, Ike, Vora, Nirav , Monteith, Stephen J., Ecker, Robert D., Schirmer, Clemens M. , Sauvageau, Eric , Chebl, Alex , Derdeyn, Colin P. , Maidan, Lucian, Badruddin, Aamir , Siddiqui, Adnan H. , Dumont, Travis M., Alhajeri, Abdulnasser, Taqi, Muhammad , Asi, Khaled, Carpenter, Jeffrey , Boulos, Alan S. , Jindal, Gaurav , Puri, Ajit S , Robinson, David , Kallmes, David F. , Baxter, Blaise, Jumaa, Mouhammad , Sunenshine, Peter, Majjhoo, Aniel, English, Joey , Fessler, Richard D., Delgado-Almandoz, Josser, Martin, Jerry C., Liebeskind, David S. , Investigators, on behalf of the STRATIS, Liebeskind, David S. , Siddiqui, Adnan H , Hassan, Ameer E , Schirmer, Clemens M , Jadhav, Ashutosh P , Haussen, Diogo C , Jahan, Reza , Saver, Jeffrey L. , Nogueira, Raul G. , Dashti, Shervin R , Chen, Peng R , Chitale, Rohan V , Deshaies, Eric Michael , Suzuki, Shuichi , Investigators, on behalf of the STRATIS, Derdeyn, Colin P

Stroke | February 19, 2019 | Volume: 50 | Issue: 3 | Pages: 697-704

10.1161/strokeaha.118.021126 Get It

Background and Purpose— Mechanical thrombectomy has been shown to improve clinical outcomes in patients with acute ischemic stroke. However, the impact of balloon guide catheter (BGC) use is not well established. Methods— STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter study of patients with large vessel occlusion treated with the Solitaire stent retriever as first-line therapy. In this study, an independent core laboratory, blinded to the clinical outcomes, reviewed all procedures and angiographic data to classify procedural technique, target clot location, recanalization after each pass, and determine the number of stent retriever passes. The primary clinical end point was functional independence (modified Rankin Scale, 0–2) at 3 months as determined on-site, and the angiographic end point was first-pass effect (FPE) success rate from a single device attempt (modified Thrombolysis in Cerebral Infarction, ≥2c) as determined by a core laboratory. Achieving modified FPE (modified Thrombolysis in Cerebral Infarction, ≥2b) was also assessed. Comparisons of clinical outcomes were made between groups and adjusted for baseline and procedural characteristics. All participating centers received institutional review board approval from their respective institutions. Results— Adjunctive technique groups included BGC (n=445), distal access catheter (n=238), and conventional guide catheter (n=62). The BGC group had a higher rate of FPE following first pass (212/443 [48%]) versus conventional guide catheter (16/62 [26%]; P =0.001) and distal access catheter (83/235 [35%]; P =0.002). Similarly, the BGC group had a higher rate of modified FPE (294/443 [66%]) versus conventional guide catheter (26/62 [42%]; P <0.001) and distal access catheter (129/234 [55%]; P =0.003). The BGC group achieved the highest rate of functional independence (253/415 [61%]) versus conventional guide catheter (23/55 [42%]; P =0.007) and distal access catheter (113/218 [52%]; P =0.027). Final revascularization and mortality rates did not differ across the groups. Conclusions— BGC use was an independent predictor of FPE, modified FPE, and functional independence, suggesting that its routine use may improve the rates of early revascularization success and good clinical outcomes. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.
Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke)
Froehler, Michael T. , Zaidat, Osama O., Aziz‐Sultan, Mohammad Ali , Klucznik, Richard , Hellinger, Frank R, Yavagal, Dileep R. , Yao, Tom L., Liebeskind, David S, Jadhav, Ashutosh P. , Gupta, Rishi , Hassan, Ameer E , Martin, Coleman, Bozorgchami, Hormozd, Kaushal, Ritesh , Gandhi, Ravi H. , Peterson, Eric C. , Given, Curtis A., Mehta, Brijesh , Deshmukh, Vivek R., Starkman, Sidney , Linfante, Italo , McPherson, Scott H., Kvamme, Peter , Grobelny, Thomas, Hussain, Muhammad Shazam , Thacker, Ike, Vora, Nirav , Monteith, Stephen J., Ecker, Robert D., Schirmer, Clemens M. , Sauvageau, Eric , Abou‐Chebl, Alex, Derdeyn, Colin P. , Maidan, Lucian, Badruddin, Aamir , Siddiqui, Adnan H. , Dumont, Travis M., Alhajeri, Abdulnasser, Taqi, Muhammad , Asi, Khaled, Carpenter, Jeffrey , Boulos, Alan S. , Jindal, Gaurav , Puri, Ajit S , Robinson, David , Kallmes, David F. , Baxter, Blaise, Jumaa, Mouhammad , Sunenshine, Peter, Majjhoo, Aniel, English, Joey , Fessler, Richard D., Martin, Jerry C., Mueller‐Kronast, Nils , Liebeskind, David S. , Liebeskind, David S. , Siddiqui, Adnan H , Hassan, Ameer E , Schirmer, Clemens M , Saver, Jeffrey L. , Jahan, Reza , Haussen, Diogo C , Nogueira, Raul G. , Dashti, Shervin R , Chen, Peng R , Chitale, Rohan V , Deshaies, Eric Michael , Suzuki, Shuichi , Almandoz, Josser E Delgado , Jadhav, Ashutosh P , Derdeyn, Colin P

Circulation | September 25, 2017 | Volume: 136 | Issue: 24 | Pages: 2311-2321

10.1161/circulationaha.117.028920 Get It

Background: Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation. Methods: STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0–2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass. Results: A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients ( P <0.001). Clinical outcomes were better in the direct group, with 60.0% (299/498) achieving functional independence compared with 52.2% (213/408) in the transfer group (odds ratio, 1.38; 95% confidence interval, 1.06–1.79; P =0.02). Likewise, excellent outcome (modified Rankin Score 0–1) was achieved in 47.4% (236/498) of direct patients versus 38.0% (155/408) of transfer patients (odds ratio, 1.47; 95% confidence interval, 1.13–1.92; P =0.005). Mortality did not differ between the 2 groups (15.1% for direct, 13.7% for transfer; P =0.55). Intravenous tissue plasminogen activator did not impact outcomes. Hypothetical bypass modeling for all transferred patients suggested that intravenous tissue plasminogen activator would be delayed by 12 minutes, but MT would be performed 91 minutes sooner if patients were routed directly to endovascular-capable centers. If bypass is limited to a 20-mile radius from onset, then intravenous tissue plasminogen activator would be delayed by 7 minutes and MT performed 94 minutes earlier. Conclusions: In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.