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Schirmer, Clemens M.

https://orcid.org/0000-0003-1743-8781

Mayo Clinic

Department of Neurosurgery, Geisinger, Wilkes-Barre, Pennsylvania;

Citations 47

Delayed presentation of acute ischemic strokes during the COVID-19 crisis
Schirmer, Clemens M. , Ringer, Andrew J. , Binning, Mandy J., Fox, W. Christopher , James, Robert F. , Levitt, Michael R. , Veznedaroglu, Erol, Walker, Melanie , Spiotta, Alejandro M , Arthur, Adam Stephen , Levitt, Michael R , Fox, W Christopher , Schirmer, Clemens M , Tawk, Rabih G.

Journal of NeuroInterventional Surgery | May 28, 2020 | Volume: 12 | Issue: 7 | Pages: 639-642

10.1136/neurintsurg-2020-016299 Get It

Background The COVID-19 pandemic has disrupted established care paths worldwide. Patient awareness of the pandemic and executive limitations imposed on public life have changed the perception of when to seek care for acute conditions in some cases. We sought to study whether there is a delay in presentation for acute ischemic stroke patients in the first month of the pandemic in the US. Methods The interval between last-known-well (LKW) time and presentation of 710 consecutive patients presenting with acute ischemic strokes to 12 stroke centers across the US were extracted from a prospectively maintained quality database. We analyzed the timing and severity of the presentation in the baseline period from February to March 2019 and compared results with the timeframe of February and March 2020. Results There were 320 patients in the 2-month baseline period in 2019, there was a marked decrease in patients from February to March of 2020 (227 patients in February, and 163 patients in March). There was no difference in the severity of the presentation between groups and no difference in age between the baseline and the COVID period. The mean interval from LKW to the presentation was significantly longer in the COVID period (603±1035 min) compared with the baseline period (442±435 min, P<0.02). Conclusion We present data supporting an association between public awareness and limitations imposed on public life during the COVID-19 pandemic in the US and a delay in presentation for acute ischemic stroke patients to a stroke center.
Prospective study on embolization of intracranial aneurysms with the pipeline device: the PREMIER study 1 year results
Kallmes, David F. , Nelson, Peter Kim , Siddiqui, Adnan H. , Szikora, István , Zaidat, Osama O. , Colby, Geoffrey P. , Schirmer, Clemens M. , Hellinger, Frank R, Given, Curtis A., Tóth, Gábor , Priest, Ryan , Kan, Peter , Frei, Don , Aagaard‐Kienitz, Beverly , Díaz, Orlando , Malek, Adel M. , Cawley, C. Michael , Puri, Ajit S , Zaidat, Osama O , Colby, Geoffrey P , Mokin, Maxim , Taussky, Philipp , Toth, Gabor , Fraser, Justin F , Fiorella, David , Siddiqui, Adnan H , Szikora, Istvan , Schirmer, Clemens M , Hanel, Ricardó A. , Lopes, Demetrius K. , Jabbour, Pascal , Mendes Pereira, Vitor , Bettegowda, Chetan , Krings, Timo , Chen, Michael , Fiorella, David

Journal of NeuroInterventional Surgery | July 15, 2019 | Volume: 12 | Issue: 1 | Pages: 62-66

10.1136/neurintsurg-2019-015091 Get It

Background Preliminary clinical studies on the safety and efficacy of the pipeline embolization device (PED) for the treatment of small/medium aneurysms have demonstrated high occlusion rates with low complications. Objective To evaluate the safety and effectiveness of the PED for treatment of wide necked small and medium intracranial aneurysms. Methods PREMIER is a prospective, multicenter, single arm trial. Patients were treated with the PED for unruptured wide necked aneurysms, measuring ≤12 mm along the internal carotid artery or vertebral artery, between July 2014 and November 2015. At 1 year post-procedure, the primary effectiveness endpoint was complete occlusion (Raymond grade 1) without major parent vessel stenosis (≤50%) or retreatment, and the primary safety endpoint was major stroke in the territory supplied by the treated artery or neurologic death. Results A total of 141 patients were treated with PEDs (mean age 54.6±11.3 years, 87.9% (124/141) women). Mean aneurysm size was 5.0±1.92 mm, and 84.4% (119/141) measured <7 mm. PED placement was successful in 99.3% (140/141) of patients. Mean number of PEDs implanted per patient was 1.1±0.26; a single PED was used in 92.9% (131/141) of patients. At 1 year, 97.9% (138/141) of patients underwent follow-up angiography with 76.8% (106/138) of patients having met the study’s primary effectiveness endpoint. The combined major morbidity and mortality rate was 2.1% (3/140). Conclusions Treatment of wide necked small/medium aneurysms with the PED results in high rates of complete occlusion without significant parent vessel stenosis and low rates of permanent neurologic complications. Trial registration NCT02186561 .
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.
Feasibility, safety, and changes in systolic blood pressure associated with endovascular revascularization of symptomatic and chronically occluded cervical internal carotid artery using a newly suggested radiographic classification of chronically occluded
Starke, Robert M. , Atallah, Elias , Chalouhi, Nohra , Singla, Amit , Guerrero, Waldo R. , Nakagawa, Daichi , Samaniego, Edgar A. , Mbabuike, Nnenna, Siddiqui, Adnan H. , Novakovic, Roberta, White, Jonathan, Schirmer, Clemens M. , Brott, Thomas G. , Shallwani, Hussain , Hopkins, L. Nelson , Siddiqui, Adnan H , Samaniego, Edgar A , Schirmer, Clemens M , Hasan, David , Zanaty, Mario , Jabbour, Pascal , Tawk, Rabih G. , Levy, Elad I. , White, Jonathan A.

Journal of Neurosurgery | May 18, 2018 | Volume: No volume available | Issue: No issue available | Pages: 1-10

10.3171/2018.1.jns172858 Get It

OBJECTIVE The overall risk of ischemic stroke from a chronically occluded internal carotid artery (COICA) is around 5%–7% per year despite receiving the best available medical therapy. Here, authors propose a radiographic classification of COICA that can be used as a guide to determine the technical success and safety of endovascular recanalization for symptomatic COICA and to assess the changes in systemic blood pressure following successful revascularization. METHODS The radiographic images of 100 consecutive subjects with COICA were analyzed. A new classification of COICA was proposed based on the morphology, location of occlusion, and presence or absence of reconstitution of the distal ICA. The classification was used to predict successful revascularization in 32 symptomatic COICAs in 31 patients, five of whom were female (5/31 [16.13%]). Patients were included in the study if they had a COICA with ischemic symptoms refractory to medical therapy. Carotid artery occlusion was defined as 100% cross-sectional occlusion of the vessel lumen as documented on CTA or MRA and confirmed by digital subtraction angiography. RESULTS Four types (A–D) of radiographic COICA were identified. Types A and B were more amenable to safe revascularization than types C and D. Recanalization was successful at a rate of 68.75% (22/32 COICAs; type A: 8/8; type B: 8/8; type C: 4/8; type D: 2/8). The perioperative complication rate was 18.75% (6/32; type A: 0/8 [0%]; type B: 1/8 [12.50%]; type C: 3/8 [37.50%], type D: 2/8 [25.00%]). None of these complications led to permanent morbidity or death. Twenty (64.52%) of 31 subjects had improvement in their symptoms at the 2–6 months’ follow-up. A statistically significant decrease in systolic blood pressure (SBP) was noted in 17/21 (80.95%) patients who had successful revascularization, which persisted on follow-up (p = 0.0001). The remaining 10 subjects in whom revascularization failed had no significant changes in SBP (p = 0.73). CONCLUSIONS The pilot study suggested that our proposed classification of COICA may be useful as an adjunctive guide to determine the technical feasibility and safety of revascularization for symptomatic COICA using endovascular techniques. Additionally, successful revascularization may lead to a significant decrease in SBP postprocedure. A Phase 2b trial in larger cohorts to assess the efficacy of endovascular revascularization using our COICA classification is warranted.
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.
A History of the Council of State Neurosurgical Societies
Zaidi, Hasan A. , Tumialán, Luis M. , Colen, Chaim B., Stroink, Ann R., Linskey, Mark E. , Schirmer, Clemens M. , Watridge, Clarence B. , Watridge, Clarence, Rosenow, Joshua M. , Schirmer, Clemens M

Neurosurgery | February 5, 2017 | Volume: 80 | Issue: 1 | Pages: 146-157

10.1093/neuros/nyw009 Get It

Abstract As neurological surgery evolved into its own subspecialty early in the 20th century, a need arose to create an environment for communication and education among those surgeons working in this burgeoning surgical discipline. As the socioeconomic climate in health care began to change in the United States, an unforeseen need arose that was outside the scope of the American Association of Neurological Surgeons, Congress of Neurological Surgeons, and Society of Neurological Surgeons. The capacity to understand and address the evolving socioeconomic landscape and to offer a platform for advocacy required a new entity. Grassroots efforts of neurosurgeons at the state level ultimately yielded a formal organization of state neurosurgical societies to fill this void by recognizing, understanding, and addressing socioeconomic factors affecting the practice of neurological surgery. This formal organization became the Council of State Neurosurgical Societies (CSNS). The CSNS provides a forum in which state societies can meet to identify, understand, and advocate for policies on behalf of organized neurosurgery. The purpose of this paper is to detail the history of the formation of the CSNS. By understanding this history and the need for the development of the CSNS, it is hoped that its evolving role as a voice for neurological surgeons in the modern era of health care will be made clear.