Thrombotic strokes are caused by occlusion of flow in a blood vessel by a clot or thrombus, resulting in disruption of oxygen and nutrients to the brain that can result in neurological deficits. There are many devices now available for safe and effective removal of thrombi from large blood vessels. This report focuses on the Zoom 0.088” large-bore catheter, which has the potential to be navigated into a large vessel for thrombus removal via aspiration, and weigh the risks and benefits of its utilization in thrombectomy patients. In this case, we discuss the use of this device for thrombectomy of a left M1 middle cerebral artery occlusion that resulted in a distal left MCA dissection and eventual loss of access to the site of the thrombus. Ultimately, the patient died from a large stroke in the left MCA territory. In light of this occurrence, we seek to explore the utility and feasibility of large-bore catheters and their risks in thrombectomy candidates.

Introduction Mechanical thrombectomy has become the standard of care to treat acute ischemic stroke patients with large vessel occlusions. Device performance and physician technique have developed since early trials proving the efficacy of the procedure1‐3. One of these techniques, direct aspiration first pass technique (ADAPT)4involves navigating a large‐bore catheter to the face of the clot and initiating suction. Navigating large‐bore catheters through intracranial neurovasculature has been accomplished using microcatheters and/or guidewires. Due to the large sizes of these aspiration catheters, the microcatheters used to help deliver the aspiration catheters into the brain form a “ledge” between the disparate lumens and prevent progression of the aspiration catheter into the distal neurovasculature and increase the risk of damaging arteries during advancement. A novel navigation support catheter, the Tenzing Delivery Catheter, has shown promising benchtop performance assisting large‐bore aspiration catheter delivery to the occlusion sitein vitro5. It demonstrated superior performance over traditional microcatheter/guidewire techniques in delivering the aspiration catheter to the occlusion in this model. While limited initial clinical experience from examining a small sample group appears to confirm this observation, a cumulative, large‐scale analysis of experience using the Tenzing catheter in clinical practice to further examine its safety, efficacy, and usability has not yet been performed. With that in mind, this study serves as an initial multicenter first‐experience investigation to assess the aforementioned factors and determine the utilization potential of Tenzing catheters. Methods This study was conducted via retrospective chart review across three institutions. Patients included in the study are 18 years old or older, underwent a thrombectomy procedure between January 1, 2020 and July 31, 2022, and whose procedures involved the use of the Tenzing delivery catheter system. Our primary outcome measures were success in delivering aspiration catheter, post treatment thrombus, and perioperative complications. Results In our sample size of n = 95, inclusive of patients from multiple institutions, it was found that in 96% of cases, the Tenzing catheter was successfully delivered to the occlusion site and successful reperfusion (mTICI less than or equal to 2b) was achieved in 90% of cases.In the majority of cases, the Tenzing delivery catheter was used to deliver an aspiration catheter to a middle cerebral artery occlusion (75%). Tenzing was advanced past the occlusion location (identified as the angiographic limit of contrast) in 59% of cases. Secondary emboli were observed 11% of the time. Other procedural complications were observed in 8% of patients while none was seen in 74%. On average, the median NIHSS decreased from 17 pre‐treatment to 10 post‐treatment. Conclusions Based on these findings, we conclude that the Tenzing Delivery Catheter is a safe and efficacious instrument in thrombectomy procedures. Given its high rate of revascularization and delivery success with few complications as demonstrated in this multicenter study.Future studies with larger patient volume are necessary to evaluate this important delivery catheter as it is used more frequently around the world.

Treatment efficacy with chimeric antigen receptor (CAR) T cell therapy in glioblastoma (GBM) is undermined by an immunosuppressive tumor microenvironment (TME). We previously showed that CAR T cell therapy targeting epidermal growth factor receptor variant III (EGFRvIII) produces anti-tumor activity against recurrent GBM and causes upregulation of programmed death-ligand 1 (PD-L1) in the TME. Here, we conducted a phase I trial to study the impact of CART-EGFRvIII cells administered concomitantly with the PD-1 inhibitor pembrolizumab in patients (n = 7) with newly diagnosed, EGFRvIII + GBM. Treatment was well tolerated without incidence of dose-limiting toxicity. However, no signal of efficacy was detected with a median progression-free survival of 5.2 months (90% CI, 2.9–6.0 months) and median overall survival of 11.8 months (90% CI, 9.2–14.2 months). In addition, PD-1 expression in the CART-EGFRvIII infusion product did not correlate with outcomes, and peripheral CAR T cell engraftment was relatively short-lived. Together, these findings show the safety of combining CAR T cells and PD-1 inhibition in GBM but given the lack of efficacy, also indicate a need to consider alternative combinatorial strategies. ClinicalTrials.gov registration: NCT03726515.