Optimization of Clot Formation Methodology for Assessment of Neurothrombectomy Devices in Large Animal Thrombectomy Models

Neurothrombectomy devices are commonly evaluated for potential clinical success in porcine models of neurothromboembolism. The majority of preclinical evaluations for these devices are performed in the vasculature of swine or dog utilizing clots created ex vivo. This investigation was conducted to develop a faster, more reliable method for creating clots ex vivo for model development. Neurothrombectomy devices are designed to perform recanalization of arterial occlusions that cause acute ischemic stroke [1]. Recanalization can be achieved via clot disruption, aspiration, or retrieval using one or more mechanical devices. In order to evaluate these devices in vivo, a fast and reliable method for creating and delivering clots to a desired artery, thereby simulating a target site for neurothrombectomy, is essential. Two types of clot analogs (soft or firm) were created using two different methods in order to compare both their mechanical properties and their ability to reliably occlude selected arteries. Utilizing both methods, pre-formed clots were qualitatively compared in vitro to evaluate elasticity, stiffness, and functionality of delivery through a catheter. These evaluations were performed prior to in vivo assessment of the effectiveness of the analogs occlusion of selected arterial vasculature.

Abstract TP18: Recanalization in Acute Stroke Interventions with Manual Aspiration Thrombectomy as a Stand Alone Technique

Background and Purpose: Manual aspiration thrombectomy (MAT) represents an alternative means to open occluded intracranial vessels. The technique involves advancing a large bore catheter into the thrombus and manually aspirating through a syringe. We have previously reported our experience with nearly 200 patients, however most cases involved the use of an adjunctive device such as the MERCI retriever to facilitate clot disruption or advancement of the catheter through the tortuous carotid siphon. This selected case series represents those patients treated with MAT alone. Methods: The University of Pittsburgh acute stroke database was retrospectively reviewed to evaluate those patients presenting with a large vessel intracranial occlusion who were treated with MAT. The decision to treat was based on the amount of brain still considered at risk based on CT, CTP, or MRI, and not on time from onset. Patients were excluded if an adjunctive device was used to facilitate catheter advancement or clot disruption/removal. These devices included the MERCI retriever, Penumbra aspiration system, Solitaire, TREVO, stent, or balloon. Intra-arterial thrombolytics or antiplatelets were allowed. Results: Forty-seven patients met the inclusion criteria. The mean/median NIHSS was 17/16. The mean/median time from last seen normal to groin puncture was 8.3/6.5 hours. The mean/median time from groin puncture to recanalization was 50/40 minutes. The target vessel was the basilar, M1, and ICA-terminus in 7, 30, and 10 patients respectively. The mean/median number of aspiration attempts was 1.7/1. All patients achieved at least TIMI 2 recanalization, owing to the fact that failure to achieve this result prompted the use of an adjunctive device. 42/47 patients achieved TICI 2B/3 recanalization. Conclusions: Pure MAT without the use of an adjunctive device represents another method to achieve intracranial recanalization with the potential for significant cost savings. Safety and outcomes must still be evaluated.

Pharmacomechanical Thrombolysis in the Management of Paget-Schroetter Syndrome

Paget-Schroetter syndrome (PSS) is a rare form of thoracic outlet syndrome caused by axillosubclavian vein thrombosis which typically presents in healthy young adults. Prompt therapy, traditionally by means of catheter-directed thrombolysis (CDT) prior to definitive surgery, can prevent the subsequent onset of postthrombotic syndrome (PTS) and considerable disability. As CDT is associated with major haemorrhage and high overall treatment cost, pharmacomechanical thrombectomy (PMT) seems to be an attractive alternative which combines pharmacological thrombolysis with mechanical clot disruption. The Trellis-8 peripheral infusion catheter is an example of such a treatment which provides topical thrombolysis in an isolated zone. We describe the use of the Trellis-8 PMT system in the successful management of three patients with PSS.

Endovascular Management in Patients with Acute Basilar Artery Obstruction: Low-Dose Intra-Arterial Urokinase and Mechanical Clot Disruption

Mechanical clot disruption for the treatment of acute basilar artery occlusion (BAO) is known to provide a benefit. We aimed to determine the safety, recanalization rate and time-to-flow restoration of mechanical clot disruption and low dose urokinase (UK) infusions for the treatment of patients with acute BAO. Between June 2006 and June 2010, 21 patients with acute BAO underwent endovascular treatment that included angioplasty or stent placement. The time to treatment, duration of the procedure, dose of urokinase (UK), recanalization rates and symptomatic hemorrhages were analyzed. Clinical outcome measures were assessed at admission and at the time of discharge using the National Institutes of Health Stroke Scale (NIHSS) score and at three months after treatment using the modified Rankin Score (mRS). On admission, the median NIHSS score was 13.2. Median time from symptom onset to arrival at hospital was 356 minutes, and median time from symptom onset to intraarterial thrombolysis (IAT) was 49 minutes. We used the following interventional treatment regimens: Intraarterial (IA) UK and a minimal mechanical procedure (n=14), IA UK with angioplasty (n=1), IA UK with angioplasty and stent placement (n=3) and IA UK with HyperForm (n=3). The recanalization (thrombolysis in cerebral ischemia grade II or III) rate was 90.5% (19/21). There was symptomatic hemorrhage in one patient (4.8%). The median NIHSS score at discharge was 6.3. The three-month outcome was favorable (mRS: 0–2) for 14 patients (66.7%) and poor (mRS: 3–6) for seven patients (33.3%). The overall mortality at three months was 14.3% (three patients died). Low-dose IAT with mechanical clot disruption is a safe and effective treatment for treatment for acute BAO.