Endovascular Therapy Proven for Stroke – Finally!

A canine model of mechanical thrombectomy in stroke

Purpose

To develop a preclinical model of stroke with a large vessel occlusion treated with mechanical thrombectomy.

Materials and methods

An ischemic stroke model was created in dogs by the introduction of an autologous clot into the middle cerebral artery (MCA). A microcatheter was navigated to the clot and a stent retriever thrombectomy was performed with the goal to achieve Thrombolysis in Cerebral Ischemia (TICI) 2b/3 reperfusion. Perfusion and diffusion MRI was acquired after clot placement and following thrombectomy to monitor the progression of restricted diffusion as well as changes in ischemia as a result of mechanical thrombectomy. Post-mortem histology was done to confirm MCA territory infarct volume.

Results

Initial MCA occlusion with TICI 0 flow was documented in all six hound-cross dogs entered into the study. TICI 2b/3 revascularization was achieved with one thrombectomy pass in four of six animals (67%). Intra-procedural events including clot autolysis leading to spontaneous revascularization (n=1) and unresolved vasospasm (n=1) accounted for thrombectomy failure. In one case, iatrogenic trauma during microcatheter navigation resulted in a direct arteriovenous fistula at the level of the cavernous carotid. Analysis of MRI indicated that a volume of tissue from the initial perfusion deficit was spared with reperfusion following thrombectomy, and there was also a volume of tissue that infarcted between MRI and ultimate recanalization.

Conclusion

We describe a large animal stroke model in which mechanical thrombectomy can be performed. This model may facilitate, in a preclinical setting, optimization of complex multimodal stroke treatment paradigms for clinical translation.

The impact of evidence: evolving therapy for acute ischemic stroke in a large healthcare system

BACKGROUND

With a recent surge of clinical trials, the treatment of ischemic stroke has undergone dramatic changes.

OBJECTIVE

To evaluate the impact of evidence and a revamped stroke protocol on a large healthcare system.

METHODS

A retrospective review of 69 patients with ischemic stroke treated with intra-arterial therapy was carried out. Cohort 1 included patients treated before implementation of a new stroke protocol, and cohort 2 after implementation. Angiographic outcome was graded using the Thrombolysis in Cerebral Infarction (TICI) score. Clinical outcomes were assessed using the National Institute of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS).

RESULTS

Primary outcomes comparing cohorts demonstrated decreased arrival-to-puncture time (cohort 2: 104 vs cohort 1: 181 min, p<0.001), similar TICI 2b/3 rates (86.5% vs 81.3%, p=0.5530), and similar percentage of patients with discharge mRS 0-2 (18.9% vs 21.9%, p=0.7740). Notable secondary outcomes for cohort 2 included decreased puncture-to-first pass time (34 vs 53 min, p <0.001), increased TICI 3 rates (37.8% vs 18.8%, p=0.0290), a trend toward greater improvements in NIHSS on postoperative day 1 (6.8 vs 2.6, p=0.0980) and discharge (9.5 vs 6.7, p=0.1130), and a trend toward increased percentage of patients discharged with mRS 0-3 (48.6% vs 34.4%, p=0.3280 NS). There were similar rates of symptomatic intracerebral hemorrhage (10.8% vs 9.4%, p=0.9570) and death (10.8% vs 15.6%, p=0.5530).

CONCLUSIONS

An interdisciplinary and rapid response to the emergence of strong clinical evidence can result in dramatic changes in a large healthcare system.