nitinol and Cerebral-Infarction

The success of local fibrinolysis in vertebrobasilar thromboembolism depends on the volume and composition of the clot. Since thrombolysis can also be time consuming and cause bleeding, we investigated the feasibility of a mechanical clot retraction device based on a nitinol basket advanced through a microcatheter.. Five patients with acute embolism of the basilar artery who presented with progressive stroke and impaired consciousness were included in a multicenter study (Neuronet Evaluation in Embolic Stroke Disease [NEED]). In 3 patients flow reversal was induced with the use of silicone balloons or coaxial catheters. Three patients required additional fibrinolysis.. The device failed to retrieve the clots in our first 2 patients with distal basilar artery embolism. After successful recanalization by local fibrinolysis, both patients survived, 1 disabled and 1 with little residual impairment. In the next 3 patients the anterograde flow in the basilar artery was reversed during the short retraction period by temporarily blocking the vertebral or subclavian arteries. Two of these patients were completely recanalized by solely mechanical means; the third patient needed additional fibrinolysis before also being recanalized. All 3 patients survived: 1 remained disabled, 1 had almost a full recovery, and 1 became asymptomatic the day after the procedure.. Mechanical thrombus extraction seems to be a feasible method for preventing infarction by rapid, complete, and safe recanalization of the basilar artery. We recommend the use of flow control to support retrieval of the thrombus (which the proximal flow would otherwise keep in place like a cork) and to protect the distal vessels from embolization by fragments.

Topics: Adolescent; Adult; Aged; Alloys; Angiography, Digital Subtraction; Basilar Artery; Brain; Catheterization; Cerebral Angiography; Cerebral Infarction; Cerebrovascular Circulation; Embolectomy; Feasibility Studies; Female; Fibrinolytic Agents; Glasgow Coma Scale; Humans; Intracranial Embolism; Male; Middle Aged; Neurosurgical Procedures; Thrombectomy; Treatment Outcome

Transcatheter aortic valve implantation for patients with severe aortic stenosis at a high-operative risk has been demonstrated to improve mortality compared to standard medical therapy. Registry data and the PARTNER trial have shown a significant risk of stroke (3-5%) following the procedure. Studies using cerebral diffusion-weighted magnetic resonance imaging have suggested the mechanism of stroke to be multiple small embolic infarcts, possibly from aortic atheroma dislodged during the movement of the valve and its apparatus around the thoracic aorta. The incidence of these infarcts is higher than clinically apparent. The Medtronic CoreValve (Medtronic, Minneapolis, Minnesota) prosthesis is a self-expanding nitinol frame with porcine valve, whose deployment is achieved by the retraction of the delivery catheter. Potential complications of this method include valve mal-positioning and dislocation. The partially deployed valve may then be resheathed following retraction back into the descending aorta and subsequently redeployed. We present two such cases with evidence of both "silent" and clinically evident cerebral infarction.

Topics: Aged, 80 and over; Alloys; Aortic Valve Stenosis; Bioprosthesis; Cardiac Catheterization; Cardiac Catheters; Cerebral Infarction; Diffusion Magnetic Resonance Imaging; Female; Heart Valve Prosthesis; Heart Valve Prosthesis Implantation; Humans; Intracranial Embolism; Prosthesis Design; Severity of Illness Index