Development and validation of a perfused cadaveric model for neurovascular transradial access with insights from angiography and angioscopy.

Abstract

Background: The development of safe and effective endovascular devices is dependent on accurate simulation of anticipated use environments during preclinical testing. We sought to optimize and evaluate the human 'live cadaver' neurovascular model for the purpose of testing radial access catheters. We aimed to assess the realism of our model during simulated neurointerventional procedures as well as explore and characterize potential challenges of radial access catheters.

Methods: A human 'live cadaver' model was developed from a cadaveric specimen consisting of the head, neck, bilateral upper limbs, and thorax. Catheters were inserted into the heart and thoracic aorta. Blood-mimicking fluid made by 0.7% carboxymethyl cellulose + 0.25% sodium propionate was circulated through the vasculature using an external peristaltic pump. Bilateral radial access was obtained using 7F sheaths. Experienced neurointerventionists (n=5) were provided with a questionnaire using a validated 5-point Likert scale and tasked with assessing the model's radial artery, aortic arch, and carotid/vertebral arteries on the parameters of anatomical accuracy, roadmap angiography, device manipulation, haptic feedback, comparison to clinical cases, radio-opacity of devices, and overall similarity to actual patients. Challenging mechanisms were identified and described by evaluation of fluoroscopic and endoscopic videos.

Results: A total of six cadavers were used. Formalin-fixed arteries showed mechanical properties comparable to those of fresh human arteries, including maximum stretch and increased tensile strength/stiffness. The contrast angiographies revealed no obstruction in the micro- or macro-vasculature. Overall similarity scores for arms (radial, brachial, axillary, and subclavian arteries) were 34.6±2.3 out of 40, for aortic arch 30.3±5.4 out of 40, and for carotid/vertebral artery access 33.0±4.2 out of 40. We identified three distinct challenges associated with market radial access catheters: (1) torque build-up followed by sudden release and whipping; (2) catheter tip entry into ulcerated or nodular aortic atheroma preventing free motion; and (3) catheter catching at a septum-like structure at the medial edge of the brachiocephalic trunk; the latter two result in herniation of the system into the arch even with favorable aortic arch angles.

Conclusions: The model provided a reliable and accurate human radial and aortic vasculature simulation, allowing for the evaluation of catheter performance and identification of challenging mechanisms likely to occur in clinical settings. These findings suggest that the modified human live cadaveric model could be a valuable testing platform to support the development of next-generation transradial systems for improved clinical performance.