A Case-Study Based Course on Device Evaluation and FDA Approval

Preclinical evaluation of new devices and therapies is an integral part of research and development in the medical device industry, and the regulatory process for FDA approval is a major driving force behind much that goes on in a company setting. A large number of graduating biomedical engineers enter this medical device industry or a related environment upon graduation from our institution. Although these engineers are equipped to address many of the technical challenges that will arise, there is currently limited formal training in or exposure to the regulatory process that is required to bring new devices to market. Knowledge of the typical progression through preclinical testing, as well as an understanding of clinical trial guidelines and the FDA regulatory process would allow students to work more effectively and productively in industry or other medically-related positions. Therefore, a course has been designed entitled “Device Evaluation and FDA Approval” as an upper division elective at our institution. The goal of this course is to expose students to the overall process of FDA approval, including aspects of both preclinical and clinical testing, in order to prepare them to succeed in a regulatory-based environment. This is a case-study based course, where cases range from small in-class examples that facilitate active student engagement in the material, to large cases that span multiple lessons and incorporate out of class assignments and projects. Cases are selected and presented such that students gain insights into the progression and complexities of “real-life” devices, while learning in vitro and in vivo preclinical evaluation techniques, clinical trial guidelines, FDA processes and requirements, and overall regulatory constraints

An Automatic Alogorithm for Detecting Stent Endothelialization from Volumetric Optical Coherence Tomography Datasets

Recent research has suggested that endothelialization of vascular stents is crucial to reducing the risk of late stent thrombosis. With a resolution of approximately 10 μm, optical coherence tomography (OCT) may be an appropriate imaging modality for visualizing the vascular response to a stent and measuring the percentage of struts covered with an anti-thrombogenic cellular lining. We developed an image analysis program to locate covered and uncovered stent struts in OCT images of tissue-engineered blood vessels. The struts were found by exploiting the highly reflective and shadowing characteristics of the metallic stent material. Coverage was evaluated by comparing the luminal surface with the depth of the strut reflection. Strut coverage calculations were compared to manual assessment of OCT images and epi-fluorescence analysis of the stented grafts. Based on the manual assessment, the strut identification algorithm operated with a sensitivity of 93% and a specificity of 99%. The strut coverage algorithm was 81% sensitive and 96% specific. The present study indicates that the program can automatically determine percent cellular coverage from volumetric OCT datasets of blood vessel mimics. The program could potentially be extended to assessments of stent endothelialization in native stented arteries. (Some figures in this article are in colour only in the electronic version

Assessment of Blood Vessel Mimics with Optical Coherence Tomography

Optical coherence tomography (OCT) is an imaging mo-dality that enables assessment of tissue structural characteristics. Studies have indicated that OCT is a useful method to assess both blood vessel morphology and the response of a vessel to a deployed stent. We evaluated the ability of OCT to visualize the cellular lining of a tissue-engineered blood vessel mimic (BVM) and the response of this lining to a bare metal stent. We develop a side-firing endoscope that obtains intraluminal, longitudinal scans within the sterile bioreactor environment, enabling time-serial assessment. Seventeen BVMs are imaged with the endoscopic OCT system. The BVMs are then evaluated via fluorescence microscopy and/or standard histologic techniques. We determine that (1) the OCT endoscope can be repeatedly inserted without visible damage to the BVM cellular lining, (2) OCT provides a precise measure of cellular lining thickness with good correlation to measurements obtained from histological sections, and (3) OCT is capable of monitoring the accumulation of cellular material in response to a metallic stent. Our studies indicate that OCT is a useful technique for monitoring the BVM cellular lining, and that OCT may facilitate the use of BVMs for early stage device assessment