Multi-sample cardiac bioptome

Abstract

Background:
An endomyocardial biopsy (EMB) is an invasive procedure where biopsy samples are taken from within the heart for diagnosis of different myocardiopathies and or heart transplant rejection monitoring. During EMB procedures, a minimum of five tissue samples are required to be taken from the heart wall for investigation.
Current bioptomes are not able to retrieve more than one sample at a time and therefore need to be re-inserted at least four times. This can lead to complications such as air embolisms. The goal of this design study was to develop a novel cardiac bioptome for endomyocardial biopsies that can take and store multiple biopsy samples during a single insertion.

Design:
The bioptome developed in this study had two major functionalities, resection of myocardial tissue and storage of multiple tissues. Each functionality could be divided into multiple sub-functionalities. From these functionalities the design requirements followed. Afterwards, the alternatives for each subfunctionality
were explored. For the tissue resection, different possibilities for the method of resection, position of the resection tool, direction of resection forces, and motion of resection, were explored. For tissue storage, different possibilities for the storage system, tissue transportation, and sample loss prevention were explored. Following this exploration, multiple design concepts were devised. Two of these concepts, the ’corer’ concept and ’ovipositor’ concept were developed further. These two concept were compared and the ’corer’ concept was chosen as the most viable option. Prototypes of this concept were developed and tested for the functioning of its working principle for tissue resection and storage and for the functioning of the actuation mechanism.

Results:
The experiments showed that the end-effector of the bioptome works as expected and that thus the working principle of the ’corer’ concept for resection and storage of biopsy samples functions as intended. The experiments also validated the functioning of the actuation mechanism within the handle. The experiments however also showed that the flexible shaft was unable to correctly transfer the motion from the actuation mechanism in the handle to the end-effector.

Discussion & conclusion:
More suitable materials are required for future prototypes to improve motion transfer. Furthermore, a steerability functionality should be added to the design to make the bioptome fully functional for EMB procedures. The final design should be tested in an environment more closely resembling the clinical scenario. If these tests are successful, it can be concluded that the bioptome can indeed improve endomyocardial biopsy procedures.