James Cezo

Abstract

A novel transaortic ventricular cannula, known as the 'double barrel' cannula (DBC), is designed to minimize the invasiveness of Ventricular Assist Device (VAD) implantation by combining the inlet and outlet cannulae into a single dual lumen cannula. Both the inlet and outlet lumen will pass through a single opening in the apex of the left ventricle with the outflow then continuing past the aortic valve, into the aortic arch. This design offers several potential advantages over the current state of-the-art. The benefits of the DBC include less invasive surgery and providing mechanical support to the septum. By routing the outflow through the aortic valve, the need to access the external structure of the ascending aorta at the time of implantation is eliminated thereby eliminating the need for open heart surgery. In designing the DBC, close attention has been paid to the outflow portion of the cannula since it was anticipated that this portion of the DBC could have the largest impact on the device's usability. The object of this study was to test the performance of the valve with the cannula passing through it. Three different geometries of similar cross-sectional area were compared. The geometries were circular, equilateral triangular, and occluded leaflet. Experiments measuring aortic insufficiency (AI), hemolysis, and differential pressure across the valve were conducted. Additionally, high speed cinematography was used to analyze the dynamics of the valve's sealing to the cannulae. All three geometries exhibited low and acceptable levels of AI ( 15% AI), with the circular geometry causing the least amount of AI (7.1%) in comparison to the control, an aortic valve with no cannula (2.4%). The hemolysis test results revealed that all three of the cannulae designs generated negligible hemolysis (<0.5% after one hour) as compared to the control case. The pressure loss across the aortic valve was found to correspond to the area open to flow. Using the high speed cinematography, several phenomena were observed during the sealing of the porcine valve; including leaflet folding, leaflet bunching, and cannula displacement due to valve closure.

Library of Congress Subject Headings

Heart valve prosthesis--Fluid dynamics; Aortic valve--Surgery; Medical instruments and apparatus--Design and construction

Publication Date

8-1-2009

Document Type

Thesis

Department, Program, or Center

Mechanical Engineering (KGCOE)

Advisor

Day, Steven

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: RD598.35.H42 C49 2009

Campus

RIT – Main Campus

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