Author

Young Choi

Date on Master's Thesis/Doctoral Dissertation

5-2016

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Bioengineering

Committee Chair

Koenig, Steven

Committee Co-Chair (if applicable)

Slaughter, Mark

Committee Member

Slaughter, Mark

Committee Member

Walsh, Kevin

Committee Member

Giridharan, Guruprasas

Committee Member

Soucy, Kevin

Abstract

Purpose: Left ventricular assist device (LVAD) therapy can be live-saving for advanced heart failure patients. Conventional anastomosis (surgical connection) of LVAD outflow grafts to the aorta requires aortic clamping and hand-suturing. Aortic clamping increases the risk for neurological complications. Hand-suturing may be time-consuming and requires significant surgical dexterity. There is currently no commercially available device for sutureless anastomosis of large vascular grafts (diameter > 5mm). To overcome these limitations, a prototype LVAD outflow graft anastomosis device (GrAD) that facilitates sutureless anastomosis was developed and tested to demonstrate proof-of-concept and feasibility for (1) secured attachment withstanding physiological pressures, and (2) comparable attachment strength to conventionally hand-sewn sutured anastomosis.

Methods: To demonstrate proof-of-concept, prototype GrADs were fabricated using a nitinol wire connector attached to a 15 mm graft, felt flanged cuff, and cyanoacrylate adhesive. To demonstrate feasibility, the GrAD was anastomosed to bovine descending aorta and tested in a mock flow loop over a range of static (0, 50, 100, 150, 200 mmHg) and dynamic pressures (normal, hypertension, heart failure, LVAD support) to quantify v leakage. The maximum pull-out force for the GrAD and sutured anastomosis were also measured after completing static and dynamic testing in the mock flow loop model.

Results: The GrAD remained securely attached during all static and dynamic pressure test conditions as evidenced by minimal leak rates during clinically equivalent normal (22.1 ± 9.3 ml/min), hypertension (23.1 ± 10.1 ml/min), heart failure (16.4 ± 6.4 ml/min), and LVAD support (16.4 ± 4.3 mL/min) test conditions. Significantly larger leak rates at normal dynamic pressure (120/80 mmHg) between the GrAD and previously reported results for hand-sutured anastomosis were not observed. Differences in peak pull-out force between GrAD (43.57 ± 17.31 N) and hand-sutured anastomosis (63.48 ± 8.72 N) were statistically indiscernible (paired t-test, p < 0.5). No indications of device damage were observed.

Conclusion: A prototype GrAD enabling a sutureless, adaptable, and angled LVAD outflow graft anastomosis was developed with preliminary feasibility testing demonstrating proof-of-concept. The proposed LVAD outflow GrAD may facilitate surgical implant by eliminating the need for hand-suturing, decrease implant time, and increase reliability and reproducibility with the potential to improve patient outcomes.

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