The Influence of Sizing on the Dynamic Function of the Free-hand Implanted 242
Porcine Aortic Homograft: An In Vitro Study
Mano J. Thubrikar PhD, Igor E. Konstantinov MD, Gamal A. Selim MS, Geoffrey G. Gong MD,
Brett Fowler BS, Francis Robicsek MD

The influence of sizing on the function of a porcine aortic valve after implantation by the free-hand technique in the subcoronary position was investigated. Dynamic function and leaflet configuration of the valve (n = 16) were first analyzed in its natural aortic root in a left heart simulator at 120/80 mmHg pressure and 4 l/min cardiac output. The valve was then implanted in the recipient porcine aortic root and re-studied. Three groups were investigated: group I (n = 4) comprised 1-2 mm smaller donor aortic valve than recipient; group II (n = 8) 3-4 mm smaller; and group III (n = 4) 5-7 mm smaller. Orifice area (OA), systolic and diastolic leaflet configuration, pattern and timing of leaflet opening and closure, commissural movement, pressure gradient and valvular regurgitation were analyzed. In the intact donor aortic root, expansion of the aorta at the commissures for a pressure change from 0 to 80 mmHg was 42%; this was reduced significantly in all assemblies. Group I showed a 34% reduction in OA and excessive leaflet bending and there was no aortic insufficiency (AI) or pressure gradient across the valve. In group III, there was a lesser reduction in OA and reduced leaflet bending, but two valves had AI. In group II, the reduction in OA was 13%, there was less leaflet bending, and no AI. Thus, the donor valve 3-4 mm smaller than the recipient seems an optimal match. The current practice of using the same size donor as recipient may lead to excessive leaflet bending and be implicated in early homograft deterioration.