The use of pulmonary allografts for aortic valve replacement. Short term results and comparative morphometric analysis of the aortic and pulmonary valves.
Academic Article
Overview
abstract
UNLABELLED: The satisfactory results of aortic valve replacement with pulmonary autograft and the limited availability of aortic allografts prompted us to use the pulmonary valve as an aortic valve substitute and to perform a morphometric analysis of the two valves in cadavers. CLINICAL STUDY: From March 1994 to March 1995 20 patients underwent an aortic valve replacement (AVR) with a pulmonary allograft (PA). Twelve patients were men, 8 women; age ranged from 15 to 58 years. In 4 cases the indication to AVR was an infective endocarditis which was acute in two patients. Functional class was NYHA II in 18 cases and NYHA III in 2 patients with active endocarditis. Left ventricular ejection fraction (LVEF%) was preserved in the majority of patients (mean LVEF=53% range 36% to 65%). End diastolic aortic valve diameters were measured by bidimensional echocardiography in parasternal long axis view and ranged from 18 mm to 29 mm. The diameters of the allografts implanted ranged from 19 mm to 27 mm. Donors age ranged from 19 years to 55 years. We tried to use the allograft from the youngest donor available. The surgical technique was the classic "Ross" coronary freehand implantation in 11 cases, a "Miniroot" implant in 8 instances and a "Miniroot" implant combined with a "Nicks" annular enlargment in 1 case. Aortic cross clamping ranged from 66 mm to 118 m (92m+/-10m). One patient died (5%) of infarction. In this patient the allograft was replaced with a mechanical valve because the echocardiography showed a rapidly increasing aortic regurgitation. At hospital discharge a slight aortic regurgitation was detected in 2 cases. In these two patients, whose annulus diameters were 26 mm and 28 mm respectively, we adopted a classic freehand technique of implantation. Mean postoperative transvalvular gradient was 4 mmHg+/-3 mmHg. The follow-up ranges from 45 days to 14 months (mean 8 months). The aortic regurgitation in the two cases remains stable and no new aortic regurgitations have been detected to date. No embolic or infective episodes occurred during the follow-up. ANATOMIC STUDY: Analysis was performed on 6 couples of valves obtained from cadevers without evidence of previous valvular disease. The normalized Free Edge (FE) dimensions and Leaflet Surfaces (LS) of the pulmonary valve (PV) proved to be larger than the corresponding aortic (AV) measurements (Free edge/Diameter: PV 1.25+/-0.2 vs AV 1.16+/-0.2 p<0.05; Annular Attachment/Diameter PV 1.9+/-0.1 vs AV 1.74+/-0.2 p=NS; Valve Surface/Leaflet Surface PV 0.97+/-0.2 vs AV 0.80+/-0.2 p=0.004) indicating that the PV has a larger coapting surface.
