THE USE OF PULMONARY ALLOGRAFTS FOR AORTIC-VALVE REPLACEMENT - SHORT-TERM RESULTS AND COMPARATIVE MORPHOMETRIC ANALYSIS OF THE AORTIC AND PULMONARY VALVES

The satisfactory results of aortic valve replacement with pulmonary au tograft and the limited availability of aortic allografts prompted us to use the pulmonary valve as an aortic valve substitute and to perfor m a morphometric analysis of the two valves in cadavers, Clinical stud y. From March 1994 to March 1995 20 patients underwent an aortic valve replacement (AVR) with a pulmonary allograft (PA). Twelve patients we re men, 8 women; age ranged from 15 to 58 years, In 4 cases the indica tion to AVR was an infective endocarditis which was acute in two patie nts. Functional class was NYHA II in 18 cases and NYHA III in 2 patien ts with active endocarditis. Left ventricular ejection fraction (LVEF% ) was preserved in the majority of patients (mean LVEF=53% range 36% t o 65%), End diastolic aortic valve diameters mere measured by bidimens ional echocardiography in parasternal long axis view and ranged from 1 8 mm to 29 mm, The diameters of the allografts implanted ranged from 1 9 mm to 27 mm. Donors age ranged from 19 years to 55 years. We tried t o use the allograft from the youngest donor available, The surgical te chnique was the classic ''Ross'' coronary freehand implantation in II cases, a ''Miniroot'' implant in 8 instances and a ''Miniroot'' implan t 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 mec hanical valve because the echocardiograph?showed a rapidly increasing aortic regurgitation, At hospital discharge a slight aortic regurgitat ion was detected in 2 cases, In these two patients, whose annulus diam eters mere 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 (m ean 8 months), The aortic regurgitation in the two cases remains stabl e and no new aortic regurgitations have been detected to date, No embo lic or infective episodes occurred during the follow-up. Anatomic stud y. Analysis was performed on 6 couples of valves obtained from cadever s without evidence of previous valvular disease, The normalized Free E dge (FE) dimensions and Leaflet Surfaces (LS) of the pulmonary valve ( PV) proved to be larger than the corresponding aortic (AV) measurement s (Free edge/Diameter: PV 1.25+/-0.2 us 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 tha t the PV has a larger coapting surface.