Geometric mismatch between homograft (allograft) and native aortic root: a 14-year clinical experience

We evaluated the effect of homograft/native aortic root geometric matching and mismatching on valve survival and myocardial remodeling.

Between January 1, 1987 and March 2000, a total of 292 patients, aged 1.5-78 years (mean, 46.2 years), underwent freehand subcoronary aortic valve (AVR; n=207) and root (ARR; n=85) replacement with matched and mismatched cryopreserved homografts. All patients had pre- and postoperative two-dimensional Doppler echocardiographic studies. Two-hundred and forty-three survivors, excluding children with complete data on sizing, were followed at a total follow-up time of 1269 patient-years. Seventy percent received matched and 30% received mismatched aortic homografts. The homograft valve sizes ranged from 19 to 28 mm.

Hospital death for elective first operation was 2.3%, and late death after a mean follow-up of 52 months was 7.9%. The patient survival at 14 years was 92+/-2%. By linear regression analysis, matched homografts were equal to or 1-2 mm less than the native aortic annulus (r(2)=0.73). The valve survival in patients with AVR and ARR was 72+/-4 and 80+/-8% at 14 years, respectively. The freedom from reoperation was 92+/-5, 77+/-4 and 48+/-10% at 14 years for matched, oversized and undersized homografts, respectively (P=0.001). The postoperative cardiac index of patients with 22 and 24 mm homografts was 3.8-4.1 l/m(2), and there was a regression of the left ventricular mass and end-diastolic diameter (P=0.001).

The aortic homograft offers an excellent long-term clinical result. A mismatched homograft is a risk factor for postoperative aortic incompetence, reinfection with pseudoaneurysmal formation and reoperation for the freehand subcoronary implantation technique during the first 7 years of the postoperative period. It is prudent therefore to avoid mismatched homografts and use rather a properly sized stentless xenograft if a root replacement is not indicated.