UP TO 30-YEAR SURVIVAL AFTER AORTIC-VALVE REPLACEMENT IN THE SMALL AORTIC ROOT

Aortic valve replacement (AVR) in the small aortic root has been repor ted to be associated with obstruction of left ventricular output. This study was designed to investigate the determinants of long-term survi val after the implantation of small size prostheses. From September 19 61 to December 1993, 2,977 patients underwent isolated aortic valve re placement at our institution. Of these patients, 447 who were older th an 18 years received small size (21 mm or less) prostheses. Long-term survival was investigated in the 404 patients who survived operation ( more than 30 days) with 92% follow-up completeness (mean +/- deviation 7.1 +/- 6.4; maximum, 31 years). The age was younger than 50 years in 62 patients, 50 to 59 years in 60, 60 to 69 years in 99, 70 to 79 yea rs in 138, and 80 to 94 years in 45; 67% were men. Thirty patients (7% ) had previous AVR. prosthesis usage included early Starr-Edwards mode ls in 130 (32%), current Starr-Edwards (model 1260 since 1969) in 50 ( 12%), Carpentier-Edwards (porcine) in 113 (28%), and other prostheses in 111 patients (27%). One hundred sixteen patients (26%) had concomit ant coronary artery bypass grafting (CABG). Eleven variables (age divi ded as above, sex, preoperative functional class, body surface area [B SA], small BSA [less than 1.6, 1.7, 1.8, or 1,9 m(2)], period of opera tion, previous AVR, type of prosthesis, size of prosthesis, concomitan t CABG, and re-replacement) were investigated with regard to the long- term survival by the Kaplan-Meier method, and age, concomitant CABG, a nd type of prosthesis were significant. Multivariable analyses (Cox pr oportional hazard regression) were performed for the whole group as we ll as subsets of patients. The multivariable analyses reveal that conc omitant CABG and age are independent variables to determine the long-t erm survival. In the subgroup of patients without concomitant CABG, ag e was the only independent variable found to determine long-term survi val and in the subgroup of the patients with concomitant CABG, BSA les s than 1.7 m(2) is the only independent variable. We conclude that pat ients with small aortic root and small BSA may have satisfactory long- term results after isolated AVR and that old age and concomitant CABG are the risk factors for long-term survival in those patients. However , mismatch between body size and prosthesis size is a negative determi nant for long-term survival in the subgroup of patients who receive sm all size of prostheses with concomitant CABG.