Subcoronary implantation or aortic root replacement for human tissue valves: sufficient data to prefer either technique?

The aortic root replacement technique with aortic allograft or pulmonary autograft might be superior to the subcoronary allograft implantation technique with regard to aortic regurgitation. We explored the influence of the learning process on the incidence of reoperation and the severity of postoperative aortic regurgitation as assessed by color Doppler echocardiography. The subcoronary implantation technique was used in 81 patients, and root replacement was done in 63 patients. The first 30 patients of each group were considered as the surgeons' learning curve. Reoperations were more common in the subcoronary implantation group. After exclusion of early reoperations, the median regurgitation score based on echocardiographic examination was 0.22 in the first 30 patients from the subcoronary implantation group and 0.14 in the root replacement group. The subsequent patients from these groups had regurgitation scores of 0.20 and 0.17, respectively. Statistical analysis of these data showed no significant difference. This interim report suggests that the learning curve for the surgical procedure and the grouping of echocardiographic data influence the interpretation of follow-up studies. The superiority of either technique with regard to aortic regurgitation has yet to be proved.