Root remodeling for aortic root dilatation.

Abstract

Dilatation of the ascending aorta has been found to be the most frequent pathogenic mechanism in aortic regurgitation (1,2). Root remodeling was first proposed by Sarsam and Yacoub as an operation for patients with aortic regurgitation and aortic aneurysm (3), with the assumption that regurgitation was solely due to aortic dilatation. The initial results were good, demonstrating that aortic valve function could be improved or even normalized. The concept of root remodeling was then challenged by aortic valve reimplantation within a vascular graft, as proposed by David (4). A complementary (rather than competitive) role of these two procedures was hypothesized (5). Experimental data investigating cusp mobility after application of these two techniques showed essentially normal cusp motion after root remodeling, which was strikingly different from the abrupt opening and closing movements after valve reimplantation (6). Subsequent studies indicated that the initial results proved difficult to reproduce. The degree of preoperative aortic regurgitation (7) or root dilatation (8), or the presence of acute aortic dissection (9) were observed as risk factors for postoperative aortic regurgitation. None of the authors, however, proposed a plausible mechanism of valve failure and it remains unclear whether failure was induced by the operation per se or the actual conduct of the operation. We have previously found that cusp prolapse can be induced by root replacement, which was for our institution the most frequent reason for secondary valve failure (10). Concomitant repair of cusp prolapse with root remodeling proved to be safe, and it did not compromise the late results (11). Based on the analysis of our failures and investigations in normal cusps, we introduced the effective height concept into aortic valve repair and valve-preserving surgery (12). Intraoperative determination of the effective height of aortic cusps allowed for more objective assessment of cusp configuration and reproducible correction of cusp prolapse (12,13). Furthermore, we have recently showed that the guided combination of prolapse repair with root remodeling has led to significantly better long-term aortic valve function compared to the isolated root procedure (14). In comparison to valve reimplantation, root remodeling consistently takes less time to perform and is applicable in acute dissection as well as in the presence of the usual cardiovascular comorbidities seen in proximal aortic dilatation. Root remodeling thus has become our preferred approach to dilatation of the aortic root. In light of the frequent existence of cusp prolapse it has become an aortic valve repair procedure rather than an aortic operation.