Predictors of proximal aortic dissection at the time of aortic valve replacement

Background-Type I aortic dissection develops in 0.6% of patients late after aortic valve replacement (AVR), and 13% of patients with type I aortic dis sections have a history of AVR. Predictors of aortic dissection at AVR, how ever, have not been characterized. Methods and Results-A study group of 33 patients with type I aortic dissect ion had aortic surgery 49 +/- 55 months after routine AVR, A group of 101 c ontrols, who did not have morphological progression of aortic diameters gre ater than or equal to 6 years after AVR, was used to identify predictors of postsurgical dissection. Multivariate analysis identified aortic regurgita tion (P < 0.002) and fragility (P < 0.001) or thinning of the aortic wall ( P < 0.007) at AVR as predictors, associated with a 14%, 22%, and 7% probabi lity of late aortic dissection, respectively. Clamping times, types of valv e prostheses, concomitant coronary artery bypass grafting, and mean ascendi ng aortic diameters of 43 +/- 10 mm at AVR did not predict late dissection. A separate analysis of 29 nondissecting aneurysms of the ascending aorta d eveloping 104 +/- 64 months after routine AVR revealed younger age at AVR ( P < 0.003) and congenitally bicuspid aortic valves (P < 0.03) as predictors of late aneurysm formation. Conclusions-Aortic regurgitation combined with fragile and thinned aortic w alls in patients with moderate aortic dilation may reflect aortic root dise ase, with a high risk for postsurgical aortic sequelae if it is treated inc ompletely by isolated valve replacement.