Is preservation of the aortic valve different between acute and chronic type A aortic dissections?

In repair of acute type A aortic dissection, the type of proximal repair of the ascending aorta has been of great interest; however, very few reports are available regarding this issue in chronic aortic dissection. The surgical strategies for proximal repair in chronic dissection may not the same as those for acute dissection. We reviewed our 10-year experience of both acute and chronic type A aortic dissections in order to elucidate the validity of valve preservation and the long-term results of aortic regurgitation (AR).

From 1990 to 1999, 93 patients (55 acute and 38 chronic dissections) underwent operation for type A aortic dissection. Five Marfan patients were included in each group. The degree of AR was evaluated by echocardiography before and after (at hospital discharge and late follow-up) operation.

In acute type A aortic dissection (n=55), 16 patients had AR grade II or greater (29%), of whom seven had AR grade III (13%). In 29 patients, dissection was found below the sinotubular junction (STJ) and 14 patients had AR grade II or greater (48%). The aortic valve was replaced in four patients (7%), of whom three had Marfan's syndrome. Only one non-Marfan patient required aortic valve replacement because of valve stenosis. In those whose aortic valve was preserved (n=51), three patients still had AR grade II at hospital discharge, while at late follow-up, AR had deteriorated to grade III in two of them, although no reoperation has been required so far. In chronic type A aortic dissection (n=38), 14 patients had AR grade II or greater (37%), of whom 11 had AR grade III or greater (29% vs. 13% in acute dissection; P=0.051). In 15 patients, dissection was found below the STJ and 12 patients had AR grade II or greater (80% vs. 48% in acute dissection; P=0.043). The aortic valve was replaced in eight patients (21% vs. 7% in acute dissection; P=0.051), including three Marfan patients. Of those whose aortic valve was preserved (n=30), two patients required reoperation for severe AR. The freedom from postoperative AR grade III or greater was 89% at 5 years for operative survivors with acute dissection and 92% for those with chronic dissection, respectively.

This retrospective study suggests that preservation of the aortic valve in acute type A aortic dissection is feasible in non-Marfan patients regardless of the degree of AR. In chronic dissection, aortic root replacement needs to be considered when the degree of AR is greater than moderate because of a dilated STJ and/or annulus. In both acute and chronic dissections, satisfactory mid- to long-term results with a low incidence of reoperation were obtained in those whose aortic valve was preserved.