Long-Term Prognosis of Ascending Aortic Aneurysm After Aortic Valve Replacement for Bicuspid Versus Tricuspid Aortic Valve Stenosis
Are there different risks of late aortic events after isolated aortic valve replacement for patients with bicuspid versus tricuspid aortic valve stenosis and concomitant mild to moderate dilatation of the proximal aorta?
A total of 325 consecutive patients (60% males, mean age 59.5 ± 10 years) with aortic valve stenosis and concomitant ascending aortic dilatation of 40-50 mm underwent isolated aortic valve replacement between 1995 and 2000. A total of 153 patients (47%) were diagnosed with bicuspid aortic valve stenosis, and the remaining 172 patients (53%) had tricuspid aortic valve stenosis. Follow-up (3,566 patient-years) was 100% complete. Adverse aortic events were defined as the need for proximal aortic surgery or the occurrence of aortic dissection/rupture or sudden death during follow-up.
Overall survival was 78 ± 4% in the bicuspid aortic valve group versus 55 ± 6% in the tricuspid aortic valve group (p = 0.006) at 15 years postoperatively, but age-adjusted survival was not significantly different between groups (p = 0.4). A total of five patients (3%) in the bicuspid aortic valve group versus nine patients (5%) in the tricuspid aortic valve group underwent proximal aortic surgery during follow-up. Aortic dissection occurred in three patients in the tricuspid aortic valve group and in no bicuspid aortic valve patients. Freedom from adverse aortic events at 15 years was 93 ± 3% in the bicuspid aortic valve group versus 82 ± 6% in the tricuspid aortic valve group (p = 0.2).
Patients with bicuspid and tricuspid aortic valve stenosis with concomitant mild to moderate ascending aortic dilatation are at comparably low risk of adverse aortic events 15 years after isolated aortic valve replacement.
Compared to patients with a tricuspid aortic valve, patients with a bicuspid valve appear to have ascending aorta dilation that is out of proportion to the severity of aortic stenosis or regurgitation; further, patients with a bicuspid aortic valve are thought to be at greater risk of progressive aortic dilation after aortic valve replacement. These observations form the basis of a proposed genetic aortopathy associated with bicuspid aortic valve, and are the basis of current guideline recommendations for more aggressive treatment of proximal ascending aorta dilation among patients with bicuspid aortic valve at the time of surgical aortic valve replacement. However, other data suggest that flow abnormalities related to fusion patterns may be a major contributor to aortic dilation among patients with bicuspid valve (e.g., MM Bissell, et al. Circ Cardiovasc Imaging 2013;6:499-507). The present study suggests that patients with a bicuspid aortic valve undergoing aortic valve replacement for aortic stenosis have a low risk of future aortic events that is similar to patients with a tricuspid aortic valve.
Keywords: Prognosis, Tricuspid Valve Stenosis
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