Natural history of the ascending aorta after aortic valve replacement: risk factor analysis for late aortic complications after aortic valve replacement

Background The purpose of this study was to clarify the natural history of the ascending aorta and to identify risk factors for late ascending aortic events after first isolated aortic valve replacement (AVR). Methods A total of 287 patients undergoing AVR were enrolled. The patients were categorized into two groups based on the diameter of the ascending aorta at the time of AVR, as determined by computed tomography: Group A (n = 233) was defined as an ascending aortic diameter <40 mm, and Group B (n = 54) was defined as an ascending aortic diameter >= 40 mm. Results The mean follow-up period was 7.6 years. The baseline diameter of the ascending aorta was 31.4 +/- 4.8 mm in Group A and 44.7 +/- 4.2 mm in Group B. These values increased to 35.9 +/- 7.4 mm in Group A and 50.1 +/- 7.3 mm in Group B during the follow-up period (P < 0.001). Ten patients had acute type A aortic dissection (Group A: 1 patient vs. Group B: 9 patients; P < 0.001), and three patients had enlargement of the ascending aorta to >= 55 mm in diameter (Group A: 1 patient vs. Group B: 2 patients). Multivariate analysis revealed that the baseline ascending aortic diameter was the only significant risk factor for developing late ascending aortic events (P < 0.001). Conclusions AVR alone may not prevent further enlargement of the ascending aorta. An ascending aorta >= 40 mm in diameter at the time of AVR increased the risk of late ascending aortic events.