Formation of pseudoaneurysm after aortic valve replacement without previous endocarditis: a case-control study.

BACKGROUND The aim of this study was to identify the predisposing factors for pseudoaneurysm formation after aortic valve replacement without previous endocarditis. METHODS Echocardiography was used to identify patients. Parameters with influence on the occurrence of pseudoaneurysms were analyzed, and the odds ratio for the influence of the type of valve was estimated. The chi2 goodness-of-fit test was used to analyze whether location or underlying etiology was associated with an accumulated occurrence of a pseudoaneurysm. Fisher's exact test was used to assess a possible relation between the occurrence of a pseudoaneurysm after composite graft implantation and etiology or location. RESULTS Patients treated with composite grafts had a 27-fold increased risk for developing pseudoaneurysms (psiMH=27; 95% confidence interval, 1.61-454.19) in comparison with aortic valve replacement only. There was a significant difference for the probability of different etiologies to occur (P=.032), with Stanford type A aortic dissection and aortic regurgitation being the most often occurring pathologies. Significant associations between the use of a composite graft and both the underlying etiology (P=.002) and the location of the pseudoaneurysm (P=.04) was found. Furthermore, patients with composite grafts had larger diameters of the aortic root compared with patients with aortic valve replacement only (P=.03). Neither the diameter of the annulus of the aortic valve (95% confidence interval, 0.89-1.32; P=.41) nor the diameter of the ascending aorta (95% confidence interval, 0.27-1.97; P=.54) had any influence on pseudoaneurysm formation. CONCLUSIONS The underlying disorder, determining the surgical procedure, influences the risk for the development of pseudoaneurysms in patients without previous endocarditis. The location of most pseudoaneurysms at the level of the aortic root may be a consequence of its larger diameter.