First-degree relatives of bicuspid aortic valve patients with normal aortic dimensions do not carry an increased risk of aortic dilatation

Abstract

Bicuspid aortic valve (BAV) is the most common congenital cardiac diseasewith an estimated incidence in the North American population of 1–2% [1]. Patients with BAV have a lifetime risk of 22–25% of surgery due to aortic valve disease and/or ascending aorta dilatation [1]. This has encouraged cardiac surgeons to be more aggressive in considering replacement of the ascending aorta at a lower diameter (50 mm) than in tricuspid aortic valve (TAV) patients (55 mm) [2]. Recent studies have questioned this kind of “paradigm” [3,4]. First-degree relatives (FDR) of BAV individuals are at an increased risk of inheriting a BAV (9%), or any congenital cardiac disease (31%) [5]. Recently, Biner et al. have shown that 32% of FDRs of BAV patients have dilated aorta [6]. Based on these data, guidelines recommend as class IC, echocardiographic evaluation of all FDR of patients with BAV in search of aortic dilatation and/or BAV [2]. In Biner et al.'s study, BAV patients from whom FDRs were contacted had normal and pathological aorta. We hypothesized that FDRs of BAV patients with normal aortic diameter share a similar risk of aortic dilatation as FDRs of TAV patients. Patients with BAV and TAV who underwent isolated aortic valve replacement and had normal aortic dimensions were identified from the database. FDRs of these patients were contacted by phone to participate in this study. The study complies with the Declaration of Helsinki. Informed consent was obtained and the ethical review board approved the study. Echocardiographic evaluation was done entirely at the echocardiography laboratory of the Department of Cardiology of the University Hospital (Hospital de Clinicas). A single observer supervised by an expert blinded to anthropometric and clinical data of participants performed the measurements. Aortic dimensions (annulus, root, sino-tubular junction, ascending aorta) were obtained during end systole and indexed to body surface area of patients. In order to calculate the sample size needed to find differences between both groups, we used published data obtained from a sample of North American individuals [6]. Based on these data our sample size calculation estimated a total of 20 individuals per group. Continuous data were presented as mean ± standard deviation (SD) and categorical variables as percentage. Continuous variables were compared using independent t test. For comparison of categorical data among the study groups, the Fisher exact test was used. Analysis was performed using the statistical software program SPSS version 18. The significance level was set at p b 0.05. Body surface area was significantly greater in FDR of TAV patients than in BAV patients (p = 0.006). This was mainly due to a higher weight (p = 0.006) (Table 1). All evaluated patients had a normal functioning tricuspid aortic valve. No differences were found at either of the aortic segments between both groups (Fig. 1). There is no evidence regarding the risk of aortopathy in tricuspid FDR of BAV individuals with normal aortic dimensions. The only published report in the matter, documents that aortic root dilation is highly prevalent (32%) in tricuspid FDRs of BAV patients [6]. In this study [6], FDRs were derived from BAV patients in whom 53% had a dilated aorta. Our results show that FDRs of BAV and TAV patients with