Comparing imaging modalities for screening aortic complications in patients with bicuspid aortic valve.

OBJECTIVE: Bicuspid aortic valve (BAV) is associated with aortic root and ascending aorta aneurysm and increased risk for aortic dissection. Guidelines recommend transthoracic echocardiography (TTE) for primary aortic evaluation, although cardiac magnetic resonance (CMR) may be superior at detecting abnormalities. This study compares TTE and CMR imaging for aortic evaluation in patients with BAV.

DESIGN: Data from all patients ≥13 years of age with BAV who underwent CMR between 2003 and 2009 at our institution were reviewed, including demographics, blood pressure (BP), and TTE findings prior to CMR. TTE and CMR aortic maximum diameter (MaxD) measurements were compared using paired t-tests. Based on CMR findings, TTE sensitivity was evaluated for aortic dilation (sinuses of Valsalva [SV] ≥ 3.5 cm, ascending aorta [AscAo] ≥ 3.8 cm), and aneurysm defined as MaxD cross-sectional area/height ≥ 10. Linear regression was used to identify risk factors associated with MaxD.

RESULTS: There were 106 patients with mean age at CMR 34 ± 13 years. Mean CMR MaxD was 37 ± 7 mm. TTE and CMR MaxD mean difference (-1.6 mm) was statistically significantly (P =.002), particularly when TTE AscAo was not measured (-2.0 mm, P =.007). TTE sensitivity was 75% (SV) and 47% (AscAo) for dilation, and 100% (SV) and 83% (AscAo) for aneurysm. Bivariate correlation showed significant positive association between MaxD and diastolic BP and weight (P <.05). With multivariate regression, MaxD was significantly smaller in patients with coarctation of the aorta (P <.001).

CONCLUSION: TTE missed aortic dilation and aneurysm, particularly when AscAo evaluation was incomplete. Therefore, CMR is a valuable adjunctive imaging modality in aortic screening of patients with BAV.