Additive Value of CT to Age, Aortic Diameter, and Echocardiography in Diagnosis and Classification of Bicuspid Aortic Valve in Patients with Severe Aortic Stenosis.

Purpose: To develop and validate a CT diagnostic algorithm for bicuspid aortic valve (BAV) classification.

Materials And Methods: This retrospective study included 212 consecutive patients with severe aortic stenosis who underwent CT followed by aortic valve replacement (mean age, 71 years [range, 27-93 years]; 125 women; 37% with a BAV) from 2012 to 2017. BAV diagnosis and BAV category were determined by using the CT diagnostic algorithm developed and were compared with those attained through surgical diagnosis. Reproducibility and agreement were assessed using the Cohen kappa (κ) coefficient. The value of adding CT to age, aortic diameter index, and transthoracic echocardiography (TTE) was evaluated by using the area under the receiver operating characteristic curve (AUC), net reclassification improvement (NRI), and decision-curve analysis.

Results: Intra- and interobserver reproducibility were good or excellent for all CT diagnoses (κ ≥ 0.6 for all). Agreement between CT and surgical diagnoses was excellent (κ = 0.90) for BAV detection and good (κ = 0.69) for BAV categorization. Sixteen percent (five of 31) of patients with functional BAV diagnosed by using CT received a diagnosis of congenital BAV at surgery. The addition of CT to age, aortic diameter, and TTE showed a higher AUC (with CT, 0.97 [95% CI: 0.91, 0.99] vs without CT, 0.91 [95% CI: 0.85, 0.95]; = .003) and NRI (1.79 [95% CI: 1.65, 1.92], < .001) and a higher net benefit among all BAV probabilities.

Conclusion: CT diagnosis was consistent with surgical diagnosis and had an additive value over traditional diagnostic methods; however, there was a risk of overlooking congenital BAV in patients with functional BAV diagnosed by using CT.© RSNA, 2021.