Evaluation of bicuspid aortic valve-associated aortopathic changes using third-generation dual-source computed...

Bicuspid aortic valve (BAV) affects 0.5%-2% of the population and is associated with progressive aortopathy leading to life-threatening complications. Aortic size index (ASI) adjusts aortic dimensions for body surface area (BSA), potentially improving risk stratification.

To characterise BAV-associated aortopathic changes using third-generation dual-source computed tomography (CT) and to derive a cohort-specific ASI threshold associated with CT-defined ascending aortic dilatation in an Indian population.

This prospective cross-sectional study enrolled 100 BAV patients (age > 18 years) from July 2022 to November 2023. All patients underwent CT aortography using 192-slice third-generation dual-source CT scanner (Somatom Force, Siemens). Aortic measurements were obtained at multiple levels including annulus, sinus of Valsalva, ascending aorta, arch, and descending thoracic aorta. ASI was calculated as maximum ascending aortic diameter divided by BSA. Statistical analysis included receiver operating characteristic curve analysis and correlation coefficients.

Mean age was 48.95 ± 13.78 years, with 64% males. Ascending aortic dilatation was present in 87% of patients, with a mean diameter of 42.79 ± 8.69 mm. Mean ASI was 25.13 ± 5.71 mm/m² with 42% having ASI > 25 mm/m² (high-risk category). ASI strongly correlated with ascending aortic diameter (rho = 0.87, P < 0.001). At ASI cutoff ≥ 23.8 mm/m² sensitivity was 84% and specificity 90% for predicting aortic dilatation > 40 mm. The mean measurement difference between CT and echocardiography was 11.72 ± 8.27 mm.

In this single-centre cohort of Indian patients with BAVs, an ASI threshold of 23.8 mm/m² was associated with CT-defined ascending aortic dilatation and may serve as a cohort-specific reference for risk stratification. Because ASI is mathematically derived from ascending aortic diameter, this finding should be interpreted as a cohort-specific threshold rather than independent validation of ASI as a predictor. Third-generation dual-source CT yielded larger absolute aortic measurements than transthoracic echocardiography; this difference is likely partly methodological, reflecting non-equivalent measurement sites, measurement conventions, and inherent limitations of 2D echocardiography in BAV.