Clinical characteristics and outcomes of aortic valve and coronary artery calcification burden in patients with bicuspid and tricuspid severe aortic stenosis in a multi-ethnic asian population

Introduction Aortic valve calcification (AVC) is associated with the severity of aortic stenosis, and the increase in the coronary artery calcium (CAC) score is associated with a higher CV risk. The association between these is rarely described in bicuspid and tricuspid severe aortic stenosis (AS), and the association with clinical outcomes is underexplored, especially in a multi-ethnic Asian population. Purpose We aimed to describe the AVC score and CAC score severity and distribution, its association with the bicuspid and tricuspid severe AS, and its association with outcomes. Methods We included patients with severe aortic stenosis who underwent computed tomography with a transcatheter aortic valve implantation (CT TAVI) protocol from 2017 to 2022. Patients were stratified based on the bicuspid aortic valve and tricuspid aortic valve. We compared the AVC score and CAC score. Clinical echocardiogram data within 6 months of the CT TAVI were obtained, and a composite outcome of heart failure admission, stroke, myocardial infarction and all-cause mortality was analyzed with Cox regression. Results 238 patients were included and stratified to the tricuspid group (n=197,83%) and bicuspid group (n=41,17%). The degenerative group was older (mean age 76.6±84 vs 72.3±7.6, p=0.003), and half were female (103, 50.2% vs 17, 41.5%). The tricuspid group had more comorbidities (diabetes 112, 56% vs 10, 24.4% p=<0.001; hypertension 180, 91.4% vs 29, 70.7% p=<0.001; hyperlipidemia 172, 87.3% vs 29, 70.7% p=0.008; coronary artery disease 114, 57% vs 14, 34% p =0.006; chronic kidney disease 77, 39% vs 7, 17% p=0.007). The mean left ventricular ejection fraction and left ventricular mass index were similar. We observed that the AVC score for the tricuspid group was significantly lower [2018AU (IQR 1238-2965) vs 3524.3AU (IQR1852.1-5066.1) p=<0.001]. Conversely, the CAC score for the degenerative group was significantly higher [1243.7 AU (IQR 432-2690.1) vs 270.5AU (IQR95.1-931.4) p=<0.001]. A majority of the degenerative group had a CAC score of more than 100AU (127,92% vs 25, 69.4% p=<0.001). We observed that an increased CAC score(>400AU) was associated with an increased hazard of the composite outcome (HR 0.97, CI 0.96 to 0.98, P <0.038). However, there was no difference in terms of composite outcome when comparing the AVC score and aortic leaflet morphology. Conclusion In patients with severe aortic stenosis, the tricuspid group had more comorbidities, a lower AVC score and higher CAC scores than the bicuspid group. This discordant distribution in calcification, suggests that the hemodynamic effects of the valve are possibly contributors to aortic valve calcification, and that the calcification mechanisms are possibly distinct from those underlying coronary artery calcification. A higher CAC score confers a poorer prognosis in this cohort of patients.