Tricuspid and Bicuspid Aortic Regurgitation in the Adult Asian Population

Tricuspid aortic valve patients in Taiwan may be at a later stage of aortic regurgitation (AR) and experience a higher incidence of aortic dissection (AD) vs patients in Taiwan with bicuspid aortic valve (BAV)-AR, according to study findings published in the Journal of the American College of Cardiology: Asia.

Researchers in Taiwan sought to evaluate the differences between tricuspid aortic valve (TAV)-AR and BAV-AR in significant AR in Asian patients, including aorta complications. Primary outcomes included all-cause death and overall survival vs expected survival. Secondary outcomes included incidence of AD, aortic valve surgery (AVS), and surgical indications.

The researchers conducted a retrospective, cohort study in a tertiary university hospital in Taiwan that included 711 consecutive patients from 2008 until 2020. Patients were at least 18 years of age with chronic moderate-to-severe and severe AR. Among the patients, there were 562 TAV-AR (mean age, 68±15 years) and 149 BAV-AR (mean age, 48±16 years; P <.0001) patients. Researchers noted at baseline that indexed left ventricle and indexed aorta size were larger in the TAV-AR group. Compared with the other cohort, patients with BAV were mostly men, had larger body surface area, lower maximal pressure-gradient of tricuspid regurgitation, smaller left atrial volume, and fewer comorbidities.

The observed total follow-up was 4.8 years (IQR, 2.0-8.4 years), 252 patients experienced AVS (51 BAV, 201 TAV), and 185 patients died during follow-up. There were 18 cases of AD (17 TAV), with a mean maximal aorta size of 60±9 mm. There was no transcatheter aortic valve replacement. The TAV-AR 10-year AVS incidence was higher (51%±4%) vs BAV-AR (40%±5%) even after adjustment for covariates (P <.0001).

Researchers found the BAV-AR 10-year survival was higher (86%±4%) vs TAV-AR (57%±3%; P <.0001) and insignificant after age adjustment (P =.33). They noted 10-year survival post-AVS was 93%±5% in BAV-AR and 78%±5% in TAV-AR, respectively (P =.08). They found the TAV-AR 10-year incidence of AD was higher (4.8%±1.5%) than in BAV-AR (0.9%±0.9%) and determined by aorta size equal to or greater than 45 mm (P =.015). Patients with BAV-AR were less frequently operated on for symptoms and more for left ventricular end-systolic dimension index greater than 50 mm compared with patients with TAV-AR.

Researchers noted TAV-AR (hazard ratio, 3.1) had reduced survival (P <.0001) compared with a sex- and age-matched population in Taiwan. Compared with a US cohort, post-AVS survival in both groups and BAV-AR overall survival were similar. TAV-AR patients in Taiwan had a larger survival gap and both groups in Taiwan had larger indexed left ventricle size, larger indexed and absolute aorta size, and lower incidence of AVS than the US cohort.

Study limitations include the presence of selection bias, the younger age and smaller sample size in the BAV-AR group, and that important images were not routinely obtained. There is also lack of genetic testing for aorta disease and measurement variations affect results.

Researchers concluded that the differences they observed between cohorts of Asian patients with TAV-AR and BAV-AR in Taiwan was not precisely the same as the differences in a US cohort. The study authors noted, “This cohort exhibited a larger baseline indexed left ventricle and aorta size for TAV-AR, suggesting that TAV-AR patients were at later stage of the AR natural course. Superior survival was noted in BAV-AR vs TAV-AR patients, who had a higher surgical incidence.” They believe this emphasizes the importance of timely management with early referral.

Reference

Yang LT, Lo HY, Lee CC, et al. Comparison between bicuspid and tricuspid aortic regurgitation: presentation, survival, and aorta complications. JACC Asia. Published online April 2, 2022. doi:10.1016/j.jacasi.2022.02.012