Transcatheter aortic valve replacement (TAVR) has become the standard therapy for elderly patients with symptomatic and severe aortic stenosis. In traditional surgical aortic valve replacement, the artificial valve is sutured to the valve ring at the aortic root, which is less prone to valve malposition; however, TAVR artificial valve is anchored to the aortic valve root by radial support without suture fixation, and is thus likely to encounter valve malposition. Severe valve malposition may result in acute severe aortic regurgitation or valve fall-off, and may entail the implantation of a second valve. Although valve malposition occurs infrequently, it is closely associated with poor prognosis.

Previous studies abroad have shown that, for patients with bicuspid aortic valve stenosis or severe valve calcification who are under TAVR treatment, those adopting self-expandable valve are more prone to valve malposition compared with those adopting balloon-expandable valve during TAVR. At present, TAVR in China mainly adopts self-expandable valve, and the proportion of Chinese patients with bicuspid aortic valve stenosis is quite high, not to mention those with severe valve calcification. Therefore, we should pay more attention to the risk of valve malposition in TAVR patients in China.

So, is there any anatomical predictor of valve malposition during self-expandable TAVR in China?

In order to figure out the answer to the aforesaid question, the team led by Professors Luo Jianfang and Li Jie conducted a multi-center retrospective study in Lingnan Valve Alliance. In this study, the team had patients with Venus A self-expandable valve divided into two groups, namely the valve malposition group and the optimal position group, and compared the CT anatomical features of the two groups of patients. Through multifactor regression analysis, the team found that conical left ventricular outflow tract (the ratio between valve ring circumference and VOT circumference (AL ratio) is lower than 0.96) and tall sinus structure (the height of sinotubular junction (STJ) is not lower than 23.8mm) were independent predictors of self-expandable TAVR valve malposition. If the both conditions were met, the risk of valve malposition would be significantly increased (OR=10.67).

Anatomical predictors of valve malposition during self-expandable TAVR

The dashed lines respectively indicate the planes of STJ, valve ring and LVOT. The arrow indicates the height of STJ. AL: valve ring circumference/LVOT circumference; LVOT: left ventricular outflow tract; OR: odds ratio; STJ: sinotubular junction; TAVR: transcatheter aortic valve replacement.

In this study, the anatomical predictors of valve malposition during self-expandable TAVR were proposed for the first time worldwide, with the specific results thereof being published in the latest issue of Frontiers in Cardiovascular Medicine, a renown journal of cardiovascular disease (IF=6.050).

According to Professor Luo Jianfang, the results of this study will help cardiac surgery teams predict the risk of valve malposition that may occur during TAVR prior to the actual implementation thereof, and formulate countermeasures in advance, which is expected to further improve the efficacy of TAVR and the prognosis of patients with aortic stenosis.