Impact of Straight Ascending Aorta Length on Difficulty of Transcatheter Heart Valve Crossing during Transcatheter Aortic Valve Replacement

Abstract

Objective: Although most transcatheter aortic valve replacement (TAVR) procedures for symptomatic severe aortic valve stenosis (AS) can be performed successfully, there are some challenging cases with several specific anatomical characteristics, such as a horizontal aorta, aortic dilatation, and bicuspid aortic valve. A short, straight ascending aorta length (SAAL) can cause the transcatheter heart valve (THV) device to lack the distance required to orient in the direction of the aortic annulus, leading to failure to cross the aortic valve. This study aimed to examine the characteristics of SAAL and its association with the difficulty of THV device crossing.

Methods: This is a retrospective study that included 307 consecutive patients with symptomatic severe AS who underwent TAVR at our hospital from October 2018 through July 2024. Patients were divided into two groups based on SAAL: the short SAAL group (<42.8 mm, n = 50) and the long SAAL group (≥42.8 mm, n = 257). The cutoff value was determined using receiver-operating characteristic (ROC) curve analysis and the Youden Index (area under the curve [AUC] = 0.75; sensitivity = 0.85; specificity = 0.71). The primary endpoint was difficulty in THV device crossing on the first attempt using the standard technique, without the aid of assistive devices such as a snare system.

Results: In the overall population, the rate of difficulty in THV device crossing through the aortic valve was 2.2%. The short SAAL group had a significantly higher rate of crossing difficulty compared to the long SAAL group (5 cases, 10.0% vs. 2 cases, 0.7%; p = 0.002). In a univariate logistic regression analysis, SAAL was significantly associated with difficult THV device crossing (per 1-mm increase: odds ratio [OR] = 0.86, 95% confidence interval [CI]: 0.77–0.96, p = 0.009; SAAL <42.8 mm: OR = 14.37, 95% CI: 2.70–76.42, p = 0.002). ROC analysis showed that SAAL was more predictive of difficulty in THV device crossing compared to other conventional anatomical factors (per 1-mm increase: AUC = 0.75, 95% CI 0.54–0.97, p = 0.019; SAAL <42.8 mm: AUC = 0.78, 95% CI 0.58–0.98, p = 0.010).

Conclusion: In patients with SAAL <42.8 mm, THV device crossing is more challenging during TAVR. Preoperative SAAL measurement, in addition to conventional anatomical factors, may provide valuable procedural guidance in determining whether an assistive device is needed, thereby helping to prevent severe complications.