Objectives: Transcatheter aortic valve implantation (TAVI) is an established therapy. To maintain transvascular access in patients not eligible for the transfemoral approach, transaxillary (TAx)-TAVI is increasingly performed. The multicenter retrospective observational TAXI (Trans-AXillary Intervention) international registry showed that percutaneous axillary access is superior to surgical access in TAx-TAVI. In this subanalysis of the TAXI registry we aimed to compare procedural success in TAx-TAVI according to different types of transcatheter heart valves (THV) with a special emphasis on anatomical conditions.

Methods: For the TAXI international registry (clinicaltrials.gov NCT02713932) anonymized data from 18 centers were collected. Follow-up was based on direct patient visits and echocardiographic controls. Acute procedural, early clinical and 1-month outcomes were adjudicated in accordance with standardized VARC-3 definitions.

Results: From a total of 432 patients, 368 patients (85.3%, SE group) received a self-expanding (SE) THV and 64 patients (14.8%, BE group) a balloon-expandable (BE) THV. Preprocedural imaging revealed lower axillary artery diameters in SE group (max/min diameter in mm: 8.4/6.6 vs. 9.4/6.8 mm; p<0.001/p=0.04) but a higher proportion of axillary tortuosity in BE group (62/368, 23.6% vs. 26/64, 42.6%; p=0.004) with steeper aorta-left ventricle (LV) inflow (55 vs. 51°; p=0.002) and left ventricular outflow tract-LV inflow angle (40.0 vs. 24.5°; 0.002). TAx-TAVI was significantly more often conducted by the right sided axillary artery in BE group (33/368, 9.0% vs. 17/64, 26.6%; p<0.001). Device success was higher in SE group (353/368, 95.9% vs. 44/64, 68.8%, p<0.001). No significant differences were found regarding other outcomes. However, in logistic regression analysis, BE THV were a risk factor for vascular complications and axillary stent implantation.

Conclusions: TAx-TAVI using SE THV leads to a significant higher rate of device success. However, patients receiving BE THV presented with significantly more axillary tortuosity, steeper inflow angles and were more often provided with a right sided access. Advantage of the flexible delivery catheter of BE THV may be the leading consideration when utilizing BE THV in more complex anatomy in TAx-TAVI, conversely the obligatory sheath may adversely impact steerability in hostile vascular conditions. Based on the herein presented data of this large multicenter registry, TAx-TAVI with SE-THV should be preferred over utilization of BE-THV unless specific anatomical considerations occur.