Clinical Course and Mid- to Long-Term Outcome of Chimney Stenting in Patients With Small Anatomy Undergoing Self-Expanding Transcatheter Aortic Valve Implantation.

Background: Coronary obstruction (CO) is a catastrophic complication of transcatheter aortic valve implantation (TAVI). Chimney stenting (CS) is one of the direct preventive measures for CO; however, data on its clinical course and characteristics are limited. We evaluated mid- to long-term outcomes of prophylactic CS during TAVI using supra-annular self-expanding bioprostheses. Methods and Results: Among 315 consecutive TAVI procedures with supra-annular self-expanding valves between November 2015 and April 2022, 14 patients at high risk for CO underwent prophylactic CS. The clinical outcomes of the CS group were investigated using a non-CS group (n=301) as a comparison reference. High-risk anatomy was identified by preprocedural computed tomography assessing the sinotubular junction, sinus of Valsalva, coronary height, and annular calcification. CS was performed when balloon aortic valvuloplasty with simultaneous aortography demonstrated absent coronary opacification or impending obstruction. Patients in the CS group were predominantly female with a smaller body size, smaller aortic root dimensions, and low left coronary height (9.6 vs. 12.5 mm; P<0.001). Dual antiplatelet therapy was administered in 93% of CS patients for a mean duration of 7.4 months. During a mean follow up of 4.3 years, mortality was similar to that of non-CS patients (log-rank P=0.756). Conclusions: The clinical outcomes of prophylactic chimney stenting were comparable with the conventional TAVI cohort; therefore, it may be considered a therapeutic option for patients at high risk of CO during supra-annular self-expanding TAVI.