Intravascular Ultrasound-Guided Contrast-Free Transcatheter Aortic Valve Implantation: A Porcine Feasibility Study

Abstract

Objective Patients undergoing transcatheter aortic valve implantation (TAVI) frequently present with chronic kidney disease and are therefore particularly susceptible to nephrotoxic influences like iodinated contrast media. Acute kidney injury after TAVI is a severe complication that independently predicts short- and long-term mortality. The present study investigates the feasibility of a contrast-free approach by using intravascular ultrasound (IVUS) in conjunction with fluoroscopy. Methods Six domestic pigs (60 ± 5 kg) were anesthetized and underwent transapical implantation of a balloon-expandable transcatheter heart valve. In the control group ( n = 3), the procedures were guided by fluoroscopy/angiography. In the study group ( n = 3), the procedures were guided by IVUS for preimplantation evaluation, intra-procedural guidance, and post-implantation evaluation, in conjunction with fluoroscopy without contrast. The procedures were evaluated by IVUS, fluoroscopy, aortic root angiography, and explantation and dissection of the hearts. Results Relevant anatomical landmarks for correct implantation were assessed by IVUS. The following annulus measurements were obtained: area (359.67 ± 29.58 mm2), perimeter (68.28 ± 2.63 mm), maximum diameter (22.20 ± 1.22 mm), minimum diameter (20.43 ± 1.12 mm), mean diameter (21.32 ± 0.70 mm), ellipticity index (1.09 ± 0.10), and area-derived diameter (21.39 ± 0.87 mm). IVUS-guided valve deployment resulted in correct expansion within the aortic annulus without signs of paravalvular leak, compromised mitral valve, or coronary obstruction. IVUS-guided post-implantation assessment confirmed circular expansion (25.88 ± 0.30 mm) of the valves. Conclusions IVUS-guided, contrast-free transapical TAVI is feasible in a porcine model.