A Novel Protocol for Contrast-Free Transcatheter Aortic Valve Replacement Evaluation and Implantation

Abstract

Background

We aimed to develop a transcatheter aortic valve replacement (TAVR) sizing algorithm and implantation method to facilitate safe and effective TAVR without contrast use in patients with severe chronic kidney disease (CKD) who do not yet require renal replacement therapy. Patients with CKD are a challenging patient subset to treat using standard TAVR care pathways which most usually require the use of iodinated contrast media both during gated computed tomography (CT) angiography sizing, and valve deployment. Iodinated contrast exposure may worsen kidney function in a dose-dependent fashion, and may result in a need for renal replacement therapy. Therefore, a method to eliminate, or greatly lessen, contrast exposure during TAVR is highly desirable.

Methods

One hundred sixty patients who underwent standard CT angiography and TAVR implantation were used to develop (100 patients) and validate (60 patients) an algorithm to predict balloon-expandable valve size using measurements available from noncontrast CT. Model accuracy was measured using Pearson correlation between algorithm-predicted valve size and actual size used based on annular area. As proof of concept, we then report a case series of 35 consecutive patients who underwent TAVR evaluation and implantation with moderate sedation and no contrast between May 2021 and April 2024.

Results

The valve sizing algorithm incorporates sinus and sinotubular junction diameters, both available from a reformatted noncontrast, cardiac-gated CT. The algorithm demonstrated a strong correlation with the actual valve size used (development cohort R = 0.81, validation cohort R = 0.76). Thirty-five patients underwent “no-contrast TAVR” with noncontrast CT for valve sizing. Forty-eight percent were urgent inpatient TAVR. Technical procedural success, as defined by the VARC3 criteria, was 100%, with no patient deaths during the index procedure. Three patients had a mild paravalvular leak. No valve embolization or need for a second valve occurred. Four patients required a pacemaker.

Conclusions

We present a novel algorithm for TAVR evaluation and implantation without the use of iodinated contrast media in a high-risk patient subset with CKD.