Impact of institutional volume and experience with CT interpretation on sizing of transcatheter aortic valves: A multicenter retrospective study.

BACKGROUND

Computed tomography (CT) has become the standard imaging modality for pre-procedural aortic annular sizing prior to transcatheter aortic valve replacement (TAVR). We hypothesized that the accuracy of CT derived annular measurements would be greater at sites with higher TAVR procedural volume.

METHODS

Within a large integrated health system, TAVR was performed at low (<40 cases), intermediate (40-75 cases), and high-volume sites (>75 cases). 181 patients underwent TAVR with a Sapien XT transcatheter heart valve (THV). Two blinded experienced readers independently remeasured the annulus on CT and compared their measurements to site reported measurements. Hypothetical THV sizes were chosen based on measurements from site CT reports and independent readers' measurements, and compared to the implanted THV size.

RESULTS

Correlation between site reported measurements and independent readers measurements of mean annulus size varied between low-volume (r=0.31, p=0.18), intermediate-volume (r=0.34, p=0.01), and high-volume sites (r=0.96, p<0.01). On multivariate analysis, interpretation of ≥20 CT scans (OR 0.29; 95% CI 0.03-0.81; p 0.02) and high-volume site (OR 0.16; 95% CI 0.10-0.82; p 0.02) were associated with reduced mismatch between the site predicted THV size and independent readers predicted THV size. Mismatch between site predicted THV size and implanted THV size was associated with a worse 30-day composite of mortality, dialysis-dependent renal failure, cerebrovascular accident, new permanent pacemaker, and hospital readmission (55.3 vs. 38.7%; p=0.05).

CONCLUSIONS

Accuracy of CT aortic annular sizing is improved with higher individual experience and site TAVR volume. These findings should be confirmed in larger, prospective studies.