Multimodality imaging evaluation before transcatheter aortic valve implantation: incidence of contrast medium-induced acute kidney injury, risk factors and prognosis

Diagnostic Performance of CCTA and CT-FFR for the Detection of CAD in TAVR Work-Up

BACKGROUND

The work-up for transcatheter aortic valve replacement (TAVR) currently uses computed tomography to evaluate the annulus diameter and peripheral vascular access plus invasive coronary angiography (ICA) to assess significant coronary artery disease (CAD). ICA might partially be redundant with the use of coronary computed tomography angiography (CCTA). Prior studies found an improvement of the diagnostic accuracy of CCTA with the use of computed tomography-derived fractional flow reserve (CT-FFR).

OBJECTIVES

The aim of this study was to assess the diagnostic performance of CT-FFR for the diagnosis of CAD in the work-up for TAVR.

METHODS

Consecutive patients with severe symptomatic aortic valve stenosis who underwent TAVR work-up between 2015 and 2019 were included in this retrospective cross-sectional study. All patients underwent CCTA and ICA within 3 months, and the diagnostic performance of both CCTA and CT-FFR was assessed using ICA as the reference.

RESULTS

Seventy-six of the 338 patients included in the analysis had ≥1 significant coronary stenosis on ICA. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy per patient were 76.9%, 64.5%, 34.0%, 92.1%, and 66.9% for CCTA and 84.6%, 88.3%, 63.2%, 96.0%, and 87.6% for CT-FFR. The area under the receiver-operating characteristic curve was significantly different between CCTA and CT-FFR (0.84 vs 0.90, P = 0.02). A CT-FFR-guided approach could avoid ICA in 57.1% versus 43.6% of patients using CCTA.

CONCLUSIONS

CT-FFR significantly improves the diagnostic accuracy of CCTA without additional testing and increases the proportion of patients in whom ICA could have been safely avoided. It has the potential to be integrated in the current clinical work-up for TAVR for diagnosing stable CAD requiring treatment.

Non-contrast MRI protocol for TAVI guidance: quiescent-interval single-shot angiography in comparison with contrast-enhanced CT

Objectives

To prospectively compare unenhanced quiescent-interval single-shot MR angiography (QISS-MRA) with contrast-enhanced computed tomography angiography (CTA) for contrast-free guidance in transcatheter aortic valve intervention (TAVI).

Methods

Twenty-six patients (mean age 83 ± 5 years, 15 female [58%]) referred for TAVI evaluation underwent QISS-MRA for aortoiliofemoral access guidance and non-contrast three-dimensional (3D) “whole heart” MRI for prosthesis sizing on a 1.5-T system. Contrast-enhanced CTA was performed as imaging gold standard for TAVI planning. Image quality was assessed by a 4-point Likert scale; continuous MRA and CTA measurements were compared with regression and Bland-Altman analyses.

Results

QISS-MRA and CTA-based measurements of aortoiliofemoral vessel diameters correlated moderately to very strong (r = 0.572 to 0.851, all p ≤ 0.002) with good to excellent inter-observer reliability (intra-class correlation coefficient (ICC) = 0.862 to 0.999, all p < 0.0001) regarding QISS assessment. Mean diameters of the infrarenal aorta and iliofemoral vessels differed significantly (bias 0.37 to 0.98 mm, p = 0.041 to < 0.0001) between the two modalities. However, inter-method decision for transfemoral access route was comparable (κ = 0.866, p < 0.0001). Aortic root parameters assessed by 3D whole heart MRI strongly correlated (r = 0.679 to 0.887, all p ≤ 0.0001) to CTA measurements.

Conclusion

QISS-MRA provides contrast-free access route evaluation in TAVI patients with moderate to strong correlations compared with CTA and substantial inter-observer agreement. Despite some significant differences in minimal vessel diameters, inter-method agreement for transfemoral accessibility is strong. Combination with 3D whole heart MRI facilitates unenhanced TAVI guidance.

Key Points

• QISS-MRA and CTA inter-method agreement for transfemoral approach is strong.

• QISS-MRA is a very good alternative to CTA and MRA especially in patients with Kidney Disease Outcomes Quality Initiativestages 4 and 5.

• Combination of QISS-MRA and 3D “whole heart” MRI facilitates fully unenhanced TAVI guidance.