Abstract
We sought to assess commissural alignment of the balloon-expandable valve on fluoroscopy. Commissural alignment was defined on fluoroscopy in 20 patients according to alignment of the valve commissural posts in the 3-cusp and the cusp-overlap view and correlated with post–transcatheter aortic valve replacement computed tomography. Agreement was strong between computed tomography and fluoroscopy (weighted Cohen’s kappa coefficient: 0.88). (Level of Difficulty: Advanced.)
Key Words: aortic valve, computed tomography, valve replacement
Graphical abstract
Commissural alignment (CA) following transcatheter aortic valve replacement (TAVR) is desirable, as severe commissural misalignment might impair transcatheter heart valve (THV) hemodynamics, future coronary access, and repeatability.1 Post-TAVR computed tomography (CT) is the gold-standard for CA evaluation1; however, it is not routinely performed. Fluoroscopic methods have been proposed to assess CA with self-expandable THVs using markers on the delivery system or on the THV.1 The next-generation SAPIEN X4 (Edwards Lifesciences) will have the ability to perform CA. Recent data have shown the possibility to assess CA with the SAPIEN 3 (Edwards Lifesciences) THV using fusion of fluoroscopy and CT images or using a trigonometric approach requiring accurate measurements and calculation.2 We aimed to provide a simplified and practical fluoroscopic method of assessing CA of the balloon-expandable THV using 2 fluoroscopic views.
Learning Objectives
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To understand the relationship between CT and fluoroscopy to assess for commissural alignment with the balloon-expandable THV.
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To identify commissural alignment on fluoroscopy with the balloon-expandable THV using 2 predefined views.
Twenty consecutive patients who underwent balloon-expandable THV implantation were included between July 2021 and July 2022 in our center. The 3-cusp and the left and right cusp-overlap views were used to assess CA following TAVR and accuracy of this method determined with post-TAVR CT. The balloon-expandable THV has 3 markers on the frame, which appears as a double line corresponding to the commissural posts that can be identified on fluoroscopy (Figure 1). CA was defined on fluoroscopy as: 1) aligned if the radiopaque markers of the THV were as followed (1-1-1 in the 3-cusp view and 2-1 in the cusp-overlap view); 2) severely misaligned if the radiopaque markers of the THV were as followed (1-1-1 in the 3-cusp view and 1-2 in the cusp-overlap view); and 3) mildly or moderately misaligned in other configurations (Figure 1). The commissural offset was assessed using an angle tool with the limbs aligned with the native commissure between the noncoronary cusp and the left coronary cusp as well as with the closest THV commissure on post-TAVR CT as previously described.2 The degree of CA was measured on post-TAVR CT in a blinded-fashion using a 3-tier scale: aligned (0°-15°), mildly to moderately misaligned (15°-30° and 30°-45°), or severely misaligned (45°-60°) (Figure 1).1,2 Both the 3-cusp and the cusp-overlap views were determined on pre-TAVR CT, and fluoroscopic images of the THV were captured in both views after THV deployment. Agreement between fluoroscopy and CT was analyzed using the weighted Cohen’s kappa coefficient Prism 7 (GraphPad Software). The protocol has been approved by the Institutional Research Ethics Board of the University of British Columbia and Providence Healthcare Research Institute.
Figure 1.
Fluoroscopic Method for CA Assessment With the Balloon-Expandable THV
(A) The transcatheter heart valve (THV) consists of 3 commissural posts (red circles). (B) Computed tomography (CT) method for measurement of offset between native commissures (green circles) and THV commissures (red circles). (C) Three-cusp (3C) and cusp-overlap (CO) views on CT and fluoroscopy showing commissural alignment (CA). (D) 3C and CO views on CT and fluoroscopy showing severe commissural misalignment. (E) Weighted Cohen’s kappa coefficient for agreement between fluoroscopy and CT. LCC = left coronary cusp; NCC = noncoronary cusp; RCC = right coronary cusp.
The 3-cusp and the left/right cusp-overlap views were achievable in all patients. This fluoroscopic method had good predictive performance for CA with strong agreement between CT and fluoroscopy, as demonstrated by a weighted Cohen’s kappa coefficient of 0.88. Based on fluoroscopy, 4 (20.0%) THVs were classified as aligned, 8 (40.0%) THVs as mildly or moderately misaligned, and 8 (40.0%) THVs as severely misaligned. On CT, 6 (30.0%) THVs were classified as aligned, 6 (30.0%) THVs as mildly (n = 3) or moderately misaligned (n = 3), and 8 (40.0%) THVs as severely misaligned (Figure 1). Only 2 patients had disagreement between fluoroscopy and CT.
We describe a simple and practical fluoroscopic method of assessing balloon-expandable THV CA, requiring only postdeployment noncontrast fluoroscopic acquisitions in the 3-cusp and the cusp-overlap views. The presence of a commissural post centered in the fluoroscopic 3-cusp view (1-1-1 configuration) confirms CA if this central post is posterior and severe misalignment if the central post is anterior. The cusp-overlap view identifies if one post is located between both coronaries (in the native left and right commissure) or if 2 posts are overlapping the coronaries. Finally, future devices may allow commissural alignment prior to THV deployment, and this method could be used in that context.
Although this method allows to reliably determine CA and severe commissural misalignment, it can neither distinguish mild and moderate commissural misalignment nor provide an exact commissural offset angle. Nevertheless, this simple approach allows identification of patients with severe commissural misalignment, which is of interest in clinical practice.
Following balloon-expandable THV deployment, CA can be reliably assessed using a simple fluoroscopic method combining 3-cusp and cusp-overlap views.
Funding Support and Author Disclosures
Dr Meier is supported by the Swiss National Science Foundation (grant P2LAP3_199561). Dr Tzimas is supported by the Fondation Vaudoise de Cardiologie and the SICPA Foundation. Dr Akodad has received research funding from Medtronic, Biotronik, Villa M, MUSE Explore, and the Federation Française de Cardiologie. Dr Leipsic has held institutional research core lab agreements with Medtronic, Edwards Lifesciences, Abbott, Boston Scientific, and Pi-Cardia. Dr Blanke has served as a consultant for Edwards Lifesciences; and provided computed tomography core lab services for Edwards Lifesciences, Medtronic, Neovasc, Boston, and Abbott, for which he has received no direct compensation. Dr Wood has served as a consultant for and received unrestricted grant support from Medtronic, Edwards Lifesciences, and Abbot Vascular. Dr Webb has served as a consultant for Edwards Lifesciences. Dr Sathananthan has served as a consultant for Edwards Lifesciences, Medtronic Boston Scientific, Medtronic, and Anteris; and received speaker fees from Edwards Lifesciences and NVT. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
References
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