Asymmetrical Expansion of Balloon-Expandable Transcatheter Aortic Valve Prostheses: Implications for Valve Hemodynamic and Clinical Outcomes.

ABSTRACT

BACKGROUND: Asymmetrical expansion of transcatheter heart valves (THVs), manifesting as stent frame deformation, is an occasional fluoroscopic finding in transcatheter aortic valve replacement (TAVR). OBJECTIVES: The aim of this study was to investigate the impact of asymmetrical expansion of balloon-expandable THVs on hemodynamic valve performance and clinical outcomes. METHODS: In a prospective registry, TAVR asymmetry index was measured using freeze-frame fluoroscopic images and was defined as the ratio of THV heights [(longer height/shorter height) - 1] × 100. THV hemodynamic performance was measured using echocardiography before hospital discharge. Impaired hemodynamic valve performance was defined as a mean residual THV gradient ≥20 mm Hg and/or moderate or greater paravalvular regurgitation. RESULTS: Among 1,216 patients undergoing transfemoral TAVR for native severe aortic valve stenosis with contemporary balloon-expandable THVs between February 2014 and June 2022, asymmetry index was an excellent predictor of impaired hemodynamic valve performance (area under the receiver-operating characteristic curve 0.88; 95% CI 0.84-0.92; P < 0.001). The optimal asymmetry index threshold for predicting impaired THV performance was >5.5% (sensitivity 77%, specificity 86%) and occurred in 17% of patients. Higher asymmetry index, as a continuous variable, was associated with impaired hemodynamic valve performance independent of total aortic valve calcium, bicuspid anatomy, balloon-expandable valve prosthesis type or size, and Society of Thoracic Surgeons Predicted Risk of Mortality score (OR 1.37; 95% CI 1.29-1.46; P < 0.001). High TAVR asymmetry index was not associated with all-cause mortality during a median of 376 days of follow-up (HR 1.00; 95% CI 0.71-1.41; P = 0.989). CONCLUSIONS: Asymmetrical expansion of balloon-expandable THVs was associated with impaired hemodynamic valve performance but not with clinical outcomes.