Right-ventricular/pulmonary artery coupling predicts long-term mortality in aortic stenosis patients with different flow types
Authors: Steffen J , Lux M , Kneidinger N , Stocker T , Low K , Doldi P , Haum M , Fischer J , Stolz L , Theiss H , Rizas K , Peterss S , Hausleiter J , Massberg S , Deseive S 
Published: November 2023

Abstract

Background
Right-ventricular (RV) dysfunction in aortic stenosis (AS) patients undergoing transcatheter aortic valve implantation (TAVI) has long been neglected. Right-ventricular to pulmonary artery coupling (RV/PAc), a parameter of RV function, can be determined by echocardiography (tricuspid annular plane systolic excursion over systolic pulmonary artery pressure). Its use for mortality prediction in contemporary AS patients warrants further evaluation, data for different flow types of AS are lacking.

Purpose
To assess the impact of pathological RV/PAc on long-term mortality in AS patients with different flow types.

Methods
All 1577 consecutive patients from our registry from 2018 to 2020 were assessed. Patients without tricuspid regurgitation (n=523) or inconclusive echocardiography images (n=111) were excluded. RV/PAc could be analysed in 862 patients. To dichotomize the cohort, a receiver operator curve (ROC) analysis for 2-year mortality was used. Primary endpoint was 2-year mortality. Patients were further analysed according to the Valve Academic Research Consortium (VARC) 3 endpoint definitions.

Results
By ROC analysis, 0.512 mm/mmHg was defined as a cut-off, dividing the cohort into 428 patients with physiological RV/PAc (above cut-off) and 434 patients with pathological RV/PAc. Patients with pathological RV/PAc were more often male, had more comorbidities, a lower ejection fraction (50% [40-55%] vs. 55% [53-58%], p&lt;0.01) and a higher Society of Thoracic Surgeons (STS) score (4.0 [2.5-6.0] vs. 2.8 [2.0-4.0], p&lt;0.01).
Procedural outcomes according to VARC-3 were comparable: the composite endpoints technical failure and device failure at 30 days occurred in 3.9% and 3.5% (p=0.75) and 11.3% and 13.3% (p=0.42) in the pathological and physiological group, respectively. Clinical outcomes in terms of New York Heart Association functional class were comparable at follow-up, with an improvement by at least one class in 76.2% (pathological group) and 79.9% (physiological group, p=0.33).
All-cause 2-year mortality was significantly higher in the pathological group (34.9% [30.2-39.2%] vs. 15.4% [11.9-18.8%], p&lt;0.01, hazard ratio, HR, 2.5 [1.9-3.4], Figure 1). The result persisted when adjusted for STS score (HR 2.3 [1.7-3.1]) or in a multivariate Cox regression. Cardiovascular mortality was increased too (pathological, 23.7% [19.3-27.8%], vs. physiological, 8.5% [5.8-11.2%], HR 2.9 [2.0-4.2], p&lt;0.01).
The fraction of patients with pathological RV/PAc differed significantly across the AS flow types (high-gradient, 40.3%, classical low-flow low-gradient (LFLG), 73.9%, paradoxical LFLG, 58.9%, and normal-flow low-gradient, 36.6%, p&lt;0.01). Mortality differences persisted in high-gradient and LFLG groups (Figure 2A-D), which was consistent after statistical adjustment.

Conclusions
RV dysfunction defined as low RV/PAc is a strong predictor for long-term mortality in TAVI patients, with a strong prognostic value also in LFLG AS.