CMR assessment of right ventricular remodeling after transcatheter therapy for severe tricuspid regurgitation
Authors: Alushi B , Bisht O , Menck N , Mattea V , Primet Y , Schindler K , Puls R , Schulz-Menger J , Lauten A 
Published: July 2021

Abstract

Funding Acknowledgements
Type of funding sources: Private hospital(s). Main funding source(s): Helios Clinical Research Institute
Background/Introduction
Patients with severe tricuspid regurgitation (TR) are characterized from severe dilatation and negative remodeling of the right heart chambers causing functional right ventricular (RV) failure and increased mortality and morbidity. The transcatheter tricuspid edge-to-edge repair (TTVR) is a new treatment option associated with symptom improvement and reduced hospitalization. The cardiac magnetic resonance imaging (CMRI) remains the gold standard for evaluating the right ventricular morphology and function and could be a useful in assessing the RV reverse remodeling after TTVR. The Tricuspid Regurgitation REgistry (TRuE) is an ongoing national prospective register of patients with severe TR that aims to identify morphofunctional parameters of the right heart chambers related to improve outcomes after TTVR.
Purpose
The present is a subanalysis of patients with serial CMRI examinations recruited in the ongoing prospective TRuE registry.

Methods
After excluding patients with intracardiac RV leads, seven patients (age 70 ±12 years) with completed thirty-day follow up were included in the present analysis. Retrospective gated steady state free precession cine images were acquired in the long and short-axis views covering the entirety of both ventricles. Aortic and pulmonary flow data were acquired with a flow-sensitive gradient echo sequence. Assessment of left ventricular (LV) and RV volumes was performed manually in the short-axis cine images (Circle Cardiovascular Imaging, Calgary, Alberta, Canada). The TR fraction was calculated as: ({total RV stroke volume (SV) – total pulmonary forward flow}/total RVSV) × 100. All volumes and flow measurements were indexed for body surface area and expressed in ml/m2. The ratio between the diameter of pulmonary artery (PA) and ascending aorta (AA) was used as indirect measurement of pulmonary arterial hypertension (PAH). CMRI parameters assessing TR quantification, RV morphology and function were analyzed at baseline and follow-up with Fisher´s test or paired t-test.

Results
At thirty days there was a significant reduction of the TR fraction (45% to 20%, p &lt; 0.001), RV dilatation (RV-end diastolic volume (EDV): 106 ± 12ml/m2 to 86 ± 9.4ml/m2, p = 0.002, RV- end sistolic volume (ESV):55 ± 6.5 to 43 ± 6.6ml, p = 0.003) and improvement of function (RVEF: 47 ± 3.6 to 53 ± 2.4 %, p = 0.006). On the left heart side, there was an improvement of LV filling, with increased LVEDV and LVESV and of the LVSV (36 ± 5.3 to 41 ± 3.7ml/m2, p = 0.040), causing an improvement of the cardiac index (2.2 ± 0.9 l/min/m2 to 2.9 ± 0.7 l/min/m2; p = 0.019. Furthermore, the PA/AA ratio improved significantly (0.91 ± 0.15 to 0.81 ± 0.14, p = 0.006).

Conclusion
TTVR is associated with positive reverse remodeling of the RV with reduction of dilatation, PAH and function improvement.