Important flow or just for show?: The utility of 4D flow to assess the pulsatile cavopulmonary anatomosis. (QF_TH_034)

Thursday, January 30, 2025

8:30 AM – 8:40 AM East Coast USA Time

Location: Blue Room PreFunction

Presenting Author(s)

MD

Marc Delaney, MD

Pediatric Cardiology Advanced Imaging Fellow
Icahn School of Medicine at Mount Sinai, Mount Sinai Kravis Children’s Hospital

Primary Author(s)

MD

Marc Delaney, MD

Pediatric Cardiology Advanced Imaging Fellow
Icahn School of Medicine at Mount Sinai, Mount Sinai Kravis Children’s Hospital

Co-Author(s)

Nadine Choueiter, MD

Director of Pediatric cardiac non invasive imaging
Kravis Children's Hospital at Mount Sinai
RP

Robert Pass, MD

Professor of Pediatrics and Chief of the Division of Pediatric Cardiology
Icahn School of Medicine at Mount Sinai, Mount Sinai Kravis Children’s Hospital
DB

David Barris, MD

Assistant Professor of Pediatric Cardiology
Icahn School of Medicine at Mount Sinai, Mount Sinai Kravis Children’s Hospital

Description of Clinical Presentation: An 18-year-old female presented for routine follow up with a history of pulmonary atresia and intact ventricular septum that was initially palliated with a Blalock-Taussig-Thomas shunt followed by shunt take-down, and a 1.5 ventricle repair consisting of a cavopulmonary anastomosis (BDG) and right ventricular outflow tract patch augmentation with pulmonary artery reconstruction to allow for preservation of anterograde pulmonary blood flow. She had recently undergone transcatheter device closure of a secundum atrial septal defect due to cyanosis with exercise. She had no symptoms at rest, 100% oxygen saturation on room air, and a to-fro murmur at the left upper sternal border on exam. An exercise stress test demonstrated mild deconditioning but normal exercise capacity.

Diagnostic Techniques and Their Most Important Findings:

Echocardiography demonstrated severe pulmonary regurgitation, mild right ventricular (RV) dilation and normal RV and LV function. A CMR was performed to quantify the degree of pulmonary regurgitation and RV dilation. This demonstrated severe pulmonary regurgitation with a 70% regurgitant fraction on 2D and 4D phase contrast (PC) MRI yet no holodiastolic flow reversal in the branch pulmonary arteries. Flow pattern visualization on 4D PC demonstrated that BDG flow accounted for the majority of the pulmonary regurgitation and that the antegrade flow across the main pulmonary artery comprised half of the systemic venous return and the other half was supplied by the Glenn anastomosis. There was only mild RV dilation (indexed end-diastolic volume 102.4 ml/m2) and normal systolic function with ejection fraction of 56%. The BDG and the branch pulmonary arteries were unobstructed.

Learning Points from this Case: 1.5 ventricle circulation is an alternative to the Fontan procedure in the setting of a hypoplastic subpulmonic ventricle. The inferior vena cava flow is actively pumped by the RV and the lungs receive passive flow from the superior vena cava (SVC). This may result in an inefficient circulation with competing sources of pulmonary blood flow. 4D PC MRI allowed for comprehensive examination of blood flow patterns in this circulation. It quantified the degree of pulmonary regurgitation and explained the mechanism by showing the contribution of pulsatile and passive circulation to pulmonary blood flow. The mild degree of RV enlargement despite substantial pulmonary regurgitation was posited due to RV diastolic dysfunction and small RV size associated with PA/IVS. The primary cardiologist discussed pulmonary valve replacement with the patient and family through a shared decision-making model, and the case was subsequently discussed at a multidisciplinary surgical conference, where there was consensus to continue close observation due to the lack of symptoms, normal exercise capacity, and strong family preference to avoid intervention. She remains clinically well with close observation of symptoms, RV size, and RV function.