CMR-Flow

1351542 - Normal and Adverse Pulmonary Arterial Flow Patterns after the Fontan Procedure and Correlation with Interventional CMR Hemodynamics

Friday, January 27, 2023

12:20 PM – 1:20 PM

Location: Pacific Jewel

Presenting Author(s)

SD

Sanja Dzelebdzic, MD

Advanced Imaging Fellow
UT Southwestern
Dallas, Texas, United States

Primary Author(s)

SD

Sanja Dzelebdzic, MD

Advanced Imaging Fellow
UT Southwestern
Dallas, Texas, United States

Co-Author(s)

DY

Daniel Young

Research Intern
UT Southwestern, United States
MF

Munes Fares, MD

Assistant Professor
The University of Texas Southwestern Medical Center
Dallas, Texas, United States
Gerald Greil, MD, PhD

Professor of Pediatric Cardiology
UT Southwestern
Dallas, Texas, United States
JD

Jeanne Dillenbeck, MD

Pediatric Radiology
The University of Texas Southwestern Medical Center
Dallas, Texas, United States
Yousef Arar, MD

Pediatric Interventional Cardiology
UT Southwestern
Dallas, Texas, United States
AD

Abhay Divekar, MD

Pediatric Interventional Cardiology
UT Southwestern, United States
LZ

Luis Zabala, MD

Anesthesiology
The University of Texas Southwestern Medical Center, Texas, United States
RJ

Robert Jaquiss, MD

Pediatric and Congenital Cardiothoracic Surgery
UT Southwestern
Dallas, Texas, United States
SR

Suren R. Reddy, MD

Pediatric Interventional Cardiology
University of Texas Southwestern Medical Center
Dallas, Texas, United States
Tarique Hussain, MD, PhD

Professor, Pediatric Cardiology & Radiology
UT Southwestern Medical Center
Dallas, Texas, United States

Disclosure(s):

Gerald Greil, MD, PhD: No financial relationships to disclose

Background:
Fontan circulation is characterized by the absence of subpulmonary ventricle. Nevertheless, branch pulmonary artery (PA) flow patterns still manifest oscillations reflecting venous pressure changes. The clinical importance of variation in branch PA flow patterns and the relationship with the single ventricle performance is not understood. We describe insights gained from simultaneous hemodynamic and phase-contrast magnetic resonance using interventional CMR (iCMR) in these patients.

Methods: 27 patients with Fontan circulation were studied using phase-contrast velocity mapping and iCMR. The isovolumetric relaxation period (IVRT) was assessed using standard or velocity-encoded cine imaging of the atrioventricular valve (AVV) and aortic valve. We qualitatively assessed branch PA flows considering four patterns: IVRT flow reversal, IVRT flow reaching baseline, and normal – phasic flow or continuous flow (Figure 1). We then collected left and right heart iCMR hemodynamic and flow data, including pressures, aortopulmonary collateral (APC) burden, and degree of AVV regurgitation. We divided patients into three groups based on the observed patterns and compared means using one-way ANOVA. Two patients were excluded from the analysis as their patterns differed from the defined groups and are described separately.

Results: Majority of patients underwent extracardiac Fontan palliation and none had significant APC burden. Cardiac cycle analysis demonstrated that flow reversal and flow reaching baseline correlated with IVRT (v-wave timing on SVC pressure). Further analysis (Table 1) showed statistically significant difference in pulmonary capillary wedge pressure (PCWp) including a-wave (p=0.018) and v-wave (p=0.002) among the described groups. The differences between PCWp mean values showed tendency towards reaching statistical significance (p=0.06). Notably, patients with IVRT flow reversal pattern had higher PCWp values and severe AVV regurgitation (Table 2). The groups were otherwise similar in regard to SVC and ventricular end-diastolic pressures.

The two excluded patients had a systemic left ventricle palliated with lateral tunnel Fontan including most of the right atrium. Both patients were noted to have brief flow reversal correlating with the time just after the a-wave (early systole). One patient had associated right-sided pulmonary vein stenosis with complete flow reversal in the ipsilateral PA.

Conclusion:
Branch PA IVRT flow reversal and IVRT baseline patterns in patients with Fontan circulation may represent indirect signs of single ventricle poor performance. Complete flow reversal occurs in ipsilateral pulmonary vein stenosis in these patients. Brief flow reversal in early systole is seen in patients with lateral tunnel Fontan including most of the right atrial mass (perhaps related to lateral tunnel atrial free wall relaxation). The pulmonary artery flow patterns in patients palliated with a Fontan procedure may be an important indicator of the single ventricle performance.