Quick Fire Cases
Tarinee Tangcharoen, MD, FSCMR
Associate Professor
Ramathibodi Hospital, Mahidol University, Thailand
Tarinee Tangcharoen, MD, FSCMR
Associate Professor
Ramathibodi Hospital, Mahidol University, Thailand
surachai kongrat, MD
Dr.
Ramathibodi Hospital, Mahidol University, Thailand
Varinsawat Prakongwong, MD
Dr.
Ramathibodi Hospital, Mahidol University, Thailand
Tananya Lueangklanlayanakhun, BSc
Technologist
Ramathibodi Hospital, Mahidol University, Thailand
Watcharee Prasertkulchai, MSc
Technologist
Ramathibodi Hospital, Mahidol University, Thailand
worakan Promphan, MD
Dr.
Queen Sirikit National Institute of Child Health, Thailand
A 38 years old woman with an underlying crisscross heart, single ventricle physiology with left-sided hypoplastic RV, VA discordance, D-TGA, large VSD, and ASD s/p RMBTs and right bidirectional Glenn shunt with PA banding at the age of two and eighteen years old respectively was sent from another hospital. At the age of 20, she underwent cardiac catheterization and cardiac CT for pre-Fontan evaluation. Cardiac CT demonstrated enlarged MPA with migration of banding, and cardiac catheterization revealed mPAP of 34 mmHg and 27 mmHg at proximal and distal MPA, respectively. Therefore, conservative treatment was suggested. The patient had been doing well until she developed two syncope episodes recently. EP study showed non-sustained atrial tachycardia and non-sustained atrial fibrillation. She underwent successful radiofrequency ablation. However, the patient still reported decreased functional class with intermittent facial edema. Echocardiography showed good ventricular systolic function and unobstructed Glenn shunt. Cardiac catheterization showed an estimated Glenn pressure of 24.54 mmHg with Qp: Qs of 1.27 and PVR 2.16 WU. She was sent to our CMR lab to evaluate the cause of increased Glenn shunt pressure.
Diagnostic Techniques and Their Most Important Findings:
CMR technique was performed with a 3T clinical scanner (Philips, the Netherlands). The sequences consisted of cine, MRA, and 4D flow images after contrast administration with a temporal resolution of 36 milliseconds/frame. FOV 300mm.x 350 mm. Spatial resolution: 2.8x 2.8× 2.5mm. VENC: 300 cm/s. Image analysis was performed with Circle CVI42, version 6.02 (Canada). Normal ventricular systolic function (EF 61%) with inadequate PA banding at mid-MPA, causing increased pulmonary blood flow with Qp: Qs = 2.5:1 was revealed. The SVC and left innominate veins were dilated, with many venous collaterals (figure 1). Q-flow analysis shows a large amount of backward flow in the SVC, with a forward flow of 29.12 ml/beat and a backward flow of 24.60 ml/beat. 4D flow postprocessing showed antegrade flow from MPA to RPA and SVC, pushing the SVC flow back to the innominate and hemiazygos vein (figure 2). Thus, the MPA flow, not the Glenn shunt, comprised most of the RPA flow. The PVR calculated by combining pulmonary blood flow obtained by CMR and pulmonary pressure obtained by cardiac catheterization showed a PVR of 4 WU at the RPA, higher than using data from cardiac catheterization alone. With comprehensive data from CMR, a multidisciplinary team conference suggested starting the PAH-specific medication and re-evaluating right heart catheterization with balloon-occluding MPA.
Learning Points from this Case:
By revealing the flow pattern, we demonstrate how 4D flow CMR helps unravel the cause of Glenn shunt failure. Furthermore, the hemodynamic data from cardiac catheterization in complex cyanotic heart disease can be inaccurate. Thus, data from CMR is crucial for PVR calculation.
