Cardiac Magnetic Imaging Findings of 11-year-old with Hypoplastic Left Heart Syndrome status post Initial Hybrid Palliation (QF_FR_094)

An 11-year-old female with hypoplastic left heart syndrome (HLHS) with intact atrial septum who remained with initial hybrid physiology presented for non-sedated cMRI and MRA for evaluation and surgical planning. To our knowledge, this is the longest surviving patient who remained with stage I hybrid palliation physiology alone. After birth, she required emergent atrial septostomy and stenting followed by a hybrid procedure consisting of branch PA banding and ductal stenting at 6 weeks of age. After her initial stage I, the parents opted against additional surgical palliation. She re-presented sporadically over the next 10 years with increasing symptoms treated with repeat ductal and atrial stent dilations in the catheterization lab. At age 11 years, she returned with worsening cyanosis and limited mobility (Table 1). At this time, the family agreed to surgical intervention. Surgical options considered were traditional Norwood procedure with placement of a Blalock-Thomas-Taussig shunt (BTTS), arch reconstruction and Glenn, or a comprehensive Fontan procedure. She underwent a successful comprehensive Fontan with reconstruction of her left pulmonary artery (LPA) and central pulmonary artery (PA) confluence with a 16mm Interposition graft, bidirectional Glenn, atrial septectomy, pulmonary vein unroofing, ductal stent removal, arch reconstruction, and extracardiac fenestrated Fontan creation.

Diagnostic Techniques and Their Most Important Findings:

Images were obtained using multiplanar MRI with ultrafast spin echo and balanced steady state free precession sequences performed both before and after contrast (MultiHANCE) administration. Phase contrast sequences and post-processing for flow velocities and 3D modeling. Magnetic resonance angiography was obtained after contrast administration enabling visualization of LPA narrowing that was obscured by metal stent artifact on other sequences. Evaluating the systemic venous flows, ventricular function, atrioventricular (AV) valve regurgitation, pulmonary artery anatomy, and lymphatic typing were all crucial factors being weighed when deciding intervention.

Learning Points from this Case:

• First cMRI obtained on a patient with hybrid anatomy 11 years removed from initial palliation which helped guide surgical decision making.


• On pre-operative MRI, her systemic right ventricle was mildly dilated with normal systolic function which favored candidacy for a successful surgical operation.


• Several factors delineated by cMRI favored proceeding with comprehensive Fontan as opposed to other surgical options including SVC flow 1.26L/min/m2 (which elevated risk for Glenn failure), mild-moderate tricuspid regurgitation, and type II lymphatics (Figure 1).


• 3D reconstruction using the MRA enabled visualization of severe LPA narrowing (Figure 2) that was obscured by metal artifact on other sequences.


• Post operative cMRI after completion of comprehensive Fontan demonstrated improved systemic ventricle size with preserved normal systolic function, stable Glenn flow, and improved tricuspid regurgitation (mild). It explained her lower saturations due to Fontan fenestration by flow quantification and Qp:Qs calculations.