Hypoplastic left heart syndrome (HLHS) is characterized by variably underdeveloped left-sided heart structures, mostly leading to single-ventricle physiology. Treatment options are limited to heart transplantation or a three-stage palliation concept. Though rare in HLHS, aortic regurgitation (AR) can lead to a coronary steal phenomenon, worsening morbidity and mortality significantly . Although AR in HLHS has primarily been treated surgically in the past, interventional concepts have emerged in the last decade [2,3]. In this case report, we present a novel, retrograde approach for transcatheter aortic valve (AoV) closure as a bailout strategy for AR in HLHS.
A full-term male German neonate (birth weight 3110g) was diagnosed postnatally with borderline mitral and aortic valve (z-score2 for both) and hypoplastic left ventricle (LV), as well as hypoplastic aortic arch with critical coarctation (CoA), perimembranous ventricular septal defect (VSD; size 34mm), and patent ductus arteriosus (PDA). His LV function was significantly impaired, so we did not take a primary corrective surgical approach initially. To preserve the option for later biventricular correction, we performed CoA resection and PDA closure on the 11th day of life with the aim of improving systemic blood perfusion and allowing for growth and functional improvement of the left-sided heart structures over time. Due to increasingly severe stenosis of the AoV, the patient underwent retrograde balloon valvuloplasty of the AoV at 3 weeks of age. However, although ballooning had moderately reduced the gradient, severe biventricular dysfunction developed as a result of the persistent pressure overload. In an emergency setting, a modified stage I Norwood palliation (aortic arch augmentation, Blalock-Taussig shunt, atrioseptectomy, VSD enlargement, resection of a subaortic membrane) was performed to acutely relieve the ventricles when the patient was aged 5 weeks. Later, increasingly severe AR of the native AoV became apparent, leading to recurring cardiac decompensation. This necessitated redo surgery with the AoV being oversewn 8 days after the stage I procedure.
At the age of 4 months, a successful Glenn operation was achieved. However, over the long term, the infants respiratory situation remained problematic, and he could not be permanently weaned from mechanical ventilation. Ultimately, the patient died at the age of 6 months due to pneumonia with subsequent sepsis and cardiac decompensation (Additional file5). Signs of endocarditis or impaired coronary perfusion were not apparent clinically or echocardiographically at any time point after device implantation.
We describe successful percutaneous retrograde AoV closure via the femoral artery with an ADO II device in a 3-month-old infant with borderline LV and failing Norwood stage I palliation. Severe native or acquired AR leading to impaired coronary perfusion is a rare but potentially life-threatening complication in HLHS. Additional anatomical features promoting LV decompression during diastole, such as a VSD, can aggravate the steal effect .
Interventional AR therapy is emerging as an alternative to operative AoV closure [2,3,5]. Previously, successful retrograde LVOT closure with an Amplatzer Vascular Plug 4 to treat AR in a child with stage II palliation  was described. Moreover, another case demonstrated the feasibility and effectiveness of AoV device closure via an antegrade transvenous approach with an Amplatzer Septal Occluder using a 6-French long sheath in an infant with failing stage I palliation . We opted for a retrograde transarterial approach with a duct occluder that has not yet been described in the MEDLINE database for interventional AoV closure in patients with HLHS. Retrograde access was enabled by the ADO IIs symmetrical design and its slim delivery system, facilitating device advancement through the infants delicate arterial vasculature. Unlike in the antegrade approach, retrograde access does not require crossing of the septum and the mitral valve or the formation of a straining loop in the LV to reach and cross the AoV with the long delivery sheath. The retrograde approach enables direct access to the AoV, thus greatly facilitating device implantation and making the technique more feasible in complex anatomies and preexisting impaired ventricular function.
Retrograde transcatheter AoV closure is a viable bailout option in the context of failing single-ventricle palliation with significant AoV regurgitation. Risks of coronary artery obstruction, VSD obstruction, and conduction block, as well as vessel damage at the access site, can be limited by careful and individualized device choice, making AoV device closure an alternative to high-risk redo surgery in certain patients.
- ADO II:Amplatzer Duct Occluder II
- AoV:Aortic valve
- AR:Aortic regurgitation
- CoA:Coarctation of the aorta
- HLHS:Hypoplastic left heart syndrome
- LV:Left ventricle
- LVOT:Left ventricular outflow tract
- PDA:Patent ductus arteriosus
- VSD:Ventricular septal defect