Dominant Atrioventricular Septal Defect Research Articles

Rescuing the Right Ventricle: Mechanical Support After Pediatric Heart Transplantation

BackgroundRight ventricular (RV) failure after heart transplantation (HT) is common in those with pretransplantation elevated pulmonary vascular resistance (PVR). Mechanical circulatory support has been used as a bridge to recovery, with mixed outcomes. We describe a patient with failed single-ventricle palliation in whom severe RV failure developed after HT. We review the current literature and outline our post-HT strategy. MethodsAn infant with trisomy 21, severely unbalanced right dominant atrioventricular septal defect, and hypoplastic aortic arch was palliated with a hybrid procedure. At 6 months of age, cardiac catheterization measured PVR index of 5.47 Wood units × m2 on maximal medical therapy. The patient was deemed unsuitable for second-stage palliation and underwent HT at 18 months of age. Despite preemptive medical therapies, acute RV failure developed, necessitating extracorporeal membrane oxygenation. He was quickly converted to main pulmonary artery to left atrial cannulation. Unloaded RV function normalized; he was weaned from support and discharged home 5 weeks after HT. ResultsFailure of medical therapy in RV failure after HT requires escalation to mechanical circulatory support. We review the literature on RV failure and support after HT. We also describe a novel cannulation strategy to provide a reliable way to directly reduce RV afterload, to allow physiologic training of the right ventricle to a higher PVR, and to maintain normal left ventricular coupling and loading. ConclusionsIn pediatric patients with elevated PVR undergoing HT, advanced therapies can be used effectively to treat acute RV failure. Unique cannulation strategies may play a role in improving survival of similar patients.

Extracorporeal membrane oxygenator as a bridge to heart–liver en bloc transplant in a patient with Fontan circulation

Extracorporeal membrane oxygenator as a bridge to heart–liver en bloc transplant in a patient with Fontan circulation

Clinical Outcomes of Ventricular Assist Device for Failing Bidirectional Glenn Physiology

Purpose The number of patients with failing single ventricle physiology is increasing, and ventricular assist device (VAD) support in this population is challenging. The purpose of this study was to describe our clinical experience with VAD for failing Glenn physiology. Methods A retrospective review of clinical outcomes was conducted in patients that underwent durable VAD placement for failing Glenn circulation between 2010 and 2020 at Texas Children's Hospital. Results Ten patients met inclusion criteria; all had a morphologic right ventricle (RV): 6 hypoplastic left heart syndrome/variant and 4 with isomerism with RV dominant atrioventricular septal defect. INTERMACS profiles were 1 in 3 patients (1 with ECMO) and 2 in 7 patients. Four patients were intubated. Age, weight, and body surface area at VAD implantation were 3.2 (0.9-10.1) years, 13.0 (7.7-22.8) kg, and 0.50 (0.36-0.90) m2, respectively. The device-strategy included HVAD in 6, Jarvik 2015 in 1, and Berlin cannula (with Berlin and/or Rotaflow pumps) in 3. Concomitant Fontan completion was performed in 5 patients (1 with fenestration), while the other 5 remained with Glenn circulation. PaO2/FiO2 ratio (median, range) on postoperative day 1 was significantly higher with Fontan completion [192 (53-336)] than without [76 (59-78), p=0.05] except a patient with Glenn circulation on ECMO. The median duration of mechanical ventilation after VAD was 2 days (range, 1 - 14). There was 1 early mortality 8 days after HVAD placement with Fontan completion due to neurologic insult intraoperatively. The remaining 9 patients (90%) were bridged to transplant at a median support duration of 3.8 (0.1-16.6) months. Five of the 6 HVAD patients were able to be discharged home prior to transplant. One patient encountered a pump thrombus requiring pump exchange and 1 patient suffered a thromboembolic stroke due to a mobile intraventricular thrombus. One patient had a subdural and subarachnoid hemorrhage 27 days after VAD implantation, with complete neurologic recovery without deficits. Conclusion This single-institutional experience suggests long term VAD support is sustainable for failing Glenn physiology with accompanying Fontan completion in selected patients. Further studies are warranted to optimize long term VAD support in this challenging population.

The matter of "unbalance" in right dominant atrioventricular septal defect.

Unbalance in atrioventricular septal defect can be found in more than one anatomic level and in different degrees at each level. The definition of “unbalance” has historically been focused in comparing the dimensions of main cardiac structures, such as the atrioventricular valve and the ventricles. However, the hemodynamic aspects of unbalance need to be considered as having, at least, similar relevance. New concepts and already described parameters must be combined and understood as a whole to help the surgical decision-making process.

Hypopituitarism due to mutation in the PROP1 gene in association with the 47,XYY karyotype and autosomal dominant atrioventricular septal defect: two case reports

Application of genetic analysis in clinical practice enables identifying a combination of two rare diseases in one patient. We report two cases of patients with hypopituitarism due to PROP1 gene mutations in combination with the 47,XYY karyotype (case 1) and autosomal dominant partial atrioventricular septal defect (case 2). These clinical cases clearly demonstrate that several rare diseases can be present in one patient. The morphology of the pituitary gland has specific features in patients with a PROP1 gene mutation: signal inversion on T1- and T2-weighted images, as well as changes in size of the pituitary gland over time. In case of short stature, the hormonal evidence of secondary hypopituitarism, low IGF-1 levels, and specific morphological features observed in MRI images, we recommended carrying out molecular genetic analysis of the PROP1 gene without conducting growth hormone stimulation test.

Modification of Hepatic Venous Conduit to Manage Pulmonary Arteriovenous Malformations

While the Fontan operation is a reliable treatment option for many complex congenital heart defects, the development of pulmonary arteriovenous malformations (PAVMs) remains a problematic outcome for some Fontan patients. Pulmonary arteriovenous malformations stem from an imbalance of hepatic blood flow in the pulmonary system. Balancing this hepatic flow has shown promising results in the treatment of PAVMs. We report the clinical course of a young patient with heterotaxy syndrome and an unbalanced right dominant atrioventricular septal defect. This patient developed PAVMs following a Fontan procedure, however, the PAVMs were resolved following the revision of the original Fontan conduit to a bifurcated conduit.

Repeated Aortopulmonary Shunt Thrombosis in a Neonatal Patient With a Low Antithrombin Level

A female infant with unbalanced right ventricular dominant atrioventricular septal defect with double-outlet right ventricle and pulmonary stenosis had recurrent aortopulmonary shunt thrombosis. She was found to have low antithrombin levels and was managed with antithrombin replacement in addition to unfractionated heparin. A subsequent aortopulmonary shunt was successfully placed, and patency was maintained. Her antithrombin levels normalized, and she was continued on low-molecular-weight heparin and aspirin until four months of age when a bidirectional superior cavopulmonary anastomosis was done. A prothrombotic evaluation at the time of the acute thrombosis and repeated at four months of age was negative except for the initially low antithrombin level. A repeat antithrombin level (off supplementation) at the time of the cavopulmonary anastomosis was normal making the diagnosis of congenital antithrombin deficiency unlikely. This case highlights the possibility of neonatal antithrombin deficiency as a cause of aortopulmonary shunt thrombosis and successful management with replacement therapy.

Right Pulmonary Artery Thrombosis After Hybrid Stage 1 Palliation: Resolution After Direct Tissue Plasminogen Activator Infusion

A patient with unbalanced right ventricular dominant atrioventricular septal defect with ascending and transverse arch hypoplasia underwent hybrid stage 1 palliation. On postoperative day 7, he experienced irritability and acute cyanosis. Echocardiography demonstrated a thrombus occluding the right pulmonary artery band. Emergency cardiac catheterization confirmed thrombosis of the right pulmonary artery at the site of the band. Direct infusion of tissue plasminogen activator successfully lysed the thrombus.

Beta-Blocker Therapy and Hemophagocytic Lymphohistiocytosis: A Case Report

Objective. The aim of this paper is to describe a fatal case of hemophagocytic lymphohistiocytosis (HLH) in a patient with severe heart failure, who was treated with low-dose propranolol. Patient and Interventions. We report on a 7-month-old boy with Downs syndrome who was born with an unbalanced, left dominant atrioventricular septal defect and aortic coarctation. Despite coarctation repair and pulmonary artery banding he developed intractable heart failure and fever of unknown origin. Since he remained in heart failure he received a trial of low-dose propranolol to stabilize his cardiopulmonary status, which resulted in unexpected immunomodulatory effects. Measurements and Main Result. Immunoactivation was evidenced by high concentrations of procalcitonin, soluble CD 25, tumor necrosis factor α, and interleukin 6 and 8. Propranolol resulting in hepatic compromise as indicated by high lactate dehydrogenase and alanine aminotransferase levels. A therapeutic switch from propranolol to the β 1-receptor blocker metoprolol appeared to be instrumental in hemodynamic improvement and allowed discharge from hospital. However, the infant ultimately died from secondary inflammatory reactivation and intractable pulmonary obstructive disease. The autopsy results revealed HLH. Conclusion. Our case describes HLH secondary to heart failure and Downs syndrome. In this highly activated inflammatory state the beneficial hemodynamic effects of propranolol may be accompanied by immunomodulatory effects and the risk of acute liver failure. HLH occurs with a distinct pathophysiology, and specific treatment might be mandatory to increase the chance of survival.