Characterization of morphology and function of the ‘neo-atria’ after a modified Mustard operation

Background: There is a pressing need to improve early and long-term results of the Mustard operation. A modification of the operation was introduced at the Aswan Heart Centre for this purpose which relies on creating new functional atria rather than the two rigid channels in the classical Mustard operation.Objectives: To evaluate the morphology and function of the neo-atria, shortly after modified mustard operation for a ‘neglected’ patient with TGA, VSD and severe pulmonary hypertension.Methods: A 6-year-old with neglected TGA, VSD and pulmonary hypertension presented with severe cyanosis, clubbing and haemoconcentration (Hb 22 g/dL), underwent the modified Aswan-Mustard operation (MAM) with rapid smooth postoperative recovery. Repeated 2D echograms and multi-slice CT scans, followed by 3D segmentation, were performed after the operation. The size, shape, and morphology of the neo-atria were measured and measurements of the patterns of instantaneous filling and emptying of the right and left ventricles were quantified.Results: The neo-systemic venous atrium consisted of three components with a combined volume of 78 mL/m2, all of which contributed to the reservoir, conduit, and importantly contractile function of the neo-atrium. The pulmonary venous atrium consisted of two components with a combined volume of 66 mL/m2. These measurements were made at atrial end diastole. The volumes of the systemic venous and the pulmonary venous diminished to 51 and 54 mL/m2, respectively, at the end atrial systole - indicating relatively preserved contractile functions.

Heart Transplantation in Mustard Patients Bridged With Continuous Flow Systemic Ventricular Assist Device - A Case Report and Review of Literature

Thirty four-year-old male with history of D-transposition of the great arteries (D-TGA) who underwent Mustard operation at 14 months of age presented in cardiogenic shock secondary to severe systemic right ventricular failure. Catheterization revealed significantly increased pulmonary pressures. Due to the patient's inotrope dependence and prohibitive pulmonary hypertension, he underwent implantation of a Heart Ware HVAD® for systemic RV support. Within 4 months of continuous flow ventricular assist device (VAD) implantation complete normalization of pulmonary vascular resistance (PVR) was achieved. He ultimately underwent orthotopic heart transplantation with favorable outcomes. This is the second report of complete normalization of PVR following VAD implantation into a systemic RV in <4 months. We conducted a thorough literature review to identify Mustard patients that received systemic RV VAD as a bridge to a successful heart transplantation. In this article, we summarize the outcomes and focus on pulmonary hypertension reversibility following VAD implant.

Pulmonary artery banding in a modified Mustard operation improves biventricular geometry and function

Patients with transposition of great arteries, with intact interventricular septum (TGA-IVS) and deconditioned left ventricle, represent a considerable challenge in developing countries. The modified Mustard operation was shown to provide a significant improvement for these patients, particularly by enhancing atrial functions and left ventricular filling. Yet, the problems of the systemic right ventricular dysfunction and the resulting secondary tricuspid regurgitation (TR) remain to be of major concern. In addition, the deviation of the interventricular septum towards the left side markedly impairs ventriculo-ventricular interaction and predisposes to dynamic left ventricular outflow tract obstruction (LVOTO). We report that adding a moderately loose pulmonary artery banding to the modified Mustard operation in a case of TGA-IVS results in improvement of biventricular geometry and function, tricuspid and mitral valve functions and disappearance of dynamic LVOTO.

Biomarker sST2 in Adults with Transposition of the Great Arteries Palliated by Mustard Procedure

Background: Transposition of the great arteries (TGA) is a congenital heart defect (CHD) in which the aorta and pulmonary artery are transposed; it requires urgent surgical intervention. The Mustard procedure was an early surgery allowing survival into adulthood. However, this procedure is associated with long-term adverse effects including arrhythmias and heart failure (HF). A key factor impairing HF management in adults with CHD is lack of biomarkers to predict outcome. Soluble ST2 (sST2) is a protein secreted by myocytes in response to mechanical strain and fibrosis. No studies have focused specifically on sST2 in TGA individuals that underwent a Mustard procedure. In this study, we hypothesized adults with TGA palliated with a Mustard procedure would have higher levels of sST2 than healthy individuals, and this would correlate with functional class status. Methods: We screened the Pediatric Cardiology database for D-TGA subjects and Mustard operation. Healthy controls were recruited from clinic and the community. Patients were matched by age to a control group of 21 healthy individuals. Severity of symptoms was assessed by NYHA functional classification. sST2 levels were obtained using Critical Diagnostics Presage ST2 Assay kit. Additionally, cTnI, BNP, lipid panel, insulin, glucose, and EKG and echocardiography (TGA) were obtained at IUSM clinical laboratories. Results: We identified 45 patients with D-TGA and Mustard operation. 19 patients were included in analysis: 12 male and 7 female subjects aged 18 to 46, mean of 34.9 years. In the Mustard group, 9 subjects were assigned to NYHA class II, and 9 to class III. The control group was asymptomatic. sST2 levels in the Mustard group were elevated in 53%, while only 29% in the controls. Of the Mustard subjects with elevated sST2, 67% had elevated cTnI, 80% arrhythmias, 70% EKG T-wave abnormalities, and 80% took cardiac medications. 90% of these patients had low HDL, 40% high LDL, and 40% low insulin. Conclusion: This study demonstrates patients with Mustard operation averaged higher sST2 levels than healthy subjects. Importantly, of the patients with elevated levels, there was a significant association of sST2 with biomarker abnormalities and clinical heart failure signs. This suggests in patients with D-TGA palliated with Mustard procedure, sST2 may add predictive value to cardiac related morbidity and mortality.

Transplantation after Mustard operation for transposition of the great arteries

As long-term outcomes of congenital heart diseases improve, the probability of adult patients presenting for heart transplantation for late failure of congenitally corrected heart disease also increases. In patients with dextro-transposition of the great arteries (d-TGA) who were initially treated in the era of Mustard or Senning procedures and before Jatene procedure was introduced, progressive systemic right ventricular failure represents a problem in the very long-term follow-up. We report a rare case of heart transplantation as a third operation 36 years after Mustard procedure in a patient with d-TGA experiencing late failure of the systemic right ventricle.

Extracorporeal Cardiopulmonary Resuscitation During Cesarean Delivery in a Patient With D-Transposition of the Great Vessels, Years Following Mustard Operation

Patients with surgically repaired complex congenital cardiac anomalies present unique characteristics that can make the implementation of extracorporeal membrane oxygenation (ECMO) support especially challenging. Very few series have reported the outcomes of ECMO support during pregnancy and peripartum. We report a case of successful extracorporeal cardiopulmonary resuscitation during cesarean delivery in a patient with surgically repaired d-transposition of the great arteries, and we discuss particular aspects that contributed to successful implementation of ECMO support and hospital discharge.