Stiff “Left Atrial” syndrome post-mustard procedure

Objectives: We describe the clinical course and management of two patients with post-capillary pulmonary hypertension due to diffuse pulmonary venous baffle calcification decades post-Mustard procedure. Background: From the late 1950s to the early 1990s, the definitive surgical repair for children with D-transposition of the great vessels (D-TGA) was an atrial switch procedure (either Senning or Mustard operation) which utilizes atrial-level baffles to shunt pulmonary venous blood to the morphologic right (systemic) ventricle and caval blood to the morphologic left (sub-pulmonary) ventricle. From a hemodynamic standpoint, baffle leaks and stenoses as well as precapillary pulmonary hypertension have all been described as both early and late complications [1]. Recently, delayed post-capillary pulmonary hypertension (in the absence of discrete baffle obstruction) decades post-atrial switch has also been described [2]. The underlying pathophysiology for this postcapillary pulmonary hypertension is unclear but is theorized to involve impaired diastology referable to the pulmonary venous baffle. Methods/Results: Using hemodynamic and imaging data, we describe two patients with extensive pulmonary venous baffle calcification and resultant pulmonary hypertension from the so-called “stiff left atrial (LA) syndrome.” This problem can be difficult to treat medically and is not amenable to catheter-based interventions. We hypothesize that this is an underlying mechanism for pulmonary hypertension in at least some post-Mustard and Senning patients. Conclusion: We describe the treatments and clinical course for each of these patients, and in particular describe how the surgical revision of the pulmonary venous baffle in one case led to the complete resolution of symptoms.

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.