Outcomes of single ventricle repair in central South Africa

Abstract

Introduction: Single ventricle physiology is a critical cardiac condition requiring early diagnosis and intervention. Surgical outcomes of Fontan procedures have improved remarkably over time. Objectives: This retrospective study reports on the management and outcomes of patients diagnosed with single ventricle physiology in Central South Africa. The prospective study examined Fontan patients' functional assessment measured by echocardiography, six-minute walk test and Ross classification. Methods: A retrospective observational analysis was conducted on patients presenting with single ventricle physiology at the Universitas Academic Hospital (UAH) in Central South Africa between November 1997 and June 2021. The prospective study evaluated nine Fontan patients during outpatient visits to the Department of Paediatric Cardiology Clinic at the Universitas Academic Hospital, Bloemfontein, South Africa. This evaluation included an echocardiographic examination, a six-minute walk test (according to The American Thoracic Society) and a modified Ross classification by the New York Heart Association (NYHA). Results: The retrospective study reported on one hundred and fifty-four patients presenting with single ventricle physiology: 114 received interventions, and 40 were not eligible for intervention. These patients were referred from the Free State province (54%), Northern Cape (29%) and Lesotho. Overall, patients presented for the first time at a median age of 34.5 days, with patients from nearby districts presenting within a few days of birth. In contrast, patients from outlying areas presented much later. Eighty- seven patients received systemic to pulmonary artery shunting or pulmonary artery banding as a first stage. Sixty-three patients proceeded to bidirectional Glenn procedures, and 30 patients (26%) had full palliation to Fontan. Twenty-one patients were demised after stage 1, six after the Glenn procedure and two after the Fontan procedure. Overall, 34 (29.8%) patients were lost to follow-up. The prospective study reported a median peak E wave (Early mitral inflow velocity) of 67.7 cm/sec, and a median peak A wave (Atrial wave inflow velocity) of 52 cm/sec, with a median E/A ratio of 1.28. The median deceleration time was 231.6ms. The median E’ was 15.5 cm/sec, and the median E/E’ was 4.6 9 cm/sec. The median MAPSE (mitral annular plane systolic excursion) was 10.3 mm, and one TAPSE (tricuspid annular plane systolic excursion) was 15.9 mm. MPI (myocardial performance index) was prolonged with a median left ventricle MPI of 0.47 and one right ventricle MPI of 0.37. The median distance covered during the 6-minute walk tests (6MWT) was 480 metres. Four patients (44%) were classified as class I and five (56%) as class II heart failure using the Ross classification. Conclusion: Patients in the retrospective study presented late, and follow-up of these patients was a challenge. The highest mortality occurs during the first stage of palliation. Outcomes from this study are comparable to other Sub-Saharan studies. Results of the prospective study demonstrated mild functional limitations in 6MWT and heart failure scores. These findings were underscored by the impairment of echocardiographic systolic function indices such as MAPSE/TAPSE and MPI.