Evaluation using a four-dimensional imaging tool before and after pulmonary valve replacement in a patient with tetralogy of Fallot: a\xa0case report

Abstract

BackgroundPulmonary regurgitation is a common complication after tetralogy of Fallot repair, resulting in right ventricular dysfunction, arrhythmia, and sudden death. However, the indications and optimal timing for pulmonary valve replacement are not fully known. We describe a case in which a four-dimensional imaging tool was useful in the decision to re-operate, thus resulting in decreased energy loss and improved right ventricular function after the re-operation for tetralogy of Fallot.Case presentationA 54-year-old Japanese woman visited our hospital due to palpitations and wide QRS tachycardia with persistent tiredness for several months. She underwent repair of tetralogy of Fallot when she was 2-years old. An electrocardiogram showed prolonged QRS duration (199 msec) with a complete right bundle branch block and an echocardiograph demonstrated that her right ventricle was highly enlarged and had poor contraction, and severe pulmonary valve regurgitation with one leaflet flail. Four-dimensional flow magnetic resonance imaging demonstrated that regurgitant volumes and regurgitant fractions of pulmonary regurgitation were calculated as 63.12 ml and 54.0%, respectively. Right ventricular end-diastolic/end-systolic volume index was 169.54/99.76 mL/m2, and the cardiac index was 1.78 L/minute per m2. Flow energy loss was 2.93 mW, which is estimated to be three times higher than normal controls. An electrophysiological study showed an intact anterior internodal pathway and a slow pathway just through the outside of the right atriotomy line scar, which is supposed to cause a re-entry circuit. We decided to perform a pulmonary valve replacement and a right maze procedure. A 27 mm bioprosthetic valve was implanted in the native pulmonary annulus with a supra-annular position. Concomitantly, the right maze procedure was performed. A four-dimensional flow magnetic resonance imaging done 3 months later showed that right ventricular end-diastolic/end-systolic volume index had significantly reduced to 85.24/55.41 mL/m2 and the cardiac index had increased from 1.78 to 2.58 L/minute per m2. Energy loss had greatly improved from 2.93 to 1.48 mW.ConclusionsA four-dimensional imaging tool was useful in the decision to re-operate, thus resulting in decreased energy loss and improved right ventricular function after the re-operation for tetralogy of Fallot.