Case

A male patient was given a diagnosis of univentricular heart and explorative sternotomy was performed while in elementary school; however, no surgical intervention was attempted because of a lack of clinical symptoms. As he reached adulthood, he had developed slightly reduced exercise tolerance and ceased to undergo regular check-ups. At 42 years of age, he was admitted to hospital complaining of dyspnoea on exertion and leg oedema. He was diagnosed with congestive heart failure and tricuspid atresia by transthoracic echocardiography. His symptoms improved with diuretic treatment, and he was referred to our hospital for further testing. Physical examination showed moderate cyanosis with an oxygen saturation of 85%. Detailed transthoracic echocardiography showed tricuspid atresia (muscular type), transposition of the great arteries, atrial septal defect, large and unobstructive ventricular septal defect in subaortic position, hypoplastic right ventricle, and dilated left ventricle. Left ventricular ejection fraction was estimated at 41%. Pulmonary valve was bicuspid and moderate stenosis (peak velocity, 3.3 m/second). Mild aortic valve regurgitation was observed. Sinus of Valsalva dilated to 51 mm in diameter. A catheterisation study revealed elevated pulmonary arterial pressure and impaired ventricular function (Table 1). Serial examinations confirmed a diagnosis of tricuspid atresia with discordant arterial ventricular connection, associated ventricular septal defect and pulmonary stenosis, and medical treatment was chosen as an appropriate option because the patient was not considered to be a candidate for Fontan circulation due to his elevated pulmonary pressure and impaired ventricular function, and sufficient medication was not administered at this time.

Table 1. Results of catheterisation studies of first presentation and 2 years later

Despite receiving intensive medical treatment, our patient required repeat hospitalisations for congestive heart failure. Transthoracic echocardiography performed 2 years after his first presentation showed more decreased left ventricular function (left ventricular ejection fraction, 37%), mild mitral valve regurgitation, and moderate-to-severe aortic valve regurgitation. A catheterisation study also revealed a further increase in his ventricular volume (Table 1). Contrast-enhanced CT showed further enlargement of sinus of Valsalva (59 mm, Supplementary Fig S1). Considering his well-balanced pulmonary-to-systemic flow ratio and atrioventricular valve function, we speculated that the chief cause of our patient’s heart failure was the progressive aortic valve regurgitation and his ventricular function improved by controlling aortic valve regurgitation. Furthermore, he was not suitable for Fontan operation because of his elevated pulmonary arterial pressure and decreased left ventricular function. Although valve sparing root replacement was considered, we chose aortic root replacement with mechanical valve because of shorter ischaemic time and secure control of the regurgitation. We performed aortic root replacement (modified Bentall procedure) with a 23-mm Regent (St. Jude Medical, Saint Paul, Minnesota, United States of America) and a 26-mm Triplex (Terumo, Shibuya, Tokyo) under general anaesthesia (Fig 1). The patient was weaned from cardiopulmonary bypass without difficulty, and there were no major complications post-operatively. He was discharged on post-operative day 30. Transthoracic echocardiography performed 2 weeks after the operation revealed improved left ventricular function (left ventricular end-diastolic volume, 354 ml; left ventricular end-systolic volume, 201 ml; left ventricular ejection fraction, 43%). His aortic saturation was almost unchanged post-operatively and his cardiopulmonary exercise testing 1 year after the operation showed somewhat reduced exercise tolerance functions (peak oxygen uptake: 13.8 ml/minute per kilogram, anaerobic threshold: 7.8 ml/minute per kilogram). However, considering the fact that he required repeat hospitalisations before the operation and was back to full-time work post-operatively, we guessed his exercise tolerance function was improved. Histopathological examination of the ascending aortic wall which was removed in this operation showed cystic medial necrosis (Supplementary Fig S2).

Figure 1. Intraoperative picture after resternotomy, showing transposition of the great arteries, dilated aortic root and hypoplastic right ventricle. Ao: aorta, LV: left ventricle, RA: right atrium.