Coronary sinus atrial septal defects in adults over the past 20 years at new Tokyo hospital: case series

An isolated coronary sinus (CS) atrial septal defect (ASD) is defined as a CS unroofed in the terminal portion without a persistent left superior vena cava or other anomalies. This defect is rare and part of the wide spectrum of unroofed CS syndrome (URCS). Recently, several reports have described this finding. The database of New Tokyo Hospital was searched to determine the incidence of this defect. Additionally, to raise awareness of this condition, the findings from five patients with CS ASD who underwent surgical repair at New Tokyo Hospital are discussed.

The patients were three women and two men with an age range of 63–77 years. All patients underwent transthoracic echocardiography and computed tomography, and one underwent magnetic resonance imaging. In two patients, the defect was found unexpectedly intraoperatively; left-to-right shunting was apparent in the other three patients preoperatively. The pulmonary-to-systemic blood flow ratio ranged from 1.42 to 3.1 following cardiac catheterization, and oxygen saturation step-up was seen on the right side of the heart. Valvular regurgitation was seen in 4/5 patients with different combinations and degrees of mitral, tricuspid, and aortic valve involvement. Right atrial and ventricular dilation were seen in 4/5 patients; three patients had left atrial dilation. Three patients experienced atrial fibrillation, and one of these also experienced paroxysmal ventricular contractions. All patients underwent surgical repair, and some underwent multiple procedures. One patient who had previously undergone kidney transplantation died approximately 1 year postoperatively; the remaining four patients are currently experiencing good activities of daily living without symptoms.

CS ASD (Kirklin and Barratt–Boyes type IV URCS) comprised 1.3% of adult congenital heart surgeries and 0.07% of adult open-heart surgeries at New Tokyo Hospital from 1999 to 2019. At New Tokyo Hospital, cardiac surgery is performed mainly for patients with acquired cardiac disease, and CS ASD is rare. Early diagnosis is important, as well as early surgical repair in symptomatic patients, especially those with blood access shunts, which may overload the heart. The case of a poor prognosis in this series is noteworthy, as similar cases have not been reported previously.