Hemi-Fontan or Bidirectional Cavopulmonary Shunt for Right Ventricular Failure after Mitral Valve Replacement and Acute Ascending Aortic Dissection: Report of Two Cases

Right ventricular failure due to right coronary artery disease, right ventricular hypertrophy, stunning, abnormal septal motion, myocardial infarction, or non-homogeneous distribution of cardioplegia is an uncommon but serious complication of open heart surgery. We report a patient with severe right ventricular hypertrophy secondary to severe mitral valve stenosis and another patient with detachment of the right coronary artery due to the dissection of the ascending aorta. The patients developed right ventricular failure, which persisted after surgery and rendered weaning from cardiopulmonary bypass unsuccessful. Through a hemi-Fontan, or bidirectional cavopulmonary shunt, and an intra-aortic balloon pump, the patients were successfully weaned from cardiopulmonary bypass. This shunt may be an alternative to a right ventricular assist device in some patients with right ventricular failure. The long-term outcome and the indication of bi-directional cavopulmonary shunt has not been confirmed, although it is believed to be effective for saving the life of patients with low cardiac output and acute right ventricular failure. In our cases, six months following the operation, there was some degree of recovery of the right ventricular function. In long-term follow-up, however, it would be interesting for the authors to know if the improved right ventricular function, with better antegrade pulsatile flow in the pulmonary artery, in any way interferes with the functioning of the bidirectional cavopulmonary shunt.