The role of a staged approach for high-risk Fontan candidates

Right ventricular dynamic cardiomyoplasty for the univentricular heart with pulmonary hypertension

OBJECTIVES

We conducted an acute experimental study to test the feasibility of dynamic cardiomyoplasty in a setting of modified Fontan procedure for univentricular heart with pulmonary hypertension to obtain a possible proxy for high-risk Fontan candidates.

METHODS

After electrical preconditioning of the left latissimuss dorsi for 6 weeks in 8 dogs, the right ventricular cavity was totally obliterated with concomittent closure of the tricuspid valve and right pulmonary artery. Modified Fontan circulation was established with the aortic homograft anastomosed between the right atrium and pulmonary trunk, incorporated with a pericardial pouch as a compression chamber (neoright ventricle) fixed onto the epicardial surface of the ventricle. After cardiopulmonary bypass termination, a latissimus dorsi was applied to wrap the pericardial pouch and ventricle clockwise and stimulated with a trained-pulse (25 Hz) at 1:1 synchronization ratio with cardiac beats.

RESULTS

Profound right heart failure was noted during Fontan circulation in increased pulmonary vascular resistance (11 +/- 3.2 Wood units), whereas graft pacing showed significant augmentation of systolic pulmonary pressure by 54 +/- 12%, the mean pulmonary flow by 68 +/- 23%, and aortic pressure by 23 +/- 5% at a physiological range of central venous pressure (13.2 +/- 0.7 mmHg). Right heart function curve analysis confirmed marked augmentation of right heart performance, restoring almost normal pulmonary circulation. These functional benefits were sustained up to 4 hours in 4 animals until experiments were terminated.

CONCLUSIONS

Dynamic cardiomyoplasty in a modified Fontan procedure is a viable surgical option for univentricular heart, not a Fontan candidate.

Staged Fontan procedure for mitral atresia associated with severe tricuspid regurgitation, pulmonary hypertension, and pulmonary artery distortion

Optimal initial palliation and a subsequent staged approach is mandatory for high-risk Fontan candidates. We describe the case of mitral atresia with severe tricuspid regurgitation and pulmonary hypertension successfully managed by repeated palliation from the neonatal period and 2-stage Fontan surgery. A 1-month-old boy diagnosed with mitral atresia and double-outlet right ventricle underwent pulmonary artery banding at 1 month of age, followed by repeated pulmonary artery banding accompanied by tricuspid annuloplasty and atrial septal defect enlargement at 6 months. Because of the presence of pulmonary artery distortion, right ventricular dysfunction, and borderline pulmonary vascular resistance, a hemi-Fontan procedure was conducted with extended pulmonary artery plasty when the boy was 3 years and 8 months old. Cardiac catheterization done 3 months after showed improvement in risk factors, and the final Fontan operation (total cavopulmonary connection) was successfully done in conjunction with repeated tricuspid annuloplasty when the boy was 4 years and 5 months old. The patient remains in excellent clinical condition at the last follow-up 5 years after the final Fontan procedure with sinus rhythm and good ventricular function.