Gonzalez, Carolyn

Introduction: Fontan pathway obstruction is a serious complication characterized by an anatomical or functional narrowing anywhere in the cavo-pulmonary pathways. Here we report the first case where an innovative Fontan conduit rehabilitation procedure with intravascular lithotripsy was used achieving a significant increase in the pathway size. Case: A 28-year-old male with tricuspid atresia status-post Fontan palliation (age 23 months) with bare metal stent implant to treat obstruction at age 15, presented with syncope, ascites and varicose veins. Imaging studies revealed a cirrhotic liver morphology and Fontan pathway obstruction with minimal diameter of 12 mm. Cardiac catheterization confirmed severe Fontan conduit obstruction in addition to LPA stenosis. Serial covered Cheatham-Platinum stents were implanted for conduit coverage followed by Palmaz stents. Non-compliant Atlas balloon dilation to 20 atm was performed without expansion of the Fontan pathway beyond 12 mm due to severe calcification. A 7.0 x 60 mm shock-wave lithotripsy balloon was added alongside the Atlas balloon to modulate the heavily calcified wall with subsequent expansion of the conduit to 21 mm after inflating the Atlas balloon to 14 atm. Discussion: Several studies demonstrated that transcatheter stenting of stenotic Fontan conduits can be safely performed. Intravascular lithotripsy has emerged as a novel therapy for the treatment of coronary vascular calcification. We report the first case of an innovative percutaneous Fontan conduit rehabilitation procedure using a lithotripsy shock wave balloon in an adult with severely calcified Fontan pathway obstruction and prior stents, achieving a 75% increase in the pathway size without significant complications. Further studies are needed to evaluate the long-term safety and efficacy of this novel approach, but this case presents an exciting option for future directions in the percutaneous treatment of Fontan pathway obstruction.

Background: Patients with ccTGA have a high incidence of atrial arrhythmias and premature failure of the systemic right ventricle. We sought to better define this risk. Methods: A retrospective review of all clinical data for patients with ccTGA followed at a large tertiary care institution was performed. The primary outcome was a composite of death and cardiac transplantation. Results: A cohort of 165 patients (age 41±16 years, 53% male) were followed for 11±8 years; 41 patients died, 7 underwent cardiac transplantation, and 4 underwent VAD placement. Male sex (HR 2.7, p=0.002), older age (HR 1.04, p<0.001), clinical heart failure symptoms (HR 7, p<0.001), heart failure hospitalization (HR 4.9, p<0.001), syncope (HR 1.8, p=0.04) and pulmonary hypertension (HR 2.77, p<0.001) were significant predictors of the primary outcome. Atrial fibrillation (HR 3.5, p=0.002), atrial flutter (HR 3.05, p=0.04), and prolonged QRS duration (HR 1.01, p=0.004) on the first ECG, as well as right and left atrial enlargement (HR 4, p<0.001 and 3.7, p<0.003) and severe systemic AV valve regurgitation (HR 3.8, p=0.03) on the first echocardiogram were associated with poor outcomes. Atrial arrhythmias occurred in 110(67%) patients: atrial fibrillation in 75(45%), atrial flutter in 50(30%), and supraventricular tachycardia in 16(9.7%) patients. Arrhythmias were largely asymptomatic in 109(66%) patients, while 25(14.5%) experienced palpitations, dizziness or presyncope, and 10(6%) presented with decompensated heart failure. Cardioversion and antiarrhythmic therapy were utilized in 53(32%) patients. Surgical pulmonary vein isolation or atrial MAZE were performed in 15(9%) patients, cryoablation of the CTI in 3 patients, and surgical ablation of an accessory pathway in 2 patients. One or more catheter ablation procedures were also performed in 18(11%) patients. Conclusions: Atrial fibrillation and flutter, heart failure, prolonged QRS duration, systemic AV valve regurgitation and pulmonary hypertension predict worse outcomes in ccTGA. Although asymptomatic in a majority of patients, atrial arrhythmias are associated with significant morbidity and mortality. Whether a rhythm control strategy even in asymptomatic patients may improve outcomes remains unknown.