Background: Implantable invasive hemodynamic monitoring (IHM) using the CardioMEMS™ HF system has been shown to reduce heart failure (HF) hospitalizations. IHM has not yet been used in congenital heart disease (CHD) patients, particularly those with a Fontan palliation for single ventricle CHD. We aimed to evaluate feasibility and describe mid-term outcomes in this population.
Methods: Six adult Fontan patients with (≥1 HF admission, NYHA FC ≥3) were enrolled (2 female, 30±7 years old, mean pulmonary artery (mPA) 16±4.7mmHg). Daily IHM transmission was encouraged and evaluated weekly. Heart failure management events included (HFME): CV medication change, hospital admission, paracentesis) and were analyzed for ≥6 months.
Results: Patients managed with the assistance of an IHM had no change in MLHFQ score (40.3±29.8 vs. 49.5±34.3, p=0.51) or peak VO2 (17±7.5 vs. 14±5.4, p=0.18). At an average follow-up of 14.9±6.6 months, subjects transmitted 7±7.7 readings per month. In total there were 674 IHM transmissions and 21 HFMEs over the first 6 months post-IHM implantation (4±5 medication changes, 1±3 paracentesis, 1±1 decompensated HF admission). There was a significant correlation between HFME and elevated mPA pressure: mPA≥14mmHg (χ2 13.39, p<0.001), mPA≥16mmHg (χ2 15.79, p<0.0001), mPA≥18mmHg (χ2 15.52, p<0.0001), mPA≥20mmHg (χ2 16.84, p<0.0001), mPA≥22mmHg (χ2 24.54, p<0.000001). Although the HFME risk was not linearly related to the degree of mPA elevation, there was an inverse relationship between freedom from HFME and higher mPA measurements (Figure).
Conclusion: In the first feasibility cohort of adult Fontan patients undergoing IHM implantation and monitoring, we demonstrate technical success with device placement. Elevated mPA pressure highly correlated in a non-linear manner with HFME but directly with freedom from events.