Abstract 2210: Performance of Cavopulmonary Palliation at Elevated Altitude: Midterm Outcomes and Risk Factors for Failure
Background: Elevated altitude leads to pulmonary vasoconstriction and increased pulmonary vascular resistance. Outcomes of patients undergoing cavopulmonary palliation for single ventricle physiology may be impacted by living at altitude, as the passive pulmonary circulation is primarily dependent on the resistance of the pulmonary vascular bed. The objective of this study is to identify risk factors for failure of cavopulmonary palliation at elevated altitude.
Methods and Results: Between January 1995 and March 2007, 120 consecutive patients living at a mean altitude of 1600 m (range 305–2570) underwent a bidirectional Glenn (BDG) procedure. There was one in-hospital mortality and 7 late deaths. Of these patients, 50 have proceeded to the Fontan procedure. Actuarial survival following BDG was 92.4% at 5 years and 83.7% at 10 years. Palliation failure resulting in heart transplantation occurred in 11 patients, 8 following failed BDG and 3 following failed Fontan. Freedom from palliation failure, defined as death, transplant, BDG/Fontan takedown or revision, was 81% at 5 years. At a mean follow-up of 39.8 months, 88 patients (75%) were in NYHA class I, free from recurrent pleural effusions and persistent hypoxemia. For the entire cohort, the baseline (pre-BDG) mean pulmonary artery pressure (PAP) was 15.4 ± 5.3 mmHg, mean indexed pulmonary vascular resistance (PVRI) was 2.38 ± 1.76 Wood U·m2, and mean transpulmonary gradient (TPG) was 8.1 ± 4.4 mmHg. Patients with failing cavopulmonary circulation resided at higher altitude (1712 ± 228 m vs. 1578 ± 314 m, p=0.05), had higher pre-BDG PAP (18.3 ± 6.1 mmHg vs. 14.8 ± 5.1 mmHg, p=0.016), and had higher pre-BDG TPG (11.2 ± 6.2 mmHg vs. 7.7 ± 4.3 mmHg, p=0.014). Post-BDG, patients with palliation failure had increased PAP (15.0 ± 5.7 mmHg vs. 10.8 ± 2.8 mmHg, p=0.008) and PVRI (2.43 ± 1.0 Wood U·m2 vs. 1.52 ± 0.9 Wood U·m2, p=0.007). Fontan failure was associated with higher ventricular end-diastolic pressures (13.3 ± 8.1 vs. 6.8 ± 1.4, p=0.006).
Conclusions: The majority of patients at moderate altitude have favorable outcomes following BDG or Fontan palliation. Risk factors for palliation failure at elevated altitude include PAP > 15 mmHg, TPG > 8 mmHg, and PVRI > 2.5 Wood U·m2.