Acute Effects of Enhanced External Counterpulsation in Adults With Fontan Circulation.

Background: Patients with Fontan circulation exhibit reduced cardiac output.

Objectives: The purpose of this study was to study the safety and acute hemodynamic effects of enhanced external counterpulsation (EECP) in a cohort of Fontan patients.

Methods: This was a pilot study of ambulatory adults with Fontan circulation at a single, large-volume adult congenital heart disease center. Patients underwent 1 hour of EECP divided into 20-minute stages (80 mm Hg, 160 mm Hg, and 240 mm Hg). Transthoracic echocardiography and pulmonary blood flow (PBF) measurement were performed at baseline, during each stage of EECP, and after EECP completion. Patients were monitored for symptoms throughout. For the primary endpoint, PBF was compared between baseline and EECP at target pressure of 240 mm Hg.

Results: There were 23 patients enrolled (52% male). The median age was 30.9 years (27.8, 37.8). Twenty-two patients (96%) completed a full hour of EECP. EECP pressure was reduced in the final stage for 3 patients due to discomfort. No patients reported adverse symptoms during EECP. PBF increased from 4.5 L/min at baseline to 5.2 L/min during the final stage of EECP (P = 0.001) and returned to baseline post-EECP (4.2 L/min [P = 0.05 vs baseline]). Oxygen saturation remained increased compared to baseline throughout EECP treatment (baseline: 93.0%, 80 mm Hg: 94.3% [P = 0.008], 160 mm Hg: 94.6% [P ≤ 0.001], 240 mm Hg: 94.6% [P = 0.007]). There was no change in mean arterial pressure, heart rate, ventricular function, or valvar regurgitation.

Conclusions: Our results suggest that EECP is well-tolerated in adult Fontan patients and acutely improves PBF. Further study is warranted to explore its longer-term therapeutic effects.