Abstract 13272: Acute Effects of Enhanced External Counterpulsation in Adults With Fontan Circulation

Abstract

Background: Patients who have undergone Fontan palliation for single ventricle CHD exhibit reduced cardiac output. Aims: To study the safety and acute hemodynamic effects of enhanced external counterpulsation (EECP) in a cohort of Fontan patients. Methods: Pilot study of adult Fontan patients recruited through the ambulatory clinic at a single, large-volume ACHD center. Patients underwent TTE and measurement of pulmonary blood flow (PBF), a surrogate for cardiac output, followed by 1 hour of EECP divided into 20-minute stages (80 mmHg, 160 mmHg, 240 mmHg). TTE and PBF measurement were repeated at each stage and 15-30 minutes after completion of EECP. Patients were monitored for symptoms throughout the visit. A repeated measures linear-mixed-model (robust to non-normality) was used to estimate the mean at each time point and to test for differences across time points. Results: There were 23 patients enrolled (52% male, 91% cis-gender, 74% White). Mean age at enrollment and at Fontan completion was 33.0 ± 7.8 years and 5.1 ± 4.1 years, respectively. Six patients (26%) had a pacemaker. Twenty-two (96%) completed a full hour of EECP. Pressure was reduced in the third stage for 3 patients due to discomfort. No patients reported chest pain or increased dyspnea during EECP. PBF was increased at each stage of EECP compared to baseline and returned to baseline post-EECP (Fig. 1). There was a small qualitative improvement in ventricular systolic function in the second and third stages of EECP compared to baseline (160 mmHg: p=0.048; 240 mmHg: p=0.024). O 2 saturation was increased at each stage of EECP compared to baseline (baseline: 93.0%, 80 mmHg: 94.3% [p=0.008], 160 mmHg: 94.6% [p=<0.001], 240 mmHg: 94.6% [p=<0.001]). Mean arterial pressure and heart rate did not change. Conclusions: EECP is well-tolerated in adult Fontan patients and acutely improves PBF at pressures as low as 80 mmHg. Further study is warranted to explore long-term therapeutic effects of EECP in these patients.