A Preliminary Study on External Counterpulsation System: An Alternative Therapeutic Option for Fontan Patients

In order to address the long-term complications that arise from poor venous return, a hallmark of the Fontan physiology, we assessed the feasibility of a non-invasive, home therapy that will improve the health of the patient during the heart transplant waiting period and ameliorate the quality of life. In order to achieve this goal we tested a device that applies pressure to the lower extremities of the body (legs and abdomen) in a pulsating fashion with the goal of augmenting systemic blood flow to the pulmonary arteries. This treatment will enhance flow from the great veins and through the lungs and serve as adjunctive clinical treatment of single ventricle physiology. The specific aim of this study was to show improvements in cardiorespiratory measurements after applying external pressure as a proxy for improved health in the Fontan patient. Various studies have shown the impaired exercise capacity of post-operative Fontan patients, but very little data exists focusing on a period much later after the surgery. Our results among the two subjects completed so far have shown a moderately beneficial improvement in exercise capacity after the compression therapy. Subjects performed a treadmill exercise stress test at VCU that was followed by six days of applied external pressure treatment and finished with a final post-treatment stress test. Cardiorespiratory data was collected and analyzed for improvements from base level. Overall an improvement in exercise duration time, VO2 peak, ventilatory threshold, and OUES was observed, with only VE / VCO2 slope having mixed results. Both subjects seem to be relatively healthy Fontan patients, as indicated by their VO2 peak, VE/VCO2 slope and OUES. As a result, benefits of treatment may vary among a cohort of Fontan patients with poor health condition; a failing Fontan physiology for instance. The improvement in exercise capacity suggests that this therapy could be very beneficial to Fontan patients. These results warrants follow up studies to explore the extent of the clinical benefits of compression treatment among the Fontan population.