Exercise Prescription Enhances Maximal Oxygen Uptake and Anaerobic Threshold in Young Single Ventricle Patients with Fontan Circulation

Henri Pyykkönen,Olli Pitkänen-Argillander,Päivi Piirilä,Heikki Tikkanen,Otto Rahkonen,Sini Lähteenmäki,Nadja Ratia

doi:10.1007/s00246-021-02806-8

Henri Pyykkönen, Olli Pitkänen-Argillander + Show 5 more

Open Access

https://doi.org/10.1007/s00246-021-02806-8

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Abstract

A modified Fontan procedure is performed to palliate single ventricle malformations. This hemodynamic arrangement sets systemic venous pressure unphysiologically high which predisposes the patient to severe long-term complications. As a means of self-care, exercise may ease transpulmonary flow. We investigated the effects of 6-month exercise prescription on pediatric Fontan patients. Eighteen stable Fontan patients (14 ± 2.6 years, 160.4 ± 11.3 cm, and 51.4 ± 14.4 kg) were recruited. Baseline fitness was assessed by physical activity questionnaire, body composition, cardiorespiratory performance, and muscle fitness tests. Exercise prescription was individually tailored for a 6-month training period at home. At entrance to the study, Fontan patients had lower than normal maximal oxygen uptake (VO2max) of 28. ± 5.9 ml/kg/min (61 ± 11% of normal). VO2max significantly correlated with weekly amount of habitual exercise and muscle mass of the lower limbs (p < 0.001 for both). After 6 months of training, the patients had improved their anaerobic threshold of 18 ± 3.5 vs 20 ± 4.8 ml/kg/min, p = 0.007, and workload tolerance of 119 ± 39 vs 132.4 ± 44 W, p = 0.001. At EUROFIT tests, the patient muscle fitness was below age-matched reference, but correlations existed between VO2max and lower limb muscle tests. Our patients with Fontan hemodynamics were able to positively respond to an exercise program by enhancing submaximal performance which should be beneficial for getting through daily activities. Future studies should correlate whether hemodynamic findings at Fontan completion influence physical activity and exercise reserves, and whether these predict predisposition to chronic complications.

Highlights

Treatment of patients born with a univentricular heart necessitates a major stepwise palliative heart surgery where the goal is to connect the systemic veins directly into the pulmonary arteries and to use the single ventricle as a pump for the aorta
Our study demonstrated that the 6-month exercise intervention in pediatric Fontan-operated patients increased weekly physical activity and improved submaximal cardiopulmonary performance, workload tolerance and lower limb strength
[10] Corroborating with these previous observations, we found that in our study patients, having fat and lean muscle mass in the normal range, the 6-month exercise program had an insignificant effect on VO2max, which remained at 61–63% of age-matched reference value [22]

Summary

Introduction

Treatment of patients born with a univentricular heart necessitates a major stepwise palliative heart surgery where the goal is to connect the systemic veins directly into the pulmonary arteries and to use the single ventricle as a pump for the aorta. The Fontan procedure results in a pulmonary circulation very different from physiological conditions, with a progressive risk of attrition over time. The systemic venous pressure increases 2- to 3-fold in comparison with physiologic normal [1]. The lack of a pulsatile flow within the pulmonary arterial tree results in impaired pulmonary artery growth and increased pulmonary vascular resistance [2, 3]. As a consequence, increased pulmonary vascular resistance will lead to reduced ventricular preload and cardiac output. The chronically increased systemic venous pressure will in most cases eventually lead to overt organ failure [4, 5]

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