Year-end Sale % OFF 
Abstract
BackgroundThe Fontan circulation is a unique palliation procedure for several congenital heart defects. Impaired exercise capacity has previously been demonstrated in these patients and also a higher risk for cardiopulmonary mortality. Hemorheology was shown to affect cardiopulmonary capacity and in turn to be affected by regular exercise and hypoxia but none of these have been investigated in Fontan patients so far. The aim of this study was to detect general differences in hemorheology in normoxia as well as possible altered hemorheological responses to hypoxia exposure and hypoxic exercise between Fontan patients and healthy controls.Methods and Findings26 Fontan patients and 20 healthy controls performed an acute exercise test (AET) on a bicycle ergometer under hypoxia with ambient 15.2% oxygen saturation (sO2). Blood samples were taken at rest in normoxia (T0), at rest in hypoxia (T1), after maximum exhaustion in hypoxia (T2), and after 50 min recovery in normoxia (T3). Hemorheological and blood parameters were investigated. Additionally, arterial stiffness was tested at T0. Red blood cell (RBC) deformability, NOx, erythropoietin (EPO) concentration, RBC count, hemoglobin (Hb) concentration and hematocrit (hct) were significantly increased in Fontan patients compared to controls. Same was observed for arterial stiffness. No changes were observed for RBC aggregation, fibrinogen concentration, free radical levels and vascular endothelial growth factor (VEGF). Hypoxia exposure did not change parameters, whereas exercise in hypoxia increased aggregation and hct significantly in both groups. Fontan patients showed significantly increased aggregation-disaggregation balance compared to controls.ConclusionAcute hypoxia exposure and exercise under hypoxia might have similar impact on hemorheology in Fontan patients and controls and was clinically well tolerated. Nevertheless, exercise alters aggregation and possibly hemodynamics which requires special attention in Fontan patients.
Highlights
The Fontan circulation is the current therapy for patients with severe congenital heart diseases (CHD) leading to a univentricular heart like tricuspid atresia or hypoplastic left heart syndrome (HLHS)
At rest in normoxia and hypoxia (T0 and T1) as well as at peak workload (T2), Fontan patients had significantly lower peripheral oxygen saturation (SpO2) compared to controls (Tables 2, 3), but the loss of SpO2 at maximum exhaustion was similar
This study demonstrated a significant correlation of AI (T0) with peak workload in controls, but not in Fontan patients, which could be due to the fact that Fontan patients did not reach their individual maximum exercise capacity, as already discussed
Summary
The Fontan circulation is the current therapy for patients with severe congenital heart diseases (CHD) leading to a univentricular heart like tricuspid atresia or HLHS. In this unique palliation procedure the inferior and superior vena cava are connected to the pulmonary artery resulting in a univentricular circulation with passive pulmonary perfusion called Fontan circulation. Studies reported approximately 60–70% of V O2peak and 47–80% of peak workload compared to healthy references (Ohuchi et al, 2001; Takken et al, 2007; Duppen et al, 2015) Reasons for these impairments are under discussion and include impaired cardiac function (e.g., impaired cardiac output), differences in skeletal muscle function, impaired lung function and/or endothelial dysfunction (Larsson et al, 2003; Binotto et al, 2005; Cordina et al, 2013; Lambert et al, 2013; Turquetto et al, 2017, 2018). The aim of this study was to detect general differences in hemorheology in normoxia as well as possible altered hemorheological responses to hypoxia exposure and hypoxic exercise between Fontan patients and healthy controls
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
