Hemodynamic, Vascular and Muscular Parameters of Exercise Capacity in Single-Ventricle Patients With Fontan Procedure
Condition: Single-ventricle; Fontan Procedure; Hemodynamic Instability; Arterial Stiffness; Muscle Oxygenation; Exercise Capacity
MeSH terms: Univentricular Heart
Study type: Observational

Summary: 
      After the Fontan procedure applied in patients with a functional or anatomical single
      ventricle, patients are faced with significant morbidity and mortality risk. Most of the
      common complications after Fontan such as arrhythmia, cyanosis, ventricular dysfunction,
      heart failure, atrioventricular valve insufficiency, protein-losing enteropathy, thrombosis,
      bleeding, venous insufficiency directly or indirectly limit exercise capacity. It has been
      reported that hemodynamic, vascular and muscular factors may be effective in the decrease of
      exercise capacity. In previous studies, it has been reported that cardiac output, one of the
      hemodynamic parameters, is the main factor affecting exercise capacity in patients with
      Fontan, and this is due to insufficient increase in stroke volume. In addition to the
      hemodynamic profile, the effects of muscle oxygenation, arterial stiffness and peripheral
      muscle strength on exercise capacity have been mentioned in different studies. For this
      reason, it is thought that examining the effects of hemodynamic, vascular and muscular
      profile together on submaximal and maximal exercise capacity in patients with Fontan will
      provide information about the mechanisms of influence of different exercise capacities and
      will provide important information in terms of determining exercise-based rehabilitation
      programs for such patients.
    

Detailed description: 
      Fontan operation is a palliative surgical procedure performed in patients with a functional
      or anatomical single ventricle. After the Fontan procedure, patients face significant risk of
      morbidity and mortality, and patients with complicated congenital heart disease need to be
      followed for life by a cardiologist experienced in the care of patients. Annual follow-up is
      recommended in uncomplicated patients, but more frequent follow-up is required in patients
      with postoperative complications. Survival rates of 15-20 years after the operation vary
      between 60-85%. Since there is no ventricular pump to push blood into the pulmonary artery
      circulation in patients undergoing the Fontan procedure, there is increased systemic venous
      pressure compared to normal biventricular circulation. Most of the common complications after
      Fontan are directly or indirectly related to elevation of central venous pressure. These
      complications include arrhythmia, cyanosis, decreased exercise capacity, ventricular
      dysfunction, heart failure, atrioventricular valve insufficiency, protein-losing enteropathy,
      thrombosis, bleeding, venous insufficiency. Patients undergoing the Fontan procedure
      generally do not experience a normal increase in cardiac output during exercise; therefore
      exercise capacity is limited. It has been emphasized that hemodynamic, vascular and muscular
      factors may be effective in decreasing exercise capacity. In previous studies, it has been
      reported that cardiac output is the main factor affecting exercise capacity in patients with
      Fontan, and this is due to insufficient increase in stroke volume. However, in previous
      studies, it has been reported that factors such as insufficient precision of measurements
      (resting echocardiography in supine position, resting cardiac MRI) and failure to see optimal
      functions with maximum effort are insufficient to interpret the effects of hemodynamic
      profile on exercise capacity. Therefore, it is important to evaluate the global and regional
      myocardial functions in more detail and to determine the hemodynamic profile with speckle
      tracking echocardiography. In a study, it was reported that atrial tension parameters
      measured by speckle tracking echocardiography in the Fontan circulation were affected and
      this was related to functional exercise capacity.. In addition to the hemodynamic profile,
      the effects of muscle oxygenation, arterial stiffness and peripheral muscle strength on
      exercise capacity were also mentioned in some separate studies. Changes in muscle oxygenation
      in children undergoing the Fontan procedure indicate that the balance between the oxygen
      demand of the tissues and the amount of oxygen supplied is impaired. It is thought that this
      may be a mechanism that causes a decrease in exercise tolerance in this patient population.
      Also, the function of peripheral muscles by acting as a pump is particularly important for
      venous return in the Fontan circulation, and skeletal muscle mass is reduced in patients with
      Fontan. Studies have shown that leg lean mass is closely related to an increase in blood flow
      during exercise, and skeletal muscle contractions can generate pulsatile pulmonary blood flow
      in some patients with Fontan circulation. A relationship was also found between arterial
      stiffness and cardiorespiratory fitness in pediatric and adult patients with fontan
      circulation, and it has been reported that practices to increase exercise capacity may be
      important for the preservation of vascular structures. Exercise capacity in children and
      adults undergoing the Fontan procedure is evaluated with field tests such as the
      cardiopulmonary exercise test (CPET) and the 6-minute walk test (6MWT). CPET is very
      important in terms of providing objective data in terms of cardiopulmonary fitness in the
      evaluation of maximal exercise capacity and being the gold standard. However, in terms of
      determining the functional levels of individuals and maintaining their daily living
      activities, submaximal exercise capacity, which is evaluated with both cheap and practical
      6MWT, also gains importance. When the literature was searched, there was no study examining
      the effects of hemodynamic, vascular and muscular profile on submaximal and maximal exercise
      capacity. Therefore, in this study, it is aimed to determine and compare the effects of
      hemodynamics, arterial stiffness and muscle oxygenation on maximal and submaximal exercise
      capacity in patients with single ventricle who underwent Fontan procedure.
    

Intervention name(s): Demographic and Clinical Characteristics, Maximal Exercise Capacity, Submaximal Exercise Capacity, Hemodynamic Parameters, Muscle Strength, Muscle Oxygenation, Vascular Function
Intervention type(s): Other
Intervention description(s): Demographic and Clinical Characteristics, Maximal Exercise Capacity, Submaximal Exercise Capacity, Hemodynamic Parameters, Muscle Strength, Muscle Oxygenation, Vascular Function
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        After obtaining informed consent, control cases will also be evaluated in terms of
        evaluation parameters within the scope of the study. Patients aged 8-50 years who underwent
        the fonton procedure and were followed by Hacettepe University, Department of Pediatric
        Cardiology will be included in the study. A medical and family history, and a physical
        examination focused on all systems, especially cardiovascular and musculoskeletal systems,
        will be essential. The eligible patients will be referred to Faculty of Physical Therapy
        and Rehabilitation after the routine evaluations are completed. Control cases planned to be
        included in the study to be compared with the results of Fontan patients will be created by
        inviting the healthy relatives of the patients who applied to our faculty to participate in
        the study. In addition, control cases will be invited to work through an online
        advertisement.