Cardiovascular, Pulmonary and Skeletal Muscle Evaluation Postoperative in Fontan Patients: Effects of Exercise Training
Condition: Congenital Heart Disease; Single Ventricle; Univentricular Heart
MeSH terms: Heart Diseases; Heart Defects, Congenital; Univentricular Heart
Study type: Interventional

Summary: 
      Introduction: The Fontan operation is the surgical treatment in most patients with either
      anatomic or functional single ventricles. In this operation, the subpulmonary ventricle is
      bypassed, connecting the systemic veins directly to the pulmonary arteries. The lack of a
      subpulmonary ventricle is associated with a nonpulsatile pulmonary flow and triggers a
      sequence of adaptive mechanisms along the life of these patients. The most frequent
      consequence of these adaptative mechanisms is the reduction in functional capacity,
      objectively measured by the decrease in peak oxygen consumption (VO2). So, cardiovascular and
      pulmonary functioning and skeletal muscle alterations can explain exercise intolerance in
      these patients.

      Objectives: 1. To compare the cardiovascular, pulmonary, and musculoskeletal system variables
      in clinically stable Fontan patients with Healthy subjects; 2. To correlate the variables of
      the cardiovascular, pulmonary, and skeletal muscle with the functional capacity in Fontan
      patients; 3. To identify predictors of low functional capacity in this population; 4. To
      evaluate four-month aerobic exercise and inspiratory muscle training on functional capacity,
      pulmonary function, and autonomic control in patients after Fontan operation and compare to
      the group with no exercise training.

      Methods: All subjects were submitted to cardiovascular, pulmonary, and skeletal muscle
      evaluation at baseline to perform a cross-sectional study comparing Fontan Patients (FP) with
      Healthy Controls (HC). In addition, the FP accepted to participate in the longitudinal
      clinical trial to evaluate exercise programs were randomized into three groups: Aerobic
      Exercise Training (AET), Inspiratory Muscle Training (IMT), and Non-exercise Training Group
      (NET, a control group). All patient groups (AET, IMT, NET) were reassessed after four months
      of training or under usual care.

      Expected Outcomes: This study expects to demonstrate that impaired pulmonary function,
      altered neurovascular control, and reduced skeletal muscle could be an additional potential
      mechanism for reducing functional capacity in clinically stable Fontan patients. And this
      impairment could be diminished by exercise training, enhancing physical capacity, and
      exercise tolerance.
    

Detailed description: 
      All subjects were submitted to cardiovascular magnetic resonance, echocardiography,
      cardiopulmonary exercise test, complete lung function, catecholamine and B-type natriuretic
      peptide (BNP) plasmatic levels, microneurography, venous occlusion plethysmography,
      six-minute walk test, phosphorus magnetic resonance spectroscopy (31P MRS) and magnetic
      resonance imaging (MRI) of skeletal muscle and quality of life (QoL) using the Short Form
      Health Survey (SF36) in the baseline. Comparative analyzes of the different systems of the
      two groups were done as well as tests to identify the predictors of low functional capacity
      in Fontan groups (FG).

      The evaluation was done at baseline in healthy subjects. And in the Fontan group at baseline
      and after four months of exercise training or usual care.

      AET Protocol: Four-month supervised exercise training was performed in the hospital three
      times a week, 60-min exercise sessions (48 sessions in total). Each session consisted of
      40min on a treadmill, 15 min of personal light resistance training (including chest press,
      squat, pull down, leg extension, shoulder press, calf raises, leg curl, and sit-ups), and
      5min of cool down and stretching. The AET was individually prescribed according to their
      heart rate (HR) from maximal cardiopulmonary exercise testing (CPT), and patients exercised
      between the ventilatory threshold (VT) and respiratory compensation point (RCP). HR, systolic
      blood pressure, oxygen saturation, and exhaustion (i.e., Borg scale from 7 to 20) were
      monitored during the sessions. An exercise physiologist supervised all sessions. In the first
      12 weeks, HR was maintained at T frequency. Between the 12th to 24thweek, there was a
      progressive increase in the effort, and HR was supported between AT and RCP. In the last 12
      sessions of the program, HR was maintained close to RCP frequency.

      IMT Protocol: Four months of exercise training were carried out daily, three sets of 30
      repetitions using the POWERbreathe® device (POWERbreathe International Limited, Southam, UK),
      three sets of 30 repetitions. Maximal inspiratory pressure (MIP) measures were performed in
      all patients before the intervention, and patients exercised at 60% of individual MIP.
      Patients were instructed to inhale using diaphragm musculature, trying to expand the rib cage
      to avoid the use of accessory muscles, and breathing at a rate of 12 to 16 breaths/min. A
      nose clip was worn to ensure patients breathed exclusively through the training device. All
      patients had a supervised session of IMT with a physiotherapist once a week for the first two
      months and once every two weeks for the last two months. The load was adjusted during the
      supervised sessions. Patients were encouraged to maintain their habitual activities during
      the protocol.
    

Intervention name(s): Aerobic Exercise Training; Inspiratory Muscle Training; No Exercise Training
Intervention type(s): Other; Other; Other
Intervention description(s): Supervised aerobic and light muscle resistance exercise training; Inspiratory muscle training with POWERbreathe device; Usual care
Other intervention name(s): AET; IMT; NET
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Fontan; Exercise; Pulmonary Function; Aerobic Capacity; Skeletal Muscle; Neurovascular control; Functional capacity