Improving Functional Capacity in Fontan Patients Through Inspiratory Muscle Training

Mechanisms that typically result in increased cardiac output, such as inotropic support, increased heart rate, and decreased afterload, have a blunted effect in Fontan circulation. The "thoracic pump" is a contributor to venous return that has been largely unexplored in patients with Fontan physiology. Inspiratory muscle training can improve the performance of competitive athletes across a range of sports and can improve quality of life and functional capacity in heart failure patients, presumably by reducing inspiratory muscle fatigue and possibly by improving peripheral blood flow during exercise. One could surmise that the effects of these changes would be particularly important in the Fontan population. The investigators propose to study the effects of inspiratory muscle training on exercise and pulmonary function parameters in a cohort of adult Fontan patients.

The investigators hypothesize that a 12-week program of inspiratory muscle training with an inspiratory impedance threshold device will improve inspiratory muscle strength and endurance, and that this will translate into improved exercise performance in patients with Fontan physiology.

Study Overview

• Status: Completed
• Conditions: Congenital Heart Disease; Single Ventricle
• Intervention / Treatment: Device: THRESHOLD(TM) INSPIRATORY MUSCLE TRAINER

• Study Type: Interventional
• Enrollment (Actual): 12
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Children's Hospital, Boston

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 18 years of age and older
• Fontan physiology
• Undergoing cardiopulmonary stress testing
• Able to complete a previous cardiopulmonary stress test in the preceding 24 months
• Ability to comply with the inspiratory muscle training protocol
• Ability to return for repeat stress testing and pulmonary function testing 12 weeks after enrollment
• Ability to provide informed consent

Exclusion Criteria:

• Status post cardiac transplantation
• Current pregnancy or plans to become pregnant within the next 3 months (for females of childbearing potential)
• Active respiratory infection
• Active cigarette smoker
• Baseline oxygen saturation <90% at the previous clinic visit or exercise test
• Forced expired volume in 1 s and/or vital capacity <60% of predicted at the previous exercise test
• Cardiac surgery or catheter-based procedure in the preceding 18 months or planned surgery or catheter-based procedure within the next 3 months

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: THRESHOLD(TM) INSPIRATORY MUSCLE TRAINER

Device: THRESHOLD(TM) INSPIRATORY MUSCLE TRAINER; Subjects will be provided with noseclips and a threshold impedance device set to 40% of their measured maximal inspiratory pressure and will be trained on using the device. Specifically, subjects will be instructed to breathe through the inspiratory muscle training device while wearing noseclips at a rate of 12 to 16 breaths per minute for 30 minutes a day, 5 days a week for 12 consecutive weeks. Each subject will be provided a customized schedule for increasing resistance by 2 cm H2O every 2 weeks to a maximum resistance of 41 cm H2O.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change in Peak VO2 Between Baseline and Post-inspiratory Muscle Training Measurements.	Baseline and after 12 weeks of training

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Innocor Measurement (Inert Gas Rebreathing Method) of Cardiac Output at Peak Exercise		12 weeks
Change in SF-36 Health Survey Score (Physical Component Summary)	The 36-Item Short Form (SF-36) Health Survey is a disease-generic survey of an individual's perceived health status and health-related quality of life. There are eight scaled scores, which are the weighted sums of the questions in their section. Each scale is transformed into a 0-100 scale on the assumption that each question carries equal weight. The lower the score the more disability. The higher the score the less disability. These eight scales are then used to calculate (using a proprietary formula) two summary scores: the physical component score (PCS), representing the four physical health scales (physical functioning, role physical, bodily pain, general health), and the mental component score (MCS), representing the four mental health scales (mental health, role emotional, vitality, social functioning). Component scores are norm-based with a mean of 50 (standardized to the US population) and a standard deviation of 10.	12 weeks

Other Outcome Measures

Outcome Measure	Time Frame
Change in Maximum Voluntary Ventilation	12 weeks
Change in Maximal Inspiratory Pressure	Baseline and after 12 weeks of training
Change in Oxygen Pulse at Peak Exercise	12 weeks
Change in Peak Work Rate During Exercise	Baseline and after 12 weeks of training
Change in VE/VCO2 Slope (Ratio) During Exercise	Baseline and after 12 weeks of training

Collaborators and Investigators

• Sponsor: Boston Children's Hospital
• Investigators: Principal Investigator: Fred Wu, MD, Boston Children's Hospital

Study record dates

Study Major Dates

• Study Start: December 1, 2013
• Primary Completion (Actual): March 1, 2015
• Study Completion (Actual): March 1, 2015

Study Registration Dates

• First Submitted: October 25, 2013
• First Submitted That Met QC Criteria: October 31, 2013
• First Posted (Estimate): November 6, 2013

Study Record Updates

• Last Update Posted (Actual): November 14, 2017
• Last Update Submitted That Met QC Criteria: October 14, 2017
• Last Verified: October 1, 2017

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Congenital Abnormalities; Cardiovascular Abnormalities; Heart Diseases; Heart Defects, Congenital; Univentricular Heart
• Other Study ID Numbers: P00006063