Is Threshold-based Training Superior in Cardiac Rehabilitation

NCT ID: NCT04114929

Last Updated: 2022-11-03

Basic Information

• Recruitment Status: WITHDRAWN
• Clinical Phase: NA
• Study Classification: INTERVENTIONAL
• Study Start Date: 2020-03-01
• Study Completion Date: 2022-08-01

Brief Summary

This study evaluates two methods of prescribing exercise intensity in a Phase IV cardiac rehabilitation programme. One method is using specific ventilatory markers and the other following standard care guidelines.

Detailed Description

Coronary heart disease (CHD) is one of the United Kingdom's (UK) biggest killers. In the UK alone 175,000 myocardial infarctions are recorded annually. While these numbers are significant advances in preventative therapy and medical treatment have contributed to an overall reduction in mortality in the UK. As such there is a growing need for effective secondary prevention. To lower the financial burden on the National Health Service (NHS), cardiac rehabilitation (CR) facilitates a systematic and multidisciplinary approach to secondary prevention aimed to improve functional capacity and health-related quality of life, lower rehospitalisation rates and reduce all-cause and cardiovascular mortality with exercise training being the cornerstones.

A 2016 Cochrane review found benefits of exercise-based CR for patients with coronary artery disease. Both cardiovascular mortality and hospital readmissions were reduced, when compared with a no-exercise control. However, in contrast to previous systematic reviews and meta-analyses, there was no significant reduction in risk of reinfarction or all-cause mortality. Further a recent systematic review and meta-analysis (2018) found no differences in outcomes between exercise-based CR and a no-exercise control at their longest follow-up period for: all-cause mortality or cardiovascular mortality. The authors also found a small reduction in hospital admissions of borderline statistical significance. One possible answer to the above findings is the under dosage of exercise intensity and duration in UK CR. A recent multicentre study of routine UK-based CR (current clinical practice) indicated that the 'exercise dose' within outpatient UK CR may be insufficient to meaningfully improve cardiorespiratory fitness (CRF) when compared with international programmes. Given the prognostic relevance of improving CRF and that exercise and physical activity has a 'dose-response' relationship with cardiovascular disease risk, these findings may explain why UK CR programmes do not appear to improve patient survival.

UK-based guidelines advocate a percentage range-based method for prescribing exercise intensity. However, there are a number of limitations of this method. The investigators and others have recently shown that prescribing exercise intensity using percentage heart rate reserve (%HRR) can lead to patients receiving different exercise training doses from what would be historically viewed as the same exercise training intervention. Prescribing exercise based on %HRR ignores the important role that metabolic perturbations play in stimulating physiological adaptation in response to exercise training. The ventilatory anaerobic threshold (VAT) is an important objective metabolic threshold that indicates when incrementally greater contributions from anaerobic metabolism are required to sustain further increases in workload. The VAT has been proposed as a minimum exercise training intensity that must be exceeded in order to improve aerobic fitness. Compelling data has shown that the occurrence of the VAT is patient-specific, and can occur at different percentage of a patient's HRR. Basing an exercise training programme on estimated, or even directly measured %HRR could therefore result in heart rate training zones being set either above, or below the VAT. Patients who are prescribed the 'same' exercise training programme based on %HRR could be exposed to different metabolic stimuli and therefore a different exercise training dose. This may explain why some patients appear to 'respond' to a treatment, whilst others may be classified as "non-responders." Prescribing exercise that can improve CRF for patients attending CR is essential, and greater consideration for how exercise is prescribed in a community-based setting is required.

Given the VAT is a significant threshold, with evidence reporting it to be a superior method, comparisons to the %HRR method are limited in clinical populations. As such the primary focus of the study is to compare the effectiveness of a threshold-based model (ventilatory threshold) versus a relative percent model (%HRR) for improving cardiorespiratory fitness in patient attending Phase IV community based cardiac rehabilitation.

Conditions

Cardiac Rehabilitation

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Threshold-Based

Patients will be prescribed exercise based on ventilatory thresholds from a maximal cardiopulmonary exercise test

Group Type: EXPERIMENTAL

Threshold-based Training

Intervention Type: OTHER

Specific ventilatory markers determined from a cardiopulmonary test and the correlating heart rate will be used to determine exercise intensity

Standard Care

Patients will be prescribed exercise based on standard guidelines

Group Type: ACTIVE_COMPARATOR

Standard Care

Intervention Type: OTHER

Using the standard care cardiac rehabilitation guidelines exercise will be based on estimated heart rate maximum followed by the karvonan method to calculate 40-70% heart rate reserve

Interventions

Threshold-based Training

Specific ventilatory markers determined from a cardiopulmonary test and the correlating heart rate will be used to determine exercise intensity

Intervention Type: OTHER

Standard Care

Using the standard care cardiac rehabilitation guidelines exercise will be based on estimated heart rate maximum followed by the karvonan method to calculate 40-70% heart rate reserve

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Patient has read and understood the Patient Information Sheet
• Diagnosis of coronary heart disease (CHD) including myocardial infarction(MI), coronary artery bypass graft (CABG) surgery, elective percutaneous coronary intervention (PCI) or exertional angina.

. Diagnosis of heart failure

• Aged between 18 and 85 years
• Absence of contraindications to exercise testing and training
• Clinically stable (symptoms and medication)
• Patient is able to and has given written informed consent
• Able to comply with guidelines for participation in exercise testing & prescription

Exclusion Criteria

• Clinically Unstable

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 85 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Hull

OTHER

Sponsor Role: collaborator

Leeds Beckett University

OTHER

Sponsor Role: collaborator

Sheffield Hallam University

OTHER

Sponsor Role: collaborator

University of Central Lancashire

OTHER

Sponsor Role: lead

Responsible Party

Stefan Birkett

Lecturer In Exercise Science

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

School of Sport and and Health Sciences

Preston, , United Kingdom

Countries

United Kingdom

Other Identifiers

UCentalLancashire

Identifier Type: -

Identifier Source: org_study_id