Abnormal diffusion capacity of the lung on exercise in patients with high blood pressure in the blood channels of the lung also known as pulmonary arterial hypertension
| ISRCTN | ISRCTN65855577 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN65855577 |
| Secondary identifying numbers | 1 |
- Submission date
- 16/02/2024
- Registration date
- 26/02/2024
- Last edited
- 26/02/2024
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Circulatory System
Plain English summary of protocol
Background and study aims
A person’s gas transfer refers to the body’s ability to transfer the oxygen that we breathe into the bag part of our lungs and transfer that through the membrane inside our lungs (known as our alveoli) and then into our bloodstream.
In a clinical setting, pulmonary function tests (PFT) are routinely performed every day around the world to assess the mechanical functions of our lungs. A PFT is a series of different breathing tests also known as the lung NCT. A PFT is completely safe and involves the patient's breathing in and out of a tube from a seated position at maximal effort. Depending on the type of breathing test the patient will be required to breathe in and out of a tube at different speeds and patterns and breathing in different gas mixtures. One of these tests is known as DLco measurement which measures gas transfer.
Patients with high blood pressure in the blood channels of the lung also known as pulmonary arterial hypertension (PAH) routinely have gas transfer measurements performed to help their respiratory physicians determine the severity of their condition. Patients with PAH tend to have abnormally low gas transfer measurements (low DLco).
The aim of this study is to see what changes occur in gas transfer measurements in PAH patients from rest to immediately when they stop exercise. Previous research has indicated that in healthy patients gas transfer should increase after exercise but no research has been conducted to determine what happens to a PAH patient's gas transfer after exercise. The reason for this avenue of investigation is to hopefully help clinicians better understand PAH which may lead to further studies that can help diagnose PAH quicker or be treated more effectively.
Who can participate?
Patients with PAH and healthy volunteers, aged 18-65 years
What does the study involve?
The exercise that the participants will be required to perform for this study is an incremental shuttle walk test (ISWT). The walk test will involve the patient walking between two cones spaced 10 metres apart from each other. The patient will have to follow the auditory beeps played on an app and walk at that pace between the two cones (10 metres). There are 12 cycles each cycle lasting for 1 minute. The patient walks for as long as they can until they finish it, are too breathless to continue or can no longer keep up with the beeps, at which time the test ends.
What are the possible benefits and risks of participating?
The ISWT is used to assess PAH patients’ exercise capacity in standard practice around the world and is extremely safe.
Where is the study run from?
Mater Hospital (Ireland)
When is the study starting and how long is it expected to run for?
November 2023 to December 2024
Who is funding the study?
Mater Hospital (Ireland)
Who is the main contact?
Dr Ciara McCormack, ciaramccormack250@gmail.com
Contact information
Public, Scientific
Dublin
Dublin
00
Ireland
 ORCID ID |
0000-0003-4508-5522 |
|---|---|
| Phone | N/A |
| ciaramccormack@eril.ie |
Principal Investigator
Dublin
Dublin
00
Ireland
| ORCID ID |
0000-0002-9261-010X |
|---|---|
| Phone | N/A |
| rehanquadery@mater.ie |
Study information
| Study design | Single-centre prospective observational proof of concept study |
|---|---|
| Primary study design | Observational |
| Secondary study design | Case-control study |
| Study setting(s) | Hospital |
| Study type | Efficacy |
| Participant information sheet | Not available in web format, please use contact details to request a participants information sheet |
| Scientific title | A pilot study: impaired pulmonary diffusion capacity on exercise in patients with pulmonary arterial hypertension |
| Study objectives | The alternative hypothesis of the study is that the patients in group 1 with pulmonary arterial hypertension (PAH) will have a significantly lower percentage change in diffusing capacity for carbon monoxide (DLCO) from their baseline to immediately following exercise when compared to the age-matched control group. The null hypothesis of the study is that the patients in group 1 with PAH will have a significant increase in percentage change in DLCO from their baseline to immediately following exercise when compared to the age-matched control group. |
| Ethics approval(s) |
Approved 14/02/2024, Mater Misericordiae University Hospital REC (Dublin, Dublin, 000, Ireland; N/A; hannahking@mater.ie), ref: 1/378/2407 |
| Health condition(s) or problem(s) studied | Pulmonary hypertension |
| Intervention | The study will involve recruiting PAH patients on PH-specific targeted therapies and ten age-matched healthy controls who will complete baseline pulmonary diffusion capacity measured at rest and immediately after completing the incremental shuttle walk test (ISWT). |
| Intervention type | Other |
| Primary outcome measure | Change in DLCO immediately (within 1-2 min) following exercise (DLCO at maximum exercise minus DLCO at rest) measured by modified Kroghs single breath method |
| Secondary outcome measures | 1. Cardiac effort: total number of heartbeats divided by the total distance travelled in the incremental shuttle walk test (ISWT) 2. Heart rate reserve at the end of exercise (maximum heart rate minus resting heart rate) 3. % of maximum predicted heart rate (maximum heart rate divided by 220-Age in years multiplied by 100) 4. % of maximum predicted walk distance achieved at the end of exercise (ISWTpred = 1449.701 − (11.735 × age) + (241.897 × gender) − (5.686 × BMI), where male gender = 1 and female gender = 0) Total walk distance achieved (m)/predicted walk distance (m)x 100 5. Heart rate recovery in the first minute immediately after the end of exercise (maximum heart rate - heart rate after 1 min of having stopped exercise) 6. Change of oxygen saturation immediately before the end of exercise (oxygen saturation at rest - minimum oxygen saturation achieved just before the end of exercise) 7. Calculated peak oxygen consumption at the end of exercise (VO2 peak (predicted) = 19.793 + (0.02 x distance walked)-(0.236 x age)) 8. Change in DLCO/heart rate slope between rest and exercise (DLCO at rest / resting heart rate minus DLCO at peak exercise / maximum heart rate achieved) 9. Breathlessness measured using modified Borg score immediately at the end of exercise 10. Body weight (kg) x distance (m) product measured at the end of exercise 11. Quality of life measured using the Emphasis 10 scale at the start of the trial Devices used to collect measures: PFT System: Vyntus ONE PFT system ISWT: Vyntus walk tablet with Spo2 Spo2/HR: Nonin Pulse Oximeter |
| Overall study start date | 10/11/2023 |
| Completion date | 10/12/2024 |
Eligibility
| Participant type(s) | Healthy volunteer, Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 65 Years |
| Sex | Both |
| Target number of participants | 30 |
| Key inclusion criteria | Group 1 PAH: 1. Patients with diagnosed idiopathic pulmonary artery hypertension (IPAH)/drug-induced pulmonary artery hypertension (DPAH)/heritable pulmonary arterial hypertension (HPAH)/connective tissue disease (CTD) PAH who are stable for the past three months on PH-specific targeted therapy. 2. Normal spirometry 3. No evidence of interstitial lung diseases (ILD)/emphysema on CT scan 4. Never smokers or ex-smokers with less than equal to 10 pack years h/o smoking 5. Age 18-65 years Age-matched controls: 1. No h/o cardiovascular disease 2. BMI <25 kg/m² 3 Never smoker 4. Normal spirometry 5. Do not currently meet the recommended physical activity government guidelines of at least 150 minutes of moderate-intensity aerobic activity per week 6. Age 18-65 years |
| Key exclusion criteria | 1. Unable to provide written consent 2. Unable to perform the incremental shuttle walk test 3. Pregnant and breastfeeding mothers 4. Healthy volunteers with abnormal pulmonary function test (PFT) data 5. Control group or PAH patients who cannot obtain two reproducible baseline DLCO measurements within three attempts |
| Date of first enrolment | 15/03/2024 |
| Date of final enrolment | 29/06/2024 |
Locations
Countries of recruitment
- Ireland
Study participating centre
Dublin
000
Ireland
Sponsor information
Hospital/treatment centre
Dublin
Dublin
000
Ireland
| Phone | +353 (0)803 2606 |
|---|---|
| jegan@mater.ie | |
| Website | https://www.mater.ie/ |
"ROR" |
https://ror.org/050batv17 |
Funders
Funder type
Hospital/treatment centre
No information available
Results and Publications
| Intention to publish date | 20/09/2024 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Stored in non-publicly available repository, Data sharing statement to be made available at a later date |
| Publication and dissemination plan | Dissemination of aggregated results from the study will take the form of publication in peer-reviewed journals, posters, and oral presentations at national and international meeting. |
| IPD sharing plan | The data-sharing plans for the current study are unknown and will be made available at a later date. |
Editorial Notes
19/02/2024: Study's existence confirmed by the Mater Misericordiae University Hospital.
