Blood Flow and Vascular Function in Cystic Fibrosis (CF-FLOW)
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ClinicalTrials.gov Identifier: NCT02057458 |
Recruitment Status :
Completed
First Posted : February 7, 2014
Results First Posted : April 24, 2020
Last Update Posted : April 24, 2020
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Condition or disease | Intervention/treatment | Phase |
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Cystic Fibrosis | Drug: Sildenafil (Acute-1 hour) Drug: Sildenafil (Subchronic-4 weeks) Drug: Placebo | Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 19 participants |
Allocation: | Randomized |
Intervention Model: | Crossover Assignment |
Masking: | Double (Participant, Investigator) |
Primary Purpose: | Treatment |
Official Title: | Role of Blood Flow and Vascular Function on Exercise Capacity in Cystic Fibrosis |
Actual Study Start Date : | April 2014 |
Actual Primary Completion Date : | July 2018 |
Actual Study Completion Date : | July 2018 |

Arm | Intervention/treatment |
---|---|
Experimental: Acute Study: Sildenafil first, then Placebo
In randomized order, on two separate days, endothelial function and exercise capacity will be determined 1 hour following a single dose of sildenafil (50 mg) or placebo.
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Drug: Sildenafil (Acute-1 hour)
Vascular function will be assessed 1 hour following oral ingestion of sildenafil (50 mg)
Other Names:
Drug: Placebo Sugar pill designed to mimic the sildenafil treatment |
Experimental: Acute Study: Placebo first, then Sildenafil
In randomized order, on two separate days, endothelial function and exercise capacity will be determined 1 hour following a single dose of sildenafil (50 mg) or placebo.
|
Drug: Sildenafil (Acute-1 hour)
Vascular function will be assessed 1 hour following oral ingestion of sildenafil (50 mg)
Other Names:
Drug: Placebo Sugar pill designed to mimic the sildenafil treatment |
Experimental: Sub-Chronic Study Sildenafil
Following the acute study, patients will be instructed to take 20 mg of sildenafil, three times a day, for 4 weeks. Endothelial function will be determined within 48 hours following the last dose.
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Drug: Sildenafil (Subchronic-4 weeks)
Vascular function will be assessed 4 weeks following 20 mg three times per day (TID) of sildenafil for four weeks
Other Names:
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- Acute Study: Percentage Flow-Mediated Dilation (FMD) [ Time Frame: pre-treatment Baseline and 1 hour post-treatment ]FMD determined one hour after ingestion of 50 mg Sildenafil or placebo
- Baseline Diameter [ Time Frame: pre-treatment Baseline and following 4 weeks sub-chronic treatment ]Brachial Artery Diameter during FMD (pre-occlusion or "baseline")
- Peak Diameter [ Time Frame: pre-treatment Baseline and following 4 weeks sub-chronic treatment ]Peak Brachial Artery Diameter during FMD (post-occlusion)
- Absolute Change in Diameter [ Time Frame: pre-treatment Baseline and following 4 weeks sub-chronic treatment ]Absolute change in brachial artery diameter taken from the FMD assessment
- FEV1 (% Predicted) [ Time Frame: pre-treatment Baseline, 1 hour post-treatment, and following 4 weeks sub-chronic treatment ]Forced Expiratory Volume in the first second expressed as a percent predicted.
- VO2 Peak (Absolute) [ Time Frame: pre-treatment Baseline, 1 hour post-treatment, and following 4 weeks sub-chronic treatment ]absolute (L/min) peak oxygen consumption during maximal exercise test
- VO2 Peak (Relative) [ Time Frame: pre-treatment Baseline, 1 hour post-treatment, and following 4 weeks sub-chronic treatment ]relative (mL/kg/min) peak oxygen consumption during maximal exercise test
- VO2 Peak (Percent Predicted) [ Time Frame: pre-treatment Baseline and 1 hour post-treatment, and 4 weeks sub-chronic treatment ]Maximal Oxygen consumption expressed as percent predicted taken from maximal exercise test.
- VE Peak [ Time Frame: pre-treatment Baseline, 1 hour post-treatment, and following 4 weeks sub-chronic treatment ]peak ventilation (L/min) during maximal exercise test
- RER Peak [ Time Frame: pre-treatment Baseline, 1 hour post-treatment, and following 4 weeks sub-chronic treatment ]peak respiratory exchange ratio during maximal exercise test

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria.
- Diagnosis of CF and healthy controls
- Men and women (greater than 18 yrs. old)
- Resting oxygen saturation (room air) greater than 90%
- Forced expiratory volume (FEV1) percent predicted greater than 30%
- Patients with or without CF related diabetes
- Traditional CF-treatment medications
- Ability to perform reliable/reproducible pulmonary function tests (PFT)
- Clinically stable for 2 weeks (no exacerbations or need for antibiotic treatment within 2 weeks of testing or major change in medical status)
Exclusion Criteria.
- Children less than 17 years old
- Body mass less than 20 kg
- A diagnosis of pulmonary arterial hypertension (PAH)
- FEV1 less than 30% of predicted
- Resting oxygen saturation (SpO2) less than 90%
- Self-reported to be a smoker
- Current use of any vaso-active medications
- History of migraine headaches
- Pregnant or nursing at the time of the investigation
- A clinical diagnosis of cardiovascular disease, hypertension, or CF related diabetes

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02057458
United States, Georgia | |
Augusta University | |
Augusta, Georgia, United States, 30912 |
Principal Investigator: | Ryan Harris, Ph.D. | Augusta University |
Documents provided by Ryan Harris, Augusta University:
Responsible Party: | Ryan Harris, Assistant Professor, Augusta University |
ClinicalTrials.gov Identifier: | NCT02057458 |
Other Study ID Numbers: |
DK100783 R21DK100783 ( U.S. NIH Grant/Contract ) |
First Posted: | February 7, 2014 Key Record Dates |
Results First Posted: | April 24, 2020 |
Last Update Posted: | April 24, 2020 |
Last Verified: | April 2020 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
arterial stiffness flow-mediated dilation endothelial function pulse wave velocity inflammation oxidative stress pulmonary function test Cystic Fibrosis |
Lung Disease Nitric Oxide Exercise Capacity CF Muscle Function Sildenafil Viagra Revatio |
Cystic Fibrosis Fibrosis Pathologic Processes Pancreatic Diseases Digestive System Diseases Lung Diseases Respiratory Tract Diseases Genetic Diseases, Inborn |
Infant, Newborn, Diseases Sildenafil Citrate Vasodilator Agents Phosphodiesterase 5 Inhibitors Phosphodiesterase Inhibitors Enzyme Inhibitors Molecular Mechanisms of Pharmacological Action Urological Agents |