Hypertension, SystolicEarly Phase 1SELECTNCT04423627
Sympathetic Regulation of Large Artery Stiffness in Humans With ISH
A Early Phase 1 study testing Clonidine and Hydrochlorothiazide in people with Hypertension, Systolic and Stiffness, Aortic, run by University of Iowa at 2 sites in United States.
Trial summary
Stiffening of your blood vessels, particularly the large vessels from your heart (called the aorta and carotids) you age contributes to the development of cardiovascular disease (CVD) such as heart attack and stroke. Read more about this study
- Who is it for?
- Ages 60 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Hypertension, Systolic, Stiffness, Aortic
- What is being tested?
- Clonidine and Hydrochlorothiazide
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- 2 sitesUnited States
- Study dates
- 1 Jun 2021to 31 Jul 2025
- Phase
- Early Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 60 to 85 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- age 60-85
- non-smoking
- clinically healthy
- untreated or treated stage 1 isolated systolic hypertension (ISH) (systolic BP 130-139 mmHg; diastolic BP <90 mmHg) or stage 2 ISH (systolic BP 140-159 mmHg; diastolic BP <90 mmHg) per 2017 AHA/ACC hypertension guidelines
- if subject is on antihypertensive medications, they will stop taking medication for a one-week washout period after Visit 1 before they return for Visit 2. They will come in at day 3 and day 7 of the one-week washout for a BP reading, to confirm that systolic BP is <160 mmHg.
Who cannot join
- no history of cardiovascular disease (e.g., myocardial infarction, bypass surgery, angioplasty/stent, heart failure, cardiomyopathy, pacemaker/defibrillator, peripheral artery disease), pulmonary disease, liver disease, Type I or II diabetes, cancer (treated by chemotherapy and/or radiation), psychiatric illness, on aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs).
- aspirin, NSAIDs, vitamins, herbal supplements, omega-3-fatty acids will have to discontinue for at least 1 week before participation and remain discontinued during the study.
- blood thinners, serotonin reuptake inhibitors (SSRIs), or PDE5 inhibitors will also be excluded.
- Women must be postmenopausal for at least 6 months (surgical or natural) and not currently on hormone replacement therapy.
- Subjects not on antihypertensive will not be eligible if their resting clinic systolic BP is <130 mmHg or >160 mmHg and diastolic BP >90 mmHg.
Trial locations and contacts
2 sites in 1 country.
United States2 sites
Amy Stroud
Iowa City, Iowa, 52240
University of Iowa
Iowa City, Iowa, 52242
About this study
Official title: Sympathetic Regulation of Large Artery Stiffness in Humans With Age-Related Isolated Systolic Hypertension
Stiffening of your blood vessels, particularly the large vessels from your heart (called the aorta and carotids) you age contributes to the development of cardiovascular disease (CVD) such as heart attack and stroke. Nerve activity from your brain to your body also increases with advancing age but it is unknown if this nerve activity contributes directly to the stiffening on your blood vessels in older adults in addition to high blood pressure. Therefore, successful completion of the proposed aims will have a significant clinical impact by identifying if nerve activity from your brain could be a novel target for therapies that would lower stiffness of the aorta and carotid arteries in older adults.
- Conditions
- Hypertension, Systolic, Stiffness, Aortic
- Being tested
- Clonidine, Hydrochlorothiazide, Placebo
- Medical subject headings
- Isolated Systolic Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ClonidineDrug
Clonidine 0.2 mg/day oral tablet
HydrochlorothiazideDrug
Hydrochlorothiazide 37.5 mg/day oral tablet
PlaceboDrug
Placebo
| Study group | Role | What they receive |
|---|---|---|
| Clonidine | Experimental | 0.2 mg/day oral Receives: Drug: Clonidine |
| Hydrochlorothiazide | Active comparator | 37.5 mg/day oral Receives: Drug: Hydrochlorothiazide |
| Placebo | Placebo comparator | Placebo Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in carotid-femoral pulse wave velocity
Aortic stiffness
Measured: Baseline and after 4 weeks
Secondary outcomes (3)
Change in carotid distensibility index
Change in carotid distensibility
Measured: Baseline and after 4 weeks
Change in carotid flow pulsatility index
Change in carotid flow pulsatility
Measured: Baseline and after 4 weeks
Change in carotid intimal medial thickness (IMT)
Change in carotid wall thickness
Measured: Baseline and after 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Jun 2020
- Study start1 Jun 2021
- Primary completion31 Jul 2025
- Study completion31 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hypertension, SystolicStudies of the same condition, open and under way.
- More trials run by University of IowaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Randomized, placebo controlled, parallel design
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 100 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Iowa
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gary L. Pierce, PhD, University of Iowa
- Investigators
- Gary Pierce, PhD, Principal investigator, University of Iowa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04423627
- Sponsor's protocol ID
- 202004244
- Acronym
- SELECT
- Status last verified
- Aug 2025
- First submitted
- 5 Jun 2020
- Last updated
- 8 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 8 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Sympathetic Regulation of Large Artery Stiffness in Humans With Age-Related Isolated Systolic Hypertension
- ClinicalTrials.gov ID
- NCT04423627
- Acronym / sponsor ID
- SELECT / 202004244
- Conditions
- Hypertension, Systolic, Stiffness, Aortic
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 100 participants (actual)
- Lead sponsor
- University of IowaUniversity, hospital or other
- Study start
- 1 Jun 2021 (actual)
- Primary completion
- 31 Jul 2025 (actual)
- Study completion
- 31 Jul 2025 (actual)
- First posted
- 9 Jun 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Stiffening of your blood vessels, particularly the large vessels from your heart (called the aorta and carotids) you age contributes to the development of cardiovascular disease (CVD) such as heart attack and stroke. Nerve activity from your brain to your body also increases with advancing age but it is unknown if this nerve activity contributes directly to the stiffening on your blood vessels in older adults in addition to high blood pressure. Therefore, successful completion of the proposed aims will have a significant clinical impact by identifying if nerve activity from your brain could be a novel target for therapies that would lower stiffness of the aorta and carotid arteries in older adults.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 3
- Model description
- Randomized, placebo controlled, parallel design
| Arm | Type | Receives |
|---|---|---|
| Clonidine | Experimental | Drug: Clonidine0.2 mg/day oral |
| Hydrochlorothiazide | Active comparator | Drug: Hydrochlorothiazide37.5 mg/day oral |
| Placebo | Placebo comparator | Drug: PlaceboPlacebo |
Who may qualify
- Ages
- 60 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- age 60-85
- non-smoking
- clinically healthy
- untreated or treated stage 1 isolated systolic hypertension (ISH) (systolic BP 130-139 mmHg; diastolic BP <90 mmHg) or stage 2 ISH (systolic BP 140-159 mmHg; diastolic BP <90 mmHg) per 2017 AHA/ACC hypertension guidelines
- if subject is on antihypertensive medications, they will stop taking medication for a one-week washout period after Visit 1 before they return for Visit 2. They will come in at day 3 and day 7 of the one-week washout for a BP reading, to confirm that systolic BP is <160 mmHg.
Key exclusion criteria (5 listed)
- no history of cardiovascular disease (e.g., myocardial infarction, bypass surgery, angioplasty/stent, heart failure, cardiomyopathy, pacemaker/defibrillator, peripheral artery disease), pulmonary disease, liver disease, Type I or II diabetes, cancer (treated by chemotherapy and/or radiation), psychiatric illness, on aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs).
- aspirin, NSAIDs, vitamins, herbal supplements, omega-3-fatty acids will have to discontinue for at least 1 week before participation and remain discontinued during the study.
- blood thinners, serotonin reuptake inhibitors (SSRIs), or PDE5 inhibitors will also be excluded.
- Women must be postmenopausal for at least 6 months (surgical or natural) and not currently on hormone replacement therapy.
- Subjects not on antihypertensive will not be eligible if their resting clinic systolic BP is <130 mmHg or >160 mmHg and diastolic BP >90 mmHg.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ClonidineClonidine 0.2 mg/day oral tablet | Drug | Clonidine |
| HydrochlorothiazideHydrochlorothiazide 37.5 mg/day oral tablet | Drug | Hydrochlorothiazide |
| PlaceboPlacebo | Drug | Placebo |
Primary outcome
Change in carotid-femoral pulse wave velocity
Time frame: Baseline and after 4 weeks
Aortic stiffness
3 secondary outcomes
Change in carotid distensibility index
Time frame: Baseline and after 4 weeks
Change in carotid flow pulsatility index
Time frame: Baseline and after 4 weeks
Change in carotid intimal medial thickness (IMT)
Time frame: Baseline and after 4 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Aug 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Gary Pierce, PhD principal investigator
University of Iowa
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Clonidine and Hydrochlorothiazide in people with Hypertension, Systolic and Stiffness, Aortic, run by University of Iowa at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 8 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in carotid-femoral pulse wave velocity (time frame: Baseline and after 4 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Aug 2025; AzTrials last refreshed its copy on 8 Nov 2026.