Air PollutionSAPIANCT05867381
Using Indoor Air Filtration to Slow Atherothrombosis Progression in Adults With Ischemic Heart Disease History
A study testing HEPA filtration in people with Air Pollution and Atherosclerosis, run by University of Southern California at 1 site in United States.
Trial summary
This double-blind, randomized, crossover trial aims to test the hypothesis that longer-term indoor air filtration intervention can slow atherothrombosis progression by reducing indoor fine particulate matter (PM2.5) exposure in adults with ischemic heart disease history. Read more about this study
- Who is it for?
- Ages 65 to 84 years
- Conditions the study is for
- Air Pollution, Atherosclerosis
- What is being tested?
- HEPA filtration
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 112 participants
- Where
- 1 siteUnited States
- Study dates
- 11 Jul 2023to 30 Jun 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 65 to 84 years
- All sexes
- No healthy volunteers
- Older adult
Who may be able to join
- Age between 65 and 84 years old;
- Weight ≥ 110 pounds;
- Nonsmokers for at least 1 year;
- Have ischemic heart disease history, clinically stable for 6 months, without any deterioration in symptoms or episodes of angina based on past electronic medical records;
- Both English and Spanish speaking participants will be included in the recruitment;
- Live in the Los Angeles County.
Who cannot join
- Have history of degenerative disease of the nervous system such as dementia and Alzheimer's;
- Currently have active cancer treatments;
- The residential house has already had HEPA filters;
- Participants will move out from the current residential address in the next 2 years;
- Participants will spend more than 1 month living outside the primary home;
- Have any health conditions that prohibit collecting health and covariate data and biospecimens;
- Participants' residential houses are not feasible for setting up air purifiers and air pollutants monitors.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Keck School of Medicine, University of Southern California
Los Angeles, California, 90033
Zhanghua Chen, PhD, 323-442-2109, zhanghuc@usc.edu
About this study
Official title: Slowing Atherothrombosis Progression Through Indoor Air Filtration: A Crossover Trial in Hispanic and Non-Hispanic Adults With Ischemic Heart Disease History
This double-blind, randomized, crossover trial aims to test the hypothesis that longer-term indoor air filtration intervention can slow atherothrombosis progression by reducing indoor fine particulate matter (PM2.5) exposure in adults with ischemic heart disease history.
Read the detailed description
This double-blind, randomized, crossover trial will recruit 112 adults with ischemic heart disease history and will investigate potential benefits of indoor high efficiency particulate air (HEPA) filtration on ameliorating the progression of atherothrombosis. Participants will be contacted and recruited to the study based on inclusion and exclusion criteria. After consenting, participants will go through a total of 21-month study period comprised of true HEPA filtration and sham filtration, each of 9-month in duration, and a 3-month wash-out period. After 3-month wash-out period, participants will be switched to the other arm of the intervention. During the trial, project specialists will complete a series of home visits before, in the middle, and after each intervention session to set up air purifiers and indoor and outdoor air pollution monitors, as well as conduct interview to collect questionnaire data, measure vascular function, blood pressure, and collect biospecimens. Participants will self-monitor their daily blood pressure through out the intervention periods. In aim 1, researchers will assess the effect of a 9-month residential HEPA intervention on atherothrombosis progression in 112 participants. In aim 2, the researchers will examine the association between reduction in indoor PM2.5 exposure brought by the intervention and the changes in atherothrombosis progression indicators adjusting for outdoor PM2.5 exposure. In aim 3, researchers will examine atherothrombosis responses (both levels and slopes of change) to the HEPA intervention within four subgroups of participants: 1) non-Hispanics, 2) Hispanics, 3) females, and 4) males.
- Conditions
- Air Pollution, Atherosclerosis
- Being tested
- HEPA filtration, Sham filtration
- Keywords
- Air pollution, Particulate matter, Air purifier, HEPA filter, Atherosclerosis, Ischemic Heart Disease, Thrombosis, Cardiovascular Disease
- Medical subject headings
- Atherosclerosis, Myocardial Ischemia, Thrombosis, Cardiovascular Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
HEPA filtrationDevice
HEPA filters with the capacity to reduce PM2.5 levels
Sham filtrationDevice
Sham filtration use the same appearance of air purifier but with HEPA filter removed.
| Study group | Role | What they receive |
|---|---|---|
| HEPA first and sham | Experimental | This group of participants will be assigned to the intervention of HEPA filtration with the capacity to reduce indoor PM2.5 levels at their residence for 9 months first. After 3-month wash-out period, participants will be assigned to sham filters (air purifier has the same appearance but HEPA filter is removed) for 9 months. Receives: Device: HEPA filtration; Device: Sham filtration |
| Sham first and HEPA | Experimental | This group of participants will be assigned to the intervention of sham filtration with HEPA filter removed at their residence for 9 months first. After 3-month wash-out period, participants will be assigned to the HEPA filtration for 9 months. Receives: Device: HEPA filtration; Device: Sham filtration |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in blood pressure
Differences between baseline and systolic and diastolic blood pressure measured during and after intervention
Measured: Blood pressure will be monitored daily during each of the 9-month intervention
Change in carotid-femoral pulse wave velocity
Differences between baseline and carotid-femoral pulse wave velocity measured with Vicorder device during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in augmentation index
Differences between baseline and augmentation index measured with Vicorder device during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in von Willebrand factor
Differences between baseline and von Willebrand factor measured during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in P-selectin
Differences between baseline and P-selectin measured during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Secondary outcomes (6)
Change in fasting glucose
Differences between baseline and fasting glucose measured during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in fasting insulin
Differences between baseline and fasting insulin measured during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Changes in lipid profiles
Differences between baseline and low-density lipoprotein, high-density lipoprotein, very-low-density lipoprotein, triglycerides, and total cholesterol levels measured during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in C-reactive protein
Differences between baseline and C-reactive protein measured during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in interleukin 6
Differences between baseline and interleukin 6 measured during and after intervention
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Changes in 384 kinds of targeted cardiovascular disease-related proteomic markers
Differences between baseline and the relative abundance of 384 kinds of targeted cardiovascular disease-related proteomic markers, such as tumor necrosis factor, E-selectin, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and leptin, measured with Olink's Explore 384 cardiometabolic panel 1 during and after intervention. The Olink kit is a relative quantification assay and there are no units for the measurements.
Measured: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 May 2023
- Study start11 Jul 2023
- Primary completion30 Jun 2028 (estimated)
- Study completion30 Jun 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Air PollutionStudies of the same condition, open and under way.
- More trials run by University of Southern CaliforniaThe 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
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 112 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Southern California
- Sponsor type
- University, hospital or other
- Collaborators
- Duke University, National Institute of Environmental Health Sciences (NIEHS)
- Responsible party
- Principal investigator, Zhanghua Chen, University of Southern California
- Investigators
- Zhanghua Chen, PhD, Principal investigator, University of Southern CaliforniaJunfeng Zhang, PhD, Principal investigator, Duke University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05867381
- Sponsor's protocol ID
- SAPIA_Study
- Other IDs
- R01ES033707
- Acronym
- SAPIA
- Status last verified
- Jun 2026
- First submitted
- 23 Apr 2023
- Last updated
- 8 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 8 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Slowing Atherothrombosis Progression Through Indoor Air Filtration: A Crossover Trial in Hispanic and Non-Hispanic Adults With Ischemic Heart Disease History
- ClinicalTrials.gov ID
- NCT05867381
- Acronym / sponsor ID
- SAPIA / SAPIA_Study
- Conditions
- Air Pollution, Atherosclerosis
- Keywords
- Air pollution, Particulate matter, Air purifier, HEPA filter, Atherosclerosis, Ischemic Heart Disease, Thrombosis, Cardiovascular Disease
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 112 participants (estimated)
- Lead sponsor
- University of Southern CaliforniaUniversity, hospital or other
- Collaborators
- Duke University, National Institute of Environmental Health Sciences (NIEHS)
- Study start
- 11 Jul 2023 (actual)
- Primary completion
- 30 Jun 2028 (estimated)
- Study completion
- 30 Jun 2028 (estimated)
- First posted
- 22 May 2023 (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.
This double-blind, randomized, crossover trial aims to test the hypothesis that longer-term indoor air filtration intervention can slow atherothrombosis progression by reducing indoor fine particulate matter (PM2.5) exposure in adults with ischemic heart disease history.
Detailed description
This double-blind, randomized, crossover trial will recruit 112 adults with ischemic heart disease history and will investigate potential benefits of indoor high efficiency particulate air (HEPA) filtration on ameliorating the progression of atherothrombosis. Participants will be contacted and recruited to the study based on inclusion and exclusion criteria. After consenting, participants will go through a total of 21-month study period comprised of true HEPA filtration and sham filtration, each of 9-month in duration, and a 3-month wash-out period. After 3-month wash-out period, participants will be switched to the other arm of the intervention. During the trial, project specialists will complete a series of home visits before, in the middle, and after each intervention session to set up air purifiers and indoor and outdoor air pollution monitors, as well as conduct interview to collect questionnaire data, measure vascular function, blood pressure, and collect biospecimens. Participants will self-monitor their daily blood pressure through out the intervention periods. In aim 1, researchers will assess the effect of a 9-month residential HEPA intervention on atherothrombosis progression in 112 participants. In aim 2, the researchers will examine the association between reduction in indoor PM2.5 exposure brought by the intervention and the changes in atherothrombosis progression indicators adjusting for outdoor PM2.5 exposure. In aim 3, researchers will examine atherothrombosis responses (both levels and slopes of change) to the HEPA intervention within four subgroups of participants: 1) non-Hispanics, 2) Hispanics, 3) females, and 4) males.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| HEPA first and sham | Experimental | Device: HEPA filtration, Device: Sham filtrationThis group of participants will be assigned to the intervention of HEPA filtration with the capacity to reduce indoor PM2.5 levels at their residence for 9 months first. After 3-month wash-out period, participants will be assigned to sham filters (air purifier has the same appearance but HEPA filter is removed) for 9 months. |
| Sham first and HEPA | Experimental | Device: HEPA filtration, Device: Sham filtrationThis group of participants will be assigned to the intervention of sham filtration with HEPA filter removed at their residence for 9 months first. After 3-month wash-out period, participants will be assigned to the HEPA filtration for 9 months. |
Who may qualify
- Ages
- 65 to 84 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Older adult
Key inclusion criteria (6 listed)
- Age between 65 and 84 years old;
- Weight ≥ 110 pounds;
- Nonsmokers for at least 1 year;
- Have ischemic heart disease history, clinically stable for 6 months, without any deterioration in symptoms or episodes of angina based on past electronic medical records;
- Both English and Spanish speaking participants will be included in the recruitment;
Key exclusion criteria (7 listed)
- Have history of degenerative disease of the nervous system such as dementia and Alzheimer's;
- Currently have active cancer treatments;
- The residential house has already had HEPA filters;
- Participants will move out from the current residential address in the next 2 years;
- Participants will spend more than 1 month living outside the primary home;
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 |
|---|---|---|
| HEPA filtrationHEPA filters with the capacity to reduce PM2.5 levels | Device | HEPA first and sham, Sham first and HEPA |
| Sham filtrationSham filtration use the same appearance of air purifier but with HEPA filter removed. | Device | HEPA first and sham, Sham first and HEPA |
Primary outcome
Change in blood pressure
Time frame: Blood pressure will be monitored daily during each of the 9-month intervention
Differences between baseline and systolic and diastolic blood pressure measured during and after intervention
Change in carotid-femoral pulse wave velocity
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Differences between baseline and carotid-femoral pulse wave velocity measured with Vicorder device during and after intervention
Change in augmentation index
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Differences between baseline and augmentation index measured with Vicorder device during and after intervention
Change in von Willebrand factor
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Differences between baseline and von Willebrand factor measured during and after intervention
Change in P-selectin
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Differences between baseline and P-selectin measured during and after intervention
6 secondary outcomes
Change in fasting glucose
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in fasting insulin
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Changes in lipid profiles
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in C-reactive protein
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Change in interleukin 6
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Changes in 384 kinds of targeted cardiovascular disease-related proteomic markers
Time frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Jun 2026.
- 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.
Zhanghua Chen, PhD principal investigator
University of Southern California
Junfeng Zhang, PhD principal investigator
Duke University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing HEPA filtration in people with Air Pollution and Atherosclerosis, run by University of Southern California at 1 site 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 6 inclusion and 7 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: looking for participants now, as of the sponsor's last update on 8 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Zhanghua Chen, PhD (323-442-2109, zhanghuc@usc.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in blood pressure (time frame: Blood pressure will be monitored daily during each of the 9-month intervention). The study lists 5 primary outcomes in all. 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 Jun 2026.