NCT05867381 · University of Southern California
Using Indoor Air Filtration to Slow Atherothrombosis Progression in Adults With Ischemic Heart Disease History
(SAPIA)
What this study is about
This where neither patients nor doctors know which treatment is given, randomly assigned, 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.
View original scientific description
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.
Interventions
DEVICE
HEPA filtration
HEPA filters with the capacity to reduce PM2.5 levels
DEVICE
Sham filtration
Sham filtration use the same appearance of air purifier but with HEPA filter removed.
Primary outcome measures
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
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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.
Exclusion criteria
- 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.
Where
- Los Angeles, California
Collaborators
Duke University, National Institute of Environmental Health Sciences (NIEHS)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 8, 2026 · Source of record for eligibility and locations