Using Indoor Air Filtration to Slow Atherothrombosis Progression in Adults With Ischemic Heart Disease History (SAPIA)

June 4, 2026 updated by: Zhanghua Chen, University of Southern California

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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 Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
112

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • California
      • Los Angeles, California, United States, 90033
        • Recruiting
        • Keck School of Medicine, University of Southern California
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Older Adult

Accepts Healthy Volunteers

No

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: HEPA first and sham
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.
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.
Experimental: Sham first and HEPA
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.
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.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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
Blood pressure will be monitored daily during each of the 9-month 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
At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
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
At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions
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
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
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
At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
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
Differences between baseline and fasting glucose measured during and after intervention
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
Differences between baseline and fasting insulin measured during and after intervention
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
Differences between baseline and low-density lipoprotein, high-density lipoprotein, very-low-density lipoprotein, triglycerides, and total cholesterol levels measured during and after intervention
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
Differences between baseline and C-reactive protein measured during and after intervention
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
Differences between baseline and interleukin 6 measured during and after intervention
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
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.
At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Southern California

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Duke University
National Institute of Environmental Health Sciences (NIEHS)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Zhanghua Chen, PhD, University of Southern California
  • Principal Investigator: Junfeng Zhang, PhD, Duke University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 11, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 30, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 30, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 23, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 15, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 22, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 4, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SAPIA_Study
  • R01ES033707 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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