Acute Coronary SyndromeTAPOSNCT07151976
Thrombus Aspiration and Pathology and OCT Study
An observational study of Acute Coronary Syndrome, run by Fujita Health University at 1 site in Japan.
Trial summary
Most acute coronary syndromes (ACS) are caused by plaque complications triggering thrombotic events in the culprit plaques. Plaque complications include plaque rupture (Ruptured Fibrous Cap-RFC) with exposure of highly thrombogenic substrate to the flow and plaque erosion (Intact Fibrous Cap-IFC) a condition… Read more about this study
- Who is it for?
- Ages 20 years and older
- Conditions the study is for
- Acute Coronary Syndrome
- What is being tested?
- PCI
- Type of treatment
- Medical device
- How many people
- 200 participants
- Where
- 1 siteJapan
- Study dates
- 1 Jul 2016to 31 Dec 2027
- How long will I take part?
- 5 Years
- Phase
- Observational
- 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 20 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Between July 2016 and December 2024, 200 consecutive patients with ACS having large angiographic thrombus burden who assumed to have a merit of thrombotic aspiration and who consented to OCT guided PCI procedures with athero-thrombotic aspiration were enrolled in the study.
Who may be able to join
- Patients with ACS showing ST-segment elevation myocardial infarction (STEMI) or non-ST-segment elevation myocardial infarction (NSTEMI) are studied.
- Only native coronary artery lesions are included in the study.
- Optical coherence tomography (OCT) was performed prospectively to compare OCT culprit lesions characteristics with histological analysis of athero-thrombotic aspirated material of the culprit lesion. For this purpose, only lesions with both athero-thrombotic aspirated material and OCT observations are included in the study.
- All patients provided written informed consent for the index procedure, follow-up, and anonymous data management.
Who cannot join
- Patients are excluded from the study when they had cardiogenic shock and contraindications to anticoagulation and anti-platelet therapy.
- Lesions located in tortuous vessels, in ostial segment and in the left main stem are excluded from the study due to the difficulty in performing high-quality intracoronary imaging.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Japan1 site, 1 recruiting
- Recruiting
Fujita Health University
Toyoake, Aichi-ken, 470-1192
YUKIO OZAKI, MD, PhD, +1 9492996512, ozakiyuk@fujita-hu.ac.jp
YUKIO OZAKI, MD, PhD, +1 9492996512, yukio.ozaki7@gmail.com
About this study
Official title: Pathologic Features of Aspirated Athero-Thrombotic Material From OCT-Verified Culprit Lesion in Acute Coronary Syndrome (TAPOS)
Most acute coronary syndromes (ACS) are caused by plaque complications triggering thrombotic events in the culprit plaques. Plaque complications include plaque rupture (Ruptured Fibrous Cap-RFC) with exposure of highly thrombogenic substrate to the flow and plaque erosion (Intact Fibrous Cap-IFC) a condition characterized by endothelial/intimal damage occurring over non-ruptured plaques. Far less commonly (<5%), calcified nodules (CN) may trigger acute coronary thrombosis. Plaque rupture accounts for 75% of fatal AMI in autopsy series, while erosion is found in about 25% of cases. These proportions have been supported by in vivo invasive studies (OCT) and OCT-pathology correlation studies. However, it remains unclear whether OCT findings consistently align with in vivo pathology-based evidence of RFC in ACS. Guidelines addressing treatments of ACS unanimously indicate percutaneous coronary intervention (PCI) to restore the coronary flow. Pre-PCI thrombus aspiration is not currently indicated by most guidelines, with the exception of cases with very high thrombus burden. The samples retrieved from thrombus aspiration can be suitable for pathology investigation and aim to evaluate the presence of plaque components in the context of the thrombotic material, a finding that demonstrates plaque rupture as the substrate for the acute coronary event. These studies are uniquely qualified to provide information on the correct OCT-based interpretation of plaque complications in ACS and require OCT imaging quality suitable to classify RFC, IFC, and CN.
Therefore, a prospective OCT-pathology study was designed using the pre-PCI aspirated material from patients with high thrombus burden, to explore the contribution of pathology study in OCT-based classification of plaque complications.
Read the detailed description
AIM Primary aim The present study aims to assess whether the composition of thrombus-aspirated material differs in samples retrieved from patients with OCT-described plaque rupture, erosion, or calcified nodules. In particular, the specific aim is to assess the presence of plaque components (atheromatous material, consisting of cholesterol clefts, foam cells, iron-loaded macrophages, cap fragments, and calcifications) in plaques described at OCT as RFC, IFC, and CN. The working hypothesis is that the pre-PCI aspirated material from plaque rupture should contain plaque components, while aspirated material from plaque erosion, should only contain thrombotic material. The pathology study was planned to be performed blindly to imaging data, and report independent descriptors of the pathology features.
Secondary aims
- A secondary aim addresses pathophysiology mechanisms, potentially related to features promoting plaque rupture. Given the proposed major role of macrophages in the context of plaque inflammation commonly observed in vulnerable plaque prone to rupture, we aimed to investigate the presence of M1 (pro-inflammatory, pro-rupture effect) and M2 (anti-inflammatory, anti-rupture effect) macrophages in samples containing plaque material.
- A further secondary aim is the assessment of short- and long-term outcomes in patients with OCT-diagnosed plaque complications, as identified by imaging and confirmed by pathology.
SAMPLE SIZE Due to the unprecedented similar in vivo studies and the non-routine possibility of performing pre-PCI thrombus aspiration according to guidelines, it was not possible to precisely calculate the sample size.
Based on the probability of plaque rupture in ACS (75% in consecutive ACS) and erosion (25% in consecutive series), a minimum number of 100 cases was considered necessary for the study scope.
PATIENT RECRUITMENT The study is conducted at the Fujita Health University Hospital, Okazaki Medical Center, and Nagoya First Red Cross Hospital. The study was approved by local ethics committees (HM 16019) and was carried out according to the guidelines of the Declaration of Helsinki. Written informed consent was obtained from all patients before index PCI.
PATHOLOGICAL ANALYSIS The pathologic study was planned to be performed at the IRCCS, Policlinico San Matteo, Pavia, Italy, where samples had to be blindly analyzed after routinely processing for histopathology.
Pathological plaque rupture (PATHO-PR) was defined as the presence within the retrieved samples of atheromatous material, consisting of cholesterol clefts, foam cells, iron-loaded macrophages, cap fragments/fibrous tissue, and calcifications.
Serial sections for each case were stained (H\&E, MOVAT, Perls', Von Kossa). The immuno-characterization of the macrophage populations was performed by immunostaining sample sections with antibodies to the pan-macrophage CD68, and M1 (CD80, CD86, IL-6) and M2 (CD163, CD206, TGF-β) polarized macrophage.
Samples with plaque material were classified as RFC-derived, while thrombus-only samples were unsuitable for plaque analysis.
CLINICAL EVALUATION Clinical outcomes were planned at 100 days and 5 years. Major adverse cardiac events (MACE) included cardiac death, non-fatal ACS, ischemia-driven revascularization, cardiogenic shock, and heart failure requiring hospitalization.
- Conditions
- Acute Coronary Syndrome
- Being tested
- PCI
- Medical subject headings
- Acute Coronary Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PCIDevice
PCI with athero-thrombotic aspiration and subsequent pathological analysis: Pathologic Characteristics of Athero-Thrombotic AsPirated Material of OCT-Verified Culprit Lesion in Acute Coronary Syndrome
What is being measured
The primary outcome is the main question the study is designed to answer.
Concordance between pathology based and optical coherence tomography (OCT) verified diagnosis of plaque rupture
TAPOS is an observational prospective study that aims to investigate the concordance between pathology versus OCT-verified features of plaque rupture in patients with STEMI and NSTEMI undergoing PCI and athero-thombus aspiration from the culprit coronary plaque. Pathology measured features are assessed in the aspirated material retrieved from the target coronary plaque and include the presence of foam or iron-loaded macrophages, cholesterol clefts, fragments of fibrous tissue, and calcifications assessed as single or combined features. OCT-based features of plaque include coronary thrombi, fibrous cap discontinuity or plaque ulceration (contraposed to non-ruptured, continuous fibrous cap with over-imposed thrombus).
Measured: From 2016 to 2027
Secondary outcomes (5)
Concordance between pathology-based and optical coherence tomography (OCT) verified detection of macrophages
TAPOS is an observational prospective study that investigates the concordance between pathology vs. OCT-verified features of plaque rupture in patients with STEMI and NSTEMI undergoing PCI and thrombus aspiration from the culprit coronary plaque. Pathology measured features assessed in the aspirated material retrieved from the target coronary plaque include the presence of foam- or iron-loaded macrophages, cholesterol clefts, fragments of fibrous tissue, and calcifications, as single or combined feature/s. OCT-based features of plaque rupture include fibrous cap discontinuity, plaque ulceration (contraposed to non-ruptured, continuous fibrous cap with over-imposed thrombus).
In addition, TAPOS investigates the correlation between the OCT-based detection of macrophages (signal-rich, distinct, or confluent punctate regions that exceed the intensity of background speckle noise) and the pathology observation of macrophages in the thrombus-aspirated material retrieved from each lesion.
Measured: From 2016 to 2027
The incidence rate of major adverse cardiac events (MACE)
Major adverse cardiac and cerebral events (MACE): the composite of cardiac death, non-fetal MI, and unstable angina requiring PCI or CABG
Measured: From 2016 to 2027
The incidence rate of major adverse cardiac and cerebrovascular events (MACCE)
Major adverse cardiac and cerebral events (MACCE): the composite of cardiac death, non-fetal MI, and unstable angina requiring PCI or CABG, and stroke
Measured: From 2016 to 2027
The incidence rate of major adverse cardiac and fatal events
Major adverse cardiac and cerebral events: the composite of all-cause death, non-fetal MI, and unstable angina requiring PCI or CABG
Measured: From 2016 to 2027
The incidence rate of major cardiac, cerebrovascular, and fatal events
Major adverse cardiac and cerebral events: the composite of all-cause death, non-fetal MI, and unstable angina requiring PCI or CABG, and stroke
Measured: From 2016 to 2027
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Sep 2025
- Study start1 Jul 2016
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acute Coronary SyndromeStudies of the same condition, open and under way.
- 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 200 participants (estimated)
- Target duration
- 5 Years
Sponsor and investigators
- Lead sponsor
- Fujita Health University
- Sponsor type
- University, hospital or other
- Collaborators
- Fondazione IRCCS Policlinico San Matteo di Pavia
- Responsible party
- Principal investigator, Yukio Ozaki, Fujita Health University
- Investigators
- YUKIO OZAKI, MD, PhD, Principal investigator, Fujita Health University, Aichi, JapanEloisa Arbustini, MD, Study chair, IRCCS Foundation Policlinico San Matteo, Pavia, Italy
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07151976
- Sponsor's protocol ID
- HM22-157
- Acronym
- TAPOS
- Status last verified
- Feb 2026
- First submitted
- 10 Feb 2022
- Last updated
- 5 Feb 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 5 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pathologic Features of Aspirated Athero-Thrombotic Material From OCT-Verified Culprit Lesion in Acute Coronary Syndrome (TAPOS)
- ClinicalTrials.gov ID
- NCT07151976
- Acronym / sponsor ID
- TAPOS / HM22-157
- Conditions
- Acute Coronary Syndrome
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Fujita Health UniversityUniversity, hospital or other
- Collaborators
- Fondazione IRCCS Policlinico San Matteo di Pavia
- Study start
- 1 Jul 2016 (actual)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 3 Sep 2025 (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.
Most acute coronary syndromes (ACS) are caused by plaque complications triggering thrombotic events in the culprit plaques. Plaque complications include plaque rupture (Ruptured Fibrous Cap-RFC) with exposure of highly thrombogenic substrate to the flow and plaque erosion (Intact Fibrous Cap-IFC) a condition characterized by endothelial/intimal damage occurring over non-ruptured plaques. Far less commonly (<5%), calcified nodules (CN) may trigger acute coronary thrombosis. Plaque rupture accounts for 75% of fatal AMI in autopsy series, while erosion is found in about 25% of cases. These proportions have been supported by in vivo invasive studies (OCT) and OCT-pathology correlation studies. However, it remains unclear whether OCT findings consistently align with in vivo pathology-based evidence of RFC in ACS. Guidelines addressing treatments of ACS unanimously indicate percutaneous coronary intervention (PCI) to restore the coronary flow. Pre-PCI thrombus aspiration is not currently indicated by most guidelines, with the exception of cases with very high thrombus burden. The samples retrieved from thrombus aspiration can be suitable for pathology investigation and aim to evaluate the presence of plaque components in the context of the thrombotic material, a finding that demonstrates plaque rupture as the substrate for the acute coronary event. These studies are uniquely qualified to provide information on the correct OCT-based interpretation of plaque complications in ACS and require OCT imaging quality suitable to classify RFC, IFC, and CN.
Therefore, a prospective OCT-pathology study was designed using the pre-PCI aspirated material from patients with high thrombus burden, to explore the contribution of pathology study in OCT-based classification of plaque complications.
Detailed description
AIM Primary aim The present study aims to assess whether the composition of thrombus-aspirated material differs in samples retrieved from patients with OCT-described plaque rupture, erosion, or calcified nodules. In particular, the specific aim is to assess the presence of plaque components (atheromatous material, consisting of cholesterol clefts, foam cells, iron-loaded macrophages, cap fragments, and calcifications) in plaques described at OCT as RFC, IFC, and CN. The working hypothesis is that the pre-PCI aspirated material from plaque rupture should contain plaque components, while aspirated material from plaque erosion, should only contain thrombotic material. The pathology study was planned to be performed blindly to imaging data, and report independent descriptors of the pathology features.
Secondary aims
- A secondary aim addresses pathophysiology mechanisms, potentially related to features promoting plaque rupture. Given the proposed major role of macrophages in the context of plaque inflammation commonly observed in vulnerable plaque prone to rupture, we aimed to investigate the presence of M1 (pro-inflammatory, pro-rupture effect) and M2 (anti-inflammatory, anti-rupture effect) macrophages in samples containing plaque material.
- A further secondary aim is the assessment of short- and long-term outcomes in patients with OCT-diagnosed plaque complications, as identified by imaging and confirmed by pathology.
SAMPLE SIZE Due to the unprecedented similar in vivo studies and the non-routine possibility of performing pre-PCI thrombus aspiration according to guidelines, it was not possible to precisely calculate the sample size.
Based on the probability of plaque rupture in ACS (75% in consecutive ACS) and erosion (25% in consecutive series), a minimum number of 100 cases was considered necessary for the study scope.
PATIENT RECRUITMENT The study is conducted at the Fujita Health University Hospital, Okazaki Medical Center, and Nagoya First Red Cross Hospital. The study was approved by local ethics committees (HM 16019) and was carried out according to the guidelines of the Declaration of Helsinki. Written informed consent was obtained from all patients before index PCI.
PATHOLOGICAL ANALYSIS The pathologic study was planned to be performed at the IRCCS, Policlinico San Matteo, Pavia, Italy, where samples had to be blindly analyzed after routinely processing for histopathology.
Pathological plaque rupture (PATHO-PR) was defined as the presence within the retrieved samples of atheromatous material, consisting of cholesterol clefts, foam cells, iron-loaded macrophages, cap fragments/fibrous tissue, and calcifications.
Serial sections for each case were stained (H\&E, MOVAT, Perls', Von Kossa). The immuno-characterization of the macrophage populations was performed by immunostaining sample sections with antibodies to the pan-macrophage CD68, and M1 (CD80, CD86, IL-6) and M2 (CD163, CD206, TGF-β) polarized macrophage.
Samples with plaque material were classified as RFC-derived, while thrombus-only samples were unsuitable for plaque analysis.
CLINICAL EVALUATION Clinical outcomes were planned at 100 days and 5 years. Major adverse cardiac events (MACE) included cardiac death, non-fatal ACS, ischemia-driven revascularization, cardiogenic shock, and heart failure requiring hospitalization.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 5 Years
Who may qualify
- Ages
- 20 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Between July 2016 and December 2024, 200 consecutive patients with ACS having large angiographic thrombus burden who assumed to have a merit of thrombotic aspiration and who consented to OCT guided PCI procedures with athero-thrombotic aspiration were enrolled in the study.
Key inclusion criteria (4 listed)
- Patients with ACS showing ST-segment elevation myocardial infarction (STEMI) or non-ST-segment elevation myocardial infarction (NSTEMI) are studied.
- Only native coronary artery lesions are included in the study.
- Optical coherence tomography (OCT) was performed prospectively to compare OCT culprit lesions characteristics with histological analysis of athero-thrombotic aspirated material of the culprit lesion. For this purpose, only lesions with both athero-thrombotic aspirated material and OCT observations are included in the study.
- All patients provided written informed consent for the index procedure, follow-up, and anonymous data management.
Key exclusion criteria (2 listed)
- Patients are excluded from the study when they had cardiogenic shock and contraindications to anticoagulation and anti-platelet therapy.
- Lesions located in tortuous vessels, in ostial segment and in the left main stem are excluded from the study due to the difficulty in performing high-quality intracoronary imaging.
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 |
|---|---|---|
| PCIPCI with athero-thrombotic aspiration and subsequent pathological analysis: Pathologic Characteristics of Athero-Thrombotic AsPirated Material of OCT-Verified Culprit Lesion in Acute Coronary Syndrome | Device | – |
Primary outcome
Concordance between pathology based and optical coherence tomography (OCT) verified diagnosis of plaque rupture
Time frame: From 2016 to 2027
TAPOS is an observational prospective study that aims to investigate the concordance between pathology versus OCT-verified features of plaque rupture in patients with STEMI and NSTEMI undergoing PCI and athero-thombus aspiration from the culprit coronary plaque. Pathology measured features are assessed in the aspirated material retrieved from the target coronary plaque and include the presence of foam or iron-loaded macrophages, cholesterol clefts, fragments of fibrous tissue, and calcifications assessed as single or combined features. OCT-based features of plaque include coronary thrombi, fibrous cap discontinuity or plaque ulceration (contraposed to non-ruptured, continuous fibrous cap with over-imposed thrombus).
5 secondary outcomes
Concordance between pathology-based and optical coherence tomography (OCT) verified detection of macrophages
Time frame: From 2016 to 2027
The incidence rate of major adverse cardiac events (MACE)
Time frame: From 2016 to 2027
The incidence rate of major adverse cardiac and cerebrovascular events (MACCE)
Time frame: From 2016 to 2027
The incidence rate of major adverse cardiac and fatal events
Time frame: From 2016 to 2027
The incidence rate of major cardiac, cerebrovascular, and fatal events
Time frame: From 2016 to 2027
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 5 Feb 2026.
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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.
YUKIO OZAKI, MD, PhD principal investigator
Fujita Health University, Aichi, Japan
Eloisa Arbustini, MD study chair
IRCCS Foundation Policlinico San Matteo, Pavia, Italy
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Acute Coronary Syndrome, run by Fujita Health University at 1 site in Japan.
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 4 inclusion and 2 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 5 Feb 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 Japan. 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 Yukio Ozaki, MD, PhD (+1 9492996512, ozakiyuk@fujita-hu.ac.jp), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Concordance between pathology based and optical coherence tomography (OCT) verified diagnosis of plaque rupture (time frame: From 2016 to 2027). 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 5 Feb 2026.