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Coronary Artery DiseasePOLARSTARNCT05600088

Intracoronary Cryotherapy Effect on Stabilization of Vulnerable Plaque in Patients With (N)STEMI or Unstable Angina

A study testing CryoTherapy System (CTS) in people with Coronary Artery Disease and Coronary Syndrome, run by Cryotherapeutics SA at 5 sites in 2 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The POLARSTAR study is an early safety and feasibility study to evaluate the performance and safety of the CryoTherapy System (CTS) for the treatment of coronary plaque lesions that are not obstructing blood flow but are at high-risk of rupture which would cause a major heart attack. Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
CryoTherapy System (CTS)
Type of treatment
Medical device
Could I receive a placebo?
No, everyone receives an active treatment
How many people
24 participants
Where
5 sitesin 2 countries
Study dates
18 May 2022to 31 Jul 2026
Phase
Interventional
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 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Subject is at least 18 years old.
  • Subject has acute cardiac pain/angina consistent with acute coronary syndrome eligible for coronary angiography meeting one of the following criteria:
  • (Non-)ST-segment elevation myocardial infarction ((N)STEMI) with rise/fall of cardiac enzymes (troponin I or T) with at least one value above the 99th percentile of the upper reference limit requiring PCI within 72 hours from diagnosis
  • Unstable angina
  • Successful PCI (defined as diameter stenosis less than 30% and TIMI 3 flow on final angiography without procedural complication) of the culprit lesion.
  • Subject has at least one high-risk plaque meeting the criteria below:
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  • Located in a non-culprit vessel,
  • High-risk plaque lesion on CCTA and at least one of the following features:
  • Presence of low-attenuation plaque (HU<50) and/or
  • Positive remodelling (remodelling index >1.1) and/or
  • Napkin ring sign and/or
  • Plaque burden ≥70%
  • Lesion length ≤ 20 mm.
  • Diameter stenosis on invasive angiography between 30% and 70% on coronary angiogram or negative physiology assessment (FFR>0.80 or non-hyperemic pressure ratios (NHPR) >0.89).
  • Reference vessel diameter (RVD) < 3.75 mm and > 2.00 mm in diameter
  • Investigator considers that lesions are accessible.
  • If more than two suitable lesions available, investigator will select the most appropriate lesion for cryotherapy treatment.
  • Subject is able to provide consent and has signed and dated the informed consent form.

Who cannot join

  • Subject is hemodynamically unstable (cardiogenic shock, hypotension needing inotropes, hypoxia needing intubation, refractory ventricular arrhythmias, and IABP).
  • Subject has ongoing ST-segment elevation myocardial infarction.
  • Subject had a procedural complication during the Acute coronary syndrome (ACS) PCI procedure.
  • Subject has history of Coronary Artery Bypass Graft (CABG) or planned CABG within 12 months after the index procedure.
  • Subject has known reduced Left Ventricular Ejection Fraction < 30%.
  • Subject has known severe valvular heart disease.
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  • Subject has known severe renal insufficiency (eGFR <30 ml/min/1.72 m2).
  • Subject has any life-threatening conditions or medical comorbidity resulting in life expectancy < 12 months.
  • Subject is currently participating in another clinical investigation that has not yet reached its primary endpoint.
  • Subject is pregnant or lactating, or NOT surgically sterile (tubal ligation or hysterectomy) or NOT postmenopausal for at least 6 months or is a female with childbearing potential without effective contraception (pill, patch, ring, diaphragm, implant and intrauterine device).
  • Angiographic exclusion criteria:
  • Visible distal embolization/no-reflow following culprit lesions PCI.
  • Left main coronary artery disease (visual diameter stenosis > 50%).
  • Stent thrombosis/restenosis as a culprit lesion.
  • CTS lesion involving a bifurcation (defined as lesions involving side branches >2.0 mm).
  • Angiographic or CCTA evidence of severe calcification and/or marked tortuosity of the index vessel and/or lesion.
  • Thrombotic lesions
  • Ostial lesions

Trial locations and contacts

5 sites in 2 countries.

5 sites in 2 countries

Lithuania3 sites

  • Hospital of Lithuanian University of health sciences Kauno Klinikos

    Kaunas, LT-50161

  • Klaipèda University Hospital

    Klaipèda, LT-92288

  • Vilnius University Hospital Santaros Klinikos

    Vilnius, LT-08661

Other trials in Lithuania

Georgia2 sites

  • Israeli-Georgian Research Clinic Helsicore

    Tbilisi, 0112

  • Tbilisi Heart Center

    Tbilisi, 0186

Other trials in Georgia

About this study

Official title: Clinical Investigation of Intracoronary Cryotherapy Using the CryoTherapy System (CTS) for High-risk Plaque in Patients With (Non-)ST-segment Elevation Myocardial Infarction (NSTEMI) or Unstable Angina

The POLARSTAR study is an early safety and feasibility study to evaluate the performance and safety of the CryoTherapy System (CTS) for the treatment of coronary plaque lesions that are not obstructing blood flow but are at high-risk of rupture which would cause a major heart attack. The CTS is used to apply local freezing of the lesion using a balloon catheter, controlled by a console that regulates in- and outflow of a cooling agent into the catheter. The treatment is expected to stabilize the lesion, diminishing the risk of rupture. The study will enrol subjects with acute coronary disease who have suitable coronary lesions. Subjects will be followed for 1 year after the CTS treatment. Baseline identification of lesions will be done using Coronary CT-angiography (CCTA), which will be repeated at 3 and 9 months after procedure.

Read the detailed description

The POLARSTAR study is an early feasibility study to evaluate the safety and performance of the CryoTherapy System (CTS) medical device, consisting of a console and a balloon catheter. The CTS is designed to deliver local cryo-energy to vulnerable plaque lesions in the coronary arteries, aiming to stabilize the plaque to reduce the risk of rupture and subsequent cardiac events. The study will enrol up to 10 subjects with NSTEMI or unstable angina, who underwent successful Percutaneous Coronary Intervention (PCI) of their culprit coronary lesion, and who were identified to have presence of at least 1 non-culprit suitable plaque lesion at high-risk of rupture. After providing informed consent the subjects will undergo a Coronary CT-angiography (CCTA) to confirm suitability of the coronary plaque lesion. A single high-risk plaque lesion will be treated by the investigators, with Intra-vascular Ultrasound (IVUS) imaging prior to and after CTS treatment. Subjects will be followed clinically for up to one year after the CTS treatment, and will have follow-up CCTA assessments at 3 and 9 months post-procedure. Primary endpoint will be Major cardiac events rate at 3 months post procedure.

Being tested
CryoTherapy System (CTS)
Medical subject headings
Coronary Artery Disease, Angina, Unstable, Myocardial Infarction, Cardiomyopathies

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • CryoTherapy System (CTS)Device

    local cryotherapy of coronary high-risk plaque lesions using the CTS consisting of a semi-compliant balloon and a console controlling the temperature of cryotherapy

Study groups in NCT05600088
Study groupRoleWhat they receive
CTS Treatment ArmExperimentalactive cryotherapy of a single suitable high-risk coronary plaque lesion with CTS device
Receives: Device: CryoTherapy System (CTS)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Safety: Rate of Cryotherapy related adverse events

    Any cryotherapy procedure related complication defined as coronary artery dissection (angiographic dissection ≥ NHLBI type B), acute vessel closure, life threatening arrythmia, need for bailout stenting, or any Major Adverse Cardia Event (MACE) defined as cardiac death, CTS-treated vessel myocardial infarction, CTS-treated lesion revascularization, rehospitalization for unstable or progressive angina adjudicated to the CTS-treated lesion

    Measured: 90 days post-procedure

Secondary outcomes (11)

  1. Safety: Rate of Cryotherapy related events

    Any cryotherapy procedure related complication defined as coronary artery dissection (angiographic dissection ≥ NHLBI type B), acute vessel closure, life threatening arrythmia, need for bailout stenting, or any MACE defined as cardiac death, CTS-treated vessel myocardial infarction, CTS-treated lesion revascularization, rehospitalization for unstable or progressive angina adjudicated to the CTS-treated lesion

    Measured: 1 year post-procedure

  2. Device success

    Number of lesions successfully treated without device deficiency

    Measured: end of CTS treatment

  3. CTS procedure success

    Number of lesions successfully treated to obtain Thrombolysis in Myocardial Infarction (TIMI) 3 flow

    Measured: end of CTS treatment

  4. Imaging: CCTA assessed Minimum lumen area (MLA)

    Change in MLA (mm²) compared to baseline

    Measured: 90 days post-procedure

  5. Imaging: CCTA assessed Minimum lumen area (MLA)

    Change in MLA (mm²) compared to baseline

    Measured: 9 months post-procedure

  6. Imaging: CCTA assessed area stenosis

    Change in area stenosis % compared to baseline

    Measured: 3 months post-procedure

  7. Imaging: CCTA assessed area stenosis

    Change in area stenosis % compared to baseline

    Measured: 9 months post-procedure

  8. Imaging: CCTA assessed lesion plaque burden

    Change in lesion plaque burden % from baseline

    Measured: 3 months post-procedure

  9. Imaging: CCTA assessed lesion plaque burden

    Change in lesion plaque burden from baseline

    Measured: 9 months post-procedure

  10. Imaging: CCTA assessed Total plaque volume

    Change in total plaque volume (mm³) from baseline

    Measured: 3 months post-procedure

  11. Imaging: CCTA assessed Total plaque volume

    Change in total plaque volume(mm³) from baseline

    Measured: 9 months post-procedure

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted31 Oct 2022
  2. Study start18 May 2022
  3. Primary completion30 Jun 2026
  4. Study completion31 Jul 2026

Resources

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
Device feasibility
Allocation
Not applicable
Intervention model
Single group
Model description
up to 10 subjects with NSTEMI or unstable angina undergoing cryotherapy treatment of coronary vulnerable plaque lesions. Once This safety cohort has been enrolled, additional 20 subjects will be enrolled to further confirm feasibility and safety of the device.
Masking
None (open label)
Enrolment
24 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05600088
Sponsor's protocol ID
CT-CD-P03-1
Acronym
POLARSTAR
Status last verified
Mar 2026
First submitted
26 Oct 2022
Last updated
30 Oct 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing CryoTherapy System (CTS) in people with Coronary Artery Disease and Coronary Syndrome, run by Cryotherapeutics SA at 5 sites in 2 countries.

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 18 inclusion and 18 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 30 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 5 sites in Lithuania, Georgia. 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?

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?

Safety: Rate of Cryotherapy related adverse events (time frame: 90 days post-procedure). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05600088.

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 30 Oct 2026.

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