Chronic Total Coronary OcclusionNCT04542460
The Nordic Baltic Chronic Total Occlusion (CTO) Arrhythmia Study
A study testing PCI in people with Chronic Total Coronary Occlusion, run by Leif Thuesen at 1 site in Denmark.
Trial summary
In patients with a chronic total coronary occlusion (CTO ), clinically significant arrhythmia seems to be an important and a poorly investigated problem. The arrhythmia prevalence in an all-comer CTO-population is unknown, but in ICD-populations with ischemic heart disease, a CTO may be found in half of patients with… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Chronic Total Coronary Occlusion
- What is being tested?
- PCI
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 1 siteDenmark
- Study dates
- 1 Nov 2020to 1 Sep 2027
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- ≥1 CTO lesion amenable to PCI.
- Stable or stabilized coronary artery disease.
- Angiographic/echocardiographic signs of reversible perfusion.
- CTO lesion in a coronary vessel supplying a significant myocardial territory (vessel diameter usually ≥3mm).
Who cannot join
- Expected survival <1 year.
- Patients with an indication of ICD due to EF < 35 or previous ventricular tachycardia.
- Patients with a cardiac device i.e. ICD, pacemaker or cardiac resynchronizing treatment device.
- Renal failure on dialysis.
- Lesions treated with PCI within one month.
- Indication for coronary artery bypass grafting (CABG). I.e. Two-or three vessel disease or left main disease and a syntax score >22.
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- Significant valvular heart disease.
- Declined informed consent.
- Regarding CMRI: allergy to contrast medium, severe obesity, claustrophobia and certain metallic implants.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Chronic Total Coronary Occlusion; Arrhythmia in Patients With Adjunction of PCI to Optimal Medical Treatment Versus Optimal Medical Treatment and in Patients With Failed PCI.
In patients with a chronic total coronary occlusion (CTO ), clinically significant arrhythmia seems to be an important and a poorly investigated problem. The arrhythmia prevalence in an all-comer CTO-population is unknown, but in ICD-populations with ischemic heart disease, a CTO may be found in half of patients with life-threatening arrhythmia.The purpose of the CTO-ARRHYTHMIA study, is to investigate the incidence of clinically significant arrhythmias in CTO patients using an implantable loop recorder. Further, the investigators intend to identify predictors for arrhythmias as well as the impact on arrhythmia of optimized pharmacological treatment and revascularization in CTO patients.
Read the detailed description
In angiographic materials, chronic total coronary occlusion (CTO) is present in approximately 15-25% of patients and in 25-50% of those with significant coronary disease. Until recently, because of low procedural success and increased risk of complications, PCI was a problematic treatment in these patients. The introduction of drug eluting stents and a variety of dedicated CTO devices combined with the evolution of specific CTO techniques have made revascularization by PCI a promising treatment.
In CTO patients, clinically significant arrhythmia seems to be an important and a poorly investigated problem. The arrhythmia prevalence in an all-comer CTO-population is unknown, but in ICD-populations with ischemic heart disease, a CTO may be found in half of patients with life-threatening arrhythmia. Further, in patients with ischemic heart disease receiving ICDs as primary prevention, presence of a CTO was an independent predictor of occurrence of ventricular arrhythmias, and in survivors of out-of-hospital cardiac arrest, the risk of ventricular arrhythmias was found to be increased in patients with a chronic total coronary occlusion. Nevertheless, the genesis of arrhythmia in CTO-patients is likely to be multifactorial. It has been documented, that ischemic heart disease patients who present with a chronic occlusion of at least one coronary artery are older and have additional risk factors such as hypertension, diabetes, lower left ventricular ejection fraction (LVEF) and more frequent myocardial infarction, i.e. a higher Chads2Vasc score (risk score for stroke in atrial fibrillation patients). Although LVEF is lower in patients with a chronic coronary occlusion, less than 1/3 are potential ICD candidates with an LVEF <35%. However, a recent study in consecutive post-AMI survivors documented the highest incidence of sudden cardiac death in patients with a relatively preserved LVEF.
The purpose of the CTO-ARRHYTHMIA study, is to investigate the incidence of clinically significant arrhythmias in CTO patients using an implantable loop recorder. Further, the investogators intend to identify predictors for arrhythmias as well as the impact on arrhythmia of optimized pharmacological treatment and revascularization in CTO patients. Here, CTO patients with failed PCI may be individuals with a particularly high risk of severe arrhythmias.
- Conditions
- Chronic Total Coronary Occlusion
- Being tested
- PCI
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PCIProcedure or surgery
Also called Loop recorder
A loop recorder is implanted i all patients in both study groups to investigate:
- Prevalence and severity of cardiac arrhythmias.
- Effect on detected arrhythmia, in particular ventricular tachyarrhythmia, of optimal medical therapy vs. coronary revascularization by PCI.
- Prevalence and severity of cardiac arrhythmias in CTO-patients with failed PCI.
- Indication for prophylactic ICD implantation in CTO-patients treated conservatively or by PCI and after failed PCI.
- Relation of arrhythmias to angina pectoris symptoms (CCS class), Quality of life questionnaire results and presence of myocardial reversible perfusion defects by CMRI.
| Study group | Role | What they receive |
|---|---|---|
| Optimal Medical Treatment | No intervention | CTO patients receiving optimal medical treatment |
| Optimal Medical Treatment and PCI | Active comparator | CTO patients receiving PCI in ajunction to optimal medical treatment Receives: Procedure: PCI |
What is being measured
The primary outcome is the main question the study is designed to answer.
Rate of clinically significant arrhythmias
Rate og clinically significant arrhythmias in PCI versus medically only treated patients by loop recorder (table 1) and in patients with failed PCI.
Measured: 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Sep 2020
- Study start1 Nov 2020
- Primary completion1 Oct 2025
- Study completion1 Sep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chronic Total Coronary OcclusionStudies 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Investigator conceived, initiated and driven 1:1 randomized open label clinical trial
- Masking
- None (open label)
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Leif Thuesen
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Leif Thuesen, Aalborg University Hospital
- Investigators
- Peter Soegaard, DMSc, Study chair, Co-PI
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04542460
- Sponsor's protocol ID
- CTO-ARRHYTHMIA
- Status last verified
- Mar 2026
- First submitted
- 3 Sep 2020
- Last updated
- 20 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data will be analyzed at site
Study at a glance
From the registry record, last updated by the sponsor on 20 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Chronic Total Coronary Occlusion; Arrhythmia in Patients With Adjunction of PCI to Optimal Medical Treatment Versus Optimal Medical Treatment and in Patients With Failed PCI.
- ClinicalTrials.gov ID
- NCT04542460
- Acronym / sponsor ID
- CTO-ARRHYTHMIA
- Conditions
- Chronic Total Coronary Occlusion
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Leif ThuesenUniversity, hospital or other
- Study start
- 1 Nov 2020 (actual)
- Primary completion
- 1 Oct 2025 (actual)
- Study completion
- 1 Sep 2027 (estimated)
- First posted
- 9 Sep 2020 (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.
In patients with a chronic total coronary occlusion (CTO ), clinically significant arrhythmia seems to be an important and a poorly investigated problem. The arrhythmia prevalence in an all-comer CTO-population is unknown, but in ICD-populations with ischemic heart disease, a CTO may be found in half of patients with life-threatening arrhythmia.The purpose of the CTO-ARRHYTHMIA study, is to investigate the incidence of clinically significant arrhythmias in CTO patients using an implantable loop recorder. Further, the investigators intend to identify predictors for arrhythmias as well as the impact on arrhythmia of optimized pharmacological treatment and revascularization in CTO patients.
Detailed description
In angiographic materials, chronic total coronary occlusion (CTO) is present in approximately 15-25% of patients and in 25-50% of those with significant coronary disease. Until recently, because of low procedural success and increased risk of complications, PCI was a problematic treatment in these patients. The introduction of drug eluting stents and a variety of dedicated CTO devices combined with the evolution of specific CTO techniques have made revascularization by PCI a promising treatment.
In CTO patients, clinically significant arrhythmia seems to be an important and a poorly investigated problem. The arrhythmia prevalence in an all-comer CTO-population is unknown, but in ICD-populations with ischemic heart disease, a CTO may be found in half of patients with life-threatening arrhythmia. Further, in patients with ischemic heart disease receiving ICDs as primary prevention, presence of a CTO was an independent predictor of occurrence of ventricular arrhythmias, and in survivors of out-of-hospital cardiac arrest, the risk of ventricular arrhythmias was found to be increased in patients with a chronic total coronary occlusion. Nevertheless, the genesis of arrhythmia in CTO-patients is likely to be multifactorial. It has been documented, that ischemic heart disease patients who present with a chronic occlusion of at least one coronary artery are older and have additional risk factors such as hypertension, diabetes, lower left ventricular ejection fraction (LVEF) and more frequent myocardial infarction, i.e. a higher Chads2Vasc score (risk score for stroke in atrial fibrillation patients). Although LVEF is lower in patients with a chronic coronary occlusion, less than 1/3 are potential ICD candidates with an LVEF <35%. However, a recent study in consecutive post-AMI survivors documented the highest incidence of sudden cardiac death in patients with a relatively preserved LVEF.
The purpose of the CTO-ARRHYTHMIA study, is to investigate the incidence of clinically significant arrhythmias in CTO patients using an implantable loop recorder. Further, the investogators intend to identify predictors for arrhythmias as well as the impact on arrhythmia of optimized pharmacological treatment and revascularization in CTO patients. Here, CTO patients with failed PCI may be individuals with a particularly high risk of severe arrhythmias.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Investigator conceived, initiated and driven 1:1 randomized open label clinical trial
| Arm | Type | Receives |
|---|---|---|
| Optimal Medical Treatment | No intervention | –CTO patients receiving optimal medical treatment |
| Optimal Medical Treatment and PCI | Active comparator | Procedure: PCICTO patients receiving PCI in ajunction to optimal medical treatment |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- ≥1 CTO lesion amenable to PCI.
- Stable or stabilized coronary artery disease.
- Angiographic/echocardiographic signs of reversible perfusion.
- CTO lesion in a coronary vessel supplying a significant myocardial territory (vessel diameter usually ≥3mm).
Key exclusion criteria (9 listed)
- Expected survival <1 year.
- Patients with an indication of ICD due to EF < 35 or previous ventricular tachycardia.
- Patients with a cardiac device i.e. ICD, pacemaker or cardiac resynchronizing treatment device.
- Renal failure on dialysis.
- Lesions treated with PCI within one month.
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 |
|---|---|---|
| PCIAlso: Loop recorderA loop recorder is implanted i all patients in both study groups to investigate: * Prevalence and severity of cardiac arrhythmias. * Effect on detected arrhythmia, in particular ventricular tachyarrhythmia, of optimal medical therapy vs. coronary revascularization by PCI. * Prevalence and severity of cardiac arrhythmias in CTO-patients with failed PCI. * Indication for prophylactic ICD implantation in CTO-patients treated conservatively or by PCI and after failed PCI. * Relation of arrhythmias to angina pectoris symptoms (CCS class), Quality of life questionnaire results and presence of myocardial reversible perfusion defects by CMRI. | Procedure or surgery | Optimal Medical Treatment and PCI |
Primary outcome
Rate of clinically significant arrhythmias
Time frame: 1 year
Rate og clinically significant arrhythmias in PCI versus medically only treated patients by loop recorder (table 1) and in patients with failed PCI.
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 20 Mar 2026.
- Individual participant dataSharing planned: No. Data will be analyzed at site
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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. This study is not recruiting at the moment.
Peter Soegaard, DMSc study chair
Co-PI
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing PCI in people with Chronic Total Coronary Occlusion, run by Leif Thuesen at 1 site in Denmark.
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 9 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: under way, not looking for participants, as of the sponsor's last update on 20 Mar 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 Denmark. 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?
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?
Rate of clinically significant arrhythmias (time frame: 1 year). 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 20 Mar 2026.