An interventional study of Disclosure of IDP results and IDP performed but results not disclosed in Microvascular Angina, Angina, Stable and Ischemia With No Obstructive Coronary Arteries (INOCA), sponsored by NHS Greater Glasgow and Clyde. Recruiting at 39 sites in 4 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-04-09.
Sponsored by NHS Greater Glasgow and Clyde · Not applicable, Interventional, and Diagnostic
The iCorMicA study is a multicentre, prospective, randomised, double-blind, sham-controlled, parallel-group, end-point trial and registry. The investigators seek to determine whether stratified medical therapy guided by an adjunctive interventional diagnostic procedure (IDP) during the invasive management of patients with known or suspected angina but no obstructive coronary artery disease improves symptoms, wellbeing, cardiovascular risk and clinical outcomes.
Ischaemic heart disease (IHD) includes coronary artery disease (or 'coronary heart disease 'CHD') and ischaemic with no obstructive coronary arteries (INOCA). Coronary angiography is standard care for the evaluation of symptomatic patients and known or suspected coronary artery disease. A considerable proportion e.g. >1 in 3, of patients undergoing invasive coronary angiography for known or suspected angina do not have obstructive epicardial coronary artery disease.
The CorMicA pilot study involved prospective enrolment of patients referred for clinically indicated coronary angiography during a 12-month period (2016-2017) in the West of Scotland). 391 patients were enrolled, 185 (47%) had no obstructive coronary disease and 151 were randomised in a clinical trial of stratified medicine based on invasive tests of coronary vascular function. A high proportion (\~4 in 5) of these patients had a diagnosis of INOCA due to a disorder of coronary vasomotion including microvascular- and/or vasospastic angina. The trial provided preliminary evidence that stratified medicine, as an adjunct to standard angiography-guided management, has potential to improve symptoms and quality of life. The mechanisms involved changes in diagnosis, treatment and lifestyle measures.
The CorMicA investigators were the first group to introduce stratified medicine for the management of ischaemic heart disease. Limitations of the CorMicA study included the setting (mainly single centre), partial blinding, short-term follow-up (primary outcome at 6 months) and the sample size. Acetylcholine reactivity testing was used to assess the susceptibility to coronary spasm (microvascular and/or macrovascular). Although acetylcholine is a naturally occurring substance, current formulations are not licensed for parenteral administration. Further, clinicians should have training and experience before implementing acetylcholine coronary reactivity testing. These considerations present a barrier to adoption in daily practice, which becomes all the more relevant given INOCA is generally under-recognised. A diagnostic coronary guidewire is already widely used in standard care and, unlike reactivity testing using acetylcholine, a guidewire has transferable potential to support stratified medicine during routine practice. This is especially the case for ad-hoc follow-on testing when obstructive coronary artery disease is excluded.
The vasoactive responses to acetylcholine reflect endothelial and vascular smooth muscle cell effects, which may overlap with the vasoactive responses to adenosine (non-endothelial dependent). Calcium channel blocker therapy is indicated for the functional endotypes associated with impaired vasodilatation and/or vasoconstriction. This raises the possibility that acetylcholine testing may not be routinely required as an adjunctive test to coronary angiography and instead could be reserved for selected cases, or in specialist centres. Instead, the diagnostic guidewire approach may be sufficient as a routine, first line test for the evaluation of INOCA during daily practice.
Anatomical imaging using coronary angiography is the standard of care and clinicians may determine any diagnosis based on all of the available information and their clinical judgement. This approach avoids the need for additional tests. With this approach, the patient's symptoms in response to empirical therapy can be assessed during follow-up and the treatment can be revised as clinically appropriate. In daily practice, adoption of adjunctive tests of coronary function is very low and, in the absence of large, multicentre trials, coronary angiography with or without adjunctive tests of coronary vascular function may be considered reasonable, reflecting equipoise.
iCorMicA is a multicentre, prospective, randomised, double-blind, sham-controlled, parallel-group, end-point (patient reported outcome measures (PROMS), health outcomes, health economics) trial and registry. The investigators aim to determine whether stratified medical therapy, guided by a guidewire-based interventional diagnostic procedure (IDP) at the time of invasive coronary angiography (i.e. functional angiography), improves outcomes in patients with known or suspected angina but no obstructive coronary artery disease. Symptoms of angina or angina-equivalent are determined according to the Rose and/or Seattle Angina questionnaires. The IDP utilises principles of thermodilution to measure coronary vascular function (IMR, CFR, RRR), which aid clinicians in establishing a diagnosis of microvascular angina, vasospastic angina, mixed (both), or none, as per Coronary Vasomotion Disorders International Study Group (COVADIS) criteria. The feasibility, safety, efficacy and effect on healthcare resource utilisation of stratified medicine will be tested in multiple hospitals in different countries in Europe.
Participants with no obstructive epicardial coronary artery disease (coronary stenosis \<50% and/or FFR >0.80) are eligible for randomisation (1:1) to either the intervention (IDP-guided, results disclosed) or blinded control (IDP undertaken but results not disclosed, standard of care) group. Medical therapy will be informed according to the clinical diagnosis (endotype). Patients in the intervention group with abnormal coronary vascular function may undergo repeated evaluations to assess the response to intracoronary therapy e.g. calcium channel blocker, enabling a personalised treatment plan. Patients who are ineligible for randomisation (e.g. obstructive coronary artery disease) may be entered into a prospective clinical registry, with individuals from each site invited to undergo similar follow-up assessments as the randomised participants.
Trial participants will be blinded to treatment group. The clinicians responsible for on-going care will also be blinded. Following invasive management, patients and clinicians will be advised of the diagnosis (endotype) but not the randomised group. The endotype will be informed by the IDP in the intervention group but not in the control group (sham procedure). Medical therapy and lifestyle measures are linked to the endotype and informed by contemporary practice guidelines. Therefore, optimal guideline-directed medical care according to the endotype is intended to be the same, regardless of the group allocation.
The sample size is 1500 randomised participants. The minimum follow-up duration is 12 months from the last participant recruitment. Follow-up will continued in the longer term including, where feasible, electronic case record linkage. The primary outcome measure is the Summary Score of the Seattle Angina Questionnaire at 12 months. Secondary outcomes include other Patient Reported Outcome Measures (PROMS) to describe other aspects of health and wellbeing. These include EQ-5D-5L, Illness perception (Brief IPQ), Treatment satisfaction (TSQM), Duke Activity Status Index (DASI), the International Physical Activity Questionnaire (IPAQ-SF) short-form and a pain questionnaire.
Additional objectives include the wider evaluation of the safety and diagnostic utility of the IDP in a multicentre, multinational setting, and the effects of stratified medicine on the rates of major adverse cardiovascular events by randomised group. The registry will represent a parallel control group. Scientific analyses of circulating biomarkers will be performed to better understand the pathophysiology of INOCA.
111 studies on the registry are indexed under Microvascular Angina; 39 are open to participants now.
This study's planned enrollment of 1,500 is above the median of 79 across 63 interventional studies indexed under Microvascular Angina.
Browse Microvascular Angina studies →NHS Greater Glasgow and Clyde is the lead sponsor of 220 studies on the registry; 39 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All randomised participants will receive stratified medicine. The subjects will undergo functional coronary angiography involving guidewire-based coronary function tests (interventional diagnostic procedure, IDP) as an adjunct to invasive coronary angiography. The IDP results will be disclosed to the catheter laboratory clinician to clarify endotypes and re-evaluate the clinical diagnosis. Linked guideline-directed medical therapy and lifestyle measures will be recommended based on the endotype. The patient and clinicians responsible for downstream care will not be informed of the randomised group but they will be informed of the endotype and linked treatment plan, in the same way as in the Standard Care control group. They will be blinded to the allocated study arm and IDP findings.
Diagnostic Test: Disclosure of IDP results
All randomised participants in this arm will receive standard angiography-guided care. The endotype will be determined based on the angiogram and all of the available clinical information. The participants in this group will also receive the IDP at time of the angiogram. The results of the IDP will be concealed from the catheter laboratory clinician who will be blinded. The cardiac physiologist / clinical scientist will remain unblinded for the purpose of data recording and quality assurance. The sham procedure is intended to be the same as in the Intervention Group. Management of the patient is as per standard of care, with therapy linked to the diagnosis (endotype). The patient and clinicians responsible for downstream care will not be informed of the randomised group but they will be informed of the endotype and linked treatment plan in the same way as in the Intervention Group. They will be blinded to the allocated study arm and IDP findings.
Other: IDP performed but results not disclosed
The results of the adjunctive IDP performed at time of invasive coronary angiography are made available to the catheter laboratory clinician, to aid in the diagnostic process.
Also known as: Stratified medicine
The results of the IDP performed at the time of invasive coronary angiography are concealed from the catheter laboratory clinician who will be blinded. The patient is managed according to standard of care.
Also known as: Standard, angiography-guided management
Seattle Angina Questionnaire (SAQ) Summary Score
The 7-item version of the SAQ reflects the frequency of angina (SAQ Angina Frequency score) and the disease-specific effect of angina on patients' physical function (SAQ Physical Limitation score) and quality of life (Quality of Life score) over the previous 4 weeks; these scores are averaged to obtain the SAQ Summary score, which is an overall measure of patients' stable ischaemic heart disease-specific health status. SAQ scores range from 0 to 100, with higher scores indicating less frequent angina, improved function, and better quality of life.
Time frame: 12 months
Feasibility of stratified medicine
Rates of enrolment, drop-out, completion of diagnostic protocol, integrity of blinding in the catheter laboratory and blinding at 1 year, loss to follow-up.
Time frame: 0-60 months
Safety of the interventional diagnostic procedure (IDP)
As reflected by SAEs related to the procedure, and those arising during longer term follow-up.
Time frame: 0-60 months
Diagnostic utility of the interventional diagnostic procedure (IDP)
To assess impact of disclosure of the coronary function test results on the diagnosis and certainty of the diagnosis. A missed diagnosis of microvascular angina is defined as a physician diagnosis of non-cardiac chest pain in the presence of objective abnormalities of coronary artery function.
Time frame: 0-60 months
Clinical utility
To assess the impact of disclosure of coronary function test results on clinical management (including treatment medication, investigations and healthcare resource utilisation).
Time frame: 0-60 months
Health status
To assess quality of life, symptoms and health status using validated, patient-administered questionnaires. The EQ5D, SAQ, angina diary, EQ-5D-5L, Brief IPQ, TSQM, DASI, IPAQ-SF, FSQ and MOCA questionnaires will be completed.
Time frame: 0-60 months
Cardiovascular risk
To assess attainment of guideline targets for measured cardiovascular risk factors, and adherence.
Time frame: 0-60 months
Health outcomes
MACE including death, re-hospitalisation for cardiovascular events including myocardial infarction, heart failure, stroke/ TIA, unstable angina and coronary revascularisation. Unscheduled hospital visits for chest pain that have not led to hospital admission will also be documented.
Time frame: 0 months - 10 years
Health economics
Health resource utilisation will also be assessed by identifying inpatient visits, procedures and medication use.
Time frame: 0 months - 10 years
Cardiovascular biomarkers
Hypothesis: Compared with standard care, stratified medicine improves circulating biomarkers of cardiovascular risk
Time frame: 0 months - 10 years
Sex differences
To assess for similarities and differences in presenting characteristics, socio-economic status, treatment, health status and clinical outcomes between males and females.
Time frame: 0 months - 10 years
Ischaemic heart disease
To assess for similarities and differences in presenting characteristics, socio-economic status, treatment, health status and clinical outcomes between patient with obstructive coronary artery disease and no obstructive CAD (including by endotype).
Time frame: 0 months - 10 years
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Plan to share: Yes
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Time frame: After the study has completed
Access criteria: Bone fide collaboration request
Data sharing details ↗ · www.gla.ac.uk
Started Dec 2020 (actual). Primary completion is estimated for Jun 2026, 66 months after the start.
Of 24 interventional studies with no phase under Microvascular Angina, half reached primary completion within 39 months of starting (the median), counting those still running; a quarter within 24 and three quarters within 64. This study's planned 66 months is above that.
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