A Study of Microcirculatory Function in Type 2 Myocardial Infarction (T2MI)

Study Overview
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Brief Summary
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The purpose of this research is to find out if patients with Type 2 Myocardial Infarction (T2MI) without significant epicardial coronary artery disease (CAD) have a greater chance of having coronary microvascular disease (CMD).

Official Title
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Assessment of Microcirculatory Function in Type 2 Myocardial Infarction

Conditions
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Myocardial Infarction, Coronary Microvascular Disease

Intervention / Treatment
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* Diagnostic Test: Coronary angiogram with coronary reactivity testing (CRT)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ability to give informed consent Structurally normal heart (normal LV and RV function, no more than mild valvular heart disease) For controls: atypical chest pain with indication for CMD testing For T2MI: meet criteria for T2MI according to the 4th Universal definition of MI (rise/fall of troponin with at least 1 value >99th centile+ evidence of symptoms or signs of myocardial ischemia) Exclusion Criteria: Acute coronary event (evidence of plaque rupture, fissure or dissection on coronary angiogram) Known to have angiographically significant CAD/pressure wire positive for epicardial CAD Inability to receive heparin products Allergy/contraindication to acetylcholine/adenosine/nitroglycerine products Prior coronary artery bypass grafting Pregnancy (if sexually active woman of reproductive age, need negative pregnancy test prior to proceeding with coronary angiography - this is standard of care in cath lab) Asthma with prior ICU admission due to bronchospasm/need for invasive ventilation

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| T2MI Patients<br>Patients with T2MI and no epicardial coronary stenosis >50% will be prospectively enrolled and undergo a routine standard of care coronary angiogram with coronary reactivity testing (CRT). | Diagnostic Test: Coronary angiogram with coronary reactivity testing (CRT)<br>* CRT is an angiography procedure (using X-ray) to examine the small blood vessels in the heart and how they respond to three drugs (adenosine, acetylcholine and nitroglycerin) as per clinical protocol.<br>|
| Controls<br>Patients with atypical chest pain and no obstructive disease on coronary angiogram who have been referred for investigation of suspected CMD and have a clinical indication for CMD testing will be retrospectively enrolled and data collected from a previous routine standard of care coronary angiogram with coronary reactivity testing (CRT) will be utilized. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Coronary Flow Reserve (CFR) | The CFR will be calculated as a ratio of coronary flow at peak hyperemia /coronary flow at rest. | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Backward Compression Wave (BCW) | The BCW is a measure of increased microvascular resistance during systole. | Baseline |