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Understanding MI With Nonobstructive Coronary Arteries

— Noel Bairey Merz, MD, says field is now coming to grips with challenging condition

Ƶ MedicalToday

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is the term recently created to describe a 75-year-old problem where patients present clinical features of an acute myocardial infarction without evidence of obstructive coronary artery disease on coronary angiography. Unfortunately, physicians are still not sure how to properly treat and prevent this type of heart disease.

In this exclusive Ƶ video, , Director, Women's Heart Center at Cedars-Sinai in Los Angeles, discusses ongoing trials and offers some clinical pearls.

The following is a transcript of her remarks:

I'm going to talk about MINOCA, which is MI with no obstructed coronary artery disease, and we'll talk about treatment because this is a very poorly defined area. The majority of these victims are women because we didn't study women, we don't know that much about it. We do have our pharmacologic PROBE trials, small trials of 75 to 150 patients blinded that demonstrate that ACE inhibitors and statins can improve endothelial function, improve exercise treadmill time, and improve angina. We now have a large MACE trial. MACE, of course, stands for major adverse cardiac events called the WARRIOR, where we're randomizing 4,422 women with persistent chest pain, no obstructed coronary disease to high-intensity statin, and ACE or ARB maximally tolerated versus usual care. Results will be out in about four years, and we will have, for the first time, some evidence to advise guidelines for these patients.

The core microstudy, which came out last year from Scotland, also randomized subjects with no obstructed coronary disease founded invasive angiography, 2) flow reserve testing with a vasospastic dose of acetylcholine and a vasodilatory dose of adenosine, what would be called an FFR, but it's actually a CFR or an IMR. On the basis of those results, the cardiologists were actually randomized to knowing the results or not knowing the results. Those that were given the results were given a protocol about how to treat microvascular angina. If it was a vasoconstrictive response, calcium channel agents. If it was a vasodilatory reduction, alpha-beta blockers. Not surprising, the results of the core MICRA trial is that Seattle Angina Questionnaire dramatically improved in the treated group and did not get better. Moreover, there were dramatic changes in care in those that had the diagnosis of microvascular angina compared to the usual care group. You end up with a non-diagnosis.

We are really starting to get information about how to treat open-artery ischemia and these additional trials will continue to inform us.

Other clinical pearls that I find helpful is sometimes just telling the patient that has persistent chest pain with evidence of ischemia and open arteries that you can probably help them because they probably have microvascular angina will sometimes bring tears of relief because they thought they were going crazy. They were sometimes told by other physicians that they were crazy, and this is one of the most important things we do as physicians is we help people heal.