A big step forward
Commenting on the study, C. Noel Bairey Merz, MD, from Cedars Sinai, Los Angeles, said it has “widespread relevance” because half of all coronary angiograms done invasively in the United States for suspected ischemia find no obstructive coronary disease. Left untreated, however, MINOCA has a 2.5% annual event rate, and a quarter of that is death.
“This is a big step forward with likely equal opportunity to improve women and men’s ischemic heart disease,” she said.
Dr. C. Noel Bairey Merz
On the other hand, all studies were conducted at centers of excellence, so safety will need to be carefully watched as testing rolls out to more community care, Dr. Merz said. “And it always needs to be underscored that this is done by an interventional cardiologist because they’re familiar with wires that can dissect arteries, and they’re familiar with minor complications that could turn into major, if someone didn’t act appropriately.”
Dr. Merz also called for unifying protocols and the need to raise awareness within the general cardiology community to ask interventionalists for acetylcholine spasm testing. Randomized controlled data from within the WISE study and the CorMica study showed that diagnostic certainty leads to greater therapeutic certainty. “You do a much better job about who and how to treat,” she said.
There are also three ongoing randomized controlled trials – WARRIOR, MINOCA-BAT, and iCorMica – in the INOCA and MINOCA populations testing different treatment strategies for hard clinical outcomes like death and myocardial infarction.
“So in addition to this publication being guideline-forming for diagnosis, we anticipate in the next several years to have clinical trial evidence about therapeutics, again, for formulation of class 1 guidelines,” Dr. Merz said.
John Beltrame, BMBS, PhD, University of Adelaide, Australia, said the meta-analysis shows that intracoronary acetylcholine spasm testing is safe and should prompt greater adoption of invasive functional angiography.
Interventionalists are quite happy to do fractional flow reserve using intravenous adenosine to assess coronary microvascular dysfunction, he said, and “what we think is that functional angiography should test both – both the spasm as well as the microvasculature – and that will give us a clear direction because the treatments are slightly different when you’re treating the large arteries as compared to the microscopic arteries. It’s an important thing.”
Dr. Beltrame and colleagues further detail the benefits of comprehensive invasive functional angiography over structural angiography in a related editorial.
He also noted that the Coronary Vasomotion Disorders International Study Group published international diagnostic criteria for microvascular angina and that several protocols for acetylcholine spasm testing are in the works, including one from Australia. Australian investigators are also organizing an accreditation program for those performing the test.
“The protocol itself is relatively straightforward, but it’s not merely picking up a manual and following the instructions,” Dr. Beltrame said. “Just the same as when you train someone in angioplasty, you don’t just go out and do it. You need to develop some experience in it and so should be proctored.”
Dr. Kobayashi reported consulting agreements with Abbott Vascular. Coauthor disclosures are listed in the paper. Dr. Beltrame and colleagues have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.