Nonobstructive MI disproportionately affects young women
Learning a heart attack patient has nonobstructive coronary arteries shouldn’t necessarily be met with relief, according to a multicenter study published in the Journal of the American Heart Association.
In fact, these patients have statistically similar mortality rates one month and one year after myocardial infarction compared to those with obstructive disease, reported Yale University researcher Basmah Safdar, MD, and colleagues.
The authors followed 2,690 patients from the VIRGO study, which enrolled myocardial infarction (MI) patients between the ages of 18 and 55 at a 2:1 ratio of women to men. Patients were grouped as having MI related to CAD (MI-CAD) if they underwent revascularization for a plaque-mediated culprit lesion, or if they had angiographic evidence of at least 50 percent stenosis. Other patients were classified as MI with nonobstructive coronary arteries (MINOCA).
Safdar et al. found:
- 88.4 percent of patients were diagnosed with MI-CAD, while 11.1 percent had MINOCA and 0.6 percent remained unclassified.
- Women were about five times as likely as men to have MINOCA (14.9 percent versus 3.5 percent), and nonwhites were 1.57 times as likely to experience that type of MI.
- 8.7 percent of MINOCA patients didn’t have traditional cardiac risk factors, compared to only 1.3 percent of MI-CAD patients.
- One-month mortality rates for MI-CAD and MINOCA were 1.7 and 1.1 percent, respectively, and one-year rates were 2.3 percent and 0.6 percent.
- Scores on a quality-of-life assessment were similar between the two groups at one year.
“In young patients with acute myocardial infarction, the course of MINOCA was not benign; one‐ and 12‐month mortality and functional and psychosocial outcomes were similar to those of patients with myocardial infarction due to coronary artery disease,” Safdar and coauthors wrote. “Patients with acute myocardial infarction who are ruled out for obstructive coronary artery disease should undergo additional testing to elucidate the underlying cause of ischemia and to initiate appropriate treatment.”
This latter point is particularly important given the varying causes of nonobstructive MI observed in the study, such as coronary artery vasospasm, spontaneous coronary artery dissection and coronary artery.
As has been reported in other cardiovascular studies, women appeared less likely to receive protective heart medications following MI. Considering more women experienced MINOCA versus MI-CAD, this could have shrunk the gap in downstream outcomes experienced by each group.
“Unfortunately, some physicians fail to realize that the absence of obstructive coronary arteries does not exclude the possibility of an AMI (acute MI),” Jacqueline E. Tamis-Holland, MD, and Hani Jneid, MD, wrote in an accompanying editorial. “As such, patients with MINOCA may be misinformed about their diagnosis and inaccurately ‘reassured’ about a favorable prognosis. Even when appropriately diagnosed, the management of this heterogeneous group of patients will vary depending on local practices and hospital resources.”
The editorialists said there is still a weak body of evidence on MINOCA and the best ways to treat it, despite it affecting a sizeable minority of young MI patients, particularly women. Researchers haven’t even settled on a uniform definition of MINOCA to ensure consistent and reliable applications from the few studies that do exist.
“The time has come to make a change," Tamis-Holland and Jneid wrote. “To favorably affect outcomes, we must erase all prior misperceptions regarding this condition and institute appropriate long‐term investigations examining a wide array of diagnostic and therapeutic strategies in MINOCA patients.”
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.