Some 38 percent of women who experienced MI with no angiographically obstructive coronary artery disease (CAD) had plaque rupture and ulceration, according to a study published in the Sept. 27 issue of Circulation. Using intravascular ultrasound (IVUS) and cardiac magnetic resonance (CMR) imaging, researchers identified abnormalities in 70 percent of the women patients, suggesting additional imaging may provide useful information for determining treatment.
Harmony R. Reynolds, MD, associate director of the Cardiovascular Clinical Research Center at New York University Langone Medical Center in New York City, led a prospective evaluation of 50 women with acute MI and no lesion with more than 50 percent diameter stenosis or evidence of plaque rupture on coronary angiography. Angiographically eligible patients underwent IVUS at the time of angiography and CMR within seven days of angiography. A small subset underwent only CMR.
Some 30 percent of the women had completely normal angiograms and the remaining 70 percent had some degree of stenosis, with the highest at 45 percent diameter stenosis.
Reynolds et al found plaque disruption in 38 percent of the women who underwent IVUS. Twelve patients had plaque rupture and four additional patients had plaque ulceration. Of the 44 patients who underwent CMR, 39 percent had at least one area of late gadolinium enhancement (LGE). T2 signal hyperintensity indicating edema was identified in nine additional patients, and was common with plaque disruption.
“We have confirmed a long-held hypothesis about the cause of MI with no obstructive CAD,” the authors wrote. “There is every reason to believe that plaque ruptures in these women were etiologic for MI. Plaque disruption was accompanied by CMR evidence of myocardial edema in the majority of cases, and all patients had acute presentation of chest pain.”
In a statement, Reynolds said the results have implications for diagnosis and treatment. “For the first time, our research findings show that disrupted plaque is the culprit behind heart attacks in many women who appear on an angiogram to have minimal or no coronary artery disease,” she said. “The findings show these women can essentially have a heart attack that is just like a heart attack typical in male and female patients whose coronary arteries do show blockage on an angiogram.”
The researchers noted that an undiagnosed MI in women who had no angiographically demonstrated CAD could result in a missed opportunity for optimal care. “Such patients would presumably benefit from treatment with antiplatelet agents and statins,” they wrote. “However, patients without obstructive CAD are less likely to be prescribed medical therapies for secondary prevention of MI, including aspirin, clopidogrel and statins.”
They concluded that IVUS and CMR offered distinct and complementary information about women with MI who show no CAD on angiography and recommended they be considered as additional techniques for this patient population. They added that their study had limitations, including being single-centered and based on a small sample size. They also noted that, because of logistical reasons and withdrawal of consent, not all patients received IVUS or CMR.