Mechanisms of Myocardial Infarction in Women Without Angiographically Obstructive Coronary Artery Disease

Abstract

Background There is no angiographically demonstrable obstructive coronary artery disease (CAD) in a significant minority of patients with myocardial infarction (MI), particularly women. We sought to determine mechanism(s) of MI in this setting using multiple imaging techniques. Methods and Results Women with MI were enrolled prospectively, prior to angiography if possible. Women with ≥50% angiographic stenosis or use of vasospastic agents were excluded. Intravascular ultrasound (IVUS) was performed during angiography and cardiac magnetic resonance imaging (CMR) within one week. Fifty women (age 57±13 years) had median peak troponin 1.60 ng/ml; 11 had ST elevation. Median diameter stenosis of the worst lesion was 20% by angiography; 15 patients (30%) had normal angiograms. Plaque disruption was observed in 16/42 patients (38%) undergoing IVUS. There were abnormal myocardial CMR findings in 26/44 patients (59%) undergoing CMR: late gadolinium enhancement (LGE) in 17 and T2 signal hyperintensity indicating edema in 9 additional patients. The most common LGE pattern was ischemic (transmural/subendocardial). Non-ischemic LGE patterns (midmyocardial/subepicardial) were also observed. LGE was infrequent with plaque disruption but T2 signal hyperintensity was common with plaque disruption. Conclusions Plaque rupture and ulceration are common in women with MI without angiographically demonstrable obstructive CAD. LGE is also common in this cohort of women, with an ischemic pattern of injury most evident. Vasospasm and embolism are possible mechanisms of ischemic LGE without plaque disruption. IVUS and CMR provide complementary mechanistic insights in female MI patients without obstructive CAD and may be useful in identifying potential etiologies and therapies.

Outcomes of Women and Men With Acute Coronary Syndrome Treated With and Without Percutaneous Coronary Revascularization

“…For instance, we observed that women were more frequently revascularized with PCI as opposed to CABG compared with men. Other studies have suggested that women with ACS are more likely to have nonobstructive epicardial coronary disease,33 smaller epicardial coronary arteries,34 less traditional focal plaque rupture on angiography,35, 36 and have more microvascular dysfunction, diffuse disease, or plaque erosion 36. The resultant higher burden of functional coronary disease, and incomplete revascularization among women with anatomical disease, predispose to a higher burden of symptoms, including angina and dyspnea, which may have driven the subsequent observed sex‐difference in risk of recurrent ACS as opposed to all‐cause mortality.…”

Myocardial Infarction With Nonobstructive Coronary Arteries (MINOCA): It's Time to Face Reality!

“…When needed and if resources permit, additional testing should be considered, including intracoronary imaging studies with intravascular ultrasound or optical coherence tomography, thrombophilia testing, provocative testing for coronary vasospasm, and cardiac magnetic resonance imaging. Studies of intracoronary imaging have shown that ≈40% of patients with MINOCA have some evidence of plaque disruption 16, 17. Although intravascular ultrasound is helpful in demonstrating plaque rupture,16 Optical coherence tomography is a better tool for identifying patients with plaque erosion18 and may be superior for the assessment of patients with spontaneous coronary artery dissection 19.…”

“…Studies of intracoronary imaging have shown that ≈40% of patients with MINOCA have some evidence of plaque disruption 16, 17. Although intravascular ultrasound is helpful in demonstrating plaque rupture,16 Optical coherence tomography is a better tool for identifying patients with plaque erosion18 and may be superior for the assessment of patients with spontaneous coronary artery dissection 19. In the current report, intracoronary imaging was not routinely utilized, and that may explain why a large number of patients with MINOCA were “undefined.” Thrombophilia disorders can be detected in up to 14% of MINOCA patients4; however, a hypercoagulability syndrome was detected in only 3% of MINOCA patients in the current report, casting doubt on whether extensive thrombophilia testing was really undertaken in VIRGO.…”

Sex Differences in Clinical Characteristics, Psychosocial Factors, and Outcomes Among Patients With Stable Coronary Heart Disease: Insights from the STABILITY (Stabilization of Atherosclerotic Plaque by Initiation of Darapladib Therapy) Trial

“…It has been hypothesized that estrogens have protective effects on the vascular endothelium, thus women require more time and risk factor load to develop coronary disease 1. Compared with men, women also have less atherosclerotic burden, with lower prevalence of obstructive lesions, and more often have MI with no obstructive CAD 16, 17. And indeed, we observed that women with stable CHD enrolled in the STABILITY trial were older and had more risk factors, such as hypertension, diabetes mellitus, and chronic kidney disease, than men.…”