As an interventional cardiologist who’s passionate about reducing the disparities in diagnosis and management in women with cardiovascular disease, I was captivated by the late-breaking science that took the main arena for Current Challenges in Coronary and Valve Disease at Scientific Sessions 2020. The Coronary OCT and Cardiac MRI (CMR) to Determine Underlying Cause of MINOCA (Myocardial Infarction with Nonobstructive Coronary Arteries) in Women Trial from the HARP (Women’s Heart Attack Research Program) investigators led by Dr. Reynolds and colleagues is truly groundbreaking for women patients with MINOCA (1). HARP-MINOCA was a multimodality imaging trial that included all women. Yes—that’s correct. An ALL Woman Trial. Why would a study enroll all women? Because MINOCA is a condition that disproportionately affects women (3). In women presenting with MI, the presence of MINOCA is 10.5% compared to 3.4% in men (4). MINOCA is a disease process that has largely been met with controversy such that clinicians have challenged the presence of a “true” myocardial infarction in the absence of coronary artery disease. Furthermore, the lack of an obstructive lesion on a coronary angiogram has misled women to believe that they’re “fine” just because their coronary arteries don’t require stenting. This is completely false. Patients with MINOCA have clinical outcomes similar to patients with obstructive CAD at the time of myocardial infarction (MI) (3). Our patients have suffered in this variability of treatment and assessment which ultimately impacts their care. The findings of this study area additive to the American Heart Association’s scientific statement on the contemporary diagnosis and management of MINOCA which sought to standardize the definition of MINOCA and create a clinically useful diagnostic framework and treatment algorithm (2). Thus, the HARP-MINOCA multimodality imaging findings deepen the roots of MINOCA as a true disease process that requires a proper diagnosis with multimodality imaging to optimize management for improved patient outcomes.
This prospective multicenter study enrolled women a total of 301 women with a clinical diagnosis of MI across 16 different sites of which 170 had MINOCA. Once invasive coronary angiography was performed and revealed <50% stenosis in all major arteries, multi-vessel optical coherence tomography (OCT) was performed, followed by CMR (cine imaging, late gadolinium enhancement, and T2-weighted imaging and/or T1 mapping). [Figure 1]
Dual imaging allowed for a thorough investigation of the following: 1) Vascular causes of MINOCA by OCT, 2) Myocardial abnormalities on CMR and 3) integration of the various underlying etiologies on OCT and CMR. The findings from OCT investigation revealed that a culprit lesion in 46% of cases included plaque rupture, thrombus without plaque rupture, intra-plaque cavity, layered plaque, dissection, or spasm. The CMR findings revealed infarction with late gadolinium enhancement 33% of cases, regional pattern of ischemic injury in 21% and 21% had non-ischemic pattern giving them an alternate diagnosis. The study did have a few limitations included a low rate of STEMI enrollment, regional myocarditis cannot be excluded from the CMR definition of ischemic injury (defined as a single coronary territory with myocardial edema) that was used, the contribution of coronary vasospasm to the presentation was not evaluated, and not all women underwent 3-vessel OCT and CMR leaving some diagnoses that may have been missed.
The integration of the dual-imaging findings revealed a specific cause for MINOCA in 85% of cases. When an OCT culprit lesion, there was CMR evidence of infarction or regional ischemic injury in 75% of cases. Multi-modality imaging was better than either imaging modality alone leading to an identified cause of MINOCA in 85% of cases. One of the cases shared during the trial presentation was eye-opening. Despite no evidence of an obstructive lesion in the LAD vessel on a coronary angiogram, OCT performed in the LAD revealed plaque rupture and subsequent CMR demonstrated a small, transmural infarction in the terminal segment of the LAD. [Figure 2]. The importance of establishing the diagnosis with additional multimodality imaging is the key findings here. MINOCA patients have pathophysiology hidden deep beyond the limitations of coronary angiography and without additional imaging, they could be subject to a missed diagnosis and ultimately poor long-term care and management.
The 2020 European Society of Cardiology for non-ST elevation MI gave the use of CMR a Class IB recommendation for MINOCA evaluation. Unfortunately, there are no such recommendations for the use of intracoronary imaging. As a community-based interventionalist who performs emergent percutaneous coronary interventions at ST-Elevation MI (STEMI) receiving centers without cardiothoracic surgical support, we have restrictions as operators when performing interventions such an intravascular imaging when no intervention is planned. The implications of this OCT relevant data would be practice-changing for interventional cardiologists practicing in my clinical setting. The feasibility of OCT may bring its own challenges with operator-experience, staff support, and contrast use. However, education regarding the important data noted from OCT in MINOCA patients is a very important first step to implement change in one’s cath lab.
This study presented here at sessions continues to advance the growing field of MINOCA science. Late-breaking science advancing the understanding of this heterogeneous population of MINOCA patients is incredibly exciting and I’m looking forward to the continuum of knowledge to transform the algorithm for diagnostic assessment and framework for MINOCA treatment.
- Reynolds et al. Coronary Optical Coherence Tomography and Cardiac Magnetic Resonance Imaging to Determine Underlying Causes of MINOCA in Women. Circulation 2020; Epub. 10.1161/CIRCULATIONAHA.120.052008
- Tamis-Holland JE et al. Contemporary diagnosis and management of patients with myocardial Infarction in the absence of obstructive coronary artery disease: a scientific statement from the American Heart Association. Circulation. 2019;139(18):e891–908.
- Safdar B et al. Presentation, clinical profile, and prognosis of young patients with myocardial infarction with nonobstructive coronary arteries (MINOCA): results from the VIRGO study. J Am Heart Assoc. 2018;7(13)
- Smilowitz NR et al. Mortality of myocardial infarction by sex, age, and obstructive coronary artery disease status in the ACTION registry-GWTG (acute coronary treatment and intervention outcomes network registry-get with the guidelines). Circ Cardiovasc Qual Outcomes. 2017;10(12):e003443.
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