Expand your idea of ischemic heart disease to include non-obstructive patterns, which as our guest, Dr Noel Bairey Merz, a clinical investigative cardiologist whose multiple roles include Director of the Barbra Streisand Women’s Heart Center and the Preventive Cardiac Center at the Smidt Cedars-Sinai Heart Institute, shares with us, is incredibly common, especially in women. Learn to recognize heart disease in women and treat according to guidelines, preventing unnecessary IHD mortality in our female (and some male) patients. We review a variety of non-obstructive pathologies and the best techniques to evaluate them.
Written and produced by: Shreya Trivedi MD, Molly Heublein MD
Hosts: Paul Williams MD, FACP; Shreya Trivedi MD; Molly Heublein MD
Edited by: Matthew Watto MD, FACP; Emi Okamoto MD
Graphics by: Hannah Abrams
Guest: Dr. C Noel Bairey Merz MD, FACC, FAHA
The paradigm of ischemic heart disease (IHD) has been focused on obstructive atherosclerosis of the large epicardial arteries. Our stress imaging looks at wall motion abnormalities caused by blockages in the large coronary arteries, and interventional cardiology focuses on addressing these. This paradigm misses 30-40% of women with heart disease and
5-10% of men, because it overlooks nonobstructive coronary disease (Galuti 2012).
A woman with chest pain, EKG changes (including STEMI), and an elevated troponin has had a myocardial infarction, even without evidence of obstructive coronary arteries on catheterization (Bugiardini, 2005). This meets WHO criteria for an MI (Mendis, 2011), and should be labeled, diagnosed, and treated appropriately.
Think about shifting our language, ischemic heart disease is a more encompassing term, as opposed to coronary artery disease (CAD) or coronary heart disease (CHD) which focuses on obstructive disease.
Think of how reproductive hormones influence fat deposition: men with focal visceral fat/abdominal obesity vs. women with diffuse obesity.
Male pattern ischemic heart disease- “lumpy bumpy” plaque, followed by remodeling, which is visible on angiography sooner.
Female pattern ischemic heart disease– diffuse, smooth, concentric atherosclerosis which is sometimes invisible to angiography.
Hormones probably have an impact. The balance of sex hormones (testosterone/estrogen) predicts IHD risk. (Zhao 2018)
Women have different patterns of vascular dysfunction and constriction (including more prone to migraines and Raynaud’s). (Sullivan 2018)
Immune mediated changes occur, driving inflammation in different ways between the sexes. (Fairweather 2015)
Myocardial infarction with non-obstructive coronary arteries (MINOCA) is an umbrella term which includes diverse etiologies including microvascular changes, spontaneous coronary artery dissection (SCAD), vasospastic angina, plaque rupture or erosion, thromboembolism, takotsubo cardiomyopathy, unrecognized myocarditis, and other forms of type-2 myocardial infarction (Agewall 2017). It is important to continue to try to differentiate the underlying cause as it changes treatment.
10-15% of NSTEMI and 5% of STEMI are MINOCA (Agewall 2017). These should be treated with guideline therapy.
The true prevalence of spontaneous coronary artery dissection (SCAD) is not known, but is more common in younger women, maybe 20% of MI in this demographic is SCAD. Treatment is just aspirin (no need to treat with statins), and patients are not usually left with persistent chest pain. (Ahmed 2017)
Myocarditis is another cause for chest pain and positive troponin. Cardiac MRI may show evidence this. (Dastidar 2015)
Embolism to coronaries can cause MINOCA, often due to underlying autoimmune disease, valvular disease, or arrhythmia. (Agewall 2017)
Typical angina (substernal pressure, worse with exercise/stress, relieved with rest/nitroglycerin), atypical angina (two of three characteristics of typical angina), and non-anginal (one or no characteristics of typical angina) chest pain do not reliably differentiate cardiac from noncardiac chest pain (Herman 2010). Do not ignore non-classical chest pain.
Women may complain of more rest chest pain, particularly when under stress. Seattle Angina Questionnaire can improve diagnosis and treatment.
Any women over age 50 and men over age 40 with new chest pain should be evaluated- they are at intermediate risk of ischemic heart disease. Guidelines suggest if the patient can walk and has a normal resting EKG, the first choice option is an exercise EKG stress test (Wolk 2014).
Stress testing provides clinically valuable points of information:
These 4 elements are all useful in predicting the likelihood of IHD, and any abnormality can be clinically significant. Review the stress tests carefully, as often risk determination is focused on only imaging.
Use the Duke treadmill score to help calculate risk.
If the patient cannot exercise or has an abnormal resting EKG, guidelines suggest coronary CT angiography (CCTA) as an alternative option (Wolk 2014). The SCOT-HEART trial showed that adding CCTA to standard care had an advantage of improved mortality, driven by more treatment in the CCTA group.
Dr Merz reminds us that a CCTA may be read as “normal”- not showing significant blockage- but could still show calcified or noncalcified plaque more diffusely. She recommends it is important to review the full report and/or discuss with a radiologist or cardiologist.
Invasive coronary angiography is a lumenogram- all you see is the dye, not the walls of the artery which primarily identifies obstructive CAD.
SPECT- compares normal to abnormal, just like you can miss triple vessel disease you can miss microvascular disease (Cassar 2009).
In a patient with normal evaluation but persistent symptoms, Dr Merz suggests considering cardiac MRI or PET which can be more sensitive for microvascular perfusion abnormalities and finding other pathologies.
AHA/ACC guidelines for secondary prevention in patients who have had acute coronary syndrome: Prescribe the 4 “magic pills” 1. low dose aspirin, 2. ACE-I/ARB (for HTN or for infarct/wall motion abnormality), 3. beta-blockers (for persistent symptoms), 4. high intensity statin (20-40 mg of rosuvastatin, 40-80 mg of atorvastatin) to reduce recurrence and morbidity.
Through the 1980s-1990s, a significant health disparity existed, with more women dying of coronary vascular disease than men. The VIRGO study evaluated women and men who both had early MI. This study evaluated a large population with MINOCA, and noted health disparities in treatment, with lower rates of appropriate secondary prevention treatment prescriptions (Safdar 2018).
Dr Merz feels “Guidelines make good doctors great doctors, and make good health systems great health systems.” Being aware of guidelines and using electronic health records to trigger reminders for treatment can help make sure everyone receives appropriate care, and has helped level outcomes for women with ischemic heart disease.
Dr Merz feels reproductive-age women should be trusted to control their contraception. A shared decision making discussion should happen- if a woman is high risk, don’t automatically withhold medication (ie statin) even if young.
Listeners will rethink their understanding of ischemic heart disease and learn the basics of diagnosis and management for myocardial infarction with nonobstructive coronary artery disease in women.
After listening to this episode listeners will…
Dr Bairey Merz reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures.
Bairey Merz, C Noel. “#153 Heart Disease in Women”. The Curbsiders Internal Medicine Podcast http://thecurbsiders.com. June 3, 2019
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