#279 Dominate Stable Angina with the CardioNerds

June 14, 2021 | By Molly Heublein

Learn how to dominate stable angina. Coronary artery disease with stable angina is a different beast than acute coronary syndrome.  We deconstruct it’s pathophysiology, diagnosis, and management with Drs. Dan Ambinder and Rick Ferraro. Topics: When to order coronary CT vs Stress testing; An approach to non-obstructive coronary disease; What treatments are life prolonging; Medical therapy vs Stenting; An approach to antianginal therapy; and how to partner with each patient. Listen as we dive deep into the recent literature and recommendations to dominate stable angina.

Credits

• Producer: Molly Heublein, MD
• Writer: Molly Heublein, MD, Michael Sternberg MD
• Show Notes: Molly Heublein, MD, Beth Garbitelli
• Infographic, Cover Art: Beth Garbitelli
• Hosts: Molly Heublein, MD; Paul Williams MD, FACP   
• Editor: (written materials); Cyrus Askin MD, Clair Morgan of nodderly.com
• Guest: Daniel Ambinder, MD; Rick Ferraro, MD

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Show Segments

• Intro, disclaimer, guest bio
• Guest one-liner
• Picks of the Week*
• Case from Kashlak
• Definitions of stable angina, unstable angina
• INOCA
• Assessing risk
• Treatment – life prolonging vs symptom relief
• Diagnosis- stress testing vs anatomical studies
• Angioplasty/stenting- ISCHEMIA trial
• Take home points
• Outro

Stable Angina Pearls

1. Stable angina and unstable angina/ACS have inherently different pathophysiologies.  The plaque blockages in stable angina are hard and fixed, so the disease does not tend to change acutely.  In ACS, patients have sudden plaque rupture with coagulation, inflammation, and acute blood flow limitation leading to infarction.
2. Anatomical testing (coronary catheterization, CT angiography) will show you what the coronary tree looks like.  Functional (stress) testing will show you what the muscle is feeling based on the blood flow.
3. Multiple trials, including the recent ISCHEMIA trial,  have shown that in patients with stable ischemia, angioplasty (stenting) does not have a mortality benefit when added to optimal medical therapy (when compared to medical therapy alone). 
4. Goals of treatment for stable angina include improving longevity (blood pressure control, statins, aspirin) and improving symptoms (beta-blockers, ranolazine, stenting).

Stable Angina 

Definitions

Stable angina is defined as chest pain or equivalent symptoms (such as chest discomfort or dyspnea) that occur predictably with exertion and are relieved with rest.  The pathophysiologic foundation is supply-demand mismatch. During times of rest, there is adequate blood flow to sustain the myocardium. During times of stress ( i.e. exercise), flow limitation causes myocardial ischemia which can manifest as pain, dyspnea, nausea, or other symptoms.

Unstable angina is diagnosed when those same types of symptoms arise with a lower amount of exercise.  Presently, this is a less common diagnosis in the era of high-sensitivity troponin testing which has resulted in more cases of unstable angina being more appropriately diagnosed as NSTEMI (non-ST-elevation myocardial infarction). 

The pathophysiology is inherently different.  In stable angina, the plaque is a fixed obstruction. The plaque is “stable” due to it being calcified and hard.  With unstable angina and NSTEMI/STEMI,  there is an acute plaque rupture or endothelial erosion. It is a dynamic process with platelet activation and ongoing thrombosis. As such, symptoms can acutely change.

Risk Factor Assessment

When assessing symptoms of chest pain, it’s important to consider the patient’s risk factors, and view their history through the lens of these known risk factors. The more risk factors, the higher the pre-test probability.  That said, there are outliers! Certainly young patients can experience ACS, and women classically can present with ACS without the traditional symptomatology so it is important to take a presentation of chest pain syndrome seriously and consider CAD (ECS 2019 Guidelines).

 4+2 for CVD prevention (Goyal 2020)

1. Qualitative risk assessment: Does the patient have diabetes, obesity, tobacco use disorder?
2. Quantitative risk assessment: Pooled cohort equation like the ASCVD Risk Calculator
3. Risk enhancing factors:  Consider things that are poorly represented in the risk calculators, like family history.
4. Consider checking a coronary artery calcium score (CAC score).  

Take these together and assess overall risk. Then the +2 is treatment: 

1. Healthy lifestyle
2. Escalate preventative measures for patients at higher risk- aspirin, high intensity statin 
   1. High intensity statins: atorvastatin 40–80 mg, rosuvastatin 20–40 mg, or (less commonly) simvastatin at 80 mg (Yu 2020)

Nonobstructive coronary heart disease (microvascular disease) and INCOA (ischemica with nonobstructive coronary arteries)  

Overall, CAD burden correlates  with ASCVD event risk.  We have focused a lot on the large coronary arteries, but microvascular coronary disease carries a significant risk.

These are being recognized more frequently.  Patients may have anginal symptoms, and potentially a positive stress test, but may have a normal cardiac catheterization or coronary CTA.  This does not mean they don’t have CAD, it just means the large vessels are open so revascularization does not help.  In this situation, risk factor modification is key, including treating with aspirin, statins, diet modification, addressing metabolic disease, etc.  

PET scans, cardiac MRI,  and other testing can be further testing to demonstrate microvascular dysfunction and demonstrate ischemia. 

The ISCHEMIA  trial enrolled patients with angina who had ischemia demonstrated through stress testing. Trial participants meeting those criteria who had no CT evidence of obstructive coronary artery disease were excluded (Maron 2020). The final portion of women with obstructive CAD in the ISCHEMIA trial was only 26%, supporting our understanding of the significant number of females who suffer from angina, have ischemia but do not have surgically intervenable CAD. A sample of these patients with ischemia but nonobstructive coronaries was further studied in the CIAO-ISCHEMIA trial, where 66% of participants were women, further highlighting the sex differences in presentation of obstructive CAD vs INOCA (Reynolds 2021).

Cardiac Testing

Stable Angina Treatment:

Patients with stable angina are stable.  The patients’ presentation and tempo reflect their need for treatment- if a symptom has been developing slowly over time, it is okay to take time to assess this and up-titrate medications.  Treatment of stable angina is focused on  life-prolonging treatments and symptom relief treatment (ESC 2019 Guidelines).  A patient with stable angina has clinical ASCVD, so you will be targeting  a cholesterol reduction of 50% or greater.

Life-prolonging: statins, low-dose aspirin, healthy diet, exercise, smoking cessation

Statins: Aim for a high potency or maximally tolerated statin to lower risk for acute MI.  A lipid lowering diet lowers your cholesterol by 10-15%, moderate intensity statin can lower your cholesterol 30-49%, high intensity statins lead to 50% or greater reduction (Grundy 2018).  In a patient with stable angina (clinical ASCVD) we want to aim for >50% reduction.  European guidelines (Mach 2019) suggest targeting LDL <55 or even <40 if recurrent events. Recheck lipids as soon as 4 weeks (and up to 12 weeks), per Dr. Ferraro.  His expert opinion is to consider adding ezetimibe or PSK-9 if not at goal in high-risk patients. 

In terms of blood pressure control, the ESC and ACC/AHA have numerous recommendations, in general suggestinga BP goal of < 130/80 in patients with known coronary artery disease (Fihn 2012 , Knuuti 2019)

Symptom-relieving: beta blockers, calcium channel blockers, nitrates, PCI

These agents reduce myocardial demand or improve blood flow.   Beta-blockers are great anti-anginals (goal HR 55-60) – with a grade I recommendation from the ESC, however, they have not been shown to have a mortality benefit in stable ischemic heart disease, like they have in patients post-MI or those suffering from heart failure (Knuuti 2019).

Persistent Symptoms: How to Counsel and When To Refer for PCI??

Basics: Describe the pathophysiology to your patient to help them understand the disease and interventions available, and the fact that stable disease is a slowly building process with hard, solid blockages that do not necessarily change day-to-day. However, if symptoms are suddenly changing or worsening, highlight that they are at increased risk and educate them about when to call their physician or go to the emergency department.  

Exercise Counseling:  In stable ischemic disease, a patient is unlikely to develop ventricular fibrillation unless there is previous MI with scarring. You may encourage them to exercise vigorously. If they start feeling pain, Dr. Ambinder does not recommend pushing through the pain. Try cardiac rehabilitation exercise if the patient is very anxious.

PCI? 

This is a controversial area and there are varying practices.  If patients have been maximized on their anti-anginal therapies, they may benefit from revascularization. Percutaneous Coronary Intervention (PCI) shows no clear benefit on mortality  in patients with stable ischemia (COURAGE Trial 2007).  Stable CAD treated with optimal medical therapy +/- PCI showed no difference in outcomes (ORBITA trial). The ISCHEMIA trial looked at  patients with moderate to severe ischemia on stress testing, then they were evaluated for obstructive CAD with a coronary CTA.  Patients with non-obstructive disease and those with what were considered high risk proximal lesions were excluded from the trial.   The study question was: Do these patients benefit from the addition of PCI to optimal medical therapy? Outcomes showed no mortality benefit at 3.3 year follow up, showing us that PCI is not life-prolonging and we can (and should!) optimize medications first.  Lastly, a  substudy by Spertus 2020 while once again, showed no benefit in mortality, did show that in patients with frequent angina, PCI improved symptoms. Whether this is physiologically driven or placebo driven is anyone’s guess!

Take home points:

1. Treat the whole patient, not the lesion. Think about risk modification and listen to your patients. 
2. “Context is the enemy of a good narrative” – listen to the story, consider risk factors, and use all the tools you have available (cognitive tools, labs, imaging, etc.) to determine what (if any) testing a patient needs.
3. Medical management is equivalent to medical management plus angioplasty for morbidity/mortality in stable angina.  
4. Aspirin, statin therapy, and lifestyle/dietary modification are key. 

Links*

1. Planet Money
2. Goodnight Moon by Margaret Wise Brown 
3. Check out Cardionerds episode 98 to dive deep into the data behind the ACC/AHA pooled cohort calculator.
4. 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes 
5. Here’s a nice graphic for the 4+2 model by Dr Amit Goyal
6. Read more at our guest Dr Rick Ferraro’s Nov 2020 paper Evaluation and Management of Patients With Stable Angina: Beyond the Ischemia Paradigm: JACC State-of-the-Art Review

*The Curbsiders participates in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising commissions by linking to Amazon. Simply put, if you click on our Amazon.com links and buy something we earn a (very) small commission, yet you don’t pay any extra.

Goal

Listeners will understand the workup and management of stable coronary artery disease/stable ischemic heart disease.

Learning objectives

1. Define stable coronary heart disease (CHD) and stable angina, and compare this to unstable disease
2. Develop an approach to the workup and management of stable angina
   1. Risk factor modification with optimal medical therapy
   2. Non-invasive testing
      1. When to pursue non-invasive testing
      2. Which type of test- CT coronary angiography vs. stress test
   3. Invasive testing and/or revascularization
3. Recognize updated evidence (ISCHEMIA trial) supporting optimal medical therapy over revascularization for the treatment of stable CHD

Disclosures

Drs. Daniel Ambinder and Rick Ferraro report no relevant financial disclosures. The Curbsiders report no relevant financial disclosures. 

Citation

Heublein M, Ambinder D, Ferraro F, Askin C, Williams PN. “#279 Dominate Stable Angina with the CardioNerds”. The Curbsiders Internal Medicine Podcast. http://thecurbsiders.com/episode-list Final publishing date June 14, 2021.