18 - Stable Coronary Artery Disease Flashcards
Describe the coronary circulation
- Right coronary artery supplies AV node; branches into right marginal branch
- SA node has its own branch, so rarely affected
- Left main artery branches into circumflex artery & left anterior descending artery
- Circumflex artery branches called obtuse marginal branches (ex: OM1, OM2, etc)
- Left anterior descending artery branches called diagonal branches (ex: D1, D2, etc.)
- Second most important artery; is this is blocked you likely die
- Posterior descending artery
Describe coronary artery disease. Symptoms and what it may result in.
- AKA coronary heart disease (CHD); once severe enough to cause ischemic heart disease
- Manifestation of atherosclerotic CV disease w/in coronary arteries
- Generally, only symptomatic w/ greater than 70% stenosis
- May result in chronic stable angina (aka stable ischemic heart disease) & most instances of acute coronary syndrome
Describe the pathophys of coronary artery disease
- Stable atherosclerotic plaques in coronary arteries cause fixed limit on blood supply causing MI due to imbalance between oxygen supply & demand
- Myocardial O2 supply determined by coronary blood flow, O2 content of blood, and O2 extraction by myocardium
- Myocardial O2 demand determined by heart rate & contractility/myocardial wall tension (heart rate can be modified, but not really contractility)
Conditions affecting myocardial O2 supply
- Coronary artery disease/spasm/dissection
- Anemia
- Hypoxemia (pneumonia, asthma, COPD, obstructive sleep apnea
- Alkalemia
Conditions affecting myocardial O2 demand
- Tachycardia
- Left ventricular hypertrophy
- Hypertension
- Aortic stenosis
- Cardiomyopathy
- Hyper/hypothermia
- Hyperthyroidism
- Cocaine/amphetamine use
- Anxiety/excitement
What is angina?
Chest pain or discomfort due to myocardial ischemia
Common characteristics of angina
- Chest pain or discomfort; sensation of pressure; discomfort unchanged w/ respiration or position
- May be radiation to arm, shoulder, neck/jaw, abdomen, or back
- Dyspnea
- Sweating
- Nausea +/- vomiting
- Dizziness, light-headedness, weakness
- Mnemonic – DDSS (dizzy, dyspneic, sweaty, sick)
- Significant variability & sx may be indistinguishable from ACS
What is the timing of angina?
- Onset & offset usually gradual
- Duration normally 1-15 minutes (stable generally lasts minutes, not seconds)
Precipitating factors of angina
- Exercise
- Hot/cold environment
- Activity after large meal
- Emotions (anger, anxiety, excitement)
- Coitus
Cause of chronic stable angina
Stable restriction in blood flow resulting in (reproducible) supply-demand mismatch
Cause and duration of unstable angina
- Unstable plaque resulting in abrupt & unpredictable change in coronary blood flow
- Duration > 20 minutes
When does unstable angina occur and what can relieve the sx?
- May occur at rest
- Not relieved by rest; may or may not respond to nitroglycerin
Class 1 angina
Occurs w/ strenuous, rapid, or prolonged exertion
Class 2 angina
- Occurs on walking or climbing stairs rapidly, on walking uphill, on walking or stair climbing after meals, in cold/wind, under emotional stress, or only during the few hours after wakening
- Angina on walking more than 2 blocks or climbing more than 1 flight of stairs
Class 3 angina
Occurs after walking 1-2 blocks or climbing 1 flight of stairs
Class 4 angina
Sx may be present at rest or w/ very little movement
Describe chest pain that is classified as typical angina
Meets 3 of the following characteristics:
- Substernal chest discomfort
- Provoked by exertion or emotional stress
- Relieved by rest and/or nitroglycerin
Describe chest pain that is classified as atypical angina
Meets 2 of the following characteristics:
- Substernal chest discomfort
- Provoked by exertion or emotional stress
- Relieved by rest and/or nitroglycerin
Describe chest pain that is classified as non-anginal chest pain
Meets 1 or none of the following characteristics:
- Substernal chest discomfort
- Provoked by exertion or emotional stress
- Relieved by rest and/or nitroglycerin
What are some non-invasive diagnostic tests for angina?
- Stress tests
- Increase myocardial O2 consumption and observe for ischemic ECG changes
Types of stress tests for angina
- Graded exercise stress test
- Pharm stress tests (adenosine, dipyridamole, or dobutamine)
What percent of people w/ angina will demonstrate ECG changes after their myocardial O2 consumption is increased?
~50%
What is an invasive test used for angina? Describe it
Coronary angiography
- Gold standard for diagnosing coronary artery disease
- Access via radial artery (previously femoral)
- Catheter advanced to coronary circulation, radio-opaque dye injected & flow observed under fluoroscope
- Indicated for px deemed to be high-risk
Goals of therapy for angina
- Relieve acute angina sx
- Prevent recurrent angina sx
- Maintain/improve activity level & QOL
- Reduce risk of CV complications
- Improve survival
What do beta blockers do?
Reduce myocardial O2 demand (decrease HR, decrease myocardial contractility, & decrease intramyocardial wall tension via decreasing BP)
Beta-blockers are first line for ___ angina
Chronic stable angina
What can beta-blockers be combined w/ for angina tx?
Nitrates and DHP CCBs
Which beta-blockers should be used in asthma, PAD, diabetes, and sexual dysfunction?
Cardio-selective agents
What can happen to angina sx w/ abrupt withdrawal of beta-blockers or CCBs? What can be done to avoid this?
- May induce ischemia, leading to increased severity and # of pain episodes
- May precipitate arrhythmia
- Taper gradually, ex: over 2 weeks
Adverse effects of beta-blockers
- Hypotension, dizziness
- Bradycardia (only worried if symptomatic)
- Fatigue
- Bronchospasm
- Cold extremities
- Erectile dysfunction (rare)
Beta 1 (cardio) selective agents
- Atenolol
- Bisoprolol (most beta 1 selective)
- Metoprolol
Non-selective beta-blockers
- Nadolol
- Propranolol
Non-selective alpha and beta blockers
- Carvedilol
- Labetalol
Cardio-selective and nitric oxide-mediated vasodilating beta blockers
Nebivolol (most beta 1 selective, but not beneficial so never used)
What do non-DHP CCBs do?
- Reduce cardiac O2 demand by decreasing HR, myocardial contractility, and myocardial wall tension (via decreasing BP)
- Increase myocardial O2 supply by vasodilating coronary arteries and preventing vasospasms
What do DHP CCBs do?
- Reduce cardiac O2 demand by decreasing myocardial wall tension (via decreasing BP)
- Increase myocardial O2 supply by vasodilating coronary arteries and preventing vasospasms
Are CCBs more or less effective than beta blockers at preventing angina?
Same efficacy
Which drugs are DHP CCBs?
- Amlodipine
- Felodipine
- Nifedipine
Do DHP or non-DHP CCBs have more arterial vasodilation?
DHP
Do DHP or non-DHP CCBs have effect on myocardial contractility?
Non-DHP; have significant inotropic effects
Do DHP or non-DHP CCBs have effect on SA or AV nodal condution?
Non-DHP; significantly reduce conduction (verapamil > diltiazem)
Which drugs are non-DHP CCBs?
- Diltiazem
- Verapamil
Adverse effects of CCBs
- Hypotension, dizziness
- Flushing
- Headache
- Peripheral edema
- Non-DHP specific
- > bradycardia, constipation, heart failure exacerbation (avoid in heart failure reduced ejection fraction)
How do nitrates work?
- Reduce myocardial O2 demand (decrease myocardial wall tension by decreased preload w/ venodilation & decreasing BP w/ arterial dilation)
- Increase myocardial O2 supply (increase coronary blood flow)
What effect do nitrates have on long-term survival?
No effect
How long do the effects of long-acting nitrates last?
Approx. half a day
Long-acting nitrates are ___ line for controlling angina sx
3rd line (after BB and CCBs)
Long-acting nitrates are generally used in combination w/ ____
BB or CCB
Adverse effects of nitrates
- Headache
- Flushing
- Hypotension
- Rash (w/ patch)
What should nitrates never be combined w/ and why?
- Phosphodiesterase-5-inhibitors
- Massive drop in BP
- No nitrate w/in 24 h of sildenafil/vardenafil, w/in 48 h of tadalafil
Examples of rapid acting nitrates
- Nitroglycerin spray
- Nitroglycerin tablet
Examples of long acting nitrates
- Isosorbide dinitrate
- Isosorbide-5-mononitrate
- Nitroglycerin patch
Rapid-acting nitroglycerin pt education
- If you experience chest pain or discomfort, stop what you’re doing & sit or lie down
- Place 1 tablet or give 1 spray under the tongue & leave it there
- If pain/discomfort not relieved after 5 mins, repeat dose
- If pain/discomfort continues after 2 doses (10 mins), use a third dose & immediately call 911
- Carry a supply of nitroglycerin w/ you at all times
- May experience headache or dizziness
Ranolazine
- Available through special access program only
- MOA unknown; doesn’t affect HR or BP
- Adjunctive tx to BB, CCB, and/or long-acting nitrates
- Indicated for px w/ chronic stable angina unresponsive or intolerant to standard anti-anginal therapy
- Doesn’t improve outcomes
Lifestyle modification for secondary prevention of angina
- Smoking cessation
- Physical activity & weight management
- 30-60 mins moderate intensity aerobic activity at least 5 (preferably 7) days/week
- Resistance training at least 2 days/week
- Dietary optimization (controlled caloric intake)
Antiplatelets for secondary prevention of angina
- Single antiplatelet therapy (ASA 81-325 mg daily or clopidogrel 75 mg daily)
- Long-term DAPT in absence of acute coronary syndrome or other indication NOT appropriate
Statins for secondary prevention of angina
- Reduced risk of atherosclerosis-associated acute events & death
- Moderate-to-high dose statin indicated in all px w/ clinical atherosclerosis
- In practice, ignore targets & use maximally tolerated dose
- Preferred = atorvastatin 40-80 mg daily or rosuvastatin 20-40 mg daily
Omega-3 fatty acids for secondary prevention of angina
- Low doses don’t appear to have benefit (ASCEND trial in moderate CV risk diabetic px)
- REDUCE-IT trial
- High-risk population
- 4 g/day EPA reduced incidence of major adverse CV event by ~25% over 4.9 years
- Px also on statin
ACE inhibitors for secondary prevention of angina
- Not proven to improve symptomatic ischemia
- Ramipril & perindopril proven to reduce risk of CV death, non-fatal MI, & non-fatal stroke (Ramipril) or cardiac arrest (perindopril)
- Indicated if concomitant HTN, prior MI, LV dysfunction, diabetes, chronic kidney disease
ARBs for secondary prevention of angina
- Mechanism similar to ACE inhibitors
- ONTARGET trial – telmisartan 80 mg daily vs. Ramipril 10 mg daily => telmisartan non-inferior to Ramipril
- Recommended for px at high-risk of CV events who are intolerant to ACE inhibitors
