> Table of Contents > Coronary Artery Disease and Stable Angina
Coronary Artery Disease and Stable Angina
Melody L. Strattan, DO
Merrill Krolick, DO, FACC, FACP, FSCAI
image BASICS
DESCRIPTION
  • Coronary artery disease (CAD) refers to the atherosclerotic narrowing of the epicardial coronary arteries. It may manifest insidiously as angina pectoris or as an acute coronary syndrome (ACS).
  • Stable angina is a chest discomfort due to myocardial ischemia that occurs predictably at a certain level of exertion or emotional stress.
  • The spectrum of ACS includes unstable angina (UA), non-ST segment elevation myocardial infarction (NSTEMI), and ST elevation myocardial infarction (STEMI). See separate chapters on these ACS.
  • Definitions
    • Typical angina: exhibits three classical characteristics: (i) substernal chest tightness, pressure, or heaviness that frequently radiates to the jaw, back, or arms and generally lasts from 2 to 15 minutes; (ii) occurs in a consistent pattern at a certain level of myocardial oxygen demand from exertion, emotional stress, or increased sympathetic tone; and (iii) relieved with rest or sublingual nitroglycerin.
    • Atypical angina: exhibits two of the above typical characteristics
    • Noncardiac chest pain: exhibits ≤1 of the above typical characteristics
    • Anginal equivalent: Patients may present without chest discomfort but with nonspecific symptoms such as dyspnea, diaphoresis, fatigue, belching, nausea, light-headedness, or indigestion that occur with exertion or stress.
    • Unstable angina: anginal symptoms that are new or changed in character to become more frequent, more severe, or both; it is considered an ACS but does not present with cardiac biomarker elevation.
    • NSTEMI: Presents with cardiac biomarker elevation. Ischemic ECG changes may be present, but there is no ST segment elevation.
    • STEMI: defined by ST elevations on ECG and elevated cardiac biomarkers; generally caused by acute plaque rupture and complete obstruction of the culprit vessel
  • Canadian Cardiovascular Society grading scale:
    • Class I: Angina does not limit ordinary physical activity, occurring only with strenuous or prolonged exertion (7 to 8 METs).
    • Class II: Angina causes slight limitation of ordinary activity. It occurs when walking rapidly, uphill, or >2 blocks; climbing >1 flight of stairs; or with emotional stress (5 to 6 METs).
    • Class III: Angina causes marked limitation of ordinary physical activity. It occurs when walking one to two blocks or climbing one flight of stairs (3 to 4 METs).
    • Class IV: Angina occurs with any physical activity and may occur at rest (1 to 2 METs).
Geriatric Considerations
  • Elderly may present with atypical symptoms.
  • Other physical limitations may delay recognition of angina until it occurs with minimal exertion or at rest.
  • Maintain a high degree of suspicion during evaluation of dyspnea and other nonspecific complaints.
  • Geriatric patients may be very sensitive to the side effects of medications used to treat angina.
EPIDEMIOLOGY
  • CAD is the leading cause of death for adults both in the United States and worldwide.
  • CAD is responsible for about 30% of all deaths, averaging 1 death every 40 seconds in the United States alone.
  • Global cost of CAD in 2010 $863 billion
  • ˜80% of CAD is preventable with healthy lifestyle.
Incidence
In the United States, the lifetime risk of a 40-year-old developing CAD is 49% for men and 32% for women.
Prevalence
In the United States, 17.6 million people carry a diagnosis of CAD, 10.2 million with angina pectoris (1).
ETIOLOGY AND PATHOPHYSIOLOGY
  • Anginal symptoms occur during times of myocardial ischemia caused by a mismatch between coronary perfusion and myocardial oxygen demand.
  • Atherosclerotic narrowing of the coronary arteries is the most common etiology of angina, but it may also occur in those with significant aortic stenosis, pulmonary hypertension, hypertrophic cardiomyopathy, coronary spasm, or volume overload.
  • Sensory nerves from the heart enter the spinal cord at levels C7-T4, causing diffuse referred pain/discomfort in the associated dermatomes.
RISK FACTORS
  • Traditional risk factors: hypertension, ↓HDL, smoking, diabetes, premature CAD in 1st-degree relatives (men <55 years old; women <65 years old), age (>45 for men, >55 for women)
  • Nontraditional risk factors: obesity, sedentary lifestyle, abnormal ankle-brachial indices, renal disease
GENERAL PREVENTION
  • Smoking cessation
  • Regular aerobic exercise program
  • Weight loss for obese patients (goal BMI <25 kg/m2)
  • BP control (goal <140/90 mm Hg; <150/90 mm Hg for those ≥60 years old) (2)
  • Diabetes management
  • Lipid-lowering therapy (statins) for those with diabetes, known CAD, and for 10-year risk ≥7.5%
  • Low-dose aspirin may be considered in those with 10-year risk ≥10%.
COMMONLY ASSOCIATED CONDITIONS
Hyperlipidemia, peripheral vascular disease, cerebrovascular disease, hypertension, obesity, diabetes
image DIAGNOSIS
PHYSICAL EXAM
  • Normal physical exam does not exclude the diagnosis of angina or CAD.
  • Cardiac exam may reveal dysrhythmias, heart murmurs indicative of valvular disease, gallops, or signs of congestive heart failure.
  • Evidence of peripheral vascular disease (diminished pulses, bruits, abdominal aortic aneurysm [AAA])
DIFFERENTIAL DIAGNOSIS
  • Vascular: aortic dissection, pericarditis, myocarditis, myocardial infarction
  • Pulmonary: pleuritis, pulmonary embolism, pneumothorax
  • Gastroesophageal: gastric reflux, esophageal spasm, peptic ulcer
  • Musculoskeletal: costochondritis, arthritis, muscle strain, rib fracture
  • Other: anxiety, psychosomatic, cocaine abuse
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
  • Serial cardiac troponin to rule out myocardial infarction (MI)
  • CBC to evaluate for anemia, infectious cause (1)[C]
  • Fasting lipid profile (1)[C]
  • Fasting glucose or hemoglobin A1C (1)[C]
  • Basic metabolic panel to rule out electrolyte abnormalities and assess renal function.
  • ECG
    • Should be routinely obtained unless there is a noncardiac cause of the chest pain (1)[C]
    • Frequently unremarkable between angina episodes; may show signs of myocardial ischemia during symptomatic episodes, evidence of old MI
    • Left bundle branch block or ventricular pacing makes interpretation unreliable.
  • Chest x-ray may exclude other causes of pain (1)[C].
Follow-Up Tests & Special Considerations
  • Goal is to detect possible high-risk coronary lesions, where intervention would improve long-term mortality or alleviate anginal symptoms.
  • Stress testing is most helpful for patients at intermediate risk of heart disease.
    • Exercise testing for those who can physically exercise (≥5 metabolic equivalents [METS]) (1)[A]
      • Standard exercise ECG for those with normal baseline ECG
      • Exercise stress testing with echo or perfusion imaging for those with abnormal baseline ECG or in premenopausal women
    • In patients who cannot tolerate exercise, consider pharmacologic stress testing (1)[A].
  • Echocardiogram should be obtained in patients with a new or loud (≥III/VI) murmur, evidence of myocardial infarction, symptoms of heart failure, concern for hypertrophic cardiomyopathy or pericardial effusion, and in those with new arrhythmias (1)[A].
  • Echocardiogram can be considered in patients with hypertension or diabetes and abnormal ECG (1)[A].
  • CT coronary angiography or MRI angiography can be alternative to stress testing in patients with continued symptoms despite negative or inconclusive stress testing for anatomic definition of disease.
P.235

Diagnostic Procedures/Other
  • Cardiac catheterization with coronary angiography is the gold standard for confirmation and delineation of coronary disease and direction of interventional therapy or surgery.
  • Significant CAD is defined as ≥50% stenosis of the left main coronary artery or ≥70% stenosis of other major coronary arteries by angiography.
  • Borderline lesions may be assessed with a pressure wire. Fractional flow reserve (FFR) of ≤0.8 demonstrates a hemodynamically significant lesion.
image TREATMENT
GENERAL MEASURES
  • BP control goal: <140/90 mm Hg for most, except in elderly (2)[A]
  • Smoking cessation goal: complete cessation, no exposure to secondhand smoke or E-cigarettes
  • Physical activity goal: 30 to 60 minutes of moderate aerobic activity, at least 5 (preferably 7) days/week
  • Weight management goal: BMI 18.5 to 24.9 kg/m2; waist circumference <35 inches (women) or <40 inches (men)
  • Glycemic control in diabetics: Goal is strict glucose control while avoiding hypoglycemic episodes.
MEDICATION
First Line
  • &bgr;-Blockers: decrease myocardial oxygen demand by lowering heart rate, BP, and contractility.
    • Improve mortality in patients with MI or heart failure; use as initial therapy (1)[A]
    • Can improve symptoms of angina
    • Metoprolol (25 to 400 mg daily [succinate] or divided BID [tartrate]) or carvedilol (3.125 to 25 mg BID). Adjust doses according to clinical response. Maintain resting heart rate 50 to 60 bpm.
    • Side effects bradycardia, fatigue, sexual dysfunction
  • Calcium channel blockers (CCBs): cause arterial vasodilation, decreased myocardial oxygen demand, and improved coronary blood flow. Similar effectiveness to &bgr;-blockers; may be used instead of, or in addition to &bgr;-blockers (1)[A]. Only long-acting CCBs should be used:
    • Dihydropyridine CCBs: nifedipine (30 to 90 mg/day), amlodipine (5 to 10 mg/day), or felodipine (2.5 to 10 mg/day): vasodilators
    • Nondihydropyridine CCBs such as diltiazem (120 to 480 mg/day) or verapamil (120 to 480 mg/day) also have negative inotropic effects; should not be used in those with EF <40%. Side effects include constipation and peripheral edema. The nondihydropyridine CCBs may also cause bradycardia or precipitate heart failure in those with severe systolic dysfunction (ejection fraction <40%).
  • Nitrates: Dilate systemic veins and arteries (including coronary vessels) and cause decreased preload. At higher doses, they decrease BP and thus, after-load, increasing myocardial flow.
    • Sublingual nitroglycerin 0.4 mg every 5 minutes for 2 to 3 doses may be used for acute anginal episodes (1)[A].
    • Long-acting nitrates such as isosorbide mononitrate (30 to 240 mg daily [extended release]) can be used for angina prophylaxis.
    • Side effects include headache and hypotension, but tend to improve with continued usage.
  • Lipid-lowering agents:
    • High-intensity statin therapy is indicated for all patients with CAD regardless of lipid levels (3)[A].
    • Statin therapy should also be encouraged for those with high CAD risk.
    • Atorvastatin (10 to 80 mg/day) and rosuvastatin (5 to 40 mg/day) are high-intensity statins.
    • Statins reduce risk of MI & revascularization need.
    • Side effects include myalgias, transaminitis, rhabdomyolysis (rare), impaired glucose tolerance.
  • Aspirin: Decreases risk of thrombosis by inhibiting cyclo-oxygenase and thromboxane.
    • Aspirin (75 to 162 mg/day) decreases risk of first MI and reduces adverse cardiovascular events in those with stable angina (1)[A].
    • Clopidogrel (75 mg/day) may be used in patients with contraindications to aspirin (1)[A].
    • Dual antiplatelet therapy with aspirin + clopidogrel, prasugrel, or ticagrelor is indicated after percutaneous coronary intervention.
  • Angiotensin-converting enzyme inhibitors (ACEIs): act on the renin-angiotensin-aldosterone system to reduce BP and afterload. They also have effects on cardiac remodeling after MI.
    • ACEIs such as lisinopril (5 to 40 mg/day) and enalapril (2.5 to 20 mg BID) have been shown to reduce both cardiovascular death and MI in patients with CAD and left ventricular systolic dysfunction (1)[A].
    • Angiotensin receptor blockers such as candesartan (4 to 32 mg daily) may be used in patients intolerant to ACEIs.
    • Side effects include cough (ACEIs only), hyperkalemia, and angioedema.
Second Line
Ranolazine (500 to 1000 mg BID) decreases calcium overload in myocytes, acting as an antianginal/anti-ischemic agent.
  • Does not affect heart rate or BP
  • Use as adjunctive therapy when symptoms persist despite optimal doses of other antianginals
  • Side effects can include nausea, constipation, dizziness, QT prolongation, and headache.
SURGERY/OTHER PROCEDURES
  • Revascularization should be considered when noninvasive testing suggests a high-risk lesion. It can also be performed if optimal medical therapy is inadequate to control symptoms.
  • Percutaneous coronary intervention (PCI) with balloon angioplasty and/or stent placement (with drug-eluting or bare-metal stent) is performed for significant lesions. Additional techniques include laser therapy and atherectomy.
  • PCI does not decrease mortality or risk of MI vs. with medical management with stable angina.
  • Coronary artery bypass graft (CABG) is preferred over PCI for those with severe left main coronary stenosis, significant lesions in ≥3 major coronary arteries, and for lesions not amenable to PCI.
COMPLEMENTARY & ALTERNATIVE MEDICINE
Relaxation/stress reduction therapy for angina
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
Inpatient evaluation of patients with changes in anginal symptoms representing unstable angina (an ACS)
Discharge Criteria
Without myonecrosis, discharge after appropriate risk stratification.
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
  • Lifestyle modifications should be aggressively stressed at every visit.
  • Patients should be followed clinically; routine stress testing is not necessary for asymptomatic patients.
Patient Monitoring
Frequent follow-up after initial event: every 4 to 6 months in 1st year, then 1 to 2 times per year
DIET
  • Reduced intake of trans-fatty acids (1)[C]
  • Adherence to dietary modification for comorbid conditions (diabetes, heart failure, hypertension)
PROGNOSIS
Variable; depends on severity of symptoms, extent of CAD, and left ventricular function
REFERENCES
1. Fihn SD, Gardin JM, Abrams J, et al. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease. J Am Coll Cardiol. 2012;60(24):e44-e164.
2. James PA, Oparil S, Carter BL, et al. 2014 Evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311(5):507-520.
3. Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults. Circulation. 2014;129(25 Suppl 2): S1-S45.
See Also
&NA;
Algorithm: Chest Pain/Acute Coronary Syndrome
Codes
&NA;
ICD10
  • I25.119 Athscl heart disease of native cor art w unsp ang pctrs
  • I25.118 Athscl heart disease of native cor art w oth ang pctrs
  • I20.9 Angina pectoris, unspecified
Clinical Pearls
&NA;
  • Maximize antianginal therapy: Combine &bgr;-blockers, CCBs, and nitrates as tolerated.
  • Lifestyle changes and optimal medical therapy must be emphasized to prevent progression of atherosclerosis and to control contributing risk factors.