chronic%20stable%20angina
CHRONIC STABLE ANGINA
Chronic stable angina is a clinical syndrome characterized by squeezing, heaviness or pressure discomfort in the chest, neck, jaw, shoulder, back, or arms which is usually precipitated by exertion or emotional stress and relieved by rest or Nitroglycerin.
It is caused by myocardial ischemia that is commonly associated with narrowing of the coronary arteries.
Angina is stable when it is not a new symptom and when there is no deterioration in frequency, duration or severity of episodes.

Diagnosis

  • Clinical examination is the key first step in the evaluation of a patient with chest pain

Classification

Clinical Classification of Chest Pain
  • Typical angina (definite)
    • Has substernal chest discomfort with a characteristic quality and duration provoked by exertion or emotional stress and relieved by rest or Nitroglycerin within minutes
  • Atypical angina (probable) has two of the characteristics of typical angina
  • Non-cardiac/anginal chest pain only has one or none of the characteristics of typical angina
Classification of Angina Severity
  • Helps determine the functional impairment, response to therapy, and prognosis of the patient
    • Eg Canadian Cardiovascular Society Classification, Duke Specific Activity Index, and Seattle Angina Questionnaire

Canadian Cardiovascular Society Angina Classification

Class

Level of Symptoms

Class I

  • Ordinary activity does not cause angina
  • Angina due to strenuous, rapid, or prolonged exertion only

Class II

  • Slight limitation of ordinary activity
  • Angina when walking or climbing stairs rapidly, walking uphill or exertion after meals, when under emotional stress, in cold or windy weather, or during the first few hours after waking up
  • Angina when walking >2 blocks on the same level and climbing >1 flight of stairs at a normal pace under normal conditions

Class III

  • Marked limitation of ordinary physical activity
  • Angina when walking 1 or 2 blocks on the same level or 1 flight of stairs at a normal pace under normal conditions

Class IV

  • Unable to carry out any physical activity without discomfort or angina at rest

Modified from: Montalescot G, Sechtem U, Achenbach S, et al. 2013 ESC guidelines on the management of stable coronary artery disease: the Task Force on the management of stable coronary artery disease of the European Society of Cardiology. Eur Heart J. 2013 Oct;34(38):2949-3003.

History

  • Thorough history is the cornerstone of the diagnosis of angina pectoris
  • In many cases, it is possible to make a diagnosis based on the history of chest pain alone but physical exam and diagnostic tests are necessary to confirm the diagnosis, determine the cause, and assess the severity of the underlying disease

Physical Examination

  • It is usually normal or nonspecific in stable angina patients
  • Exam during or immediately after an episode of pain may be beneficial since S4 or S3 heart sound or gallop, mitral regurgitation murmur, paradoxically split S2, basilar rales, or chest wall heave that dissipates when pain decreases are all predictive of ischemic heart disease (IHD)
  • Careful cardiovascular (CV) exam may reveal other related conditions such as heart failure, valvular heart disease, or hypertrophic cardiomyopathy
  • Audible rub suggests pericardial or pleural disease
  • Presence of carotid bruit, renal artery bruit, diminished pedal pulse, or palpable abdominal aneurysm are evidences of vascular disease
  • Elevated blood pressure (BP), xanthomas, and retinal exudates are signs which suggest the presence of IHD risk factors
  • Chest pain elicited by pressure on the chest wall can be caused by musculoskeletal syndromes but does not eliminate the possibility of angina due to IHD
  • Body mass index (BMI), waist circumference and waist-to-hip ratio should also be taken to determine possible metabolic syndrome, non-coronary vascular disease, and other signs of comorbid conditions

Laboratory Tests

  • Provide information related to the possible causes of ischemia, establish cardiovascular risk factors, and determine prognosis
  • Fasting lipid profile
    • To determine the presence of dyslipidemia, establish the patient’s risk profile and help determine the need for treatment
  • Fasting blood glucose and glycated hemoglobin (HbA1c)
    •  To identify undiagnosed diabetes mellitus (DM) and establish patient’s risk profile
    •  An oral glucose tolerance test is recommended if both tests are inconclusive
  •  Complete blood count (CBC) that includes hemoglobin and white cell count
    •  To check underlying anemia and/or infection
    • For prognostic information
  •  Serum creatinine
    •  To assess renal function
  •  Cardiac enzymes (Troponins, creatine kinase)
    •  To rule out myocardial injury/necrosis
    •  Creatine kinase measurement may be decreased for patients on statin therapy with accompanying symptoms of cardiac injury
  •  Liver function tests
    •  Recommended prior to initiation of statin therapy
  •  Thyroid function test
    •  To identify other causes of ischemia

Non-invasive Cardiac Investigations

  • Imaging tests are recommended for patients with clinical pre-test probability (PTP) of 65-85%, ejection fraction of >50% without typical angina or echocardiography (ECG) abnormalities
  • Used in the assessment of angina, in diagnosis, evaluation of treatment efficacy, and risk stratification

Resting Electrocardiogram (ECG)

  • Recommended in all patients with suspected angina pectoris
  • Should be done during or immediately after an episode of chest pain to detect ST-segment changes in the presence of ischemia
  • Also used in patients without an obvious noncardiac cause of chest pain
  • Normal resting ECG is common even in patients with severe angina which does not exclude the possibility of ischemia
  • Assists in clarifying the differential diagnosis if taken in the presence of pain which can detect dynamic ST-segment changes in the presence of ischemia or by identifying features of pericardial disease
  • ECG during an episode of chest pain is useful if vasospasm is suspected
  • ECG abnormalities indicating a worse prognosis:
    • Evidence of prior myocardial infarction (MI), especially Q waves in multiple leads or an R wave in V1
    • Persistent ST-T wave inversions, particularly in leads V1 to V3
    • Left bundle branch block (LBBB), bifascicular block, second- or third-degree atrioventricular (AV) block, or ventricular tachyarrhythmia
    • Left ventricular hypertrophy

Exercise Electrocardiogram (ECG) or Electrocardiogram (ECG) Stress Test

  • Cornerstone of diagnostic testing of ischemic heart disease (IHD)
  • Preferred test to determine inducible ischemia for patients with suspected stable angina, PTP of 15-60%, and left ventricular ejection fraction (LVEF) 50%
  • Only for diagnostic confirmation in patients with an intermediate pretest probability of IHD who have an interpretable ECG and at least moderate physical functioning or no disabling comorbidity
    • Should only be done on high-risk populations for determination of prognosis
  • Should be done only after clinical examination and resting ECG under careful monitoring
  • Complications during exercise testing are few but severe arrhythmia and sudden death may occur
  • Absolute contraindications to exercise ECG are:
    • Myocardial infarction (MI) within the last 2days, cardiac arrhythmias causing symptoms or hemodynamiccompromise, symptomatic and severe aortic stenosis, hypertrophic cardiomyopathy, symptomatic heart failure,pulmonary embolism, pulmonary infarction, myocarditis, pericarditis, and acute aortic dissection
  • More sensitive and specific than resting ECG for detecting myocardial ischemia
  • Test should be standardized using nomograms taking into account age, gender, and body size
  • No diagnostic value in patients with LBBB, paced rhythm, and Wolff -Parkinson-White (WPW) syndrome
  • Normal test in patients taking anti-ischemic drugs does not rule out significant coronary disease
    • Withhold beta-blockers for 24-48 hours prior to testing to prevent false negative findings
  • In patients unable to perform adequate amount of treadmill or bicycle exercise and various types of pharmacological stress tests can be useful (eg Adenosine, Dipyridamole)
    • Selection and type of pharmacological stress will depend on individual patient factors
  • Treatment can be initiated without stress test if patient has high probability of coronary artery disease (CAD) but the test is contraindicated because of comorbidity or patient preference
  • Can be useful for prognostic stratification, to assess the efficacy of medical therapy or revascularization, or to assist prescription of exercise after control of symptoms
  • Prognostic value is increased by considering heart rate (HR) variability, predicted maximum HR, and HR recovery index

Stress Testing in Combination with Imaging

  • Most well-established stress imaging modalities that may be used with either exercise test or pharmacological stress tests are:
    • Stress echocardiography
    • Myocardial perfusion scintigraphy (single photon emission computed tomography, positron emission tomography)
    • Stress cardiac magnetic resonance
    • Others [hybrid Single-photon emission computed tomography (SPECT) and computed tomography (CT), positron emission tomography (PET) and CT, PET and Cardiac magnetic resonance imaging (CMR)]
      • Further studies are needed to prove the accuracy of hybrid techniques for coronary artery disease imaging
  • Recommended for patients within the higher range of PTP, or LVEF<50% without typical angina, and in patients with resting ECG abnormalities, especially symptomatic patients with previous percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG)
  • Exercise imaging is preferable if possible because it allows more physiological reproduction of ischemia andassessment of symptoms
  • Pharmacological stress testing is indicated in patients who are not able to exercise adequately or may be used as an option to exercise stress tests
    • Two approaches are used:
      • Infusion of short-acting sympathomimetic drugs (eg. Dobutamine) in an incremental dose which increases myocardial oxygen consumption and mimics the effect of physical exercise
      • Infusion of coronary vasodilators (eg Adenosine and Dipyridamole) which provide a contrast between regionssupplied by non-diseased coronary arteries where perfusion increases and regions supplied by significant stenotic coronary arteries where perfusion will increase less or even decrease (steal phenomenon)
  • Advantages of stress imaging over conventional exercise ECG testing:
    • Superior diagnostic performance for detecting obstructive coronary disease
    • Ability to quantify and localize ischemic areas
    • Ability to provide diagnostic information if there are resting ECG abnormalities or the patients are unable to exercise
    • Ability to establish the functional significance of lesions in patients with confirmed lesions by invasive coronary angiography
    • Ability to show myocardial viability

Imaging

Chest X-ray
  • Commonly used to evaluate patients with suspected heart disease but does not provide the exact diagnosis nor classify risk group
  • More helpful in patients with signs or symptoms of heart failure, valvular heart disease, pericardial disease, aortic dissection, aortic aneurysm, or pulmonary disease
  • Presence of cardiomegaly, pulmonary congestion, atrial enlargement, and cardiac calcifications has been related to poor outcome
If patient has low probability of ischemic heart disease (IHD), then appropriate diagnostic tests should focus on noncardiac causes of chest pain

Resting Echocardiography
  • Recommended in the initial evaluation of all patients with symptoms suggestive of stable ischemic heart disease (SIHD)
  • Resting 2-dimensional and Doppler echocardiography are useful to evaluate ventricular function and detect or rule out other CV disorders (eg valvular heart disease, hypertrophic cardiomyopathy)
  • Estimation of left ventricular ejection fraction (LVEF) and left ventricular diastolic function which are very important in risk stratification
  • Not indicated for repeated use on a regular basis in patients with uncomplicated stable angina in the absence or change in clinical condition
  • Carotid artery ultrasonography may be done afterwards to assess for presence of plaque or narrowing
Computed Tomography (CT)
  • Ultra-fast or electron beam CT and multi-detector or multi-slice CT are two modalities of CT imaging that were developed to improve spatial and temporal resolution in CT
  • Recommended in patients with a low clinical pre-test probability (PTP) [15-50%] of disease, and with intermediate to high PTP with non-conclusive exercise electrocardiogram (ECG) or stress imaging test
  • Effective in detecting coronary calcium and quantifying the extent of coronary calcification
    • Calcium is deposited in atherosclerotic plaques within the coronary arteries
    • Coronary calcification increases with age
    • Extent of coronary calcification correlates more closely with the overall burden of plaque than with the location or severity of stenoses
  • Detection of coronary calcium may identify those at higher risk of significant coronary disease, but assessment of coronary calcification is not recommended routinely for the diagnostic evaluation of patients with stable angina
Cardiac Magnetic Resonance Imaging (CMR)
  • Used to define structural cardiac abnormalities and evaluate ventricular function
  • In conjunction with Dobutamine or adenosine infusion, CMR stress testing can be used to detect wall motion abnormalities or perfusion defect induced by ischemia
Ambulatory Electrocardiogram (Holter) Monitoring
  • A diagnostic monitoring option for patients suspected of having arrhythmia or vasospastic angina
Invasive Cardiac Investigation

Coronary Computed Tomography Angiography (CCTA)
  • Radiographic visualization of the coronary vessels after injection of radiopaque contrast material
  • Identifies the presence or absence of coronary lumen stenosis, provides therapeutic options (eg medical therapy or revascularization), and helps determine prognosis
  • Extent and severity of angiographic coronary artery disease (CAD) are the most important prognostic factors and essential for revascularization decision making
  • Has high sensitivity and specificity for detecting obstructive CAD
    • Sensitive to heart rate, body weight and the presence of calcification
    • A very high negative predictive value for obstructive CAD is an advantage of CCTA over standard functional testing
    •  Should not be performed in patients who are at high risk for CAD or have extensive calcification because the presence of significant calcification can preclude the accurate assessment of lesion severity or may result to a false positive study
    •  Not advisable for patients unwilling to undergo invasive procedures and revascularization, not candidates for percutaneous coronary intervention (PCI), coronary artery bypass graft (CABG), and those with low probability of recovering even after revascularization
    •  Indications for coronary angiography:
    •  Severe stable angina with a high pre-test probability of disease, particularly if the symptoms are inadequately responding to medical therapy
    •  Survivors of cardiac arrest
    •  Serious ventricular arrhythmias
    •  Previously treated by myocardial revascularization (PCI, CABG) who develop early recurrence of moderate or severe angina pectoris
    •  Inconclusive diagnosis on non-invasive testing or discordant test results from different non-invasive modalities at intermediate to high risk of coronary level
    •  High risk of restenosis after PCI if PCI has been performed in a prognostically important site
Invasive Coronary Angiography (ICA)
  • Recommended in patients with high PTP either as an initial test or after an initial noninvasive study with stress imaging or treadmill exercise test in specific clinical circumstances
  • Recommended as an initial diagnostic and prognostic test in clinically stable SIHD patients who develop signs and symptoms of heart failure despite receiving medical treatment
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