cardiovascular disorders
Angina Pectoris
Diagnosis of Angina Pectoris
Typical symptoms Electrocardiography (ECG) Stress testing with ECG or imaging (using echocardiography, radionuclide imaging, positron emission tomography [PET], or MRI) CT angiography or CT fractional flow reserve (CT FFR) Coronary angiography for significant symptoms, positive stress test, or significant lesions noted on CT FFR. Diagnosis of angina is suspected if chest discomfort is typical and is precipitated by exertion and relieved by rest. Presence in the history of significant risk factors for Risk Factors (CAD) adds weight to reported symptoms. Patients whose chest discomfort lasts Chest Pain may also be caused by gastrointestinal disorders (eg, ECG is always done. More specific tests include stress testing with ECG or with myocardial imaging (eg, echocardiography, radionuclide imaging, PET, MRI) and coronary angiography. Noninvasive tests are considered first. If typical exertional symptoms are present, Electrocardiography is indicated. Because angina resolves quickly with rest, ECG rarely can be done during an attack except during stress testing. If doneduring an angina attack,ECG is likely to show reversible ischemic changes: T wave discordant to the QRS vector ST-segment depression (typically) ST-segment elevation Decreased R-wave height Intraventricular or bundle branch conduction disturbances Arrhythmia (usually ventricular extrasystoles) Between angina attacks,the ECG (and usually LV function) at rest is normal in about 30% of patients with a typical history of angina pectoris, even those with extensive 3-vessel disease. In the remaining 70%, the ECG shows evidence of previous infarction, hypertrophy, or nonspecific ST-segment and T-wave (ST-T) abnormalities. An abnormal resting ECG alone does not establish or refute the diagnosis. Stress Testing is needed to Confirm the diagnosis Evaluate disease severity Determine appropriate exercise levels for the patient Help predict prognosis If the clinical or working diagnosis is unstable angina, early stress testing is contraindicated. Exercise stress testing with ECGis done if a patient has a normal resting ECG and can exercise. In men with chest discomfort suggesting angina, stress ECG testing has a specificity of 70%; sensitivity is 90%. Sensitivity is similar in women, but specificity is lower, particularly in women<55 (<70%). However, women are more likely than men to have an abnormal resting ECG when CAD is present (32% vs 23%). Although sensitivity is reasonably high, exercise ECG can miss severe CAD (even left main or 3-vessel disease). In patients with atypical symptoms, a negative stress ECG usually rules out angina pectoris and CAD; a positive result may or may not represent coronary ischemia and indicates need for further testing. Stress testing with myocardial imagingis done when the resting ECG is abnormal because false-positive ST-segment shifts are common on the stress ECG. Exercise or pharmacologic stress (eg, withdobutamineordipyridamoleinfusion) may be used. Imaging options include stress echocardiography, myocardial perfusion imaging with single-photon emission CT (SPECT) or PET, and stress MRI. The choice of imaging technique depends on institutional availability and expertise. Imaging tests can help assess LV function and response to stress; identify areas of ischemia, infarction, and viable tissue; and determine the site and extent of myocardium at risk. Stress echocardiography can also detect ischemia-induced mitral regurgitation. Angiography None Intravascular ultrasonographyprovides images of coronary artery structure. An ultrasound probe on the tip of a catheter is inserted in the coronary arteries during angiography. This test can provide more information about coronary anatomy than other tests; it is indicated when the nature of lesions is unclear or when apparent disease severity does not match symptom severity. Used with angioplasty, it can help ensure optimal placement of stents. Guidewires with pressure or flow sensorscan be used to estimate blood flow across stenoses. Blood flow is expressed as fractional flow reserve (FFR), which is the ratio of maximal flow through the stenotic area to normal maximal flow. These flow measurements are most useful when evaluating the need for angioplasty or CABG in patients with lesions of questionable severity (40 to 70% stenosis). An FFR of 1.0 is considered normal, while an FFR < 0.75 to 0.8 is associated with myocardial ischemia. Lesions with an FFR > 0.8 are less likely to benefit from stent placement. Imaging studies done at rest can evaluate the coronary arteries. can detect the amount of calcium present in coronary artery plaque. The calcium score is roughly proportional to the risk of subsequent coronary events. However, because calcium may be present in the absence of significant stenosis, the score does not correlate well with the need for angioplasty or CABG. Thus, the American Heart Association recommends that screening with electron beam CT should be done only for select groups of patients and is most valuable when combined with historical and clinical data to estimate risk of death or nonfatal myocardial infarction ( Diagnosis references ). These groups may include asymptomatic patients with an intermediate 10-year atherosclerotic cardiovascular disease (ASCVD) risk estimate (10 to 20%) and symptomatic patients with equivocal stress test results. Electron beam CT is particularly useful in ruling out significant CAD in patients presenting to the emergency department with atypical symptoms, normal troponin levels, and a low probability of hemodynamically significant coronary artery disease. These patients may have noninvasive testing as outpatients. can accurately identify coronary stenosis and has a number of advantages. The test is noninvasive, can exclude coronary stenosis with high accuracy, can establish stent or bypass graft patency, can show cardiac and coronary venous anatomy, and can assess calcified and noncalcified plaque burden. Estimation of the fractional flow reserve (FFR) across significant lesions and estimation of lesion-specific ischemia are also possible ( Diagnosis references ). However, radiation exposure is significant, and the test is not suitable for patients with a heart rate of Evolving indications for MDRCT coronary angiography include Asymptomatic high-risk patients or patients with atypical or typical angina who have inconclusive exercise stress test results, cannot undergo exercise stress testing, or need to undergo major noncardiac surgery Patients in whom invasive coronary angiography was unable to locate a major coronary artery or graft Cardiac MRIis invaluable in evaluating many cardiac and great vessel abnormalities. It may be used to evaluate CAD by several techniques, which enable direct visualization of coronary stenosis, assessment of flow in the coronary arteries, evaluation of myocardial perfusion and metabolism, evaluation of wall motion abnormalities during stress, and assessment of infarcted myocardium vs viable myocardium. Indications for cardiac MRI include evaluation of cardiac structure and function and assessment of myocardial viability. Cardiac MRI, specifically stress perfusion MRI and quantitative myocardial blood flow analysis, may also be indicated for diagnosis and risk assessment in patients with either known or suspected CAD. 1.Taylor AJ, Cerqueira M, Hodgson J McB, et al: ACCF/SCCT/ACR/AHA/ASE/ASNC/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography.J Am Coll Cardiol56: 1864–1894, 2010. doi: 10.1016/j.jacc.2010.07.005 2.Gulati M, Levy PD, Mukherjee D, et al: 2021 AHA/ACC Guideline for Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.Circulation144:e368–e454, 2021. https://www.ahajournals.org/doi/epdf/10.1161/CIR.0000000000001029 