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Excluding heart disease in the patient with chest pain
1Eisenhower Medical Center, Rancho Mirage, California.
Insights
Angina pectoris, a chest discomfort from myocardial ischemia, is diagnosed using various tests. Positron emission tomography (PET) scanning offers high accuracy for detecting coronary artery disease and assessing its functional significance.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Internal Medicine
Background:
- Angina pectoris results from myocardial ischemia when coronary blood flow is insufficient to meet demand.
- This imbalance leads to lactate accumulation, ventricular dysfunction, and characteristic chest discomfort.
- Clinical presentation involves midanterior chest pressure, triggered by exertion or stress, relieved by rest or nitroglycerin.
Purpose of the Study:
- To review diagnostic modalities for assessing myocardial ischemia and angina pectoris.
- To evaluate the accuracy and utility of various diagnostic tests, including exercise testing, imaging, and angiography.
- To highlight the role of Positron Emission Tomography (PET) scanning in diagnosing and assessing coronary artery disease.
Main Methods:
- Review of diagnostic studies for myocardial ischemia: treadmill exercise testing, Holter monitoring, coronary angiography.
- Comparison of imaging techniques: thallium-201 scintigraphy, exercise echocardiography, and PET scanning.
- Inclusion of Doppler flow studies and quantitative angiography for assessing coronary stenosis and flow.
Main Results:
- Treadmill exercise testing alone has low accuracy; combining it with imaging improves detection rates.
- Thallium-201 scintigraphy and exercise echocardiography show moderate sensitivity and specificity in low-risk populations.
- PET scanning demonstrates high predictive accuracy (90% sensitivity, 90-95% specificity) and assesses functional significance of stenoses.
- Holter monitoring is not suitable for screening but can assess ischemic burden in known disease.
- Coronary angiography remains the gold standard for diagnosing stenoses, with Doppler studies evaluating flow reserve.
Conclusions:
- Accurate diagnosis of angina requires correlating clinical symptoms with objective findings of myocardial ischemia.
- PET scanning offers superior accuracy for screening, assessing stenosis significance, and differentiating viable from infarcted myocardium.
- A comprehensive diagnostic approach, integrating clinical evaluation with advanced imaging and angiography, is crucial for managing coronary artery disease.
Abstract:
Angina pectoris is chest discomfort associated with myocardial ischemia. When coronary blood flow is inadequate to meet myocardial tissue demand, lactate accumulates, resulting in diastolic and systolic left ventricular dysfunction. This leads to ST-segment abnormalities and eventually to angina pectoris. Angina, most commonly a pressure-type sensation in the midanterior chest precipitated by exercise, stress, or cold, typically lasts 1-5 minutes and is alleviated by rest or nitroglycerin. Diagnostic studies to assess myocardial ischemia include treadmill exercise testing, Holter monitoring, and coronary angiography. Treadmill exercise testing has a relatively low accuracy for diagnosing coronary artery disease. This can be improved by combining exercise with thallium-201 imaging, two-dimensional echocardiography, or positron emission tomography (PET). Thallium-201 scintigraphy and exercise echocardiography have reported sensitivities of 70-85% and specificities of 50-60% when applied to low-risk, asymptomatic populations. PET scanning has a high predictive accuracy (sensitivity 90%, specificity 90-95%) and is more useful as a screening test; it can also assess the functional significance of coronary artery stenoses and differentiate viable myocardium from infarcted tissue. Holter monitoring is too insensitive and nonspecific to be used as a screening test for coronary artery disease; it can, however, assess the total ischemic burden in patients with known coronary artery disease and correlate symptoms and ST-segment abnormalities during episodes of pain at rest. Coronary angiography has been the gold standard for diagnosing coronary artery stenoses. Quantitative angiography has improved the assessment of coronary artery narrowing but is still limited in evaluating coronary blood flow. Doppler flow studies provide useful information regarding coronary flow reserve. Myocardial ischemia as a cause of chest pain is determined by evaluating the clinical characteristics consistent with angina, correlating electrocardiographic abnormalities with perfusion defects or wall motion abnormalities, and determining the extent and functional significance of coronary artery stenoses by coronary angiography.