Chronic stable angina overview: Difference between revisions
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==Pathophysiology== | ==Pathophysiology== | ||
The primary causes of [[myocardial ischemia]] in chronic stable angina are: fixed epicardial stenosis, spasm of the epicardial artery and/or microvascualar disease. The causation of angina is not mutually exclusive. Two or more causes may coexist in the same patient. | |||
==Clinical Presentation== | ==Clinical Presentation== |
Revision as of 16:07, 25 January 2013
Chronic stable angina Microchapters | ||
Classification | ||
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Differentiating Chronic Stable Angina from Acute Coronary Syndromes | ||
Diagnosis | ||
Alternative Therapies for Refractory Angina | ||
Discharge Care | ||
Guidelines for Asymptomatic Patients | ||
Case Studies | ||
Chronic stable angina overview On the Web | ||
Risk calculators and risk factors for Chronic stable angina overview | ||
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Maheep Singh Sangha, M.B.B.S.; Cafer Zorkun, M.D., Ph.D. [2]
Overview
Angina pectoris, commonly known as angina, is chest pain[1] due to ischemia (a lack of blood and subsequent lack of oxygen supply) of the heart muscle. It is most often due to obstruction or spasm of the coronary arteries (the heart's blood vessels). Coronary artery disease, also referred to as atherosclerosis of the coronary arteries, is the most common cause of angina. The term derives from the Greek ankhon ("strangling") and the Latin pectus ("chest") meaning "a strangling feeling in the chest". In angina pectoris, symptomatic onset may include chest discomfort indicated by a feeling of tightness, heaviness, or pain in the chest cavity.
Historical Perspective
Chronic stable angina is a form of chest pain characterized by an insufficient blood flow to the myocardium of the heart to match myocardial energy demands (ischemia). The term angina was originally derived from the Greek word ankhon and the Latin word pectus, which when combined, loosely translates as "a strangling feeling in the chest." Attempts to classify this disease state began as early as the 4th century B.C., when Lucius Annaeus Seneca first described the symptoms he was experiencing as "to have any other malady is to be sick; to have this is to be dying." Throughout history many renowned researchers and health care professionals have contributed to the understanding, definition, and recognition of angina.
Classification
Chronic Stable Angina
Angina pectoris is a sensation of chest discomfort that is often described as: a feeling of tightness, heaviness, or pain. Angina pectoris is a characteristic of coronary heart disease. When it occurs chronically, this is referred to as stable angina.
Walk Through Angina
Walk through angina is the appearance of anginal chest discomfort early in the course of exertion which subsequently subsides despite continued exertion.
Mixed Angina
Mixed or variable threshold angina pectoris is a syndrome in which there is substantial variation in the magnitude of physical activity that induces anginal chest pain.
Nocturnal Angina
Nocturnal angina is the occurrence of anginal discomfort either during the first hours of sleep or during the early morning hours. It is speculated that discomfort caused during the first hours of sleep is due to increased venous return, whereas the discomfort caused during the early morning hours is due to increased vascular tone.
Postprandial Angina
Postprandial angina pectoris is anginal chest discomfort that occurs following meals. It is thought to be due to an increase in vascular tone or a reduction in coronary blood flow.
Syndrome X
Syndrome X may refer to cardiac syndrome X, metabolic syndrome and single X syndrome, where an individual has a single X chromosome, typically described as turner syndrome. The otherwise unidentifiable rare disease afflicting Brooke Greenberg and only about half a dozen other people in the world.
Vasospastic Angina
Coronary vasospasm is a multi-factorial, transient, and abrupt reduction of luminal diameter of an epicardial coronary artery due to inappropriate constriction of coronary smooth muscle that can generate distal ischemia. This may occur spontaneously or in the context of angioplasty, particularly if denudation of the endothelium or dissection occurs. In addition, the vasospasm can either be focal or multifocal (which compromises more than one vessel).
Differentiating Chronic Stable Angina from Urgent Conditions
Stable angina must be differentiated from unstable angina and acute coronary syndromes. If the pattern of angina is stable, this is termed chronic stable angina. If the magnitude, threshold or frequency of chest pain accelerates, this is termed an acute coronary syndrome.
Pathophysiology
The primary causes of myocardial ischemia in chronic stable angina are: fixed epicardial stenosis, spasm of the epicardial artery and/or microvascualar disease. The causation of angina is not mutually exclusive. Two or more causes may coexist in the same patient.
Clinical Presentation
The majority of patients present with history of either, chest pain or discomfort categorized as: typical or atypical. Typical presentation would include pain or discomfort in the front or anterior precordium. Atypical presentation can be more convoluted in presentation and involve a wide range of symptoms. For example, an atypical patient may present with dyspnea instead of chest pain and this is termed an angina equivalent.
In addition to the historical presentation of chest pain or discomfort, the patient history should be extensively evaluated to include an assessment of cardiovascular risk factors. Physical examination may be normal or asymptomatic. In some cases, a physical examination may reveal heart failure. Additional findings can be important in understanding the onset of the condition. For instance, the presence of peripheral vascular disease may be associated with an increased risk of coronary artery disease (CAD).
Pretest Probability of Coronary Artery Disease
Pretest probability is the probability of a given disorder before the result of the diagnostic test(s) are known. In the case of angina, the initial history and physical examination can help categorize the patient into a low, intermediate or high probability group. Assessment of the pretest probability of disease aids in the selection of diagnostic studies and in the initiation of treatment.
Diagnostic tests
Initial Studies
- The goal of initial testing is to exclude the presence of an acute coronary syndrome such as ST elevation MI, non ST elevation MI and unstable angina. Therefore, an electrocardiogram is performed in the patient who first presents with chronic stable angina.
- The EKG may be normal in the majority of cases if ischemia is not present at the time the EKG is obtained.
- Other relevant findings would include evidence of left ventricular hypertrophy, or Q waves in multiple leads suggestive of old MI.
Exclusion of Factors That Would Exacerbate A Supply Demand Mismatch
In the patient who first presents with unstable angina a hemoglobin, hematocrit, and TSH should be obtained to exclude factors that would exacerbate a supply demand mismatch.
Studies to aid in the Management of Chronic Risk Factors
This includes lab tests like a lipid profile and the assessment of the Hb a1C and glucose.
Imaging Studies and Studies to Assess the Magnitude of Ischemia
- A chest x ray is often performed to assess for the presence of cardiomegaly and congestive heart failure.
- Specific cardiac tests for angina include exercise ECG testing, myocardial perfusion imaging, echocardiography, stress echocardiography and coronary angiography[2].
Diagnostic Criteria
To confirm or qualify for the diagnosis of chronic stable angina, at least one of the following additional criteria for coronary artery disease and/or ischemia must be present:
- New and/or dynamic ST-depression >0.05 mV, ST-elevation >0.1 mV, or symmetric T wave inversion >0.2 mV on a resting ECG
- Definite evidence of ischemia on stress echocardiography, myocardial scintigraphy (e.g. an area of clear reversible ischemia), or ECG-only stress test (e.g., significant dynamic ST shift, horizontal or downsloping)
- Angiographic evidence of epicardial coronary artery stenosis of >70% diameter reduction and/or evidence for intraluminal arterial thrombus.
Treatment
- Treatment for chronic stable angina includes:
- Lifestyle modification
- Pharmacotherapy
- Revascularization procedures(percutaneous coronary intervention (PCI), coronary artery bypass surgery (CABG)).
- It is also important to identify any exacerbating factors like anemia, thyrotoxicosis, valvular heart disease or decompensated heart failure and treat them.
- Smoking cessation counseling, diet and weight management, promoting physical exercise, blood pressure and diabetes control are all components of risk factor modifications and should be stressed at each clinic visit.
- Specific medical therapy includes antiplatelets (like ASA, clopidogrel), antianginals (like nitrates, beta blockers, calcium channel blockers, lipid-lowering agents, ACE inhibitors and angiotensin receptor blocking agents.
- Coronary revascularization is recommended when optimal medical therapy has failed to reduce symptoms or severe atherosclerotic disease or high risk criteria on noninvasive testing [3].
- Options available for revascularization include: percutaneous coronary intervention PCI and coronary artery bypass grafting CABG.
- In patients with chronic stable angina, the factors influencing the choice of coronary revascularization therapy (percutaneous coronary intervention or coronary artery bypass surgery) are varied and complex. The severity of symptoms, lifestyle, extent of objective ischemia, and underlying risks must be weighed against the benefits of revascularization and the patient’s preference, as well as local availability and expertise.
- Evidence from randomized trials and large revascularization registers can guide these decisions.
- In the past decade there has been significant improvements in medical treatment, bypass surgery and percutaneous coronary intervention.
Prognosis of Chronic Stable Angina
Ischemic heart disease remains as the number one cause of mortality in developed countries. The prognosis of stable angina varies widely depending on severity of symptoms, extent of atherosclerosis and presence of other risk factors and co-morbidities. The presence of impaired left ventricular function is associated with a poor prognosis.
References
- ↑ "MerckMedicus : Dorland's Medical Dictionary". Retrieved 2009-01-09.
- ↑ ACC/AHA 2002 guideline update for the management of patients with chronic stable angina--summary article: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines (Committee on the Management of Patients With Chronic Stable Angina). Gibbons RJ, Abrams J, Chatterjee K, Daley J, Deedwania PC, Douglas JS, Ferguson TB Jr, Fihn SD, Fraker TD Jr, Gardin JM, O'Rourke RA, Pasternak RC, Williams SV; American College of Cardiology; American Heart Association Task Force on practice guidelines (Committee on the Management of Patients With Chronic Stable Angina). J Am Coll Cardiol. 2003 Jan 1;41(1):159-68. No abstract available. PMID: 12570960
- ↑ 2007 chronic angina focused update of the ACC/AHA 2002 guidelines for the management of patients with chronic stable angina: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines Writing Group to develop the focused update of the 2002 guidelines for the management of patients with chronic stable angina. Fraker TD Jr, Fihn SD; 2002 Chronic Stable Angina Writing Committee; American College of Cardiology; American Heart Association, Gibbons RJ, Abrams J, Chatterjee K, Daley J, Deedwania PC, Douglas JS, Ferguson TB Jr, Gardin JM, O'Rourke RA, Williams SV, Smith SC Jr, Jacobs AK, Adams CD, Anderson JL, Buller CE, Creager MA, Ettinger SM, Halperin JL, Hunt SA, Krumholz HM, Kushner FG, Lytle BW, Nishimura R, Page RL, Riegel B, Tarkington LG, Yancy CW. J Am Coll Cardiol. 2007 Dec 4;50(23):2264-74. No abstract available. Erratum in: J Am Coll Cardiol. 2007 Dec 4;50(23):e1. Pasternak, Richard C [removed]. PMID: 18061078