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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5537_Библиотеки_им_академика_М_И_Перельмана.pdf
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Cardiology
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187
Approach to Chest Pain
Kevin G. Dunsky*
Key Pearls
• Cardiovascular causes of chest pain include myocardial ischemia,
aortic dissection, myocarditis, pericarditis and coronary spasm.
• Myocardial perfusion imaging, which includes two common agents,
thallium-201 and technetium-99 sestamibi, increases the diagnostic
accuracy of stress testing.
• Stress echocardiography looks at stress-induced decreases in wall
motion which may indicate underlying coronary ischemia. These
results are similar to SPECT imaging.
6
• Perhaps the greatest utility of cardiac computed tomography is its
strong negative predictive value. Various studies have shown the
negative predictive value to be 96–100%.
• Although there is no evidence that chest pain units decrease adverse
outcomes, they may reduce length of stay and rate of hospital
admissions.
Chest pain remains a diagnostic challenge to the physician in both
the — inpatient and outpatient setting. It is a common complaint and
the ramifications for the patient can range from a minimal issue to a lifethreatening disorder.
18
Chapter
*Mount Sinai School of Medicine, New York, NY, USA.
Key History Elements and Physical Exam Findings
As is true in all of medicine, the history and physical examination are critical in making the proper diagnosis. The duration, location and quality of
the pain should always be determined. One should ask if the pain is related
to food and whether or not it occurs during coughing or deep inspiration.
It is important to know if anything exacerbates or relieves the pain.
Associated symptoms such as dyspnea, nausea, vomiting and radiating
pain should be included when talking to the patient.
Special attention to the physical exam needs to be performed. Just by
looking at the patient, one can assess for diaphoresis or cyanosis. Taking
blood pressures in both arms is important because this can provide clues
to the presence of an aortic dissection. Simple inspection of the chest wall
for lesions indicating the presence of herpes zoster is important. Crepitus
indicating the presence of subcutaneous air may be seen in the presence
of an esophageal rupture. Proper auscultation of the lungs can help diagnose congestive heart failure or the possible presence of a pneumothorax.
Friction rubs can help to diagnose pericarditis. The presence of an S3
can indicate the presence of congestive heart failure, whereas an S4 is
present in myocardial ischemia and at times in diastolic dysfunction.
Simple palpation of the abdomen can help identify potential problems
such as masses or organomegaly. Right upper quadrant tenderness may
increase the likelihood of cholecystitis.
Differential Diagnosis
Chest pain can be caused by a variety of disorders. Essentially, any input
through the thoracic autonomic ganglia can cause chest pain. Esophageal
rupture is a critical disorder and should be considered. Chest X-ray and
esophagography can often aid in confirming this diagnosis. Peptic ulcer disease and gastroesophageal reflux may also masquerade as chest pain.
Pancreatitis and biliary tract disease should also be considered. Pancreatitis
is often associated with an elevated amylase or lipase. Patients with biliary
disease often present with recurrent right upper quadrant pain or pain after
eating. It is quite uncommon that exertion would elicit any of these findings.
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K.G. Dunsky
Pulmonary etiologies, including pleuritis and pneumonia, may also
present as chest pain. Pain during breathing or coughing may be seen in
pleuritis. Fevers and productive sputum are often seen in patients with
pneumonia. Life-threatening pulmonary disorders such as a pulmonary
embolism is always of great concern. Various diagnostic tools are available to diagnose pulmonary embolism. Clinical risk predictors include
signs and symptoms of deep venous thrombosis, tachycardia, immobilization for more than three days, hemoptysis, previous deep venous
thrombosis or pulmonary embolus, or surgery within four weeks.¹
Diagnostic tools include a V/Q scan or CT angiogram. A tension pneumothorax can also be a life-threatening disorder and this is often diagnosed clinically as well as on a routine chest X-ray.
Musculoskeletal disorders such as costochondritis and trauma can
cause chest pain and should be considered. Herpes zoster can clearly
cause chest pain and in fact the chest pain, may precede the vesicular rash
by several days.
Cardiovascular causes clearly need to be identified due to the possible fatal implications. Thus, myocardial ischemia and aortic dissection are
two findings that can clearly cause chest pain. Myocarditis and pericarditis should also be included in this list. Intermittent or constant chest pain
that is exacerbated by breathing is commonly described in patients with
pericarditis. It is often worse in the supine position and is relieved by the
patient leaning forward. A friction rub may be present on physical exam.
Myocardits is often associated with fever and a recent infection. Coronary
artery spasm may cause chest pain that may be indistinguishable from a
person experiencing an acute coronary syndrome.
Since heart disease is a leading cause of mortality, it is essential to
identify whether such a diagnosis can be confirmed. Identifying risk factors such as hypertension, hypercholesterolemia, tobacco use, diabetes
and an early family history of coronary artery disease should always be
carried out. A full physical, ECG and cardiac biomarkers such as troponins should be obtained. If the chest pain is not related to exertion whatsoever, it is less likely that the pain is due to an acute coronary syndrome.
It should be noted, however, that critical disease can be caused from silent
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Approach to Chest Pain
ischemia, and the patient may not exhibit any of the usual signs or symptoms of chest pain.
Cardiac Testing
Stress testing is a significant tool in diagnosing heart disease. An exercise
stress test will attempt to reproduce the chest pain and assess for ECG
changes which may be indicative of coronary ischemia. The American
College of Cardiology and the American Heart Association performed a
meta-analysis of the diagnostic accuracy of exercise stress testing involving 24,045 patients who underwent both coronary angiography and exercise stress testing. The results indicated a mean sensitivity of 68% and a
mean specificity of 77%. If patients with previous MI’s were excluded,
the mean sensitivity was 67% and the mean specificity was 72% of exercise stress testing for diagnosing coronary artery disease.²
Myocardial perfusion imaging, which includes two common agents,
thallium-201 and technetium-99 sestamibi, increases the diagnostic accuracy of stress testing. The ACC/AHA guidelines report that when both exercise and pharmacologic stress tests with SPECT imaging are compared with
angiography, the test is 87–89% sensitive and 73–75% specific for significant stenosis (>50%).³ Vanzetto performed a six year follow-up study which
showed that in patients with a normal thallium-201 perfusion study, the rate
of myocardial infarction or death was only 0.88%.
4
Iskander performed a
meta-analysis which showed that a normal technetium-99 sestamibi imaging result was associated with a 0.6% cardiac event rate per year.
5
Stress echocardiography looks at stress-induced decreases in wall
motion which may indicate underlying coronary ischemia. A study by
Fleischmann showed that stress echocardiography had a sensitivity of
85% and a specificity of 77% as compared with coronary angiography.
Although this test is operator dependent, these results are similar to
SPECT imaging.
6
Cardiac computed tomography can measure calcification in the walls
of the coronary arteries. The amount of calcium is expressed as an
Agatston score. If any calcification is present, the test is considered
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K.G. Dunsky
positive. Calcium scores greater than 1000 are associated with increases
in morbidity and mortality. In fact, such a score indicates a patient having
a 20% chance of suffering a myocardial infarction or cardiac death within
a year. However, it should be noted that a high score does not necessarily
mean that there is an obstructive lesion. A positive scan indicates atherosclerosis, but that does not mean significant obstruction is present.
7
Perhaps the greatest utility of this test is its strong negative predictive
value. Anegative test has a 96–100% negative predictive value for obstructive lesions.
8
Thus, patients with a normal study are unlikely to have significant stenosis. This can be of great help to physicians evaluating chest
pain patients in acute settings.
Chest Pain Units
Patients often present to the Emergency Department with complaints of
chest pain. Chest pain units have been developed to help physicians choose
which patients would benefit from further testing and inpatient admission.
Protocols including a history and physical, observation period and serial
measurements of serum biomarkers are used to help improve risk stratifying this patient population. Although there is no evidence that chest pain
units decrease adverse outcomes, there are a number of trials which indicate
that they may reduce length of stay and rate of hospital admissions. As a
result, chest pain protocols for evaluating patients with suspected acute
coronary syndromes (ACS) and chest pain in the Emergency Department
received a Class I recommendation by the 2010 American Heart
Association Guidelines for Cardiopulmonary Resuscitation and Emergency
Cardiovascular Care.
9
Conclusion
Chest pain is a common presentation that all physicians face. The differential diagnosis is wide and includes many different etiologies, including
pulmonary, gastrointestinal, infectious as well as cardiac. A careful history
and physical will help to narrow the diagnosis. Since cardiac disease is a
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Approach to Chest Pain
leading cause of mortality, it is essential to make the proper diagnosis. The
various imaging tests described above will greatly help the physician to
make the proper diagnosis and as a result help to facilitate the proper care
of the patient.
References
1. Wells PS, Anderson DR, Rodger M, et al. (2000) Derivation of a sim-
ple clinical model to categorize patients’ probability of pulmonary
embolism: Increasing the model utility with the SimpliREDD-dimer.
Thromb Haemost 83: 418.
2. Gianrossi R, Detrano R, Mulvihill D, et al. Exercise-induced ST
depression in the diagnosis of coronary artery disease. A meta-analysis.
Circulation 80: 87–98.
3. Gibbons RJ, Balady GJ, Beasley JW, et al. (1997) ACC/AHA
Guidelines for Exercise Testing. A report of the American College of
Cardiology/American Heart Association Task Force on Practice
Guidelines (Committee on Exercise Testing). J Am Coll Cardiol
30(1): 260–311.
4. Vanzetto G, Ormezzano O, Fagret D, et al. (1999) Long-term additive
prognostic value of thallium-201 myocardial perfusion imaging over
clinical and exercise stress test in low to intermediate risk patients:
Study in 1137 patients with 6-year follow-up. Circulation 100(14):
1521–7.
5. Iskander S, Iskandrian AE. (1998) Risk assessment using single-
photon emission computed tomographic technetium-99m sestamibi
imaging. J Am Coll Cardiol 32(1): 57–62.
6. Fleischmann KE, Hunink MG, Kuntz KM, et al. (1998) Exercise
echocardiography or, exercise SPECT imaging? A meta-analysis of
diagnostic test performance. JAMA 280(10): 913–20.
7. Pletcher MJ, Tice JA, Pignone M, Browner WS. (2004) Using the
coronary artery calcium score to predict coronary heart disease
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events: A systematic review and meta-analysis. Arch Intern Med 164:
1285–1292.
8. Budoff MJ, Achenbachs S, Roger S, et al. (2006) Assessment of coro-
nary artery disease by cardiac computed tomography. A scientific
statement from the American Heart Association Committee on
Cardiovascular Imaging and Intervention, Council on Cardiovascular
Radiology and Intervention, and Committee on Cardiac Imaging,
Council on Clinical Cardiology. Circulation 114 : 1761–1791.
9. O’Connor, Robert E. et al. (2010) Part 10: Acute coronary syndromes:
2010 American Heart Association Guidelines for Cardiopulmonary
Resuscitation and Emergency Cardiovascular Care. Circulation 122:
S787–S817.
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Approach to Chest Pain