• Particularly useful in imaging the aorta in suspected aortic dissection
• HRCT with contrast has been shown to have sensitivity and specificity comparable to that of contrast pulmonary angiography,
and in recent years, HRCT has been accepted both as the preferred primary diagnostic modality, and also as the criterion standard for making or excluding the diagnosis of pulmonary embolism.
Ventilation-perfusion (V/Q) Scans
• V/Q scan remains an important part of the evaluation for detecting pulmonary thromboembolism when HRCT angio-graphy is not available.
Myocardial Perfusion Imaging
• Intravenous administration of a radioiso-tope (e.g. 201thallium or tetrafosmin) at rest and during stress provides additional information about myocardial perfusion.
Areas of decreased uptake during exercise, followed by normal uptake at rest suggest ischemia; whereas areas of persistent defect indicate infarction.
Coronary Angiography
• This technique, which delineates coronary artery anatomy, is the gold standard and indicated in those patients who are at high risk for CAD by noninvasive tests, and for those with persistent symptoms despite medical therapy, i.e. medical vs. surgical management, including stenting and CABG.
Intravascular Ultrasound (IVUS)
• Coronary angiography, although generally accepted to be the gold standard of diagnosis, is not 100% sensitive for exclusion of coronary artery disease. Coronary angiography detects the later stage of atherosclerosis (negative remodeling stage), when larger plaques significantly impinge on the coronary lumen.
Angiography may fail to detect the early stage of atherosclerosis (positive remodeling stage), when smaller plaques cause minimal or no
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luminal impingement. This stage is detectable only by intravascular coronary ultrasono-graphy.11
Multislice Computed Tomography (MSCT)/
64-Slice Spiral Computed Tomography
• Multislice computed tomography coronary angiography (MSCT-CA) has emerged as a powerful noninvasive diagnostic modality to visualize the coronary arteries and to detect significant coronary stenoses. The latest generation 64-slice computed tomo-graphy (CT) scanners are a robust technique which allows high-resolution, isotropic, nearly motion-free coronary imaging.
Coronary stenoses are detected with high sensitivity and a normal scan accurately rules out the presence of a coronary stenosis.
With the introduction of further novel concepts in CT-technology one may expect that MSCT-CA will become a clinically used diagnostic tool.12
GI Studies
• Common GI causes of acute noncardiac chest pain include esophageal spasm, reflux eso-phagitis, peptic ulcer, pancreatitis, cholecystitis, and esophageal perforation. According to one study, GI disease is the most common cause for which patients are admitted to a coronary care unit to have MI ruled out, accounting for 42%
of all cases of chest pain.13
• Esophagogastroduodenoscopy, 3 hours monitoring of esophageal pH, esophageal mano-metry, Bernstein test, and ultrasonic examination of the abdomen may be indi-cated where symptoms are atypical, or cardiac evaluation is normal.
PFTs
• Can be helpful in patients with pulmonary chest pain, in differentiating obstructive vs.
restrictive disease and its severity.
TFTs
• Both hyper- and hypothyroidism can precipitate CAD. Low or undetectable TSH in hyperthyroidism may contribute to anxiety associated chest pain.
CLINICAL NOTES
• Regardless of where care is given – primary or emergency department—the critical first step in managing patients with chest pain is to explore the possibility of potentially life-threatening causes of the symptoms, including ACS, aortic dissection, and PE
• A focussed, expeditiously performed phy-sical examination should include: heart rate, palpation of peripheral pulses, BP measure-ment in both arms, and estimation of oxygen saturation. Other salient features are listed in Table 8.1.
Besides coronary risk factors’ stratific-ation, few key investigations to search for evidence of CAD (a 12-lead ECG, CXR, and serial measurements of cardiac enzymes) may be indicated in patients with acute undifferentiated chest pain
• Physical examination usually does not reveal any abnormality in the diagnosis of aortic dissection and PE; thus clinical suspicion must be heightened in order to diagnose these conditions
• If acute CAD seems unlikely to be the cause of the chest pain,the possibility of pul-monary, GI, and musculoskeletalconditions, as well as pericarditis and other cardio-vascularcauses (e.g. cardiomyopathy, CSX) should be investigated
• For clinical evaluation, patients with chest pain can be classified into three broad groups, namely: acute pain of recent onset;
recurrent pain – lasting for minutes; and persistent pain – lasting for hours or even days (Table 8.2).
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Table 8.1: Physical findings in acute chest pain
Features Cause
Altered mental state; cold Low cardiac output: MI; LVF extremities; pulsus alternans;
tachycardia; hypotension; S4
Dyspnea; tachycardia; hypoxia; Acute pulmonary edema: MI;
elevated JVP; rales; S3 gallop LVF
Pulse deficit; hypertension; Aortic dissection BP difference between two arms;
murmur of aortic insufficiency;
neurological deficit
Tachypnea; hypotension; Pulmonary embolism elevated JVP; right ventricular
lift; accentuated P2; pulmonary rales, consolidation, effusion
Dyspnea, dysphagia, hypoxia; Cardiac tamponade elevated JVP; hypotension;
tachycardia; pulses paradoxus;
muffled heart sounds;
pericardial rub
Dyspnea; hypoxia; tachycardia; Pneumothorax mediastinal shift; hyperresonance;
absent/diminished breath sounds;
subcutaneous emphysema
Hamman’s sign (crunching, Pneumomediastinum;
rasping sound, synchronous Pneumopericardium;
with heartbeat) esophageal rupture
Table 8.2: Classification and examples of chest pain based on duration
Duration Examples
Acute chest pain–lasting Cardiac: ACS; HCM; aortic stenosis;
for few seconds to few pericarditis Vascular: Aortic minutes dissection; PE; PH Pulmonary:
pneumonia; tracheobronchitis;
pleuritis; pneumothorax; mass lesion GI: GERD; PUD; biliary disease;
pancreatitis
Musculoskeletal: costochondritis;
cervical disk Lesion; trauma
Others: breast disorders; herpes zoster;
anxiety; emotional Recurrent chest pain – Cardiac: (same as in above) lasting for minutes vascular: PE; PH
pulmonary: (same as in above, except pneumothorax)
GI / musculoskeletal, and others: (same as in above)
Persistent – lasting for hours Cardiac: pericarditis
and days together Pulmonary: ( same as in above, except pneumothorax)
GI / musculoskeletal, and others:
(same as in above)
• Careful assessment of patient’s history and cardiac risk factors is often the most helpful starting point. Historical features generally useful in the diagnosis of cardiac origin of chest pain include:
Location (diffuse, anterior retrosternal pain, chest pain, interscapular pain)
Radiation (to the neck, jaw, shoulders or arms)
Aggravating factors (exertion, meals, cold weather, and stress)
Duration (brief pain lasting few seconds to few minutes)
Relieving factors (rest)
Associated symptoms (dyspnea, cough, diaphoresis, presyncope, syncope).
• Common features of atypical chest pain are listed in Table 8.3
• Coronary risk factors include—Age, family history of heart problems, diabetes, hypercholesterolemia, smoking, hyper-tension, obesity, sedentary lifestyle, and stress or competitive occupation
• Although cardiac risk factors are common in patients with ACS, they are not a pre-requisite; absence of such risk factors does not lower the risk of ACS14
• The key distinctive point in the clinical diagnosis of chest pain caused byCAD is in its relation to physical exertion.If the chest discomfort is not precipitated by physical exertion,it is highly unlikely that coronary artery disease of any significantdegree is present (Table 8.4)
• Occasionally, effort-induced ischemic pain disappears while the activity continues; this is known as walkthrough or second wind angina
• Occasionally, diagnosis based solely on history may not be possible; e.g. descriptions of chest pain of cardiac, upper gastroin-testinal, or gallbladder origin can be identical.
Hence, although patient’s history is usually a valuable starting point, it may not provide a definite diagnosis because of their poor specificity in diagnosis of chest pain15
• Symptoms of angina equivalents, i.e. cardiac ischemia without chest pain, such as
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• The pain of diffuse esophageal spasm may mimic that of angina pectoris, including that the relief in many cases is obtained with nitroglycerine
• Severe chest pain, retrosternal, accompanied by dyspnea, cough, and hemoptysis deve-loping in a patient who has been immo-bilized or bedridden is suggestive of pulmonary embolism
• Pulmonary hypertensive pain may resem-ble angina in that it is precipitated by effort.
Associated moderate or severe dyspnea and evidence of signs of pulmonary hypertension suggest its diagnosis
• Chest discomfort due to pericarditis is typi-cally retrosternal, aggravated by coughing, deep respiration, or change in position; worse in supine, and relieved in sitting upright and leaning forward
• The acute onset of pleuritic pain and dyspnea in a patient with a history of asthma or emphysema is suggestive of pneumothorax
• Psychogenic chest pain is often associated with hyperventilation and other somatic symptoms such as chronic headache, diz-ziness, sweating, paresthesia, and a sense of
‘impending doom’.
RED FLAGS
• Lack of chest pain does not exclude IHD
• Over-reliance on tests with poor sensitivity, such as ECG, or on the initial values of cardiac biomarkers will miss many patients with MI
• In a patient with chest pain, the clinical response to GI cocktail (a mixture of liquid antacid, viscous lidocaine, and an anticholinergic), or sublingual nitroglycerin (NTG), cannot reliably identify the source of pain. Failure to respond to NTG should not be used to exclude the possibility of CAD7,17
• A history of a psychiatric diagnosis or overwhelming anxiety in a patient with
Table 8.3: Symptoms of atypical chest pain
• Features suggesting atypical, also called as non-cardiac/ nonanginal pain includes:
• Pain—dull ache, sharp, shooting,’ knife-like’, pleuritic, pain brought on by respiratory movements or cough.
• Location—pain localized with one finger, left sub-mammary.
• Aggravating factors – body movements, respiration, swallowing, palpation of chest.
• Duration – brief episodes lasting a few seconds, or constant lasting for days.
Table 8.4: Questions to differentiate patients with non-cardiac chest pain from those with coronary heart disease#
Response
Question Typical Atypical
If you go up a hill (or other stressor) on 10/10 <10/10 10 separate occasions on how many
do you get the pain?
Of 10 pains in a row, how many occur at rest? <2/10 ≥2/10 How many minutes does the pain usually last? <5 ≥5 When answers to all three questions are “atypical” the chance of coronary disease is only 2% in patients aged <55 years and 12% in those aged ≥55
#Christopher Bass et al. Clinical review ABC of psychological medicine chest pain. BMJ 2002; 325:588-91.
breathlessness; profound, unexplained, sudden-onset fatigue, especially in the elderly and diabetic patients is common
• Pain that radiates to the left arm and shoulder is often assumed to indicate coronary ischemia, whereas pain that radiates to the right shoulder is thought to suggest a biliary source. However, chest pain that radiates to the right shoulder is more specific for pain of cardiac origin than pain that radiates to the left shoulder. Radiation of chest discomfort to the right arm is also consistent with the diagnosis of acute IHD16
• Acute, sudden and severe chest pain described as ripping or tearing that is maximal at onset and radiates to interscapular area raises the possibility of aortic dissection. Important diagnostic feature is the inequality in the pulses, e.g. carotid, radial and femoral, and a blood pressure differential of greater than 20 mm Hg
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