By Ahmed Adlan
26 October 2014
ABBREVIATIONS
Acute chest pain is the commonest cardiology-related presentation to the emergency department [1]. Given the high prevalence of cardiovascular disease it is important to identify and treat acute coronary syndromes. In order to do this the admitting doctor must be able to appropriately assess patients presenting with acute chest pain. In this short article we will provide a suggested strategy for the assessment of acute chest pain.
Step 1. Perform a 12 lead ECG
The most important investigation in the assessment of acute chest pain is the 12 lead ECG. It must be performed immediately in patients presenting with acute chest pain. ST elevation in at least 2 contiguous leads (at least 1 mm in limb leads, 2 mm in chest leads) or left bundle branch block (not known to be old) in the context of acute chest pain is diagnostic for STEMI. Once the diagnosis of STEMI is confirmed arrangements should be made for immediate emergency primary PCI as per the local hospital protocols.
Interpretation of the 12 lead ECG may point to the correct diagnosis before the patient is even seen. The important and common features to recognise on an ECG in acute chest pain is covered in another article.
Step 2. Characterise the pain
In order to detect ischaemic chest pain one must rely on a focussed history. In ACS patients often have a prior history of angina although it may be their first presentation. The important features of ischaemic chest pain are:
Based on the presence or absence of these features the chest pain can now be classified as typical (all 3 features), atypical (2 features) or non-anginal chest pain (1 or no features) [2].
Step 3. Risk factors
Determine whether the patient has risk factors for cardiovascular disease. The presence of one or more risk factors increases the probability of underlying IHD. Pertinent risk factors are found in Table 1.
Step 4. Assess bleeding risk
An assessment of bleeding risk is vitally important to make in patients with suspected ACS or indeed in pulmonary embolism, prior to commencing anti-thrombotic/anti-platelet agents. For example in patients with known bleeding disorders or recent haemorrhaging stroke anti-thrombotic/anti-platelet agents may well be contra-indicated. In such cases the benefit-risk of treatment will need to be considered and possibly delayed until the diagnosis is confirmed. In some cases the risk of treatment may outweigh the benefits and hence no treatment is given.
Step 5. Emergency room treatment
When assessing critically ill patients with acute chest pain it is recommended to follow the A, B, C, D approach (Airways, Breathing, Circulation, Disability) [3]. Administer high flow oxygen, attach the patient to a cardiac monitor, obtain intravenous access and send appropriate blood samples. Take vital observations including temperature, pulse rate, blood pressure (in both arms), respiratory rate, oxygen saturations and blood sugar. As mentioned above a 12 lead ECG should also be obtained. The above can be performed by a colleague (e.g. trained nurse or doctor) while you make the initial assessment (steps 2-4). If the patient is complaining of ongoing chest pain then a trial of sublingual GTN would be useful to aid diagnosis. It would s also important to repeat the ECG in cases of ongoing chest pain as it may evolve into a STEMI.
Step 6. Consider the probability of acute coronary syndrome
By this stage, within several minutes, one may able to gauge the probability of ACS - highly unlikely, improbable, uncertain, probably or highly likely. In cases where the diagnosis of ACS appears uncertain or improbable then further history must be obtained. There are certain features which may point to an alternative diagnosis (Table 2).
Step 7. Focussed examination
By now one should have in mind a potential diagnosis and a focussed examination should be performed to help confirm the diagnosis. One should assess the patient and observe for respiratory distress, sweatiness, skin temperature and perfusion, and cyanosis. The pulse should be felt to assess rate, rhythm and character. Brady- and tachy-arrhythmias can present with acute chest pain and may be a consequence of an ischaemic event. Radio-femoral or radio-radial delay (indicating coarctation of the aorta) should also be noted.
One can assess for the presence of anaemia. Auscultation of the heart sounds and the presence of murmurs is key especially detecting aortic stenosis (or hypertrophic cardiomyopathy) which may present with angina. The presence or absence of the features of decompensated heart failure should also be noted (i.e. elevated JVP, displaced apex, bibasal crackles or pleural effusions, bilateral leg oedema).
A full respiratory assessment is also required to detect or exclude respiratory pathology (e.g. pneumothorax, consolidation or lung collapse). The presence or absence of clinical features of a DVT should be noted.
Observe the chest wall for any signs of trauma and palate for chest wall tenderness. It may be useful to examine the shoulders to assess whether movement of the shoulders exacerbates the chest pain. Finally it is advisable to palpate the abdomen for epigastric, right upper quadrant tenderness and presence of hepatomegaly.
Step 8. Repeat a 12-lead ECG
By this stage the initial clinical assessment is almost complete. Unfortunately the correct diagnosis is often missed because only one 12-lead ECG has been performed. Serial ECGs are important to aid diagnosis and identify high risk patients with ongoing ischaemia and/or evolving myocardial infarction. Similarly an abnormal presenting ECG with fixed abnormalities may suggest a degree of stability.
Step 9. Arrange relevant investigations
It is important that the relevant investigations are arranged. These include routine blood tests (full blood count, renal and liver function, clotting factors, inflammatory markers such as C-reactive protein). Cardiac enzymes are essential in all suspected acute coronary syndromes. Creatinine kinase (including myoglobin sub-types) were traditionally and are still used as markers of cardiac muscle damage however newer blood assays are now available. High sensitivity Troponin (T or I) should be taken according to local laboratory protocols. Typically two blood tests are required either 6 hours or 12 hours apart. Use local laboratory guidelines to define a positive or negative result. A positive result is usually a value higher than a particular threshold associated with a percentage change between the two samples (e.g. 20% rise or fall).
In ACS the presence of a positive Troponin level helps to distinguish between NSTEMI (positive Troponin) and UA (negative Troponin). However in all cases of suspected ACS one must initiate anti-thrombotic treatment before the Troponin results are available. In negative-Troponin-ACS anti-thrombotic treatment may be stopped (although the patient should remain on at least one anti-platelet agent e.g. Aspirin). The management of acute coronary syndromes will be covered in another article.
A plain chest radiograph should also be performed in all cases of acute chest pain in order to detect lung pathology and features to suggest cardiovascular disease (e.g. cardiomegaly or acute pulmonary oedema).
In cases where pulmonary embolism is suspected CTPA can be arranged. In selected cases where suspicion of pulmonary embolism is low, a d-dimer blood test may be useful to help decide whether CTPA is required. In patients with a low suspicion for PE a negative d-dimer effectively rules out the possibility of PE, whilst a positive result necessitates a CTPA.
For patients with suspected aortic dissection (e.g. severe, sharp chest pain radiating to the back, discrepancy in blood pressure of at least 20 mmHg between arms and legs, and a widened mediastinum) CT aortic angiogram should be performed. An echocardiogram may also be useful to detect aortic dissection and coarctation of the aorta.
Emergency echocardiography has been recognised as a useful tool in the assessment of acute chest pain although not routinely used. Echocardiography can be useful to detect left ventricular dysfunction and regional wall motion abnormalities suggestive of IHD and acute MI. Additionally aortic stenosis or outflow tract obstruction, aortic dissection, coarctation of the aorta, and pericardial effusions can be identified on echocardiography. Right ventricular strain and elevated right heart pressure may indicate the presence of a large significant PE.
In certain cases an abdominal ultrasound or an oesophageal gastro-duodenoscopy may be useful to detect gastrointestinal causes for chest pain.
In ACS coronary angiography may be considered to assess the coronary arteries, confirm the diagnosis and plan appropriate re-vascularisation.
Step 10. Review the patient and reconsider the diagnosis
Patients with acute chest pain should be monitored at least until the diagnosis is confirmed especially in cases of suspected acute coronary syndromes. Treatment should be initiated and the patient should be reviewed on a regular basis in order to assess response to treatment and track evolution of their condition. New features may later become evident and point to the correct diagnosis e.g. the development of fever, hypoxia, or new ECG changes. The diagnosis may often need to be reconsidered in light of subsequent investigations. For example, in the event of normal coronary angiography an alternative diagnosis for the chest pain should be considered and the initial diagnosis of ACS may be revoked.
Summary
In summary the assessment of acute chest pain is an important skill required by emergency medicine, acute medicine and cardiology doctors. The recognition of ACS and assessment allows emergency treatment to be initiated promptly.
A 12 lead ECG should be performed in all patients with acute chest pain ideally at the time of pain, at presentation and subsequently at regular time intervals. A focussed history should be obtained to quickly characterise the chest pain, assess risk factors for cardiovascular disease as well as bleeding risk. The probability of ACS may become evident with this brief history and emergency room treatment should be initiated at this point. This includes obtaining intravenous access and blood sampling, cardiac monitoring, and the administration of oxygen, nitrates, morphine and/or Aspirin. A focussed examination followed by a repeat ECG should be performed in order to help with the diagnosis. At this stage relevant investigations can be arranged including serial Troponin blood tests, plain chest radiography and in selected cases inflammatory markers and d-dimers. The results of investigations along with regular review of the patients' symptoms and clinical state will help confirm the diagnosis or perhaps point to an alternative diagnosis. A senior review is also recommended with prompt referral to relevant specialists (e.g. Cardiology, Respiratory, Cardiothoracic surgery).
References
1. Bhuiya FA, Pitts SR, McCaig LF. Emergency department visits for chest pain and abdominal pain: United States, 1999-2008. NCHS Data Brief 2010; 43: 1-8.
2. National Institute for Health and Clinical Excellence. Chest pain of recent onset: assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin. Clinical guideline CG95. London NICE; 2010. http://www.nice.org.uk/guidance/cg95/resources/guidance-chest-pain-of-recent-onset-pdf (accessed 26 Oct 2014)
3. Nolan JP, Soar J, Zideman DA et al. European Resuscitation Council Guidelines for Resuscitation 2010 Section 1. Executive summary. Resuscitation. 2010; 81 (10): 1219-76.
26 October 2014
ABBREVIATIONS
ACS Acute Coronary Syndrome; CABG Coronary Artery Bypass Graft; CT Computed Tomography; CTPA Computed Tomography Pulmonary Angiography; DVT Deep Vein Thrombosis; ECG Electrocardiogram; GORD Gastro-Oesophageal Reflux Disease; GTN Glyceryl -Tri-Nitrate; IHD Ischaemic Heart Disease; JVP Jugular Venous Pressure; MI Myocardial Infarction; NSTEMI Non-ST-segment Elevation Myocardial Infarction; PCI Percutaneous Coronary Intervention; PE Pulmonary Embolism; STEMI ST-segment Elevation Myocardial Infarction;
Acute chest pain is the commonest cardiology-related presentation to the emergency department [1]. Given the high prevalence of cardiovascular disease it is important to identify and treat acute coronary syndromes. In order to do this the admitting doctor must be able to appropriately assess patients presenting with acute chest pain. In this short article we will provide a suggested strategy for the assessment of acute chest pain.
Step 1. Perform a 12 lead ECG
The most important investigation in the assessment of acute chest pain is the 12 lead ECG. It must be performed immediately in patients presenting with acute chest pain. ST elevation in at least 2 contiguous leads (at least 1 mm in limb leads, 2 mm in chest leads) or left bundle branch block (not known to be old) in the context of acute chest pain is diagnostic for STEMI. Once the diagnosis of STEMI is confirmed arrangements should be made for immediate emergency primary PCI as per the local hospital protocols.
Interpretation of the 12 lead ECG may point to the correct diagnosis before the patient is even seen. The important and common features to recognise on an ECG in acute chest pain is covered in another article.
Step 2. Characterise the pain
In order to detect ischaemic chest pain one must rely on a focussed history. In ACS patients often have a prior history of angina although it may be their first presentation. The important features of ischaemic chest pain are:
- constricting discomfort in the front of the chest, or in the neck, shoulders, jaw or arms
- precipitated by physical exertion
- relieved by rest or GTN within 5 minutes (except in the case of ACS where the pain may last longer than 10 minutes and may not be relieved by rest or only slightly relieved by GTN)
Based on the presence or absence of these features the chest pain can now be classified as typical (all 3 features), atypical (2 features) or non-anginal chest pain (1 or no features) [2].
Step 3. Risk factors
Determine whether the patient has risk factors for cardiovascular disease. The presence of one or more risk factors increases the probability of underlying IHD. Pertinent risk factors are found in Table 1.
Table 1. Risk
factors for IHD
|
Age
|
Male
|
Known IHD (angina, previous MI, stents or CABG)
|
Diabetes mellitus
|
Hypertension
|
Hypercholesterolaemia
|
Smoking
|
Family history of cardiovascular disease
|
Inflammatory diseases (e.g. rheumatoid arthritis)
|
Step 4. Assess bleeding risk
An assessment of bleeding risk is vitally important to make in patients with suspected ACS or indeed in pulmonary embolism, prior to commencing anti-thrombotic/anti-platelet agents. For example in patients with known bleeding disorders or recent haemorrhaging stroke anti-thrombotic/anti-platelet agents may well be contra-indicated. In such cases the benefit-risk of treatment will need to be considered and possibly delayed until the diagnosis is confirmed. In some cases the risk of treatment may outweigh the benefits and hence no treatment is given.
Step 5. Emergency room treatment
When assessing critically ill patients with acute chest pain it is recommended to follow the A, B, C, D approach (Airways, Breathing, Circulation, Disability) [3]. Administer high flow oxygen, attach the patient to a cardiac monitor, obtain intravenous access and send appropriate blood samples. Take vital observations including temperature, pulse rate, blood pressure (in both arms), respiratory rate, oxygen saturations and blood sugar. As mentioned above a 12 lead ECG should also be obtained. The above can be performed by a colleague (e.g. trained nurse or doctor) while you make the initial assessment (steps 2-4). If the patient is complaining of ongoing chest pain then a trial of sublingual GTN would be useful to aid diagnosis. It would s also important to repeat the ECG in cases of ongoing chest pain as it may evolve into a STEMI.
Step 6. Consider the probability of acute coronary syndrome
By this stage, within several minutes, one may able to gauge the probability of ACS - highly unlikely, improbable, uncertain, probably or highly likely. In cases where the diagnosis of ACS appears uncertain or improbable then further history must be obtained. There are certain features which may point to an alternative diagnosis (Table 2).
Table 2.
Features suggestive of non-ischaemic chest pain
|
|
Feature
|
Diagnosis
|
Pleuritic
|
Pneumothorax, PE, pleurisy, chest infection
|
Risk factors for DVT
|
PE
|
Fever, cough (may be productive)
|
Chest infection/pneumonia
|
Radiation to back/shoulder blades
|
Aortic
dissection, pericarditis
|
Restrosternal/epigastric/relation to food
|
GORD, gastritis, oesophagitis
|
Abdominal pain
|
Gastric,
cholecystitis, pancreatitis
|
Positional relieved by leaning forward
|
Pericarditis
|
Postional worse on movement
|
Costochondritis,
musculoskeletal
|
Recent trauma
|
Musculoskeletal, rib fracture,
pneumo/haemothorax
|
Fatigue, pallor or bleeding history
|
Anaemia
|
Step 7. Focussed examination
By now one should have in mind a potential diagnosis and a focussed examination should be performed to help confirm the diagnosis. One should assess the patient and observe for respiratory distress, sweatiness, skin temperature and perfusion, and cyanosis. The pulse should be felt to assess rate, rhythm and character. Brady- and tachy-arrhythmias can present with acute chest pain and may be a consequence of an ischaemic event. Radio-femoral or radio-radial delay (indicating coarctation of the aorta) should also be noted.
One can assess for the presence of anaemia. Auscultation of the heart sounds and the presence of murmurs is key especially detecting aortic stenosis (or hypertrophic cardiomyopathy) which may present with angina. The presence or absence of the features of decompensated heart failure should also be noted (i.e. elevated JVP, displaced apex, bibasal crackles or pleural effusions, bilateral leg oedema).
A full respiratory assessment is also required to detect or exclude respiratory pathology (e.g. pneumothorax, consolidation or lung collapse). The presence or absence of clinical features of a DVT should be noted.
Observe the chest wall for any signs of trauma and palate for chest wall tenderness. It may be useful to examine the shoulders to assess whether movement of the shoulders exacerbates the chest pain. Finally it is advisable to palpate the abdomen for epigastric, right upper quadrant tenderness and presence of hepatomegaly.
Step 8. Repeat a 12-lead ECG
By this stage the initial clinical assessment is almost complete. Unfortunately the correct diagnosis is often missed because only one 12-lead ECG has been performed. Serial ECGs are important to aid diagnosis and identify high risk patients with ongoing ischaemia and/or evolving myocardial infarction. Similarly an abnormal presenting ECG with fixed abnormalities may suggest a degree of stability.
Step 9. Arrange relevant investigations
It is important that the relevant investigations are arranged. These include routine blood tests (full blood count, renal and liver function, clotting factors, inflammatory markers such as C-reactive protein). Cardiac enzymes are essential in all suspected acute coronary syndromes. Creatinine kinase (including myoglobin sub-types) were traditionally and are still used as markers of cardiac muscle damage however newer blood assays are now available. High sensitivity Troponin (T or I) should be taken according to local laboratory protocols. Typically two blood tests are required either 6 hours or 12 hours apart. Use local laboratory guidelines to define a positive or negative result. A positive result is usually a value higher than a particular threshold associated with a percentage change between the two samples (e.g. 20% rise or fall).
In ACS the presence of a positive Troponin level helps to distinguish between NSTEMI (positive Troponin) and UA (negative Troponin). However in all cases of suspected ACS one must initiate anti-thrombotic treatment before the Troponin results are available. In negative-Troponin-ACS anti-thrombotic treatment may be stopped (although the patient should remain on at least one anti-platelet agent e.g. Aspirin). The management of acute coronary syndromes will be covered in another article.
A plain chest radiograph should also be performed in all cases of acute chest pain in order to detect lung pathology and features to suggest cardiovascular disease (e.g. cardiomegaly or acute pulmonary oedema).
In cases where pulmonary embolism is suspected CTPA can be arranged. In selected cases where suspicion of pulmonary embolism is low, a d-dimer blood test may be useful to help decide whether CTPA is required. In patients with a low suspicion for PE a negative d-dimer effectively rules out the possibility of PE, whilst a positive result necessitates a CTPA.
For patients with suspected aortic dissection (e.g. severe, sharp chest pain radiating to the back, discrepancy in blood pressure of at least 20 mmHg between arms and legs, and a widened mediastinum) CT aortic angiogram should be performed. An echocardiogram may also be useful to detect aortic dissection and coarctation of the aorta.
Emergency echocardiography has been recognised as a useful tool in the assessment of acute chest pain although not routinely used. Echocardiography can be useful to detect left ventricular dysfunction and regional wall motion abnormalities suggestive of IHD and acute MI. Additionally aortic stenosis or outflow tract obstruction, aortic dissection, coarctation of the aorta, and pericardial effusions can be identified on echocardiography. Right ventricular strain and elevated right heart pressure may indicate the presence of a large significant PE.
In certain cases an abdominal ultrasound or an oesophageal gastro-duodenoscopy may be useful to detect gastrointestinal causes for chest pain.
In ACS coronary angiography may be considered to assess the coronary arteries, confirm the diagnosis and plan appropriate re-vascularisation.
Step 10. Review the patient and reconsider the diagnosis
Patients with acute chest pain should be monitored at least until the diagnosis is confirmed especially in cases of suspected acute coronary syndromes. Treatment should be initiated and the patient should be reviewed on a regular basis in order to assess response to treatment and track evolution of their condition. New features may later become evident and point to the correct diagnosis e.g. the development of fever, hypoxia, or new ECG changes. The diagnosis may often need to be reconsidered in light of subsequent investigations. For example, in the event of normal coronary angiography an alternative diagnosis for the chest pain should be considered and the initial diagnosis of ACS may be revoked.
Summary
In summary the assessment of acute chest pain is an important skill required by emergency medicine, acute medicine and cardiology doctors. The recognition of ACS and assessment allows emergency treatment to be initiated promptly.
A 12 lead ECG should be performed in all patients with acute chest pain ideally at the time of pain, at presentation and subsequently at regular time intervals. A focussed history should be obtained to quickly characterise the chest pain, assess risk factors for cardiovascular disease as well as bleeding risk. The probability of ACS may become evident with this brief history and emergency room treatment should be initiated at this point. This includes obtaining intravenous access and blood sampling, cardiac monitoring, and the administration of oxygen, nitrates, morphine and/or Aspirin. A focussed examination followed by a repeat ECG should be performed in order to help with the diagnosis. At this stage relevant investigations can be arranged including serial Troponin blood tests, plain chest radiography and in selected cases inflammatory markers and d-dimers. The results of investigations along with regular review of the patients' symptoms and clinical state will help confirm the diagnosis or perhaps point to an alternative diagnosis. A senior review is also recommended with prompt referral to relevant specialists (e.g. Cardiology, Respiratory, Cardiothoracic surgery).
References
1. Bhuiya FA, Pitts SR, McCaig LF. Emergency department visits for chest pain and abdominal pain: United States, 1999-2008. NCHS Data Brief 2010; 43: 1-8.
2. National Institute for Health and Clinical Excellence. Chest pain of recent onset: assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin. Clinical guideline CG95. London NICE; 2010. http://www.nice.org.uk/guidance/cg95/resources/guidance-chest-pain-of-recent-onset-pdf (accessed 26 Oct 2014)
3. Nolan JP, Soar J, Zideman DA et al. European Resuscitation Council Guidelines for Resuscitation 2010 Section 1. Executive summary. Resuscitation. 2010; 81 (10): 1219-76.
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