Chest Pain

Case Study

Patient 1:  Mr. Smith

Mr. Smith is a 50-year-old male past medical history of HTN and smoking presents to the Emergency Department by ambulance complaining the first time ever of severe crushing chest pain that just started while running on the treadmill. He immediately called 911.  Mr. Smith is diaphoretic and moderately ill appearing.  He received nitroglycerin 0.4 mg SL prehospital with no change in pain. Vitals: BP:140/90, P:80, RR = 24, T: 98.3F, O2 sat: 98%.

Patient 2: Ms. Jones

Ms. Jones is a 69-year-old female with history of HTN presents to the emergency department via triage.  complaining of worsening shortness of breath, chest and epigastric pain x 24 hrs. She has nausea/vomiting, weakness, and fatigue. She “feels terrible.”  She is ill appearing. No medications.

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Objectives

Upon completion of this self-study module, you should be able to:

1. Describe the initial actions taken for high risk patients with chest pain.
2. List critical diagnoses for chest pain and key features.
3. Recognize that “Classic” symptoms may or may not be present and that serial biomarkers with prolonged observation may be required. 
4. Use clinical decision rules to prioritize diagnosis and risk stratify patients such as HEART Score and PERC rule 

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Introduction

Chest pain is one of the highest risk chief complaints you will see in the Emergency Department setting.  However, accurately diagnosing the etiology of acute chest pain in the emergency department is very difficult because neither the quality nor intensity of the pain is specific to any organ or diagnosis.  Chief complaints may vary and be listed as abdominal pain, back pain, and shoulder pain. Furthermore, presentations vary significantly even amongst the most common life-threatening diseases. The potential for a life-threatening process (see Table. 1) always exists even if there are normal initial vital signs or atypical features.   In almost every case of severe undifferentiated chest pain the experienced clinicians should initially consider the top three common causes of morbidity and mortality: ACS, pulmonary embolism, and aortic dissection.  In many cases, the experienced clinician will also consider and prepare for potential several other less common life-threatening conditions:  tension pneumothorax, esophageal rupture, and pericarditis with potential cardiac tamponade.

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Initial Actions and Primary Survey

As you’re walking toward his room, these are the actions that you should perform upon arrival:

• Determine “Sick vs “Not Sick” clinical gestalt
• Assesses primary survey: ABC’s and vital signs (Stable vs unstable)
• Obtain focused history and exam
• Obtain ECG and rapid diagnostics

Assessment of all high-risk patients with chest pain should always begin with getting an initial impression then assessing the airway, breathing and circulation paired with vital signs.  

Chest pain is a team sport. Simultaneously, with initial history the team should begin initiating treatment and diagnosis.  Consider starting IV / O2-if hypoxic/ monitor.  Initially, prepare for the worst.  Consider placing a set of defibrillator/cardioversion pads on those patients who appear potentially unstable. 

Should you have a patient who presents with or develops acute distress or cardiac arrest, your diagnosis and treatment need to occur simultaneously with resuscitating the patient.  Chest pain patients with ACS may present in acute pulmonary edema from cardiogenic shock needing immediate airway support with intubation or BIPAP. Some patients with critical illness may quickly become hypotensive with overt shock needing IVF and/or a pressor. Without warning, a patient may suddenly go into cardiac arrest and require emergent cardioversion or defibrillation.  Rapid specific interventions are critical!

Initially, it is important to focus on the ABC’s. Interventions that may be indicated are listed in Table. 2 below.

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Presentation

Evaluating chest pain is not simple. Serial ECGs, serial biomarkers, clinical assessment, imaging and observation may all still be needed to further differentiate many patients.  In patients with a high-risk chief complaint, the worst diagnosis should be considered first.  Obviously, there are other less acute possible sources for chest pain, such as costochondritis, pleurisy, gastroesophageal reflux or an anxiety attack.  However, arrival at a likely non-emergent diagnosis should occur only after evaluation of more serious causes. In an elderly patient with multiple co-morbidities even after a detailed history primary and secondary survey the differential could still include three or more of the high-risk diagnoses. 

Key features are used in a focused history and physical to rapidly differentiate these critical illnesses. You should be able to identify “Classic’ presentations rapidly (See Table. 3).  It is hard to encapsulate such a broad list of potential diagnosis. Simple rules of thumb to remember including:

• Exertional shortness of breath is usually serious.
• You should not exclude ACS just based on history and exam.
• Clear lungs and hypoxia think pulmonary embolism! 
• ACS, Dissection and PE will fool you! 

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Diagnostic Testing

Electrocardiogram (ECG)
High risk patients with undifferentiated chest pain should receive an ECG within 5-10 minutes of arriving to the emergency department.  The attending physician and the ED team need to look at that ECG as soon as it’s done.  It can yield a wealth of information. A rapid screen is done to look for STEMI/ ischemia (Fig. 1) and arrthymia (Fig 2). Serial ECGs in patients with ongoing chest pain are critical to improve sensitivity for STEMI. An example of the evolution of Myocardial Infarction as seen on serial ECG is seen in Figure 3.

Fig. 3 Evolution of Myocardial Infarction on ECG

It is important to note that even a normal ECG does not rule out acute coronary syndrome, and a large percentage of patients with acute coronary syndrome have a normal ECG. Also, even though every medical student is taught that the ECG finding of S1Q3T3 can be found in pulmonary embolisms, sinus tachycardia is a more common ECG finding. Table 4 lists some common ECG findings in life-threatening causes of chest pain.

Point of Care Ultrasound (POCUS)

Cardiac ultrasound can be very helpful in the patient with acute chest pain. The ultrasound can assess for pericardial effusion as well as tamponade physiology. In addition, it can assess the cardiac contractility to assess the left ventricular function. In the patient in extremis, the presence of right ventricular strain can be suggestive of a massive pulmonary embolism.

Lung ultrasound can be very helpful for the evaluation for a pneumothorax. Studies suggest that it is more sensitive than a chest xray.

Radiology 

Use portable screening chest x-ray to evaluate for pneumothorax, CHF, sign of dissection and pneumomediastinum (esophageal rupture). Definitive studies can include CT scan, Echo, and nuclear scans such VQ. Examples of each of these can be found in the specific chapters in the CDEM curriculum. Congestive Heart Failure, Pneumothorax, Aotic dissection.

Biomarkers and D-dimer

Serial biomarker Troponin I and Troponin T are critical to assess for ACS. Repeat testing at time zero and at 3 hours is used in clinical pathways such as the HEART score. A negative d-dimer in a low risk patient can help exclude pulmonary embolism.

Clinical Decision Rules  

Clinical Decision Rules can be used as cognitive checks and to risk stratify cases of “chest pain”.  There are several decision rules that can be utilized to help direct management of patients presenting with chest pain. It is important to remember that you should only apply clinical decision rules to the populations that they were derived in. Including patients that were not originally 

The PERC score (Table. 5), for example, may be used to risk stratify patients with concern for pulmonary embolism low risk patient to limited testing. Low risk patient who are PERC negative do not need a CT scan or d-dimer based on clinical assessment. In order to satisfy the PERC criteria, each of the criteria must be negative.  Patients who are not PERC negative may need further testing such as a d-dimer, CT PE, venous duplex ultrasound or a V/Q scan based on the pretest probability.

Clinical decision rules are very helpful in the management of suspected acute coronary syndrome because history and physical exam is often not sensitive enough. Another commonly used decision rule is the HEART Score (Table. 6)  for patients at risk for acute coronary artery syndromes.  The majority of ACS patient you see may have initial non-diagnostic initial testing. By scoring these patients based on history, ECG and biomarkers you are assessing the probability of 30-day risk of a major cardiac event (MACE).  This can be incorporated into a clinical pathway or guideline. Low risk patients Heart score 0-3 may be discharged with follow-up due to a low probability of a major cardiac event 0.0-1.7%   Higher risk patients Heart Score 3-5 should be admitted for provocative testing and observation in the hospital or ED observation unit. Patients with the highest HEART score > 5 probably need more cardiology consultation and admission to the hospital 

*Risk factors: hypertension, hypercholesterolemia, diabetes mellitus, obesity (BMI>30kg/m2), smoking (within the past three months), positive family history (parent or sibling with CAD before age 65), and atherosclerotic disease

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Treatment

Encapsulating all the possibilities therapies for chest pain can be difficult. A way to think about treat is to beak it into initial ED management and definitive treatment.  Also, realize that definitive treatment may entail including medical versus surgical options. The ED physician activating the cath lab or calling cardiac surgery for a type A dissection can be the rate limiting step to definite therapy. A few initial treatment options are included in Table. 7 and encompass abbreviated treatment options. Full treatment options can be found in individual chapters throughout the CDEM curriculum.

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Pearls and Pitfalls

• If the EKG is not diagnostic, a secondary survey focused on the key features of life-threatening chest pain will be needed. 
• Keep a broad differential initially!  
• Try to formulate a systematic differential using a system that you such as CARD Common, Atypical, Rare, Don’t Miss.   
• Re-assess ABC’s frequently as a patient’s status may change at any moment. 
• Do not rely on a normal EKG and a normal Troponin to rule out acute coronary syndrome, they are not sensitive enough! Clinical decision rules can be helpful to guide disposition.

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Case Study

Your Cases: Mr Smith and Ms. Jones
Initial assessment upon walking into the room is that both patients are “Potentially Sick”, but not in cardiac arrest. You then begin a primary survey: ABC’s and vital signs to determine stable vs unstable.  Both patients are awake and talking, and so you ascertain that both patients are maintaining their airway. A quick assessment reveals clear lungs, an adequate work of breathing and normal pulse oximetry.  Both patients have a normal blood pressure and an intact radial pulse with adequate perfusion.  Primary survey has been assessed and appears intact. ECG was obtained and is provided below:

Figure 4. STEMI. Courtesy of Paul Zgurzynski

The team begins by placing the patients on the cardiac monitor, giving aspirin 325 mg and placing an 18 gauge IV.  Next, an EKG is obtained. Note: early EKG makes the diagnosis in both patients.  Both have the exact same process with relatively “Classic “features. ECG shows an acute ST segment elevation inferior lateral MI. Both patient are given heparin, tigrelacor, placed on defibrillator pads and had the cath lab activated by the ED team. Both undergo emergent PCI /stenting within 60 minutes. Both patients did very well due to quick diagnosis and treatment. 

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References

Singh B, Mommer SK, Erwin PJ, et al

1. Pulmonary embolism rule-out criteria (PERC) in pulmonary embolism—revisited: A systematic review and meta-analysis Emerg Med J 2013;30:701-706. 
2. Mahler SA, Riley RF, Hiestand BC, et al. The HEART Pathway randomized trial: identifying emergency department patients with acute chest pain for early discharge. Circ Cardiovasc Qual Outcomes. 2015;8(2):195-203.
3. Six, A.J., Backus, B.E. & Kelder, J.C. A prospective validation of the HEART score for chest pain patients at the emergency department. NHJL (2008) 16: 191. https://doi.org/10.1007/BF03086144