Chest Pain/ACS

This essay concerns the evaluation of patients who present with “just” chest pain. That is to say that chest pain is truly the primary complaint.

Chest pain is a source of major concern for patients and physicians. Both are aware of the morbidity and mortality of acute heart disease. Physicians are acutely aware of liability issues related to chest pain. Some simple principles can be applied to chest pain patients and lessen the anxiety for all concerned. The essence of this approach is that there are three high-yield acute life threats that present with “just” chest pain. They are:

While these “big three” usually have other associated symptoms (and in that sense can be more then “just” chest pain), they represent the three conditions that must always be “ruled out” when the primary complaint is indeed chest pain. That’s because of their high morbidity and mortality (and especially the first two because they are often treatable). What about pneumonia, pneumothorax, pericarditis, esophageal disasters, etc., etc.? Well, these other thoracic conditions may present with chest pain as part of the symptom complex, but they are often not cases of “just” chest pain. Even if they do present as just chest pain, the suggested work up for patients in whom the H+PE doesn’t lead to another diagnosis will usually discover them. A different approach is appropriate when the presentation is not “just” chest pain. For example:

Occam’s Razor, Chest Pain and what does "Rule Out" Mean?
Occam’s Razor is the principle that suggests when faced with competing hypotheses selecting the one that makes the fewest new assumptions is most likely to be correct.

Applying this principle to the diagnosis of chest pain leads to the conclusion that the most efficient way to rule out each of the big three (or any diagnosis) is to rule something else in. Some examples: The history may reveal chest trauma, leading to completely different diagnostic paradigm. It would be more than unusual for a patient with minor chest trauma to have a coexisting MI, PE, or TAA. Localized reproducible chest wall tenderness noted on physical exam leads to the diagnosis of chest wall pain. A unilateral dermatomal rash may be diagnostic of shingles. And so on, the examples are nearly endless.

As with any other test, the diagnostic value of such findings on history and physical exam depend on the pre-test probability of another condition and on the skill of the examiner in performing and interpreting the findings.

An alternate diagnosis to ACS to be cautious of making clinically is GERD/esophagitis. A “burning” character of chest pain in and of itself does not exclude ACS. The fewer the other risk factors for CAD and more like GERD/esophagitis the clinical presentation the more reasonable it is to make this diagnosis.

Items suggestive of acid/peptic GI disease include:

Another specific caveat is that not all ACS patients present with chest pain. Dyspnea is notable in this regard especially in females and the non-white patient.

 

Factors which are uncharacteristic of ACS include:

Workup of the Chest Pain Patient
So now we are at the point of being more specific. The H+PE does not reveal another specific cause for chest pain or lead to a different diagnostic paradigm. What do you do?

EKG: obviously. The big daddy of all chest pain diagnoses is acute ST-segment elevation MI (STEMI). Among the big three it is the most common and also most treatable. The goal once a STEMI has been identified is to institute a reperfusion strategy ASAP. Keep the following in mind regarding the EKG.

CXR: The chest x-ray is not diagnostic of any of the “big three”. Nonetheless it is important. It should be scrutinized for specific findings that may explain the signs and symptoms such as pneumothorax or pneumomediastinum or lead the workup in another direction. A two-view (PA and lateral) chest x-ray is preferable to a portable single view.

When and how should a chest pain patient be evaluated and treated when the H+PE, EKG and CXR fail to lead to a diagnosis? ACS needs to be further ruled out in patients at more than trivial risk when acute chest pain is not otherwise explained by the H+PE, CXR, and EKG and is also not suggestive of PE or aortic dissection. The goal of the evaluation is to “risk stratify” patients into three groups: those who should be admitted to the hospital, admitted to an observation unit, or be sent home for outpatient follow up. The minimum additional workup in these patients is a test for cardiac specific troponin (TnT or TnI).
Which chest pain patients can be considered for discharge?

Can a single troponin be used? This is surprisingly difficult question. Some physicians’ feel it can, including your author but others do not. My opinion is that a single troponin is useful in the following circumstances. When they are met and the troponin is negative, discharge is reasonable.

*How to assign a possible ACS patient to the very low risk category?
Patients with these characteristics have very low risk of suffering a cardiac event subsequent to D/C: nearly zero at one month. This is especially true when they are younger patients.

Which “possible ACS” patients should be admitted to observation status?

Which chest pain patients need admission to inpatient status for further ACS workup?

Which chest pain patients need work up for pulmonary embolism?
Pulmonary embolism is an often treatable disease with considerable morbidity and mortality. The widespread use of CT pulmonary angiography has resulted in a doubling of the reported incidence of PE but no apparent decrease in mortality. Autopsy studies suggest that PE is still often undiagnosed pre mortem. Symptoms and signs of significant PE include the following.

How should possible PE be ruled out?
The two basic choices are D-dimer testing or pulmonary CTA. There is voluminous literature on this subject. For the moment, most clinicians agree on the following approach.

When should PE be treated/diagnosed in the ED?
The diagnosis of suspected massive PE should be pursued rapidly. When highly suspected, massive PE should be treated empirically pending imaging. Patients being admitted in whom non-massive but symptomatic PE remains on the list of differential diagnoses can reasonably be treated with a low molecular weight heparinoid pending further observation and evaluation.

Which chest pain patients need work up for aortic dissection? Thoracic aortic dissection (TAD) is much less common than ACS in chest pain patients. It is also much less common than PE. More often than not it also presents with more than “just chest pain” but I include it because of the high associated morbidity and mortality. Common associated signs and symptoms are:

Chest pain patients who have the above pattern should be considered for CT angiography of the chest to rule out TAD. Acute MI is a rare complication of proximal aortic dissection so a STEMI on EKG does not definitively rule out TAD. A cardiac interventionalist can perform a contrast angiogram of the aortic arch as well as the coronary arteries. The technique used in CT scanning for PE and aortic dissection are different. Be clear in your thought process about which diagnosis you are considering and order the appropriate test

GERD/Esophagitis
Usually it is easy to diagnose symptoms related to GERD/esophagitis. Definitive diagnosis is by endoscopy but the history and physical are usually sufficient to make a provisional diagnosis, initiate treatment, and discharge for follow-up. The typical history and symptoms supporting a GERD/esophagitis dx are:

If typical symptoms are present, no testing is necessary and empiric treatment can be started. Chest pain as a sole symptom MAY be due to GERD/esophagitis but usually has at least a couple of the features noted. When a patient presents with chest pain and without the characteristics of GERD/esophagitis the work-up should proceed as noted above before attributing the pain to GERD/esophagitis.