what all things to know regarding low risk chest pain? based on emergency medicine curriculum

1. LOW RISK CHEST PAIN
The Ultimate Dilemma
Dr. Krishna Prasad G

2. • Classic diagnostic challenge
• Need to find out the minority of patients
prone to develop problems
• Need to minimize unnecessary diagnostic
testing or hospital admission

3. Definition
• Low-risk chest pain is defined by the ACC/AHA
as those patients with a normal or “near-
normal” ECG (unchanged from prior or no ST
or T wave changes in contiguous leads),
normal cardiac enzymes, normal cardiac
rhythms, and normal hemodynamics.

5. Objective of this talk
• This session addresses the clinical assessment
and management of patients with low risk
chest pain, specifically the identification of
patients with acute coronary syndrome.

6. Pre-test

16. Chest Pain Low Risk ‘Rule-Out’
Pathways
• Clinical History: What Does the Evidence
Show?
• + [positive]
• Radiation of pain to the arms or shoulders and
association with exertion, diaphoresis, nausea
or vomiting are useful for ruling in the
diagnosis of AMI.

17. Chest Pain Low Risk ‘Rule-Out’
Pathways
•- [negative]
• a history of pain that is sharp, positional or
pleuritic decreases the probability of AMI.

18. What about burning pain?
• Traditionally, this was meant for GERD
• But recent data shows this type of pain
increases the probability of AMI

19. How useful is clinical examination?
• In low risk chest pain – very minimal
information obtained
• The only useful finding that is seen with any
frequency is reproduction of pain by chest
wall palpation, which reduces the probability
of AMI but does not, on its own, rule out AMI.

20. How useful is the ECG?
• ST segment deviation and deep T wave inversion
indicate acute coronary syndrome with a
substantial risk of adverse outcome. These
changes must be identified and the patient
admitted.
• Other changes on the initial ECG are less specific.
Minor T wave inversions (<3mm), flat or biphasic
T waves may suggest myocardial ischaemia, but
may also be positional or due to hyperventilation,
hypertension, ventricular strain or previous
cardiac disease.

21. Troponins
• Troponin levels have been shown to predict
subsequent risk of adverse outcome.
• Higher levels are associated with progressively
higher risk, but any elevation of troponin
appears to be prognostically significant.
• A negative troponin level does not exclude
coronary heart disease, but a low risk patient
with a negative troponin level will be at very
low risk of adverse outcome.

23. Clinical Decision Rules and Predictive
Scores
• Goldman algorithm
• ACI TIPI
• TIMI
• GRACE
• New Vancouver Chest Pain rule
• ADAPT Trial
• Sanchis score
• HEART score
• EDACS

24. Practical approach to Low risk chest
pain

25. TIMI vs HEART SCORE
• Sun B et al. Circulation 2015: 8,255 patients –>
Receiving Operator Characteristic (ROC) Curve
= HEART 0.75 vs TIMI 0.68
• Backus et al Current Cardiology Reviews 2011
–> c-statistic = HEART 0.9 vs TIMI 0.65
• The HEART Score is more accurate than TIMI
and specifically outperforms TIMI at “low risk”
thresholds

27. HEART SCORE
• Values 0-3 – considered low risk

29. how good is a HEART Score of 0 – 3 at
predicting 30 – 45 day MACE?
• 11 Trials with >17,000 patients
• Almost 40% identified as low risk
• 30 – 45d MACE Rate = 1.6%

31. Can We do Better than 1.6% MACE?
• Mahler et al have published 2 external
validation studies of the HEART Score in the
US using a HEART Score of 0 – 3 +
contemporary troponin at 0 and 3 hrs.
• 2 Trials with >1000 patients
• Identified approximately 25% as low risk
• 30 day MACE = 0.8%

33. Is there anything more we can do to
decrease this risk?
• Hess et al published The Chest Pain Choice
Trial in 2012 - 204 patients
• Usual Care vs Decision Aid
• Patients felt more informed with the decision
aid

35. • I tell my patients at this point in your work up, for
every 100 patients who come in to the ED with
chest pain and negative results like yourself, 1 in
100 will have a heart attack or pre-heart attack
diagnosis in the next 30 days. So we really have 3
options:
– Admit you to the observation unit for stress testing,
however this could lead to a false positive test and
more testing (It’s hard to get to less than 0.8%)
– Discharge you home to follow up with your primary
care doctor in the next 30 days for further evaluation
of your chest pain?
– If you don’t have a primary care doctor I can get you
an appointment in one of our clinics in the next 30
days to further evaluate this chest pain.
• I then document whatever conversation and
decision is made in the patient chart.

39. University of Maryland ADP

40. CAD Probability - Coronary Artery
Disease (CAD) Probability Assessment
• The presence of an appropriately timed
negative troponin in a patient with a normal
or non-diagnostic ECG and low risk chest pain,
risk stratifies the patient to a very low 30 day
risk of an adverse cardiac event and allows
safe discharge from the ED; it does not
exclude coronary artery disease (CAD) as a
cause of their presenting complaint.

41. NICE 2010 guidelines
• Advises the use of pre-test CAD probability
assessment for patients who have presented
with cardiac-sounding chest pain and who
have had an acute coronary syndrome or AMI
clinically and biochemically excluded. The pre-
test probability of CAD will determine the
need for further investigation.

42. CAD probability assessment can be done by the emergency
physician using a combination of factors as shown in Table 1.

43. NICE further recommends that the pre-test probability of CAD
determines the need (or otherwise) for further investigation as
follows

44. References
• Than M et al. A 2-h diagnostic protocol to assess patients with chest pain
symptoms in the Asia-Pacific region (ASPECT): a prospective observational
validation study. Lancet 2011; 377 (9771): 1077-84. PMID: 21435709
• SJ Aldous et al. A new improved accelerated diagnostic protocol safely identifies
low-risk patients with chest pain in the emergency department. Acad Emerg Med
2012; 19 (5): 510 – 6. PMID: 22594354
• Than M et al. 2-Hour accelerated diagnostic protocol to assess patients with chest
pain symptoms using contemporary troponins as the only biomarker: the ADAPT
trial. J Am Coll Cardiol 2012; 59(23): 2091 – 8. PMID: 22578923
• Sun B et al. Assessment of Chest Pain in the Emergency Department. Circulation
2015; 132: A13647. Abstract Only
• Backus BE et al. Risk Scores for Patients with Chest Pain: Evaluation in the
Emergency Department. Curr Cardiol Reviews 2011; 7(1): 2 – 8. PMCID:
PMC3131711
• Hess EP et al. The Chest Pain Choice Decision Aid: A Randomized Trial. Circ
Cardiovasc Qual Outcomes 2012; 5(3): 251 – 9. PMID: 22496116
• Sun BC et al. Comparison of the HEART and TIMI Risk Scores for Suspected Acute
Coronary Syndrome in the Emergency Department. Crit Pathw Cardiol 2016; 15
(1): 1 – 5. PMID: 26881812

45. • Thank you