2 Low-ProbabIlity ACS

Question 1

Chest pain feature with the highest risk for acute coronary syndrome (ACS)

Answer 1

radiation to the right arm or shoulder

Question 2

Positional changes in chest pain suggest:

Answer 2

Pericarditis - chest pain is most severe when the patient is SUPINE and is relieved when the patient sits up and leans forward

Question 3

Usual laboratory testing in the primary evaluation of acute chest pain

Answer 3

CBC
Serum electrolytes
Renal function tests
Serum troponin

Laboratory testing during the primary evaluation focuses on two goals: detecting myocardial necrosis and excluding alternative causes of chest pain

Question 4

two clinical decision aids that help in identifying a very-low-risk (<1%) cohort that does not require further cardiac testing and that is eligible for discharge

Answer 4

the HEAR Score, and
Emergency Department Assessment of Chest Pain Score

Question 5

What to be reminded of before calculating a HEAR Score?

Answer 5

Obtain an ECG and review the past medical history for known CAD.
If there are any ischemic changes or the patient has known CAD, the patient is in a HIGH-RISK CATEGORY and does NOT need a formal score.

Question 6

Cardiac risk factors [as per the HEAR score]

Answer 6

1. Diabetes mellitus
2. Current or recent (in the past 90 days) smoker
3. Hypertension
4. Hypercholesterolemia
5. Family history of CAD
6. Obesity (BMI >30 kg/m2)
7. History of significant atherosclerosis (coronary revascularization, myocardial infarction, stroke, or peripheral artery disease)

Question 6

How to interpret HEAR score

Answer 6

0-3: low risk
≥4: high risk

Question 7

How to interpret Emergency Department Assessment of Chest Pain Score

Answer 7

0-15 points: low risk
≥16 points: non-low risk

Question 8

Remarks on high-sensitivity troponin assays

Answer 8

These may make one test for troponin or a shorter sequential two-test interval enough

Question 9

To reiterate, these subsets of patients are automatically labeled as “high-risk” and do not need a formal HEAR score

Answer 9

those with ischemic changes in ECG
or those with known CAD

Question 10

When do we discharge patients with initial suspicion of [rule out] ACS?

Answer 10

Low-risk (i.e., ≤3 HEAR score)
with negative cardiac biomarkers

Question 11

What to do with high-risk patients but with negative initial cardiac biomarkers?

Answer 11

Proceed with secondary evaluation
1. Place patient in an ED observation unit or admit
2. Serial ECGs
3. Serial cardiac markers (to exclude AMI)
4. Objective cardiac testing (to exclude unstable angina)

Question 12

Examples of advanced/objective cardiac testing

Answer 12

Stress testing
Echocardiography
Nuclear medicine testing
Cardiac MRI
CT coronary angiography (CTCA)

Question 13

Some remarks on echocardiogram in relation to ACS

Answer 13

1. cannot distinguish between myocardial ischemia and acute infarction.
2. may be falsely interpreted as positive in the presence of several conditions (e.g., conduction disturbances, volume overload, heart surgery, or trauma)
3. transient wall motion abnormalities may resolve wihtin minutes of an ischemic episode
4. Resting echocardiography within 12 hours of ED arrival does NOT provide additional predictive value for myocardial infarction over myocardial markers alone
5. A normal resting echocardiogram does not exclude ACS, although it lowers the likelihood

Question 14

Nuclear medicine technique that has advantage for ED use

Answer 14

Use of technetium-99m-labeled agents such as sestamibi
- shorter half-life
- which makes larger doses possible = superior image quality
- higher ACS detection specificity

NOT thallium-201

Question 15

Disposition after the secondary evaluation

Answer 15

Discharge the patient if:
with negative cardiac markers, no dynamic ECG changes, and negative objective cardiac testing.
(give appropriate return-to-ED precautions, and arrange follow up to primary care physician within the next 2-3 days)

Admit for cardiac care if:
with positive cardiac markers, diagnostic ECG changes, or diagnostic cardiac testing supporting ACS

Question 16

Again, the usual approach for patients with “possible ACS” is:

Answer 16

serial cardiac markers followed by objective cardiac testing

this remains the foundation of ED and other observation unit protocols

Question 17

Therapy for patients with possible ACS

Answer 17

Linked to the patient’s stratification level.

In general, patients at low risk of adverse events receive aspirin and anti-ischemic therapy with nitroglycerin while their evaluation is being completed