ACS - Stress Testing
Revision as of 00:41, 20 September 2013 by Ostermayer (talk | contribs)
Background
- Stress testing is recommended for pts w/ low-moderate pretest probability of CAD
- Not helpful in pts w/ very low risk or high risk
ECG-Based Exercise Treadmill Testing
- 68% sn, 77% sp
- Contraindications to Exercise Testing
- Absolute
- MI (within 2 days)
- High-risk unstable angina
- Uncontrolled cardiac dysrhythmias
- Symptomaticaortic stenosis
- Uncontrolled symptomatic heart failure
- Acute pulmonary embolus or pulmonary infarction
- Acute myocarditis or pericarditis
- Acute aortic dissection
- Relative
- Baseline ST segment abnormalities
- Left main coronary stenosis
- Moderate stenotic valvular heart disease
- Electrolyte abnormalities
- Severe HTN (>200 sys, >110 dia)
- Tachydysrhythmias or bradydysrhythmias
- HOCM
- Mental or physical impairment
- High-degree atrioventricular block
- Absolute
- The Bottom Line:
- ETT has low sensitivity and specificity overall (especially for women) and as such is not a good test for patients in whom suspicion for ACS is high
- ETT is safe in low-risk and select intermediate-risk patients as a way of determining who is at low risk for short term adverse events (and therefore can go home)
- ETT does not have prognostic value for patients who return to the ED with concerning symptoms or EKG changes
- The Bottom Line:
Echocardiography
- Sn 80% sp 84%
- When used in low-risk pts, NPV 97-100%
- Who should be tested (ACC/AHA Class IIa)
- patients with abnormal baseline EKG
- patients unable to exercise
- women with low- to intermediate-risk
- Who shouldn’t be tested with stress echo
- patients in whom a sub-optimal study is likely (very obese, COPD with expanded AP chest diameter, etc)
- patients with grossly abnormal baseline LV or valvular function (e.g. severe AS)
- The Bottom Line
- Stress echocardiography (chemical or exercise induced) has greater sensitivity and specificity than ETT for ACS (especially for women)
- Patients with normal stress echos are at very low risk for mortality within 1 year
- A normal stress echo does not preclude subsequent ACS, nor should it lower suspicion for ACS when a patient presents with new symptoms!
Nuclear Medicine aka PMIBI
- Who Should be Tested
- patients with intermediate risk ACS who have uninterpretable EKGs or are unable to exercise
- patients in whom stress echocardiography is unlikely to yield a technically adequate study
- Who Shouldn’t be
- Low risk patients
- The Bottom Line
- P-MIBI has greater sensitivity than stress echo in the diagnosis of CAD (not what we’re interested in) at much higher cost and technical difficulty
- Both studies have good sensitivity and specificity for the diagnosis of ACS and good NPV for short-term events (what we’re interested in)
See Also
Acute Coronary Syndrome (Main)
Source
Tintinalli Rosens