- Do we still need to send CK-MB’s when testing for ACS?
- How does conventional troponin (c-TN) compare to high sensitivity troponin (hs-TN) in patients with chest pain?
- Is the current approach to testing with cardiac biomarkers problematic?
- Is there evidence for a link between anger/mental stress and myocardial ischemia?
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1. Do we still need to send CK-MB’s when testing for ACS?
Le RD, Kosowsky JM, Landman AB, et al. Clinical and financial impact of removing creatine kinase-MB from the routine testing menu in the emergency setting. Am J Emerg Med. 2015;33(1):72–5. PMID: 25455047.
- Troponin (TN) testing has become standard
- Correlates with prognosis
- Incorporated into the universal definition of myocardial infarction
- CK-MB was removed from cardiac lab panel at large academic medical center (BWH)
- CK-MB could still be ordered manually by physicians
- Data collected during a 12 month period (6 months pre- & post-removal of CK-MB from panel)
- Specimens with normal TN’s, but elevated CK-MB and CK-MB indexes were considered discrepant, and independently reviewed by 2 ED physicians for presence of ACS and documentation of final diagnosis
- Of 6444 cases included in the analysis, only 17 were discrepant
- Of all 17 cases, no patients were diagnosed with ACS
- Removal of CK and CK-MB from the panel translated to ~ $47,000 in savings
CK-MB can be removed from the routine ED cardiac panel without adversely affecting patient care. Substantial cost savings can be achieved by reducing unnecessary CK-MB and associated CK orders.
Saenger AK, Jaffe AS. Requiem for a heavyweight: the demise of creatine kinase-MB. Circulation. 2008;118(21):2200–6. PMID: 19015414.
2. How does conventional troponin (c-TN) compare to high sensitivity troponin (hs-TN) in patients with chest pain?
Lipinski MJ, Baker NC, Escárcega RO, et al. Comparison of conventional and high-sensitivity troponin in patients with chest pain: A collaborative meta-analysis. Am Heart J. 2015;169(1):6–16.e6. PMID: 25497242.
- Comparison of conventional troponin (c-TN) vs. high-sensitivity troponin (hs-TN) in patients with chest pain
- Evaluated 17 studies (n=8644) and compared sensitivity and specificity of the biomarkers for diagnosis of acute MI and assessment of prognosis
- Baseline and 2nd serial levels were obtained
- Summary of results from pooled analysis
- Baseline values: hs-TN had significantly greater sensitivity vs. c-TN (88.4% vs. 74.9%)
- 2nd serial values (q2-3 hrs): hs-TN was slightly more sensitive vs. c-TN (92.8% vs. 89.5%)
- Baseline values: hs-TN had significantly lower specificity vs. c-TN (81.6% vs. 93.8%)
- 2nd serial values (q2-3 hrs): hs-TN had significantly lower specificity vs. c-TN (80.7% vs. 95.2%)
- hs-TN’s have the benefit of significantly greater early sensitivity and NPV with a lower negative LR compared with c-TN. However, this is at the cost of specificity, PPV, and positive LR
- Elevation of baseline hs-TN identified a greater number of patients who died or had nonfatal MI during follow up compared with elevation of baseline c-TN
- Baseline elevation of hs-TN, but with a negative baseline c-TN was associated with an incremental increase in risk for death or nonfatal MI during follow-up (average of 12.3 months)
- Although hs-TN’s may enable rapid rule out of ED chest pain patients, their reduction in specificity and PPV may prompt costly cardiovascular workup that does not necessarily result in improved patient oriented outcomes
- Remember, you can have unstable angina and ischemia with a negative troponin. Focus on the HPI and ECG to guide your management.
- It is critical to interpret these biomarkers in the clinical context of the patient. The importance of clinical history and appropriate ECG evaluation cannot be underestimated!
Newby LK, Jesse RL, Babb JD, et al. ACCF 2012 expert consensus document on practical clinical considerations in the interpretation of troponin elevations: a report of the American College of Cardiology Foundation task force on Clinical Expert Consensus Documents. JACC.
2012;60(23):2427–63. PMID: 23154053
- Troponins can be elevated in many nonischemic conditions (CHF, PE, renal failure, infection/sepsis, stroke, SAH, inflammation, trauma, electrical shock, malignancy, stress CM, etc.). They can provide prognostic information, but will not cause you to change your acute management.
3. Is the current approach to testing with cardiac biomarkers problematic?
Makam AN, Nguyen OK. Use of cardiac biomarker testing in the emergency department. JAMA Intern Med. 2015;175(1):67–75. PMID: 25401720.
- Retrospective study of ED adult visits from 2009-2010 National Hospital Ambulatory Medical Care Survey
- 44,448 ED visits
- Cardiac biomarkers (CBs; TN & CK-MB) were tested about 17% of visits
- CBs were obtained in 8.2% of visits despite the absence of typical or atypical signs and symptoms (S/Sx) of ACS
- Overall, 1/3 of all visits with CB testing had no typical or atypical S/Sx of ACS
- Among admissions, CB testing was done in 47% of all visits (~35% had no typical or atypical S/Sx of ACS
- Of all visits with CB testing, ~ 27 % did not have an ECG!
- Greatest predictors of CB testing:
- S/Sx of ACS, suspicion of ACS
- Visit duration
- Number of other tests performed in ED
- 50% likely to get CBs if 5-10 other tests ordered
- 80% likely to get CBs if > 10 other tests ordered
- This approach to ordering CBs is problematic
- Increased costs
- Low risk populations = low specificity ➔more false positives ➔need for serial testing
- Results in unnecessary admissions
- Unnecessary additional workups and procedures
- Unnecessary consultations
Shot-gunning labs is costly and may not be in the best interest of your patients. Only order CB’s for ACS when there is a reasonable suspicion based on your HPI and ECG!
Wellness and ACS
4. Is there evidence for a link between anger/mental stress and myocardial ischemia?
Pimple P, Shah A, Rooks C, et al. Association between anger and mental stress-induced myocardial ischemia. Am Heart J. 2015;169(1):115–121.e2. PMID: 25497256.
- Assessed “angry personality” using a validated scoring system
- Anger, both as an emotional state and as a personality trait, is significantly associated with a propensity to develop myocardial ischemia during mental stress but not during exercise/pharmacological stress. Bottom line…angry people really need to chill out!