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Three Part Question

In [stable adult patients with acute pericarditis] does [measurement of cardiac troponins] enable [accurate prediction of complications and facilitate hospital discharge]?

Clinical Scenario

A 25 year-old man presents to the Emergency Department with central sharp chest pain that is eased by sitting forward. ECG shows widespread saddle shaped ST elevation consistent with acute pericarditis.

The patient is clinically stable with normal heart rate and blood pressure and no signs of left ventricular failure. You wonder whether it will be worthwhile sending blood for troponin to rule out significant myocardial damage in relation to myopericarditis. As such you wonder whether a normal troponin will reassure you that the patient is at low risk of complications and suitable for out-patient treatment. Similarly, you wonder whether a raised troponin would indicate the need for hospital admission.

Search Strategy

Ovid MEDLINE 1950 - April Week 5 2008
Ovid EMBASE 1980 - 2008 Week 18
[exp Pericarditis OR pericarditis.mp.] AND [exp Early Diagnosis/ OR exp Diagnosis/ OR exp Diagnosis, Differential/ OR diagnosis.mp. OR exp Sensitivity and Specificity/ OR sensitivity.mp. OR exp "Predictive Value of Tests"/ OR negative predictive value.mp.] AND [exp Troponin/ OR troponin$.mp.] limit to human and English language

Search Outcome

Altogether 70 papers were identified using MEDLINE, 3 of which were relevant to the three-part question. 24 papers were identified using EMBASE, including the same 3 relevant papers.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Brandt et al, 2001, Germany	All patients (n = 14) admitted through the ED of a German hospital with a diagnosis of acute pericarditis (defined by at least two of: typical chest pain, pericardial friction rub, characteristic ECG changes) within 24 h of symptom onset over 2 years. All patients underwent serial TnI and CK-MB estimation over 5 days	Prospective observational cohort study	Detectable circulating TnI	Present in 10 of 14 patients (71%). In half of these 10, the highest values were present on day of admission; in the remaining patients it was reached on the second day	Small numbers. No follow up data. Potential selection bias. Only hospitalised patients included
			Echocardiography	All patients underwent echocardiography within 24 h. 2 of 14 patients (14%) had a pericardial effusion. All patients had normal left ventricular function with no regional wall motion abnormalities
			Duration of troponin elevations	TnI levels detectable for a maximum of 6 days after symptom onset
Imazio et al, 2003, Italy	118 Consecutive patients who presented to the ED or Cardiology Department (including ambulatory and day hospital service) and were diagnosed with acute pericarditis within 24 h of symptom onset. Acute pericarditis was defined by the presence of at least two of: pericarditic chest pain, pericardial friction rub and widespread ST elevation on the ECG. Patients with causes other than viral or idiopathic pericarditis were subsequently excluded. Patients underwent serial estimation of TnI, serial echocardiography and follow-up for at least 1 year	Prospective observational cohort study	TnI values	A TnI rise was detectable in 38 patients (32.2%). Mean TnI 1.02 (1.21) ng/ml (range 0.2–28.0 ng/ml)	Less potential selection bias than other relevant studies but patients discharged from the ED may still have been missed thus selecting a sicker group of patients
			ST elevation to detect important myocardial injury (TnI ≥1.5 ng/ml)	Sensitivity 88.9%, specificity 32.1%
			ST elevation or PR depression to detect important myocardial injury	Sensitivity 100%
			Features more commonly associated with positive TnI	Younger age (31.9 vs 57.3 years, p<0.001); male gender (71% vs 42.5%, p = 0.007); ST elevation (97.4% vs 56.2%, p<0.001); pericardial effusion at presentation (86.8% vs 60.0%, p = 0.007)
			Temporal pattern of TnI rise	Group 1 (TnI <0.4 ng/ml, CK-MB normal, 24.6% of all cases). Detectable levels for 2–3 days
			Complications at follow-up	Similar rate of complications in patients with positive or negative TnI (recurrent pericarditis 18.4% vs 18.7%; constrictive pericarditis 0 vs 1.3%; no cases of cardiac tamponade, residual left ventricular dysfunction, congestive heart failure or dilated cardiomyopathy, p = NS for all)
Bonnefoy et al, 2000, France	69 Consecutive patients hospitalised with acute idiopathic pericarditis between January 1996 and December 1997 and who had TnI measurement on admission. Pericarditis defined as typical chest pain with at least one of: pericardial friction rub, serial compatible ST-T changes, pericardial effusion on echocardiography. All patients had a single TnI level measured at presentation	Retrospective cohort study	Incidence of TnI elevation	TnI detectable in 34 patients (49%). Mean TnI 8 (12) ng/ml (median 1) TnI >1.5 ng/ml (AMI diagnostic threshold) in 15% (22)	Small numbers. Retrospective design. 12 Patients identified did not undergo troponin testing. Time of follow-up not standardised
			Mean length of hospital stay	No difference between patients with detectable TnI (6.4 (4.4), median 5 days) vs none (4.9 (3.1), median 4 days)
			Follow-up data	Follow-up complete in 61 patients. No difference in relapse rate between TnI-positive (27%) and TnI-negative (19%) patients, p = 0.4. 20% of TnI-positive and 19% of TnI-negative patients were rehospitalised. Same frequencies observed with TnI ≥1.5 ng/ml
			ST elevation for detecting patients with raised TnI	ST elevation present in 67% of patients with detectable TnI and 62% of those without. For detecting TnI ≥1.5 ng/ml sensitivity 93%, specificity 43%
			Echocardiographic wall motion abnormalities	All patients with echocardiographic wall motion abnormality (n = 5) had detectable TnI, four had TnI ≥1.5 ng/ml
			Clinical data	Patients with TnI ≥1.5 ng/ml more likely to be younger (37 (14) vs 52 (16) years, p = 0.0002) and more likely to have had a recent infection (60% vs 31%, p = 0.01). No significant relationship with pericardial friction rub, pericardial effusion, fever, PR deviation, ESR, CRP elevation

Comment(s)

The prognostic value of troponins in acute coronary syndromes has been well documented (Hamm CW et al. 1997;Heidenreich PA et al. 2001;Sayre MR et al. 1998). Further, myocarditis is a potentially serious condition that is often associated with pericarditis and often causes troponin elevations. Stable patients who are diagnosed with acute pericarditis in the Emergency Department are often discharged and treated on an out-patient basis. However some people advocate troponin testing prior to discharge in order to exclude significant myocardial injury. The three relevant studies identified in this short-cut review suggest that the incidence of troponin elevations in patients with acute pericarditis is relatively high (32.2 – 71%), although all of these studies are subject to potential selection bias. Nonetheless, the incidence of complications is relatively low and none of the studies have demonstrated significant differences in the rates of important complications between troponin positive and troponin negative patients. There is therefore no evidence that troponins carry prognostic information in patients with acute pericarditis. Perhaps significantly, however, all patients with echocardiographic wall motion abnormalities in the study by Bonnefoy et al had detectable TnI. When the diagnosis is not in doubt, it remains unclear how TnI may be used to guide patient disposition in the ED. Further prospective studies should focus upon recruiting undifferentiated ED patients who meet diagnostic criteria for acute pericarditis.

Editor Comment

AMI, acute myocardial infarction; CK-MB, creatine kinase (myocardial type); CRP, C-reactive protein; ED, emergency department; ESR, erythrocyte sedimentation rate; PR, pulse rate; TnI, troponin I.

Clinical Bottom Line

Troponin elevations are common in patients with acute pericarditis but there is no evidence that they carry prognostic information in this clinical setting. It remains uncertain how troponins may be used to guide the management of these patients in the Emergency Department.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Brandt RR, Filzmaier K, Hanrath P. Circulating cardiac troponin I in acute pericarditis. Am J Cardiol 2001;87:1326–8.
2. Imazio M, Demichelis B, Cecchi E, et al. Cardiac troponin I in acute pericarditis. J Am Coll Cardiol 2003;42:2144–8.
3. Bonnefoy E, Godon P, Kirkorian G, et al. Serum cardiac troponin I and ST segment elevation in patients with acute pericarditis. Eur Heart J 2000;21:832–6.
4. Hamm CW, Goldmann BU, Heeschen C, et al. Emergency room triage of patients with acute chest pain by means of rapid testing for cardiac troponin T or troponin I. N Engl J Med 1997;337:1648–53.
5. Heidenreich PA, Alloggiamento T, Melsop K, et al. The prognostic value of troponin in patients with non-ST elevation acute coronary syndromes: a meta-analysis. J Am Coll Cardiol 2001;38:478–85.
6. Sayre MR, Kaufmann KH, Chen IW, et al. Measurement of cardiac troponin T is an effective method for predicting complications among emergency department patients with chest pain. Ann Emerg Med 1998;31:539–49.