Report by Rick Body, Specialist Registrar in Emergency Medicine

Checked by Craig Ferguson, Specialist Registrar in Emergency Medicine

Institution: Manchester Royal Infirmary, Manchester, UK

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 (ED) 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 I (TnI) to rule out significant myocardial damage in relation to myopericarditis. As such you wonder whether a normal TnI will reassure you that the patient is at low risk of complications and suitable for outpatient treatment. Similarly, you wonder whether a raised TnI 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, four of which were relevant to the three-part question. 24 Papers were identified using EMBASE, including the same four relevant papers.

COMMENT(S)

The prognostic value of TnI in acute coronary syndromes has been well documented (Hamm et al, 1997; Heidenreich et al, 2001; Sayre et al, 1998). Furthermore, myocarditis is a potentially serious condition that is often associated with pericarditis and often causes TnI elevations. Stable patients who are diagnosed with acute pericarditis in the ED are often discharged and treated on an outpatient basis. Some people, however, advocate TnI testing before discharge in order to exclude significant myocardial injury. The three relevant studies identified in this short-cut review suggest that the incidence of TnI elevations in patients with acute pericarditis is relatively high (32.2–71%), although all of the 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 TnI-positive and TnI-negative patients. There is therefore no evidence that TnI 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.