Open Access Research BMJ Open: first published as 10.1136/bmjopen-2013-004449 on 24 March 2014. Downloaded from Diagnostic accuracy of copeptin sensitivity and specificity in patients with suspected non-ST-elevation myocardial infarction with troponin I below the 99th centile at presentation Jonathan Duchenne,1 Stéphanie Mestres,2 Nicolas Dublanchet,3 Nicolas Combaret,4 Geoffroy Marceau,2 Laurent Caumon,1 Laurent Dutoit,5 Sylvie Ughetto,6 Pascal Motreff,4 Vincent Sapin,2 Jeannot Schmidt3 To cite: Duchenne J, ABSTRACT Strengths and limitations of this study Mestres S, Dublanchet N, Objective: To determine whether copeptin-us can rule et al. Diagnostic accuracy of out diagnosis of non-ST-segment elevation myocardial ▪ copeptin sensitivity and To our knowledge, our prospective multicentric infarction (NSTEMI) without prolonged monitoring and specificity in patients with study is the only one that includes only patients suspected non-ST-elevation serial blood sampling in patients with high-sensitive with suspected non-ST-segment elevation myo- myocardial infarction with cardiac troponin I (hs-cTnT) below the 99th centile at cardial infarction and high-sensitive cardiac troponin I below the 99th presentation to the emergency department (ED). troponin I below the 99th centile at presentation centile at presentation. BMJ Design: Prospective, non-randomised, individual to the emergency department, to limit spectrum Open 2014;4:e004449. blinded diagnostic accuracy study. bias. doi:10.1136/bmjopen-2013- Setting: Two EDs of a rural region of France. ▪ The main limitation of our study is the number 004449 Participants: Patients with chest pain suspected of of patients included. Indeed we are below the NSTEMI with onset within the last 12 h were prevalence. This may be explained by the fact ▸ Prepublication history for considered for enrolment. that our study included only patients with nega- this paper is available online. Interventions: Serial clinical, electrographical and tive ultrasensitive troponin at admission. http://bmjopen.bmj.com/ To view these files please biochemical investigations were performed at However, this is the only group of patients for visit the journal online which a multimarker rule-out strategy could add (http://dx.doi.org/10.1136/ admission and after 2, 4, 6 and 12 h. Hs-cTnT was bmjopen-2013-004449). measured using an assay with Dimension VISTA, diagnostic value. Siemens. Copeptin was measured by the BRAHMS ▪ Moreover, we evaluated the sensitivity troponin Received 6 December 2013 copeptin-us assay on the KRYPTOR Compact Plus and copeptin for all patients with the same assay Revised 7 February 2014 system. The follow-up period was 90 days. technique which enabled to control the occur- Accepted 27 February 2014 Primary and secondary outcome measures: rence of methodological bias. Copeptin, troponin, myoglobin and creatine kinase on September 25, 2021 by guest. Protected copyright. values. Clinical and paraclinical events. The final diagnosis was adjudicated blinded to copeptin result. INTRODUCTION Results: During 12 months, 102 patients were analysed. Final diagnosis was NSTEMI for 7.8% (n=8), Detection of a rise and/or fall of cardiac unstable angina for 3.9% (n=4), cardiac but non- troponin with clinical symptoms of ischaemia coronary artery disease for 8.8% (n=9), non-cardiac or abnormal ECG or imaging findings chest pain for 52% (n=53) and unknown for 27.5% remains the gold standard for the identifica- (n=28). There was no statistical difference for copeptin tion of myocardial infarction (MI).1 At an values between patients with NSTEMI and others emergency department (ED), patients with (respectively 5.5 pmol/L IQR (3.1–7.9) and 6.5 pmol/L non-ST-segment elevation MI (NSTEMI) – IQR (3.9 12.1), p=0.49). Only one patient with working diagnosis require serial measure- NSTEMI had a copeptin value above the cut-off of 95th ment of troponin.2 However, most of these centile at admission. patients do not have acute coronary syn- For numbered affiliations see Conclusions: In this study, copeptin does not add a drome (ACS). Identifying patients suffering end of article. diagnostic value at admission to ED for patients with suspected acute coronary syndrome without ST-segment from non-life-threatening diseases with only one blood sample is a challenge. Many bio- Correspondence to elevation and with hs-cTnT below the 99th centile. Dr Jonathan Duchenne; Trial registration number: Clinicaltrials.gov identifier: markers were evaluated, alone or in combin- 34 duchenne.jonathan NCT01334645. ation with troponin. Copeptin accuracy @ch-aurillac.fr was explored recently in this rule-out Duchenne J, Mestres S, Dublanchet N, et al. BMJ Open 2014;4:e004449. doi:10.1136/bmjopen-2013-004449 1 Open Access BMJ Open: first published as 10.1136/bmjopen-2013-004449 on 24 March 2014. Downloaded from diagnostic strategy. This glycopeptide, which is the criteria for pain suggestive of ACS were those of usual C-terminal part of the arginine vasopressin (AVP) pre- clinical practice of investigators. It should be non- cursor, is secreted stoichiometrically with AVP from the traumatic. Written informed consent was obtained from neurohypophysis. AVP is a marker of endogenous stress all participating patients. Patients with ST-segment eleva- but routine measurement of AVP is limited due to its tion, legal incapacity, sepsis, shock, lung neoplasms, ter- instability and difficulty of the assay.5 Copeptin now minal kidney failure requiring dialysis and life appears to be an attractive alternative to AVP because of expectancy of less than 6 months were excluded. After its stability and development of automated technique for the result of the first blood sample, patients with hypo- – reliable and reproducible dosage.6 8 natraemia <135 mmol/L or hs-cTnT >0.045 μg/L were Since the first publication making this indication in released of the study. – 2009, several studies have investigated copeptin.9 35 ST-segment elevation, measured at the J point, was Some of these studies suggest that the association of diagnosed according to the third universal definition of troponin and copeptin at the first measurement has a MI.1 It should be found in two contiguous leads with the powerful negative predictive value (NPV) to rule out cut-off points: ≥0.1 mV in all leads other than leads patients without NSTEMI. V2–V3 where the following cut points apply: ≥0.2 mV in Interpretation of the copeptin diagnostic accuracy men ≥40 years; ≥0.25 mV in men <40 years, or ≥0.15 mV through these studies is not evident, first, because ana- in women. lysis comparisons are disrupted by the development of Sepsis, shock, lung neoplasms, terminal kidney failure high-sensitivity cardiac troponin T and I assays and the requiring dialysis and hyponatraemia are diseases in availability of three commercial assays for copeptin which the rate of vasopressin, and thus of copeptin, may (LUMItest, Copeptin Kryptor, Copeptin-us Kryptor). be modified. These patients were not included to min- Furthermore, many protocols included patients with imise confounding factors. STEMI and patients with a high-sensitive cardiac tropo- nin above the 99th centile at admission. For these Study protocol patients, copeptin does not add diagnostic information, On admission, all patients underwent an initial clinical and urgent revascularisation or serial blood samples, assessment, including medical history, temperature, respectively, remain necessary. respiratory rate, cardiac frequency, blood pressure, pulse The aim of this study was to determine whether oxymetry, 18-lead ECG, chest X-ray and screening blood copeptin-us can rule out diagnosis of acute MI without test including C reactive protein, natraemia, creatinine, prolonged monitoring and serial blood sampling in hs-cTnT and creatine kinase (CK). Risk factors and patients with suspected NSTEMI and high-sensitive medical history were collected as stated by the patients, cardiac troponin I (hs-cTnT) below the 99th centile at and also the treatment received. Family history of coron- http://bmjopen.bmj.com/ presentation to ED. ary artery disease (CAD) was noted if a member of the first-degree relatives had CAD before 65 years. Blood samples were collected for hs-cTnT and CK analysis and METHODS 18-lead ECG was performed after 2, 4, 6 and 12 h. At Study design and setting each time point, blood sample was centrifuged and This diagnostic test evaluation is a prospective non- plasma was frozen at −80°C for copeptin and myoglobin randomised individual blinded multicentric cohort testing at the end of the study recruitment, blinded to study. The Clermont-Ferrand University Hospital final diagnosis. Further investigations and treatment of on September 25, 2021 by guest. Protected copyright. designed and coordinated the study. The duration of patients were not modified by the study. At 90 days, clin- the study was 1 year, between March 2011 and March ical events were collected from the patients, their 2012 at the ED of two hospitals of Auvergne, a rural general practitioners and the hospitals where they were fi region of France (1.3 million people). The rst one, examined. Gabriel Montpied in Clermont-Ferrand, is a teaching Concentration of copeptin was measured by the hospital and provincial referral centre with 48 000 ED BRAHMS copeptin-us immunoluminometric assay on admissions/year. The second hospital, Henri Mondor in the KRYPTOR Compact Plus system (Thermo Fisher Aurillac, is a general hospital with 25 000 ED admis- Scientific). The detection limit as described by the sions/year. Each unit had a catheterisation laboratory manufacturer was signified as being 0.9 pmol/L and the available 24 h a day. lowest concentration measurable with a coefficient of variation (CV) <10% has been reported <4 pmol/L. The Population direct measuring range was 0.9–500 pmol/L. The 95th Consecutive patients admitted with chest pain suspected centile among healthy participants was <12.0 pmol/L of NSTEMI in the ED were considered for enrolment in and was specified for rapid exclusion of acute MI (AMI).