title: Use of a highly-sensitive cardiac troponin I assay in a screening population for hypertrophic cardiomyopathy: a case-referent study.
abstract: BACKGROUND
  Hypertrophic cardiomyopathy (HCM) is a genetic condition, and relatives of affected persons may be at risk. Cardiac troponin biomarkers have previously been shown to be elevated in HCM. This study examines the new highly-sensitive cardiac troponin I (hsTnI) assay in a HCM screening population.
  
  
  METHODS
  Nested case-control study of consecutive HCM sufferers and their relatives recruited from May 2010 to September 2011. After informed consent, participants provided venous blood samples and clinical and echocardiographic features were recorded. Associations between the natural log (ln) of the contemporary troponin I (cTnI) and hsTnI assays and markers of cardiac hypertrophy were examined. Multiple regression models were fitted to examine the predictive ability of hsTnI for borderline or definite HCM.
  
  
  RESULTS
  Of 107 patients, 24 had borderline and 19 had definite changes of HCM. Both TnI assays showed significant, positive correlations with measures of cardiac muscle mass. After age and sex adjustment, the area under the receiver operator characteristic (AUROC) curve for the outcome of HCM was 0.78, 95% CI [0.65, 0.90], for ln(hsTnI), and 0.66, 95% CI [0.51, 0.82], for ln(cTnI) (p=0.11). Including the hsTnI assay in a multiple-adjusted "screening" model for HCM resulted in a non-significant improvement in both the AUROC and integrated discrimination index.
  
  
  CONCLUSIONS
  Both cTnI and hsTnI show a graded, positive association with measures of cardiac muscle mass in persons at risk of HCM. Further studies will be required to evaluate the utility of these assays in ECG- and symptom-based identification of HCM in at-risk families.
authors.affiliation: Department of Cardiology, Mater Misericordiae University Hospital, Eccles St,, Dublin 7, Ireland. catherine.mcgorrian@ucd.ie.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: McGorrian
authors.forename: Sarah
authors.initials: S
authors.lastname: Lyster
authors.forename: Andrew
authors.initials: A
authors.lastname: Roy
authors.forename: Heloise
authors.initials: H
authors.lastname: Tarrant
authors.forename: Mary
authors.initials: M
authors.lastname: Codd
authors.forename: Peter
authors.initials: P
authors.lastname: Doran
authors.forename: Maria
authors.initials: M
authors.lastname: Fitzgibbon
authors.forename: Joseph
authors.initials: J
authors.lastname: Galvin
authors.forename: Niall G
authors.initials: NG
authors.lastname: Mahon
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002138:Calibration; D002312:Cardiomyopathy, Hypertrophic / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D016022:Case-Control Studies; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods*; D011446:Prospective Studies; D016037:Single-Blind Method; D020107:Troponin T / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D020107:Troponin T
references.citation: Circ J. 2011;75(4):919-26
references.pmid: 21304210
references.citation: J Am Coll Cardiol. 2008 Mar 11;51(10):1033-9
references.pmid: 18325444
references.citation: Circulation. 2011 Apr 5;123(13):1367-76
references.pmid: 21422391
references.citation: Eur Heart J. 2009 Jan;30(2):139-51
references.pmid: 19136482
references.citation: J Am Soc Echocardiogr. 2005 Dec;18(12):1440-63
references.pmid: 16376782
references.citation: Circulation. 2009 May 5;119(17):2408-16
references.pmid: 19364974
references.citation: Nat Clin Pract Cardiovasc Med. 2008 Mar;5(3):158-68
references.pmid: 18227814
references.citation: Br J Sports Med. 2008 Mar;42(3):207-11
references.pmid: 17717062
references.citation: JAMA. 2002 Mar 13;287(10):1308-20
references.pmid: 11886323
references.citation: J Am Soc Echocardiogr. 2004 Oct;17(10):1086-119
references.pmid: 15452478
references.citation: J Am Coll Cardiol. 2003 Nov 5;42(9):1687-713
references.pmid: 14607462
references.citation: J Am Coll Cardiol. 2011 Dec 13;58(25):e212-60
references.pmid: 22075469
references.citation: Heart Vessels. 2006 Nov;21(6):344-9
references.pmid: 17143708
references.citation: Heart. 2003 Jun;89(6):659-60
references.pmid: 12748227
references.citation: Circ Cardiovasc Imaging. 2011 Mar;4(2):156-68
references.pmid: 21406662
references.citation: Clin Chem. 2012 Jan;58(1):54-61
references.pmid: 21965555
references.citation: Clin Cardiol. 2010 Feb;33(2):E1-7
references.pmid: 20043329
references.citation: Eur Heart J. 2005 Sep;26(18):1882-6
references.pmid: 15860513
references.citation: N Engl J Med. 2000 Jun 15;342(24):1778-85
references.pmid: 10853000
references.citation: Stat Med. 2008 Jan 30;27(2):157-72; discussion 207-12
references.pmid: 17569110
references.citation: Radiology. 1982 Apr;143(1):29-36
references.pmid: 7063747
references.citation: J Card Fail. 2010 Dec;16(12):950-6
references.pmid: 21111984
references.citation: Clin Chem. 2012 Jan;58(1):200-8
references.pmid: 22156668
references.citation: Br J Sports Med. 2009 Sep;43(9):649-56
references.pmid: 19734498
references.citation: J Am Coll Cardiol. 2008 Dec 9;52(24):1981-9
references.pmid: 19055989
references.citation: BMC Cardiovasc Disord. 2011 Jan 31;11:6
references.pmid: 21281467
references.citation: Eur Heart J. 2010 Jul;31(13):1599-607
references.pmid: 20439259