title: Quantifying late gadolinium enhancement on CMR provides additional prognostic information in early risk-stratification of nonischemic cardiomyopathy: a cohort study.
abstract: BACKGROUND
  Suspected nonischemic cardiomyopathy (NICM) is a common clinical setting with highly variable prognosis. Early noninvasive risk-stratification is important for justification of invasive examinations, specific treatment and patient surveillance. We studied the additional prognostic value of late gadolinium enhancement (LGE) and segmental wall motion abnormality (SWMA) extent on cardiovascular magnetic resonance (CMR) compared to traditional risk factors in suspected NICM.
  
  
  METHODS
  In this observational cohort study, we enrolled 86 consecutive patients referred for CMR due to suspected NICM. Patients with ischemic cardiomyopathy were excluded. CMR images were analysed for left ventricular LGE and SWMA extents and patients were followed-up for major adverse cardiac events (MACE), including cardiovascular death, aborted sudden death and cardiac transplantation.
  
  
  RESULTS
  Of 86 patients (median age: 53 years, 45% female), mainly presenting with ventricular arrhythmias (40%) and congestive heart failure (44%), 76% were finally diagnosed with NICM, 17% with left ventricle hypertrophy and 7% with idiopathic arrhythmia. On CMR, 61 patients (71%) had LGE and 56 (65%) SWMA. During median follow-up of 835 days, 15 patients (17%) reached MACE. In univariant analysis, LGE volume (hazard ratio [HR] 1.028 per 1% increase in LGE, p < 0.001), left ventricular ejection fraction (LVEF) (HR 0.959, p = 0.009) and SWMA score (HR 1.067, p = 0.012) had strongest associations with MACE. In multivariate analysis, the best overall model for event prediction included LGE volume (HR 1.027, p = 0.003), sustained ventricular tachycardia (HR 4.7, p = 0.011) and LVEF (HR 0.962, p = 0.034). Among patients with LGE, there was an event rate of 26% (14 of 61) versus 4% (1 of 25) in patients without LGE (p = 0.041, Log-rank). The highest event rate was observed in patients with LGE volume of ≥ 17%. Patients without SWMA did not experience MACE (p = 0.002, Log-rank), giving additional information in the subgroup of patients with preserved LVEF (≥ 50%).
  
  
  CONCLUSIONS
  In suspected NICM, presenting with ventricular arrhythmias or heart failure, LGE extent gives additional prognostic information compared to traditional risk factors, while the absence of SWMA may give prognostic information beyond normal LVEF. Even though the final diagnosis is uncertain in NICM, extensive amount of LGE should be considered as a sign of poor prognosis.
authors.affiliation: Heart and Lung Center, Division of Cardiology, Helsinki University Central Hospital, Po BOX 340, 00029 HUCH Helsinki, Finland. pauli.poyhonen@helsinki.fi.
authors.forename: Pauli
authors.initials: P
authors.lastname: Pöyhönen
authors.forename: Sari
authors.initials: S
authors.lastname: Kivistö
authors.forename: Miia
authors.initials: M
authors.lastname: Holmström
authors.forename: Helena
authors.initials: H
authors.lastname: Hänninen
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000209:etiology; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006333:Heart Failure / Q000209:etiology; D006352:Heart Ventricles / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D016277:Ventricular Function, Left
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine