Prognostic value of T1 mapping and extracellular volume fraction in cardiovascular disease: a systematic review and meta-analysis.

T1 mapping and extracellular volume (ECV) fraction are useful new magnetic resonance imaging (MRI) techniques to evaluate myocardial fibrosis; however, their prognostic value has not been well described. In this study, a systematic review and meta-analysis evaluating the prognostic value of these techniques is performed in patients with ischemic and non-ischemic cardiomyopathy. PubMed, Cochrane CENTRAL, and Meta-Register of Controlled Trials were searched for studies that utilized T1 mapping and ECV and that also had ≥ 12 months of follow-up data. The primary endpoints included were cardiovascular death and non-fatal cardiac events (heart failure, acute coronary syndrome). Six studies involving a total of 1524 patients and a mean follow-up of 26.3 months were included. Patients had a mean age of 57.6 years and 56.5% were male. Summary effect estimates were generated with fixed/random-effects modeling and hazard ratios were assessed. Patients with a higher ECV value had a significantly higher incidence of cardiovascular death (hazard ratio [HR] 1.79 [95% CI 1.24 to 2.58; P = 0.09) and combined cardiac events (HR 1.11 [95% CI 1.08-1.15]; P < 0.0001). Patients with higher native T1 values and (HR 1.06 [95% CI 0.96 to 1.17]; P = 0.27) and lower post contrast T1 value (HR 0.99 [95% CI 0.98-0.99], P < 0.001) overall had no increased risk for cardiovascular events. Comparing with other CMR parameters, ECV has excellent potential prognostic value and can help guide risk stratification of patients with ischemic or non-ischemic cardiomyopathy into high and low risk for adverse cardiovascular events.