Prognostic value of non-contrast myocardial T1 mapping in cardiovascular diseases: a systematic review and meta-analysis.

Myocardial fibrosis predisposes the development of main adverse cardiovascular events (MACEs) in various cardiac disorders. Native T1 derived from cardiac magnetic resonance allows the quantitative assessment of myocardial fibrosis without the use of contrast media. However, the prognostic value of native T1 in risk stratification remains uncertain. We searched MEDLINE®, Embase, and the Cochrane Library for cohort studies up to July 31, 2021, that reported prognostic data for native T1 in various cardiac disorders; the studies enrolling patients with myocardial iron or amyloid deposition, edema, and inflammation were excluded. A random effects meta-analysis was conducted. Heterogeneity was assessed using I2 statistic. Nineteen studies with 5,380 patients were included in this meta-analysis. Patients with MACEs had higher native T1 than those without [weighted mean difference: 27.35 (15.55-39.16), I2 = 23.2%]. The increase of native T1 per 1 ms [pooled adjusted hazard ratio (HR): 1.02 (1.00-1.03), I2 = 41.8%] and per ≥ 10 ms [pooled adjusted HR: 1.11 (1.07-1.16), I2 = 28.6%] was both associated with the development of MACEs; the categorical variable derived from native T1 also has the predicative value for MACEs [pooled adjusted HR: 5.97 (3.69-9.68), I2 = 0.0%].Myocardial native T1 potentially serves as a prognostic biomarker in patients with various cardiac disorders. Different variable definitions of native T1 have different positively predictive value for outcome; the categorical variable derived from native T1 may be more helpful in identifying high-risk patients.