Native T1 adds independent value for cardiovascular risk assessment beyond GLS in an all-comers real-world clinical patient population

Background Deformation imaging remains underused for cardiovascular risk assessment. As tissue characterisation has now been recognised as an additional assessment tool, we sought to investigate the significance of native T1 and extracellular volume (ECV) in an unselected clinical routine population. Methods The single-centre, prospective cardiovascular magnetic resonance (CMR) registry included patients referred for clinical CMR. LV global longitudinal strain (GLS) was evaluated in long-axis views. Native T1 and ECV were assessed on septal, basal, or midventricular short axis positions. Follow-up was conducted for primary (all-cause mortality and heart failure hospitalisation) and secondary (all-cause mortality, hospitalised angina and myocardial infarction) endpoints. Results The final population consisted of n=1633 patients who met primary (n=68) and secondary (n=90) endpoints during median follow-up of 395 days. A 10 ms T1 increase was associated with a hazard ratio (HR) of 1.11 (95% CI 1.07-1.15, p<0.001) for the primary endpoint independent of ECV (p=0.738). T1 (HR 1.07, 95% CI 1.03-1.11, p=0.001) but not ECV (p=0.674) was an independent predictor for the primary endpoint after correction for common risk factors including age, NYHA class, biomarker NT-proBNP/glomerular filtration rate, and GLS. After dichotomisation at the median of 1126 ms, T1 added incremental value for primary endpoint prediction on Kaplan-Meier plots in patients with LVEF above/below (p=0.019/0.017) the median of 55% and GLS above/below (p=0.019/0.041) the median of -16.4%. Conclusion Native T1 was found to be an independent risk predictor beyond GLS as well as common clinical risk factors. This may justify the use of non-contrast CMR protocols in selected patients if contrast application is contraindicated.