1Kerckhoff Klinik GmbH Abteilung für Kardiologie Bad Nauheim, Deutschland; 2Kardiologie-am-Main Privatpraxis für Kardiologie Frankfurt am Main, Deutschland; 3Justus-Liebig-Universität Giessen Franz-Groedel-Institut (FGI) Bad Nauheim, Deutschland; 4Universitätsklinikum Frankfurt Goethe CVI Frankfurt am Main, Deutschland; 5Universitätsklinikum Frankfurt Kardiovaskuläre Bildgebung Frankfurt am Main, Deutschland; 6Universitätsklinikum Gießen und Marburg GmbH Medizinische Klinik I - Kardiologie und Angiologie Gießen, Deutschland
Background: Quantification of fibrotic remodelling by native T1 mapping and assessment of impaired myocardial contractility by cardiac magnetic resonance feature tracking (CMR-FT) strain can both detect changes in myocardial morphology and function very early in the evolution of heart failure and have been shown to aid in conferring prognosis. However, it is not clear whether function follows morphology, as fibrosis triggers impaired function, or whether these two measures mirror different aspects of heart failure.
Objective: To evaluate the interdependence of fibrosis and myocardial contractility and their relative impact on prognosis.
Methods: Patients with clinically indicated CMR were included in a high-volume, single-center registry and followed up for one year. The primary endpoint was all-cause mortality, and two combined secondary endpoints were defined: (1) all-cause mortality and hospitalization for heart failure (2) non-fatal myocardial infarction, non-fatal stroke, hospitalization for unstable angina, or revascularization. Linear regression analysis was used to examine the dependence of global longitudinal strain (GLS) on native T1. Univariate and multivariable Cox regression analyses were used to evaluate the predictive power of GLS and T1 for the specified endpoints.
Results: Out of 2308 patients enrolled since April 2017, 1288 completed a one-year follow-up, 21 patients died, 48 patients reached endpoint (1), and 148 patients reached endpoint (2). There was a modest but significant correlation between GLS and native T1 time (-coefficient 0.311, R2 0.09, p < 0.001). Only native T1 was found to be an independent prognosticator of all-cause mortality (hazard ratio [HR] 1.01, 95 % confidence interval [CI] 1.0 – 1.01, p <0.001). Native T1 time was the strongest predictor of endpoint (1) (HR 1.01, 95% CI 1.01 – 1.0, p < 0.001), whereas GLS was the strongest predictor of endpoint (2) (HR 1.078, 95% CI 1.04 – 1.12, p <0.001).
Conclusion: Even though native T1 and GLS are modestly correlated, they have different and independent prognostic implications for heart failure (endpoint 1) and ischemic events (endpoint 2), where native T1 best predicts heart failure events and GLS is the strongest predictor of ischemia. Hence, these measures represent independent aspects of myocardial failure.