Limitations of a non-invasive model of the estimation of pulmonary vascular resistance by magnetic resonance imaging in patients with heart failure

Abstract

Funding Acknowledgements Type of funding sources: None. Introduction. Pulmonary vascular resistance (PVR) is a hemodynamic parameter with important diagnostic and prognostic implications in patients with heart failure. Currently the gold standard technique for its quantification is right heart catheterization (RHC). However, cardiovascular magnetic resonance imaging (CMR) has been postulated as a non-invasive alternative for its estimation. The aim of this study is to assess the accuracy of a non-invasive model of PVR estimated by CMR in a specific subgroup of patients with acute heart failure (AHF). Methods. Between January 2014 and December 2018, 108 patients with AHF who underwent RHC and CMR on the same day were prospectively included. PVR was assessed by CMR using the model: 19.38 - [4.62 x Ln mean pulmonary artery velocity - 0.08 x right ventricular ejection fraction (RVEF)]. During RHC, PVR were calculated using the ratio between transpulmonary gradient and cardiac output. We evaluated their correlation using the Spearman correlation coefficient, receiver operating characteristic [ROC] curves, and Bland-Altman analysis. Results. The mean age of our cohort was 65 ± 11 years and 64.8% were male. The median PVR (Wood Units, WU) assessed by CMR and RHC were 5.1 WU (3.4 - 6.8) and 3 WU (1.5 - 3.9); p < 0.001, respectively. A weak correlation was observed between the PVR obtained by RHC and those obtained by CMR in our population (r = 0.21; p = 0.02). On Bland-Altman analysis, the mean bias was -1.7, and the 95% limits of agreement ranged from -10.02 to 6.6 WU. The area under the ROC curve for PVR assessed by CMR to detect PVR ³3 WU was 0.57, 95% confidence interval (CI): 0.47-0.68. Conclusions. In patients with AHF, the non-invasive estimation of PVR using CMR shows poor accuracy, as well as a limited capacity to discriminate increased PVR values.