Left Ventricular Morphology and Function as a Determinant of Pulmonary Hypertension in Patients with Severe Aortic Stenosis: Cardiovascular Magnetic Resonance Imaging Study

Abstract

Background and Objectives: The influence of cardiac magnetic resonance (CMR) derived left ventricular (LV) parameters on the prognosis of patients with aortic stenosis (AS) was analyzed in several studies. However, the data on the relations between the LV parameters and the development of pulmonary hypertension (PH) in severe AS is lacking. Our objectives were to evaluate the CMR-derived changes of the LV size, morphology, and function in patients with isolated severe AS and PH, and to investigate the prognostic impact of these parameters on elevated systolic pulmonary artery pressure (sPAP). Materials and Methods: Thirty patients with isolated severe AS (aortic valve area ≤1 cm²) underwent a 2D-echocardiography (2D echo) and CMR before aortic valve replacement. Indices of the LV mass and volumes and ejection fraction were analyzed by CMR. The LV global longitudinal (LV LGS) and circumferential strain (LV CS) were calculated using CMR feature tracking (CMR-FT) software (Medis Suite QStrain 2.0, Medis Medical Imaging Systems B.V., Leiden, The Netherlands). The LV fibrosis expansion was assessed using a late gadolinium enhancement sequence. PH was defined as having an estimated sPAP of ≥45 mm Hg. The statistical analysis as performed using SPSS version 23.0 (SPSS, Chicago, IL, USA) Results: 30 patients with severe AS were included in the study, 23% with severe isolated AS had PH (mean sPAP 55 ± 6.6 mm Hg). More severe LV anatomical and functional abnormalities were observed in patients with PH when compared with patients without PH-a higher LV end-diastolic volume index (EDVi) (140 [120.0-160.0] vs. 90.0 mL/m² [82.5-103.0], p = 0.04), larger LV fibrosis area (7.8 [5.6-8.0] vs. 1.3% [1.2-1.5], p = 0.005), as well as lower LV global longitudinal strain (GLS; -14.0 [-14.9-(-8.9)] vs. -21.1% [-23.4-(-17.8)], p = 0.004). By receiver-operating characteristic (ROC) curve analysis, LV EDVi > 107.7 mL/m² (Area Under the Curve (AUC) 95.7%), LV GLS < -15.5% (AUC 86.3%), and LV fibrosis area >5% (AUC 89.3) were found to be robust predictors of PH in severe AS patients. Conclusions: In patients with severe aortic stenosis, a larger end-diastolic LV volume, impaired LV global longitudinal strain, and larger LV fibrosis extent can predict the development of pulmonary hypertension.

Keywords: aortic stenosis; cardiovascular magnetic resonance; feature tracking; left ventricular; pulmonary hypertension.

Figure 1

Receiver–operating characteristic (ROC) curve analysis of CMR-derived LV LGS, LV EDVi, and LV fibrosis in the prediction of sPAP ≥ 45 mm Hg.