Prognostic Value of Left Ventricular Function and Mechanics in Pulmonary Hypertension: A Pilot Cardiovascular Magnetic Resonance Feature Tracking Study

Abstract

Background and objective: Cardiovascular magnetic resonance (CMR) - based feature tracking (FT) can detect left ventricular (LV) strain abnormalities in pulmonary hypertension (PH) patients, but little is known about the prognostic value of LV function and mechanics in PH patients. The aim of this study was to evaluate LV systolic function by conventional CMR and LV global strains by CMR-based FT analysis in precapillary PH patients, thereby defining the prognostic value of LV function and mechanics. Methods: We prospectively enrolled 43 patients with precapillary PH (mean pulmonary artery pressure (mPAP) 55.91 ± 15.87 mmHg, pulmonary arterial wedge pressure (PAWP) ≤15 mmHg) referred to CMR for PH evaluation. Using FT software, the LV global longitudinal strain (GLS) and global circumferential strain (GCS), also right ventricular (RV) GLS were analyzed. Results: Patients were classified into two groups according to survival (survival/non-survival). LV GLS was significantly reduced in the non-survival group (-12.4% [-19.0⁻(-7.8)] vs. -18.4% [-22.5⁻(-15.5)], p = 0.009). By ROC curve analysis, LV GLS > -14.2% (CI: 3.229 to 37.301, p < 0.001) was found to be robust predictor of mortality in PH patients. Univariable analysis using the Cox model showed that severely reduced LV GLS > -14.2%, with good sensitivity (77.8%) and high specificity (93.5%) indicated an increase of the risk of death by 11-fold. LV GLS significantly correlated in PH patients with RV ESVI (r = 0.322, p = 0.035), RV EF (r = 0.444, p < 0.003). Conclusions: LV systolic function and LV global longitudinal strain measurements using CMR-FT correlates with RV dysfunction and is associated with poor clinical outcomes in precapillary PH patients.

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

Figure 1

Measurement window of feature tracking software of patient with precapillary PH from four chamber long axis view. Middle figures show graphical display of 7 segments: three septal, three lateral and apical segments. Right panel depicts the corresponding longitudinal strain values. Left black box shows peak values and time to peak for corresponding segments.

Figure 2

Receiver Operating Characteristics (ROC) curves of (a) LV GLS and RV ESVI, (b) RVEF and LVEF. LV GLS > −14.2% (CI: 3.229 to 37.301, p < 0.001), RVESVI > 60 mL/m² (CI: 0.949 to 9.433, p = 0.025), RVEF < 25.5% (CI: 1.109 to 11.053, p = 0.016)) and LVEF < 52% (CI: 0.977 to 10.809, p = 0.024) were found to be robust predictors of mortality in precapillary pulmonary hypertension patients. LV—left ventricle; GLS—global longitudinal strain; RV—right ventricle; ESVI—end-systolic volume index; EF—ejection fraction.

Figure 3

Kaplan-Meier curve—estimation of the time to death by (a) LV GLS (>−14.2%), (b) RV ESVI (>60 mL/m²), (c) RV EF (<25.5%) and (d) LV EF (<52%). Severely reduced LV GLS > −14.2%, increased RV ESVI > 60 mL/m², decreased RV EF < 25.5% and LV EF < 52% indicate a greater risk of death in precapillary pulmonary hypertension. LV—left ventricle; GLS—global longitudinal strain, RV—right ventricle; ESVI—end-systolic volume index, EF—ejection fraction.