Cine MRI detects elevated left heart pressure in pulmonary hypertension

Cine MRI-derived radiomics features indicate hemodynamic changes in the pulmonary artery

Although cine MRI-derived radiomics features in the cardiac blood pool have been used to represent cardiac function and motion, the clinical relevance of radiomics features in the great vessels is still unknown. The aim of the present study was to test the hypothesis that cine MRI-derived radiomics features of the pulmonary artery (PA) can represent hemodynamic abnormalities in pulmonary hypertension (PH). With the approval of the institutional review board (IRB), 50 PH patients (21 males, 36-89 years old, diagnosed with right heart catheterization [RHC]) and 23 healthy volunteers (14 males, 26-80 years old) were retrospectively enrolled in this study. All participants underwent cardiac 4D flow and cine MRI (25 retrospective phases) at the right ventricular (RV) outflow tract (RVOT). A total of 93 radiomics features were extracted from RVOT cine images through a fixed size region of interest (ROI) at the proximal part of the PA. The peak values of the 6 first order features were different between the PH patients and controls. 4D flow-derived mean velocity in PA was related to 'Kurtosis' (r = 0.452,), 'Range' (r = 0.426), 'Autocorrelation' (r = 0.407), 'Joint Average' (r = 0.459), 'Sum Average' (r = 0.459), 'High Gray Level Emphasis' (r = 0.41), 'Large Dependence High Gray Level Emphasis' (r = 0.44), 'High Gray Level Run Emphasis' (r = 0.422), 'Gray Level Variance' (r = 0.419), 'High Gray Level Zone Emphasis' (r = 0.451), and 'Small Area High Gray Level Emphasis' (r = 0.415). Mean RV pressure was related to 'Inverse Variance' (r = 0.43) and 'Run Percentage' (r = 0.403). All p values < 0.05. Cine MRI-derived PA radiomics features have the potential to serve as novel imaging biomarkers for representing hemodynamic changes in pulmonary circulation.

Left atrial acceleration factor as a magnetic resonance 4D flow measure of mean pulmonary artery wedge pressure in pulmonary hypertension

Background

Mean pulmonary artery wedge pressure (PAWP) represents a right heart catheter (RHC) surrogate measure for mean left atrial (LA) pressure and is crucial for the clinical classification of pulmonary hypertension (PH). Hypothesizing that PAWP is related to acceleration of blood throughout the LA, we investigated whether an adequately introduced LA acceleration factor derived from magnetic resonance (MR) four-dimensional (4D) flow imaging could provide an estimate of PAWP in patients with known or suspected PH.

Methods

LA 4D flow data of 62 patients with known or suspected PH who underwent RHC and near-term 1.5 T cardiac MR (ClinicalTrials.gov identifier: NCT00575692) were retrospectively analyzed. Early diastolic LA peak outflow velocity (v_E) as well as systolic (v_S) and early diastolic (v_D) LA peak inflow velocities were determined with prototype software to calculate the LA acceleration factor (α) defined as α = v_E/[(v_S + v_D)/2]. Correlation, regression and Bland-Altman analysis were employed to investigate the relationship between α and PAWP, α-based diagnosis of elevated PAWP (>15 mmHg) was analyzed by receiver operating characteristic curve analysis.

Results

α correlated very strongly with PAWP (r = 0.94). Standard deviation of differences between RHC-derived PAWP and PAWP estimated from linear regression model (α = 0.61 + 0.10·PAWP) was 2.0 mmHg. Employing the linear-regression-derived cut-off α = 2.10, the α-based diagnosis of elevated PAWP revealed the area under the curve 0.97 with sensitivity/specificity 93%/92%.

Conclusions

The very close relationship between the LA acceleration factor α and RHC-derived PAWP suggests α as potential non-invasive parameter for the estimation of PAWP and the distinction between pre- and post-capillary PH.

Do the Current Guidelines for Heart Failure Diagnosis and Treatment Fit with Clinical Complexity?

Heart failure (HF) is a clinical syndrome defined by specific symptoms and signs due to structural and/or functional heart abnormalities, which lead to inadequate cardiac output and/or increased intraventricular filling pressure. Importantly, HF becomes progressively a multisystemic disease. However, in August 2021, the European Society of Cardiology published the new Guidelines for the diagnosis and treatment of acute and chronic HF, according to which the left ventricular ejection fraction (LVEF) continues to represent the pivotal parameter for HF patients’ evaluation, risk stratification and therapeutic management despite its limitations are well known. Indeed, HF has a complex pathophysiology because it first involves the heart, progressively becoming a multisystemic disease, leading to multiorgan failure and death. In these terms, HF is comparable to cancer. As for cancer, surviving, morbidity and hospitalisation are related not only to the primary neoplastic mass but mainly to the metastatic involvement. In HF, multiorgan involvement has a great impact on prognosis, and multiorgan protective therapies are equally important as conventional cardioprotective therapies. In the light of these considerations, a revision of the HF concept is needed, starting from its definition up to its therapy, to overcome the old and simplistic HF perspective.

Cine MRI characterizes HFpEF and HFrEF in post-capillary pulmonary hypertension

PURPOSE

To test the hypothesis that cine MRI can be used to characterize features of left and right ventricles in post-capillary pulmonary hypertension (PH) caused by heart failure (HF) with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF).

METHODS

With the approval of institution review board (IRB), 28 consecutive post-capillary PH patients (11 males, 62.1 ± 13.4 years old, range 39-89 years old) underwent cine MRI scans. Cine MRI-derived left ventricular (LV) ejection fraction (LVEF) and other function, motion, and deformation indices (acquired with heart deformation analysis [HDA]) were compared between PH-HFpEF (defined as LVEF ≥ 50 %]) and PH-HFrEF (LVEF < 50 %) patients and were related with right ventricular (RV) indices and right heart catheterization (RHC)-derived pulmonary artery measurements.

RESULTS

Totally 19 patients (68 %, 95 % confident interval [CI] 49 %-86 %) were assigned to PH-HFpEF group while 9 (32 %) was assigned to the PH-HFrEF group. There were differences of LV and right ventricular (RV) global functional indices, LV mass, LV displacement, velocity, strain and strain rate between the two patient groups. Cine MRI-derived LV indices had broad associations with RV indices and RHC measurements. LVEF was negatively correlated with pulmonary capillary wedge pressure (PCWP) (r = -0.5, p = 0.007). LV cardiac index (LVCI) was associated with systolic pulmonary artery pressure (sPAP) (r = 0.443, p = 0.018).

CONCLUSIONS

PH-HFpEF and PH-HFrEF patients present dissimilar function, motion and deformation features in LV and RV. Cine MRI-derived LV measures are correlated with hemodynamic abnormalities of PH.