Aim of the study is to compare novel parameters of right ventricle (RV) function from right heart catheterization (RHC) and magnetic resonance imaging (MRI) with PET-derived RV FDG uptake.

Objectives In pilot study investigators aimed to compare novel parameters of right ventricle (RV) function from right heart catheterization (RHC) and magnetic resonance imaging (MRI) with PET-derived RV FDG uptake.

Background Right ventricular (RV) function is a major determinant of survival in patients with pulmonary arterial hypertension (PAH). Hemodynamic parameters like end-systolic elastance (Ees), arterial elastance (Ea), pulmonary arterial compliance (PAC) and Ees/Ea ratio have been shown to reflect RV function and prognosis in PAH. Increased RV 18F-fluoro-2-deoxyglucose (FDG) uptake in positron emission tomography (PET) was recently associated with progressive RV dysfunction in these patients.

Methods Twenty-five stable PAH patients (49.92±15.94 years) and twelve healthy subjects (control group, 44.75±13.51 years) had simultaneous PET and MRI scans performed. FDG was used as a tracer and its uptake was presented as a standardized uptake value (SUV) for both left (LV) and right ventricle.

Inclusion Criteria:

- PAH

Exclusion Criteria:

The exclusion criteria were the following: patients in IV WHO class, Eisenmenger physiology, PAH associated with prevalent systemic-to-pulmonary shunts due to moderate to large defects (according to European guidelines) [16], group II, III, IV, V of pulmonary hypertension, diabetes mellitus and contraindications to cardiac MRI.

We enrolled twenty-five stable adult patients diagnosed with pulmonary arterial hypertension. A diagnosis of pre-capillary pulmonary hypertension (PH) was confirmed by right heart catheterization [mean pulmonary artery pressure (mPAP) ≥25 mmHg, pulmonary artery wedge pressure (PAWP) ≤15 mmHg] and the use of an algorithm that included perfusion lung scan, echocardiography, respiratory function tests, and computer tomography to rule out secondary PH causes according to European guidelines [16]. The control group consisted of twelve healthy controls who were matched based on sex and age. During the baseline evaluation, we performed a physical examination, six-minute walk test, laboratory tests e.g. serum B-type natriuretic peptide (BNP), morphology and renal function parameters.