Objective Right ventricular (RV) function is a major determinant of survival in patients with pulmonary arterial hypertension (PAH). Metabolic alterations may precede haemodynamic and clinical deterioration. Increased RV fluorodeoxyglucose (FDG) uptake in positron emission tomography (PET) was recently associated with progressive RV dysfunction in MRI, but the prognostic value of their combination has not been established.
Methods Twenty-six clinically stable patients with PAH (49.9±15.2 years) and 12 healthy subjects (control group, 44.7±13.5 years) had simultaneous PET/MRI scans. FDG uptake was quantified as mean standardised uptake value (SUV) for both left ventricle (LV) and RV. Mean follow-up time of this study was 14.2±7.3 months and the clinical end point was defined as death or clinical deterioration.
Results Median SUVRV/SUVLV ratio was 1.02 (IQR 0.42–1.21) in PAH group and 0.16 (0.13–0.25) in controls, p<0.001. In PAH group, SUVRV/SUVLV significantly correlated with RV haemodynamic deterioration. In comparison to the stable ones, 12 patients who experienced clinical end point had significantly higher baseline SUVRV/SUVLV ratio (1.21 (IQR 0.87–1.95) vs 0.53 (0.24–1.08), p=0.01) and lower RV ejection fraction (RVEF) (37.9±5.2 vs 46.8±5.7, p=0.03). Cox regression revealed that SUVRV/SUVLV ratio was significantly associated with the time to clinical end point. Kaplan-Meier analysis showed that combination of RVEF from MRI and SUVRV/SUVLV assessment may help to predict prognosis.
Conclusions Increased RV glucose uptake in PET and decreased RVEF identify patients with PAH with worse prognosis. Combining parameters from PET and MRI may help to identify patients at higher risk who potentially benefit from therapy escalation, but this hypothesis requires prospective validation.
- positron emission tomographic (PET) imaging
- primary pulmonary hypertension
- cardiac magnetic resonance (CMR) imaging
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Contributors RK: took part in all activities related to the conduct of the study and contributed to the study idea, data collection, statistical analysis, discussion and writing of the manuscript. PS, SG: PET results analysis. LM, BM-W, JM: analysis of MRI results. PB, DJ: contributed to the data collection. MH: preparation of MRI procedures and scans. MK, BS, JM, RG, WJM: contributed to data collection and the editing of the manuscript. KAK is the guarantor of the content of the manuscript, oversaw all activities related to the conduct of the study and conceived the study idea, contributed to the statistical analysis, writing and editing of the manuscript.
Funding This work was supported by National Center for Science in Poland ('Preludium' grant 2017/25/N/NZ5/02689 to RK), statutory grants of Medical University of Bialystok and by Leading National Research Center in Bialystok.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, conduct, reporting or dissemination plans of this research.
Patient consent for publication Not required.
Ethics approval The study was approved by the local Bioethics Committee. The study complied with the Declaration of Helsinki. All patients gave written informed consent for participating in the study, including taking and storage of blood samples.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request.
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