Abstract 10137: Functional Brain Imaging Reveals Decreased Cerebellar Volume and Altered Brain Connectivity in Pulmonary Arterial Hypertension

Abstract

Introduction: Psychiatric and cognitive deficiencies are increasingly appreciated in pulmonary arterial hypertension (PAH). Brain abnormalities potentially underlying these disease manifestations have been ill-defined. Hypothesis: Altered brain structure and functional connectivity correlate with neurocognitive changes in PAH patients. Methods: PAH patients at UPMC were enrolled from 2017 to 2018. Participants underwent T1/T2 structural and resting functional brain MRI (fMRI) in addition to cognitive testing. Case data were compared in a 1:4 ratio to that of age-, gender-, and education-matched non-PAH controls. Linear regression analysis with clustered sandwich estimator and adjustment for multiple hypothesis testing was used for comparisons. Most recent hemodynamic data for PAH patients were reviewed including pulmonary vascular resistance (PVR). Pearson correlations were computed between PVR and brain volumes. Results: 12 PAH patients (median age, 45 years [range 26-61]; 9 women) were enrolled. T1/T2 MRI analysis identified 18 regions with volumetric differences (q<0.05), with notable involvement of limbic (6/18, 33%) and basal ganglia (4/18, 22%) structures. PAH patients showed decreased left cerebellar cortical (45178 ± 1417 vs 53295 ± 583 mm 3 ; q=0.01) and right cerebellar white matter volumes (16458 ± 727 vs 39675 ± 5846 mm 3 ; q=0.018). Structural changes concorded with results from fMRI analysis: PAH patients had decreased functional connectivity in the left cerebellum (q=0.003). Corresponding with modulation of executive functions by the cerebellum, a trend was seen toward decreased inhibitory control and attention (83 ± 3 vs 95 ± 1; q=0.07) and pattern comparison processing speed (93 ± 5 vs 106 ± 4; q=0.07) in PAH patients. A trend toward negative correlation of PVR with left cerebellar white matter volume (r = -0.82, q = 0.06) was also observed. Conclusion: Limbic, basal ganglia, and cerebellar regions were smaller and less functionally connected in PAH cases than in matched controls. Decreased cerebellar volume may correlate with more severe hemodynamic disease. Any links among brain changes, cognitive dysfunction, and PAH pathophysiology deserve further study and may lead to neurologic modalities to diagnose and treat disease.