Peripheral Microangiopathy in Pre-capillary Pulmonary Hypertension: A Nailfold Video Capillaroscopy Prospective Study

Abstract Background: Although pulmonary vascular bed has been the main subject of research for many years in pulmonary hypertension (PH), interest has recently started to divert towards the possibility of a co-existing peripheral microangiopathy. The aim of this study was to investigate the presence of peripheral microangiopathy in patients with precapillary pulmonary hypertension by exploring nailfold video-capillaroscopic (NVC) structural changes among various subgroups with precapillary PH and to identify possible associations of NVC characteristics with markers of disease severity. Methods: Α cross-sectional study was performed in 46 consecutive patients with precapillary PH [14 with idiopathic pulmonary arterial hypertension (IPAH), 18 with PAH associated with connective tissue diseases (CTD-PAH) and 14 with chronic thromboembolic pulmonary hypertension (CTEPH)] and 30 healthy controls. NVC quantitative and qualitative parameters were evaluated. Results: Patients with precapillary PH (71.7% were women, mean age 60.8 ± 13.4 years) presented reduced capillary density compared to healthy controls (7.5 ± 1.6 loops/mm vs. 9.7 ± 0.81 loops/mm, p<0.001) and increased capillary loop width (18.8 ± 6.7 μm vs. 11.5 ± 2.3 μm, p<0.001) detected mainly in PAH-CTD. Half of patients presented microhaemorrhages on capillary nailfold, while morphological capillary abnormalities where also detected compared to healthy controls. Log10 (NT-proBNP) was independently associated with capillary density in patients with precapillary PH [r= -0.68, B= -1.9, 95% CI (-3,3, -0.4) p=0.014].Conclusion: Significant NVC microvascular changes were detected in patients with various types of precapillary PH, suggesting an impaired peripheral microcirculation associated with right ventricular remodeling parallel to pulmonary vasculopathy.