Peripheral Arterial Tonometry in Pulmonary Vasculitis

Vascular wall inflammation in primary vasculitides results in diminished vessel dilation and finally impaired blood flow, causing multiple organs dysfunction and ultimate damage. In granulomatosis with polyangiitis (GPA), the inflammatory process concerns small and medium sized vessels and its pulmonary location is often predominant. The pivotal role in the development of that pathology plays vascular endothelium. Endothelial vasodilatory function strongly depends on the instant production and release of nitrogen oxide (NO), a potent local factor controlling vascular tonus. NO output is triggered by a variety of stimuli, especially by ischemia. The endothelial vasodilatory ability can be measured indirectly by a few of methods, one of them is peripheral arterial tonometry (PAT). The method assesses reactive hyperemia, mediated mostly by NO release, as a response to vessel occlusion. The vasodilatory reaction depends on the quality of the endothelium which deteriorates with time of GPA disease progression. The aim of the present study was to estimate a correlation between the clinical status, reflected by the disease extent index (DEI), and the vasodilatory endothelial function reflected by the index of arterial reactive hyperemia (RHI), measured by PAT in 27 patients with GPA, having a significant pulmonary involvement. We found a moderate inverse correlation between DEI and log-transformed RHI (r = -0.46, p < 0.05). The conclusion is that impaired endothelial function, as assessed by RHI-PAT, might predict the GPA progression.