Clinical features of pulmonary hypertension in lymphangioleiomyomatosis

<bold>Background:</bold> The incidence of pulmonary hypertension (PH) in patients with lymphangioleiomyomatosis (LAM) is low. There are few studies on LAM-related pulmonary hypertension. The aims of our study were to describe the prevalence of LAM-PH in our center, to explore the clinical features of patients with LAM-PH, and to evaluate the role of pulmonary artery optical coherence tomography (OCT) in the diagnosis of LAM-PH. <bold>Methods:</bold> 15 LAM patients with PH indicated by echocardiography were selected as the LAM-PH group, and 32 patients were randomly selected from the LAM patients without PH as the control group. We compared the demographic data, clinical manifestations, pulmonary function, blood gas analysis, and serum VEGF-D levels between the two groups, and evaluated the data from right heart catheterization (RHC) in five patients and the images from OCT of pulmonary arteries in two patients. <bold>Results:</bold> The prevalence of LAM-PH was 6.4% in patients with LAM. Patients with PH had lower FEV1, FVC, FEV1/FVC, DLCO and higher serum VEGF-D levels compared with those without PH. RHC revealed that four patients had a pre-capillary pattern and three of these patients had severe PH. OCT showed that there were no obvious abnormalities in the intima and lumen of the blood vessels in the two patients. <bold>Conclusions:</bold> The prevalence of PH in LAM is low. Patients in the LAM-PH group had more severe hypoxemia, worse pulmonary function and higher serum VEGF-D levels than those in the control group. PH in LAM is mainly pre-capillary. OCT can evaluate the pulmonary artery vascular condition and help to identify the cause of PH in LAM patients.