[Clinical features of pulmonary hypertension in lymphangioleiomyomatosis]

Objective: To describe the prevalence of lymphangioleiomyomatosis-pulmonary hypertension (LAM-PH), 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. Methods: Among 234 patients diagnosed with LAM in our center from June 2017 to August 2023, echocardiography was performed in 167 patients, 15 patients with PH indicated by echocardiography were selected as the LAM-PH group. From the remaining 152 patients, 32 patients were randomly selected as the control group. We compared the demographic data, clinical manifestations, pulmonary function, blood gas analysis, and serum vascular endothelial growth factor D (VEGF-D) levels between the two groups. We also evaluated the data from right heart catheterization in five patients and the images from optical coherence tomography of pulmonary arteries in two patients. Results: Echocardiography showed pulmonary hypertension in 15 patients (8.98%). Compared with the control group, LAM-PH group had a higher proportion of patients receiving oxygen therapy. Patients with PH had lower FEV₁, FVC, FEV₁/FVC, DLCO and higher serum VEGF-D levels compared with those without PH. Right heart catheterization was performed in five patients. Five patients had a pre-capillary pattern and three of these patients had severe pulmonary hypertension. Optical coherence tomography showed that there were no obvious abnormalities in the intima and lumen of the blood vessels in the two patients. Conclusions: The prevalence of PH in LAM is low. Patients in the LAM-PH group had more severe hypoxemia, worse lung function and higher serum VEGF-D levels than those in the control group. PH in LAM is mainly pre-capillary. Optical coherence tomography can evaluate the pulmonary artery vascular condition and help to identify the cause of pulmonary hypertension in LAM patients.