Non-thromboembolic pulmonary hypertension in multiple myeloma, after thalidomide treatment: A pilot study

Background: Multiple myeloma (MM) is thrombogenic as a consequence of multiple hemostatic effects and endothelial damage. Thalidomide has been associated with an increased risk of thromboembolic pulmonary hypertension (PH). PH in the absence of venous thromboembolism has also been described in MM patients during thalidomide treatment. Aim: Detection of clinical and subclinical nonthromboembolic PH in MM patients after thalidomide treatment. Patients and methods: Eighty-two patients, 46-82 years (median age 61 years), 42 males, were studied. They underwent echocardiographic study at baseline, 1 month thereafter, 6 months later and whenever symptoms indicating deterioration of cardiac function appeared. Echocardiographic signs of PH were especially identified. Results: Clinical and echocardiographic evaluation revealed four patients (out of 82 patients, 4.87%) with PH. Nonimaging and imaging diagnostic methods excluded thromboembolic PH. Statistical analysis demonstrated significant correlation between structural heart disease and PH (r = 14.078; P = 0.008). No significant correlation between age (r = 0.770; P = 0.724), gender (r = 1.157; P = 0.285), International Staging System (ISS) (r = 0.316; P = 0.716) and PH was found. Conclusions: Preexisted endothelial dysfunction due to structural cardiac disease enhances the vasoactive substances release causing increased pulmonary vascular resistance. Thalidomide possibly causes a vasodilator and vasoconstriction imbalance, which may cause abnormal pulmonary vascular response interfering to a vicious circle perpetuating PH.