ObjectiveTo probe plasma calcitonin gene related peptide (CGRP) levels during thrombolytic therapy in patients with iliofemoral venous thrombosis in order to investigate its regularity of the alteration and its clinical significance.MethodsFifty patients with acute iliofemoral venous thrombosis and 30 patients with chronic iliofemoral venous thrombosis were given urokinase and prostaglandin E1 from veins for 15 days. The CGRP levels were determined by radioimmunoassay before treatment and on the 6th hour, 1st day, 3rd day, 7th day, 14th day, 30th day after treatment.ResultsThe plasma CGRP levels were increased in patients with acute iliofemoral venous thrombosis compared with the contrast ones. The CGRP levels in serious group was lower than those in mild group. However, the CGRP levels of 30 chronic patients and 12 patients who received the second course of thrombolysis as on effective were not different from those of contrast ones. The plasma CGRP levels were increased at the 6th hour,reached the peak at the 3th day and returned to normal at the 14th day after thrombolytic therapy in acute group which just consistent with the therapeutic effectiveness.ConclusionIt is helpful to judge whether the thrombolytic therapy is effective and the illness has come to chronic stage according to the levels of plasma CGRP in patients with iliofemoral venous thrombosis.