The effective systematic heparin pre-treatment on thrombus formation on pulmonary artery catheter tips during pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension: a randomized, double-blind study

Pulmonary artery (PA) catheters are routinely used for hemodynamic management in patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing pulmonary endarterectomy (PEA). Tip-associated thrombi are frequently detected and might increase the peri-operative risk in these patients. The aim of the study was to investigate the effects of low-dose heparinization before the insertion of the PA catheter on thrombus formation and thrombus weight during PEA surgery. From September 2013 to February 2015, 60 CTEPH patients undergoing PEA were included in the study and randomized into two groups of 30 patients each, including a heparin group (heparin bolus (70 IU per kg body weight) administration before PA catheter insertion) and a control group (pretreatment with placebo). During the PEA procedure the distal part of the PA catheter was drawn out of the PA and thrombus presence and weight were recorded. There were no significant differences in baseline characteristics between the two groups. Twelve patients (20%) had thrombophilic disorders. In the control group, thrombi were detected in 17 patients (57%) with a median thrombus weight of 27 mg (IQR 41). In the heparin group, tip-associated thrombi were found in five patients (17%) with a median weight of 12 mg (IQR 7). There were no bleeding complications in either group. This study demonstrates a high risk of PA catheter-related thrombi in patients with CTEPH. Prophylactic administration of low-dose heparin reduces thrombus formation and thrombus weight without an increased rate of bleeding complications.