Influence of heparin thromboprophylaxis on plasma leucocyte elastase levels following lobectomy for lung carcinoma

Recent in vitro studies and animal investigation indicate that plasma leucocyte elastase (PLE) can dissolve pulmonary structural proteins, such as elastin, and produce lesions in the lung similar to that seen in adult respiratory distress syndrome (ARDS) and emphysema. In contrast, heparin strongly inhibits PLE and protects elastin from elastolysis. On the basis of these findings, PLE levels were monitored in 24 patients with non-small cell lung carcinoma (NSCLC) undergoing lobectomy. Ten patients from Killingbeck Hospital (Group 1) received 5000 IU subcutaneous (s.c.) heparin commenced 2 h prior to surgery and continued at 8 h intervals until the patient was fully ambulatory. Fourteen patients from Bradford Royal Infirmary (Group 2) received no heparin as standard policy. There was no significant difference in pre-operative PLE levels between groups. The post operative PLE levels in both groups increased significantly (P < 0.02) on the first post operation day (POD). However, PLE levels of Group 2 were 2.5 to 5.3 times higher than those of Group 1 at each postoperative interval (first, third, and seventh POD) respectively (0.002 < P < 0.02). There was no difference in blood loss between groups (P = 0.17). These results indicate that post operative PLE activity is elevated in NSCLC patients following lobectomy and s.c. heparin administration as thromboprophylaxis may inhibit PLE activity post operatively without increasing blood loss. Therefore, heparin may have a role to play in protecting lung tissue against the pulmonary lesions caused by proteolytic activity of PLE, and theoretically reduce post-operative complications, such as ARDS or emphysema.