Efficacy and Safety of Tinzaparin Sodium as a Bridging Agent for Patients on Oral Anticoagulant Undergoing General Surgery: Clinical Experience with the First 100 Consecutive Patients.

The aim of the present prospective study was to test the efficacy and safety of a bridging protocol in patients under oral anticoagulants (OA) who need to undergo general surgery. One hundred consecutive patients receiving oral anticoagulant accenocoumarol for various cardiovascular disorders entered the study. Patients underwent 107 scheduled operations (among them 41 cholecystectomies, 24 colectomies, 13 hernia repairs and 9 ERCPs, the 7 followed by cholecystectomy), receiving the low molecular weight heparin (LMWH) tinzaparin sodium as the bridging agent. At least 4 days prior to the operation the OA was replaced with tinzaparin at a daily dose of 175 anti-Xa IU per kg of body weight. Patients received no LMWH on the day of the operation and the OA was co-administered with tinzaparin on the second post-operative day and for at least 2 days. When target INR (2.5 to 3) was achieved, tinzaparin administration was stopped. Lower limbs color duplex was performed pre-operatively and on the 2^nd, 8^th–10^th and 20^th–30^th post-operative day. Complete anticoagulation profile, intra-operative bleeding and post-operative blood loss, large haematoma development (over 5 cm in diameter), deep vein thrombosis (DVT) and 30-day morbidity and mortality were thoroughly recorded. During the 30-day period 1 patient died (from sepsis), 9 developed wound infections and three underwent re-operations (two for anastomotic leaks and one for duodenal perforation following ERCP). None of these events was related to the bridging process. There were no proximal DVTs. Three asymptomatic distal vein thromboses (2 posterior tibial and one peroneal ) were identified on post-operative duplex scan. No large wound haematomas were seen. One colorectal surgery patient had a drain blood loss of 460 ml on the first and 140 ml on the second post-operative day, requiring blood transfusion; tinzaparin administration was delayed for three days in this case. Finally, in 17 cases we had difficulties in adjusting INR levels to the desired range; in these cases tinzaparin administration was prolonged for 2–5 days. We conclude that our bridging protocol, using therapeutic doses of the LMWH tinzaparin sodium as the bridging agent, is both safe and effective for replacing OAs in patients undergoing general surgery operations.