NEW YORK (Reuters Health) – Anticoagulation with low-molecular-weight heparin (LMWH) dalteparin following heart valve surgery leads to fewer adverse events than does unfractionated heparin, Canadian researchers report in a December 24th on-line paper in the American Journal of Cardiology.

Dr. Claudia Bucci of the University of Toronto and colleagues note that although unfractionated heparin is widely used, cardiovascular surgery patients have a particularly high risk for developing heparin-induced thrombocytopenia (HIT).

Because of this, in 2006 the team switched to exclusive use of LMWH after cardiovascular surgery at Sunnybrook Health Sciences Center.

To determine whether the change increased safety, the researchers retrospectively studied data on 103 heart valve surgery patients who received dalteparin and a further 100 who in earlier years had had unfractionated heparin.

There were fewer thrombotic events in the LMWH-treated group (4% versus 11%). This was also true of bleeding events (3% versus 10%).

In the LMWH group, 3 patients developed HIT, 1 of whom had HIT with thrombosis. In the unfractionated heparin group, the corresponding numbers were 6 and 4.

There was 1 case of valve thrombosis in the unfractionated heparin group. There were none in LMWH group.

“Our study,” the researchers conclude, “provides data supporting the use of LMWH in patients with newly implanted heart valves.”

Reference:
Comparison of the Effectiveness and Safety of Low-Molecular Weight Heparin Versus Unfractionated Heparin Anticoagulation After Heart Valve Surgery
Am J Cardiol 2011.