Safety of outpatient dalteparin therapy in veterans with mechanical heart valves

To determine the rate of bleeding and thromboembolic events within 1 month of outpatient dalteparin therapy in veterans with mechanical heart valves, to evaluate potential risk factors associated with these events, and to examine the prescribing patterns of dalteparin in this patient population.

Single-center retrospective electronic chart review.

Large, academically affiliated Veterans Affairs hospital.

Thirty-eight men with mechanical heart valves who received outpatient prescriptions for dalteparin from October 1, 1998-June 30, 2003.

Charts were reviewed for thromboembolic and bleeding events. Demographic, clinical, and drug utilization variables were assessed. The associations of adverse events with potential risk factors, indication for dalteparin therapy, and prescribing clinic were analyzed. Sixty-four dalteparin regimens were evaluated. No thromboembolic events were reported in any case within 1 month after receiving dalteparin for thromboembolic prophylaxis during warfarin interruption for periprocedural anticoagulation or for anticoagulation during an unintentional subtherapeutic international normalized ratio. Bleeding events occurred in 15 (23%) of the 64 regimens. Most bleeding events resolved spontaneously and without intervention. No potential risk factors for bleeding were identified.

Dalteparin appeared to be a safe, effective means of short-term thromboembolic prophylaxis in this population of ambulatory male veterans with mechanical heart valves. Large, randomized, controlled, prospective trials are warranted.