December 21st, 2012
Dabigatran Shouldn’t Be Used in Patients with Mechanical Heart Valves
Kristin J. Kelley, CardioExchange Staff
Dabigatran (Pradaxa) should not be prescribed to prevent blood clots or stroke in patients with mechanical heart valves, the FDA warned.
The warning follows the termination of a European clinical trial in which patients taking dabigatran had more frequent thromboembolic events than those on warfarin. Dabigatran patients also experienced more bleeding after valve surgery.
Patients with mechanical heart valves should be transitioned from dabigatran to another anticoagulant, the FDA recommends; stopping dabigatran use suddenly can increase blood clot and stroke risk.
I consider this likely drastically premature: how was the medicine prescribed, was it taken as ordered, etc issues that may be the reason for these tragic valvular occlusions. The question of effectiveness should be formally studied including animal models first, in vitro testing, etc. HRS, MD, FACC
Based on the trial design published in Am Heart J in June 2012, the doses of dabigatran in the RE-ALIGN study were adjusted based on measuring trough dabigatran plasma levels to achieve levels ≥ 50 ng/mL at steady state. Doses ranged between 150 mg twice a day and 300 mg twice a day. Thus, this is higher than the doses studied in the Afib patients in the RE-LY study (110mg or 150mg). This is appropriate obviously because of the higher INR target that we have with mechanical valves than with AFib.