Renal function decline common in patients treated with DOACs

Anna GarrettDeterioration of renal function and an increase in related adverse events is not unusual in patients treated with direct oral anticoagulants (DOACs), reported a recently published study.

The study included 807 patients with atrial fibrillation (AF) who had a baseline creatinine clearance of at least 50 mL/minute. Patients were treated with one of three DOACs (dabigatran, rivaroxaban, or apixaban) and divided into two groups, depending on their renal function.

During follow-up, group A (n=751) had an estimated creatinine clearance of at least 50 mL/minute, whereas patients in group B (n=56; 7%) had an estimated clearance of less than 50 mL/minute. Declining renal function correlated with increasing CHADS₂ or CHA₂DS₂-VASc scores. Advanced age, lower body weight, and congestive heart failure were independent indicators of renal deterioration among patients in group A.  

Bleeding events were more common in patients in group B than in group A (21% vs. 8%), as were adverse events (36% vs. 24%) and drug discontinuation due to adverse events (27% vs. 13%).

Source: Miyamoto K, Alba T, Arihiro S, et al. Impact of renal function deterioration on adverse events during anticoagulation therapy using non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation. Heart Vessels 2015. Published online August 15, 2015. http://link.springer.com/article/10.1007/s00380-015-0725-6. Accessed August 29, 2015.

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Bridging may be unnecessary in AF patients

A new study published in NEJM suggests that patients with AF who are treated with warfarin may not need bridging with heparin around surgical procedures.

The study included nearly 1,900 patients who were having elective surgery or other invasive procedures and were taking warfarin to treat AF. Patients were assigned to receive dalteparin subcutaneously twice daily, from three days pre-procedure until 24 hours pre-procedure and then for five to 10 days post-procedure. Warfarin was stopped five days before the procedure and was resumed within 24 hours after the procedure. Follow-up of patients continued for 30 days. The primary outcomes were arterial thromboembolism (stroke, systemic embolism, or transient ischemic attack) and major bleeding.

Heparin showed no effect on thromboembolic risk vs. placebo. Just 0.3% of treated patients developed a clot within a month of their procedure, versus 0.4% of patients given placebo. Heparin increased the risk of serious bleeding (3.2%) vs. placebo (1.3%).

The authors concluded that bridging is unnecessary for most AF patients unless they are at particularly high risk of an event (e.g., previous stroke).

Source: Douketis JD, Spyropoulos AC, Kaatz S, et al. Perioperative bridging anticoagulation in patients with atrial fibrillation. NEJM 2015; 373:823–833.

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Warfarin and LMWH have similar efficacy in cancer patients

Warfarin and tinzaparin, a low molecular-weight heparin (LMWH), reduced major blood clots to a similar extent in cancer patients treated for acute venous thromboembolism (VTE), according to the results of a clinical trial published in the JAMA.

The trial, CATCH (Comparison of Acute Treatments in Cancer Hemostasis), is the largest clinical trial to compare the efficacy of LMWH to warfarin for the treatment of acute VTE in patients with cancer. The trial randomized 900 patients with active disease and a history of a VTE to six months of either daily subcutaneous LMWH injections or warfarin. Patients were followed for six months after completion of therapy.

The six-month cumulative incidence of recurrent VTE was 7.2% among patients treated with LMWH, compared with 10.5% among patients treated with warfarin. The number of major bleeding events was similar, as was overall mortality. All results were statistically insignificant.  A total of 49 of 449 (10.9%) patients in the LMWH group had a non-major bleeding event, compared with 69 of 451 patients (15.3%) in the warfarin group.

Treatment with LMWH is the current recommended standard of care. These results suggest that more treatment options may be open to cancer patients with VTE.

Source: Lee AYY, Kamphuisen PW, Meyer G et al. Tinzaparin vs. warfarin for treatment of acute venous thromboembolism in patients with active cancer: A randomized clinical trial. JAMA 2015;314(7):677–686.