The Effect of Preoperative Vitamin K on the INR in Bridging Therapy

We investigated a bridging protocol using oral Vitamin K three days before scheduled surgery. 60 patients in two bridging protocols, 30 cases per protocol. The first cohort (Control group) had its warfarin held on Day-5 (five days before surgery). The intervention cohort (Vitamin K group) routinely received 2.5 mg of oral Vitamin K on Day-3 but was otherwise identically bridged. Primary outcome was INR on Day-1. Secondary outcomes included patients with INRs ≥1.5 on Day-1, bleeding episodes and elevated INR post surgery. Day-1 INR for the Vitamin K group was 1.16, vs. 1.28 for the Control group (p = 0.037). Postoperative INR was similar. Only the Control group had patients with INRs ≥1.5 on Day-1, or patients with significant bleeding. Adding Vitamin K on Day-3 leads to a safe preoperative INR and may limit other complications.