INR and vitamin K–dependent factor levels after vitamin K antagonist reversal with 4F-PCC or plasma

Restoration of the international normalized ratio (INR) to values <1.5 is commonly targeted to achieve hemostasis in patients with major bleeding or undergoing urgent surgery who are treated using vitamin K antagonists (VKAs). However, the relationship between corrected INR and vitamin K-dependent factor (VKDF) levels for hemostasis is uncertain. We aim to examine the impact of 4-factor prothrombin complex concentrate (4F-PCC) or plasma on INR correction and VKDF restoration and evaluate the relationship between INR values and VKDF levels in patients with acute major bleeding or patients requiring an urgent surgical procedure. Adult patients treated with VKA with an elevated INR (≥2.0 within 3 hours before study treatment) who received 4F-PCC or plasma after major bleeding or before an urgent surgery or invasive procedure were included in this retrospective analysis of data from 2 prospective phase 3b randomized controlled trials. Of the 370 patients included in this analysis, 185 received 4F-PCC, and 185 received plasma. In the 4F-PCC group, 159 of 185 (85.9%) had an INR ≤1.5 at 30 minutes after the end of infusion compared with only 72 of 184 (39.1%) in the plasma group. After 4F-PCC treatment, all VKDF levels exceeded 50% activity regardless of the postinfusion INR value. However, after plasma administration, mean activity levels for factors II and X were <50% at all time points assessed within 3 hours after starting the infusion, regardless of the postinfusion INR value. This retrospective analysis demonstrated that treatment with 4F-PCC among patients treated with VKA rapidly restores VKDFs to hemostatic levels irrespective of the postinfusion INR value, whereas treatment with plasma does not.