Hemostatic Levels of Coagulation Factors in Patients with Mild Prolongation of Prothrombin Time / INR: Implications for Transfusion Medicine Practice.
Authors: Matevosyan Karen , Cimo Michael , Madden Christopher , Sarode Ravindra 
Published: October 2019

OBJECTIVE: To investigate hemostatically important clotting factors in patients with mild to moderate prolongation of PT/INR, who generally receive prophylactic FFP transfusions, especially in neurosurgery, because there is scant data in the literature supporting prophylactic plasma therapy. METHODS: 36 plasma samples from 31 neurosurgical patients with PT/INR 12.5–15.0/1.3–1.5 were separated and frozen within 8 hours of collection; these were tested for coagulation factors II, VII and VIII levels, and PT/INR/PTT values were correlated with the factor levels. Retrospective analysis of all neurosurgery patients for whom FFP was ordered with similar PT/INR values was performed both during 5 months of study period and 5 months post-study period, when changes were implemented in FFP administration guidelines. The PT/INR/PTT values were studied 24 hours following the FFP requests in order to evaluate the effect of plasma infusion. Each group was divided in two subgroups: those who received FFP transfusion within 24 hours of the FFP requests, and those who did not. RESULTS: PT/INR/PTT and coagulation factor levels of the 36 samples are seen in Table 1.

PT mean 13.78 INR mean 1.38 PTT mean 29.29 PT median 13.5 INR median 1.3 PTT median 29.5 PT range 10.7–18.6 INR range 0.9–1.9 PTT range 19.3–37.9 FII mean 68% FVII mean 53% FVIII mean 156% FII median 66% FVII median 51% FVIII median 126% FII range 34–107% FVII range 28–124% FVIII range 55–547%

There was no correlation between PT/INR with FVII levels (p>0.05). All patients had FVII > 15–25%, level recommended as safe for surgery. FII was also hemostatically normal, whereas mean factor VIII level was elevated, that correlated with shortened PTT in many of these patients. Retrospective analysis revealed that during the study period there were a total of 99 FFP requests (69 patients). Of these 68 requests (46 patients) did and 31 (29 patients) did not receive FFP transfusions within the next 24 hours. Mean number of FFP units transfused was 3.03 (median 2, range 1–7). During the post study period a total of 15 requests (for 14 patients) were received; of these 2 did and 13 did not receive FFP transfusions within the next 24 hours. Mean and median number of FFP was 2. PT/INR/PTT at time of request and 24 hours post transfusion are presented in the Table 2

Study Period (99 FFP requests) Post Study Period (15 FFP requests) Transfused (68) Non-Transfused (31) Transfused (2) Non-Transfused (13) At FFP Request At 24 hrs At FFP Request At 24 hrs At FFP Request At 24 hrs At FFP Request At 24 hrs *PT;†INR;♠PTT 13.42* 12.1 11.9 11.29 14.1 12.8 12.22 11.54 1.3† 1.18 1.16 1.1 1.4 1.3 1.18 1.14 28.9♠ 27.98 27.65 27.43 26.6 27.1 27.4 26.99

CONCLUSION: In patients with a mild prolongation of PT/INR, plasma levels of FII and FVII were hemostatically normal, whereas FVIII levels were increased. After FFP transfusions, PT/INR and PTT values did not change suggesting that plasma therapy in these patients was not warranted. After the study there was a drastic reduction (85%) in FFP orders for prophylactic plasma transfusions.