Monitoring of the global haemostatic capacity is desired to optimize the treatment with bypassing agents in inhibitor patients. Thrombelastographic methods have been used in ex vivo studies and were suggested useful to evaluate the individual response to bypassing agents. This study aimed at assessing changes in thrombelastographic profiles and their association to clinical outcome in patients treated with recombinant factor VIIa (rFVIIa). Ten patients with acquired haemophilia were treated with rFVIIa for acute bleeding. Thrombelastography was performed after activation with a small amount of tissue factor in samples obtained before and after in vivo administration of rFVIIa. In patients studied before and after a first dose, correction of the thrombelastographic profile was observed but did not predict cessation of bleeding. During steady-state dosing, the median Alpha angle tended to be higher in patients with a good clinical treatment response as compared with patients with a partial or poor response. Similar trends were observed for clotting time and clot formation time. A good clinical treatment response was more frequent in patients with a fully corrected trough-level thrombelastographic profile as compared with patients with an abnormal profile. However, a poor treatment response was observed also in a surgical patient with a normal thrombelastographic profile during steady-state dosing. In conclusion, thrombelastographic monitoring was sensitive to haemostatic changes in response to treatment with rFVIIa. In the limited number of patients studied here, a better clotting profile during steady-state dosing was associated with a better clinical treatment response.
Prophylactic platelet transfusion is frequently administered to reduce the risk of hemorrhage in patients undergoing chemotherapy for leukemia or cancer. A platelet count of 10 or 20x109 L−1 is often used as an occasion for platelet transfusion. In clinical studies, the bleeding risk was similar using either threshold (Rebulla, NEJM1997; 337:1870, Wand, Blood1998; 91:3601). Moreover, serious bleeding events were not related to the patients’ platelet count. Thromboelastometry with ROTEM® Whole-Blood Coagulation Analyzer (Pentapharm, Munich, Germany) is a method that may provide a better estimate of the risk of hemorrhage because it also depends on platelet function and plasma coagulation. We therefore performed a pilot study in 13 adult patients receiving prophylactic platelet transfusion after chemotherapy for leukemia or lymphoma. ROTEM® was performed using an ellagic acid based activating reagent (in-TEM®, Pentapharm). Clotting profiles were evaluated using the following thromboelastometric measures: clotting time (CT), clot formation time (CFT), and maximum clot firmness (MCF). The median platelet count before transfusion was 9x109 L−1 (range 1 to 20). CT was within the normal range in all patients (median 168 s, range 125–212, reference range 100–240). In contrast, a prolonged CFT (median 139 s, range 51–4526, reference range 30–110) and reduced MCF (median 34 mm, range 19–54, reference range 50–72) was recorded. Correlation between platelet count and CFT (R=−0.41, Spearman) or MCF (R=+0.48) was weak and not statistically significant. 15 min after platelet transfusion, there was an increase in platelet count (median 39x109 L−1, range 23–48) and a substantial improvement of CFT (median 99 s, range 44–332) and MCF (median 49 mm, range 40–64). Changes in thromboelastometric measures were due to platelet transfusion as the addition of cytochalasin D (fib-TEM®, Pentapharm) resulted in identical profiles before and after transfusion. Changes in platelet count correlated with changes in MCF (R=+0.73, P<0.01), but not CFT (R=−0.40, P=0.17). Comparing patients who had a maximum of one mild bleeding symptom (n=9) with patients who experienced one severe or at least two mild bleeding symptoms (n=4), there was no difference in platelet counts (median 10 vs. 9x109 L−1, p=0.77). In contrast, there was a trend towards a shorter CFT (median 111 vs. 388 s, P=0.09) and higher MCF (median 39 vs. 29.5 mm, P=0.09) in the group of non-bleeding patients. In summary, ROTEM® seems to be a sensitive method to detect hemostatic changes in patients with severe thrombocytopenia receiving platelet transfusion and to identify thrombocytopenic patients with an increased bleeding risk. Therefore, further studies to evaluate ROTEM® as a means to estimate the bleeding risk in thrombocytopenic patients are warranted.
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