Abstract
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.
A randomized, placebo-controlled trial of intravenous gammaglobulin in alloimmunized thrombocytopenic patients