BACKGROUND: The dose-response relationship for platelet transfusion has become increasingly important as the use of platelet transfusion has grown.
STUDY DESIGN AND METHODS: One hundred fifty-eight prophylactic apheresis platelet transfusions were administered to 46 patients undergoing high-dose therapy followed by hematopoietic progenitor cell transplantation in a prospective, randomized, double-blind, multiple-crossover study. Transfusions were administered in pairs, differing only in platelet content. Each pair consisted of a lower-dose platelet component (LDP) and a higher-dose platelet component (HDP) administered in random order to the same patient. LDPs contained a mean of 3.1 × 1011 platelets (range, 2.3-3.5 × 1011), and HDPs contained a mean of 5.0 × 1011 platelets (range, 4.5-6.1 × 1011). Patients with active bleeding and those who were refractory to platelet transfusions were excluded.
RESULTS: The mean posttransfusion platelet count increment with LDP was 17,010 per μL, and that with HDP was 31,057 per μL (p<0.0001). Only 37 percent of LDPs resulted in platelet count increments of at least 20,000 per μL, whereas 81 percent of HDPs resulted in increments above this level (p<0.0001). The mean transfusion-free interval with LDP was 2.16 days, whereas that with HDP was 3.03 days (p<0.01). Administration of LDPs was associated with a 39 to 82 percent increase in the relative risk (per day) of requiring subsequent platelet transfusions (p<0.0001).
CONCLUSION: As compared to the administration of HDPs, the administration of LDPs for prophylactic transfusion in hematopoietic progenitor cell transplant patients results in a lower platelet count increment, a lower likelihood of obtaining a posttransfusion platelet increment >20,000 per μL, a shorter transfusion-free interval, and a greater relative risk per day of requiring additional transfusions.