Lower threshold for platelet transfusions appears safer


Photo by Chris Horry

Infant in a neonatal intensive care unit

A lower threshold for platelet transfusions may be safer for preterm infants with severe thrombocytopenia, a new study suggests.

Researchers randomized preterm infants with severe thrombocytopenia to receive transfusions at platelet count thresholds of 50,000/mm3 or 25,000/mm3.

The team found that patients in the high-threshold group had a significantly higher risk of major bleeding or death.

Anna Curley, MD, of the National Maternity Hospital in Dublin, Ireland, and her colleagues reported this finding in The New England Journal of Medicine.

The researchers studied 660 infants with a mean gestational age of 26.6 weeks. They were randomized to receive platelet transfusions at a high platelet-count threshold of 50,000/mm3 or a low threshold of 25,000/mm3.

Within 28 days of randomization, a new major bleeding episode or death occurred in 26% of the high-threshold group and 19% of the low-threshold group.

When the researchers adjusted for gestational age, intrauterine growth restriction, and trial site, the odds ratio (OR) for major bleeding or death was 1.57 (95% confidence interval [CI], 1.06-2.32; P=0.02).

The OR for death alone was 1.56 (95% CI, 0.95-2.55), and the hazard ratio for at least one major bleeding episode was 1.32 (95% CI, 1.00-1.74).

The rates of serious adverse events, not including major bleeding, were similar between the high- and low-threshold groups—25% and 22%, respectively (OR=1.14; 95% CI, 0.78-1.67).

The researchers said the results of this trial suggest that reducing the transfusion threshold from 50,000/mm3 to 25,000/mm3 may prevent death or major bleeding in 7 of 100 preterm neonates with severe thrombocytopenia.

However, the team also acknowledged that it isn’t clear why reducing the threshold may reduce the risk of mortality or major bleeding in this patient group.

The researchers said a range of factors might play a role in adverse outcomes of platelet transfusion in preterm neonates, including inflammatory consequences, hemodynamic shifts, fragility of the germinal matrix, disturbances in organ and brain blood flow, preterm lungs with a large capillary bed and abundant immune cells, platelet-derived reactive oxygen species, proangiogenic factors, and vessel occlusion by platelet microthrombi.

This study was supported by the National Health Service Blood and Transplant Research and Development Committee, Sanquin Research, Addenbrooke’s Charitable Trust, the Neonatal Breath of Life Fund, and the National Institute for Health Research Clinical Research Network.

One study author reported consulting for Sanquin Research, and another declared travel funds from Cerus Corporation.

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