Effect of extending the platelet storage time on platelet utilization: predictions from a mathematical model of prophylactic platelet support.

Bacterial culturing (BCU) or photochemical treatment (PCT) of platelet (PLT) concentrates may permit extending the storage time to 7 days at the cost of decreased viability of transfused PLTs. This study was aimed at predicting the impact this may have on the routine management of patients on prophylactic PLT support. The method included a mathematical model that represents the dynamics of prophylactic PLT support with standard, BCU or PCT PLTs. Data on posttransfusion PLT kinetics and the effect of PCT or storage time on PLT recovery and survival were obtained from published studies. Variables that influenced the level of PLT usage were the proportion of transfusions supplied with PLT on the last day of shelf-life, the use of PCT and the assumed degree of synergy between clinical factors of PLT consumption and either PCT or storage time. In the reference-case scenario, extending the PLT shelf-life to 7 days by BCU or PCT increased by 9 and 19%, respectively, the number of PLT transfusions per patient-year. In the worst-case scenario, these figures rose to 27 and 38%, respectively. Despite more intensive PLT usage, in most scenarios, the time that patients spent at PLT counts <10 x 10(9) L(-1) increased. Extending the shelf-life of PLT products will increase PLT usage. Such increase may be disproportionately larger for patients with complex conditions if there is a synergic interaction between storage time or PCT and clinical factors of PLT consumption, an issue that is worth further clinical research.