Abstract
Thromboembolic events (TE) are serious complications of treatment for childhood acute
lymphoblastic leukemia (ALL) that result in significant morbidity and occasionally
mortality. These events are strongly associated with the administration of L'asparaginase
(ASP). There have been many studies reporting TE and assessing the coagulopathy associated
with treatment. The intention of these studies was to determine a potential mechanism
for thrombosis. This article reviews the current literature in this area. First, data
on thrombotic complications in terms of incidence, location, diagnosis, and timing
of events are summarized. The second section discusses the coagulopathy associated
with the disease and treatment. To minimize the effects of confounding treatments,
the data are divided into sections covering pretreatment, after ASP only, after combination
chemotherapy without ASP, and after combination chemotherapy with ASP. In addition,
the effects of glucocorticoid steroids on the hemostatic system are discussed. As
thrombin regulation is critically important to hemostasis, the next section of the
review discusses the regulation of thrombin in children with ALL, both in vitro and
in vivo, and the link between impaired thrombin regulation and TE in this population.
Finally current hypothesis on mechanisms for TE and proposed preventative strategies
are examined.
Key words:
Acute lymphoblastic leukemia - thrombosis - hemostasis - L'asparaginase - antithrombin
