Increased Risk for Venous Thromboembolism in Patients with Acute Leukemia.

Introduction: Patients with solid tumors have an increased risk for venous thromboembolisms (VTE) associated with substantial morbidity and mortality, but so far there exists little data on hematologic malignancies. We have recently found a VTE rate of 7,7% in patients with malignant lymphoma. However, information on patients with acute leukemia (AL) is very limited so far.

Patients and methods: Medical records of all patients with AL treated in our institution between january 1992 and april 2005 were reviewed and data was collected and analyzed in a microsoft excel data base. P-values to show correlation of VTE with leukemia type, patient age and gender were calculated using Fisher’s exact test. All reported p-values are two-sided.

Results: Of a total of 455 patients 310 (68%) had AML, 108 (24%) had ALL and 37 (8%) had blast crisis. 248 patients (55%) were male and 207 (45%) were female, median age was 60 years. 55 patients with AL (12,1%) had at least one VTE, occuring during therapy in 82% of events. 27 patients (5,9%) had central venous catheter associated VTE, whereas 28 patients (6,2%) had deep vein thrombosis and/or pulmonary embolism. Neither leukemia lineage - myeloid versus lymphocytic - (p=1,0) nor patient gender (p=.193) had an impact on the VTE risk. However, central venous catheter associated VTE more likely occured in younger patients (< 60 years) than in patients ≥ 60 years (p=.003). There was no statistically significant difference in the incidence of non-central venous catheter associated VTE between both age groups (p=.563).

Discussion: Patients with acute leukemia have a substantial risk for VTE, half of which occur with the use of central venous catheters. A recently published study analysed the incidence of VTE in close temporal relationship to onset of disease and found a VTE rate of 2,09% with equal risk in ALL and AML. Our study included VTE occuring prior to diagnosis of AL as well as during chemotherapy and follow up, revealing a VTE rate that is 6-fold higher and showing a considerable association with central venous catheters.

Conclusions: The risk of VTE is surprisingly high in patients with acute leukemia, thus improvement of prophylactic measures, especially in regard to central venous catheter use is warranted.