High rate of abnormal blood values and vascular complications before diagnosis of myeloproliferative neoplasms.

BACKGROUND

Vascular complications occurring before the diagnosis of myeloproliferative neoplasms (MPN) in 612 patients from four centers in Sweden, Denmark and France were retrospectively studied.

RESULTS

Vascular complications were observed in 151 (25%) of the 612 patients. Of these, 66% occurred during the two years preceding diagnosis. The majority of events were thromboembolic (95%), and included myocardial infarction (n=46), ischemic stroke (n=43), transient ischemic attack (TIA) (n=22), deep vein thrombosis/pulmonary embolism (n=19), splanchnic vein thrombosis (n=7), and peripheral embolism (n=7). Bleeding was observed in only 7 (5%) of the 151 patients with vascular events (3 with intracranial bleeding, 2 with epistaxis and 2 with gastrointestinal bleeding). Full blood counts obtained at least 3 months prior to the MPN diagnosis showed that 269 (44%) had abnormal blood values, fulfilling the diagnostic criteria for MPN. During the time from the abnormal blood test to the diagnosis of MPN, 50 patients suffered from a vascular complication.

CONCLUSION

We therefore conclude that a large proportion of MPN patients suffer severe thromboembolic complications prior to diagnosis. If MPN were diagnosed earlier, a large proportion of these events might be prevented. An MPN should always be suspected and ruled out in patients with unexplained elevated hematocrit, leukocyte and/or platelet counts.