Arterial stenosis and atherothrombotic events in polycythemia vera and essential thrombocythemia

Patients with polycythemia vera (PV) and essential thrombocythemia (ET) are at risk of developing arterial and venous thromboembolic complications. Given the complex interaction between blood cells and the vessel wall, it is possible that atherogenesis may also be accelerated in these patients. We used Doppler arterial ultrasound to assess the presence of arterial stenosis in a cohort of PV and ET patients.

A total of 37 patients, 29 with PV and 8 with ET, were investigated. Aside from an extensive clinical and hematological evaluation, arterial Doppler ultrasonography was performed in all patients; in 3 patients arteriography/coronarography was also performed.

Twenty four patients (65%) had a history of atherothrombotic events including cerebral ischemic attacks (CIA) in 12 patients, ischemic heart disease (IHD) in 10 patients and peripheral occlusive arterial disease (POAD) in 12 patients. Eight patients had multiple atherothrombotic events. Twenty five patients (67%) had other atherosclerotic risk factors such as smoking, dyslipidemia, hypertension and diabetes. Significant arterial stenosis was found in 23 patients (62.1%), including 12 patients with carotid plaques, 10 with peripheral arterial stenosis, 3 with coronary stenosis, 2 with aortic plaque and 2 with common iliac artery stenosis. In 12 patients multiple arterial stenoses were found. The presence of arterial stenosis was significantly correlated with the occurrence or thrombotic events (p = 0.0003) and was also correlated with the concomitant presence of polyglobulia and thrombocytosis. Both the thrombotic risk and the probability of stenosis detection were augmented by additional risk factors such as smoking, hypertension and dyslipidemia.

The high incidence of arterial thrombotic events in our PV and ET patients was associated with a high incidence of stenosis detectable by arterial ultrasound. Hyperviscosity, endothelial damage due to leukocyte activation with subsequent thrombus formation, hyperhomocysteinemia and hyperexpression of activating genes such as JAK2 and STAT5 are all features characteristic of PV and ET that may contribute, along with other risk factors, to the development and progression of atherothrombosis. Cytotoxic treatment in PV and TE may be beneficial both through its antiproliferative effect on hematopoiesis and on the atherosclerotic plaques, atherogenesis being described as a proliferative disease of the vessel wall.