[Essential thrombocythemia and hypertension as a result of stenosis of the renal artery].

Primary thrombocythemia may cause vascular thrombosis; it has been rarely involved in coronary atherosclerosis with myocardial infarction. We report three cases of renal arteries atherosclerosis occurring in association with primary thrombocythemia. These cases are three young women (20, 40 and 42 years old) with severe hypertension secondary to atherosclerosis with stenosis of renal arteries, one or both sided, and in association in one case with diffuse arterial stenosis. Systematic investigation revealed thrombocytosis with latent myeloproliferative syndrome of megacaryocytic colony. Thrombocytosis was previously present as attested by a blood count one year before (in one case) and by long-term peripheral vasomotor troubles, electively improved by aspirin (in two cases). In none of these three cases, vascular risk factors, nor hereditary vascular diseases were present. So we assume that platelets high levels are responsible for this early atherosclerosis, in keeping with the well-know role of platelets in atherosclerosis pathogenesis. Platelets investigations must be done in case of renovascular hypertension, occurring without any classical vascular risk factors.