Management of intradialytic hypertension: the ongoing challenge.

There is no widely accepted definition of intradialytic hypertension. Arbitrary clinical definitions have included an increase in blood pressure during or immediately after hemodialysis, a rise in blood pressure during the second or third hour of dialysis, and an increase in blood pressure that is resistant to ultrafiltration. To date, no studies have evaluated the prevalence and prognostic importance of intradialytic hypertension. The pathogenesis of intradialytic hypertension is complex and is due in part to extracellular fluid volume expansion, increased cardiac output, activation of the renin-angiotensin system and the sympathetic nervous system, increased circulating vasoactive substances resulting in peripheral vasoconstriction, erythropoietin use, and fluctuations in electrolytes and removal of antihypertensive medications during the dialysis procedure. Management strategies of intradialytic hypertension are based on expert opinion using the pathophysiologic principles described above. We conclude that additional epidemiologic, basic science, and interventional studies are needed to further elucidate the prevalence, prognostic importance, pathophysiology, and potential treatment of intradialytic hypertension.