Control of blood pressure in long slow hemodialysis.

Hypertension is a major cause of mortality and morbidity in hemodialysis patients. A long slow dialysis (8 h/session) was used in 692 unselected patients. It allowed for an excellent control of blood pressure without the need of antihypertensive medications. Cardiovascular morbidity and mortality were lower in the subgroups of patients presenting with a lower predialysis mean arterial pressure. The control of the extracellular volume with a low rate of intradialytic hypotensive episodes is the most probable explanation of this result. Another possible mechanism is the restoration by the large dose of dialysis of the nitric oxide vasodilator action inhibited by the accumulation of dimethylarginine in the serum of uremic patients.