Arterial blood pressure vs intracranial pressure in normal pressure hydrocephalus.

OBJECTIVE To characterize the association between arterial blood pressure (ABP) and intracranial pressure (ICP) in idiopathic normal pressure hydrocephalus (iNPH) patients, and its impact on outcome of shunt surgery. MATERIALS AND METHODS We analyzed all 35 iNPH patients whose ABP and ICP were recorded simultaneously during 6 years (2002-2007). The static and pulsatile pressures were averaged over consecutive 6-s intervals; the moving correlations between ICP and ABP (static and pulsatile) were determined during consecutive 4-min periods to explore time-related variations. RESULTS Neither static nor pulsatile ABP were altered in iNPH shunt responders. Elevated pulsatile ICP, but normal static ICP, was seen in responders. The time-varying correlations of static and of pulsatile pressures were generally low, and did not differ between shunt responders/non-responders. CONCLUSIONS In iNPH shunt responders, static or pulsatile ABP were not altered and only pulsatile ICP was elevated.