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.