The Pruitt-Inahara shunt maintains mean middle cerebral artery velocities within 10% of preoperative values during carotid endarterectomy.
OBJECTIVE
The purpose of this study was to assess the ability of the Pruitt-Inahara shunt to maintain adequate middle cerebral artery velocities during carotid endarterectomy.


METHODS
Prospectively collected data recorded during 548 carotid endarterectomies performed at a single university hospital were analyzed to look at changes in cerebral blood flow velocities at different stages during the procedure. Parallel data relating to blood pressure and end-tidal carbon dioxide were also examined.


RESULTS
During the first carotid artery cross clamp, middle cerebral artery velocity fell by 42%. A total of 169 patients (31%) had velocities that fell below 15 cm/s (electrical activity in the brain becomes altered below this level). After shunt insertion, only 2% of patients had middle cerebral artery velocities less than 15 cm/s. In only one patient was the velocity less than 10 cm/s. Increased systolic or diastolic blood pressure raised flow through the shunt significantly (P =.001). When two criteria used for selective shunt use were compared, only a moderate correlation was found between absolute middle cerebral artery velocity after carotid cross clamping and percentage change in middle cerebral artery velocity relative to preclamp values.


CONCLUSIONS
The Pruitt-Inahara shunt is able to maintain adequate middle cerebral artery velocity in 98% of patients undergoing carotid endarterectomy. Alterations in blood pressure can significantly affect flow through the shunt.
Department of Surgery, Leicester Royal Infirmary, Leicester, United Kingdom.
P D
PD
Hayes
T
T
Vainas
S
S
Hartley
M M
MM
Thompson
N J
NJ
London
P R
PR
Bell
A R
AR
Naylor
D001783:Blood Flow Velocity; D002536:Cerebral Arteries / Q000502:physiology*; D002560:Cerebrovascular Circulation; D016894:Endarterectomy, Carotid; D006801:Humans; D007430:Intraoperative Care / Q000379:methods*; D011300:Preoperative Care; D011446:Prospective Studies; D014656:Vascular Surgical Procedures / Q000379:methods