Lower perfusion pressure during hypothermic cardiopulmonary bypass is associated with decreased cerebral blood flow and impaired memory performance 6 months postoperatively.
OBJECTIVE
We undertook to determine the influence of perfusion pressure during hypothermic cardiopulmonary bypass (CPB) on cerebral blood flow (CBF) and cognitive memory outcome at 6 months postoperatively.


METHODS
Nineteen patients who underwent hypothermic nonpulsatile CPB for elective coronary artery bypass (CAB) surgery were evaluated by (133)Xe measurement of the CBF and by the Incidental Memory Assessment for evaluating cognitive memory (IMTscore), both at baseline before the operation (T(1)) and again at 5 to 6 months postoperatively (T(2)).


RESULTS
Overall, the mean CBF fell significantly from 39 +/- 5 mL.(100 g)(-1).min(-1) at T(1) to 33 +/- 3 mL.(100 g)(-1).min(-1) at T(2) (P < .001). The decrease in CBF from T(1) to T(2) (DeltaCBF(2-1)) correlated with a significant reduction in the IMTscore from T1 to T2 (DeltaIMTscore(2-1)) (P < .001) and with a mean arterial pressure during CPB (MAPCPB) of <60 mm Hg (P = .05). Cluster analysis of DeltaCBF(2-1) and DeltaIMTscore(2-1) demonstrated that the patients with the greatest decrease in CBF showed the greatest decrease in IMTscore, whereas cluster analysis of DeltaCBF(2-1) and MAPCPB indicated that patients with a perfusion pressure maintained at a mean of <60 mm Hg during CPB were prone to a greater decrease in later postoperative CBF.


CONCLUSIONS
This study demonstrated that a MAPCPB of <60 mm Hg during CPB was associated with a significant decrease in CBF 6 months after CAB surgery and with an associated decrease in memory performance.
Paolin
Adolfo
A
Department of Hospital Services, General Hospital S. Maria dei Battuti, Treviso, Italy. apaolin@ulss.tv.it
Michielon
Paolo
P
Betetto
Michele
M
Sartori
Giuseppe
G
Valfré
Carlo
C
Rodriguez
Guido
G
Murkin
John M
JM
D001794:Blood Pressure; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D002561:Cerebrovascular Disorders / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects*; D008137:Longitudinal Studies; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology*; D008875:Middle Aged; D010477:Perfusion / Q000009:adverse effects; D016896:Treatment Outcome