Dynamic cerebral autoregulation is transiently impaired for one week after large-vessel acute XXXX .

@entity1 @entity64 @entity385
BACKGROUND: Dynamic cerebral autoregulation (DCA) is the continuous counterregulation of cerebral blood flow to fluctuations in blood pressure. DCA can become impaired after @entity64 , but it remains unclear to what extent and over what interval this occurs. METHODS: We included 28 @entity1 (NIHSS = 12    6.5, age = 68.4    17.1, 16F) with acute large-vessel @entity385 in the middle cerebral artery territory and 29 healthy controls (mean age 54.9    9, 16F). DCA was assessed by simultaneous measurement of blood pressure together with blood flow velocities using finger plethysmography/arterial catheter and transcranial Doppler over three 10-minute recordings on days 0-2, 3-6 and >= 7 days after @entity64 . Transfer function analysis was applied to calculate average phase shift (PS) in the low frequency range (0.06-0.12 Hz). Less PS indicated poorer autoregulation. The affected side was compared with the unaffected side and controls. Univariate comparisons of data were performed using t tests at single time points, and generalized estimating equations with an exchangeable correlation matrix to examine the change in PS over time. RESULTS: At mean 1.3    0.5 days after @entity64 the average PS in the affected hemisphere was 29.6    10.5 vs. 42.5    13 degrees in the unaffected hemisphere (p = 0.004). At 4.1    1 days, the PS in affected and unaffected hemisphere was 23.2    19.1 vs. 41.7    18.5 degrees, respectively (p = 0.003). At mean 9.75    2.2 days @entity64 there was no difference between the affected and the unaffected hemisphere (53.2    28.2 vs. 50.7    29.2 degrees, p = 0.69). Control subjects had an average PS = 47.9    16.8, significantly different from @entity1 ' affected hemisphere at the first two measurements (p = 0.001), but not the third (p = 0.37). The PS in controls remained unchanged on repeat testing after an average 19.1 days (48.4    17.1, p = 0.61). Using the last recording as the reference, the average PS in the affected hemisphere was -23.54 (-44.1, -3) degrees lower on recording one (p = 0.025), and -31.6 (-56.1, -7.1) degrees lower on recording two (p < 0.011). Changes in the unaffected hemisphere over time were nonsignificant. DISCUSSION: These data suggest that dynamic cerebral autoregulation is impaired in the affected hemisphere throughout the first week after large-vessel @entity385 , and then normalizes by week two. These findings may have important implications for acute blood pressure management after @entity64 .
