Artikel
Correlation of clinical outcome and angiographic vasospasm with the dynamic autoregulatory response after aneurysmal subarachnoid hemorrhage
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Veröffentlicht: | 28. April 2011 |
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Gliederung
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Objective: Preliminary evidence has already been presented to demonstrate a certain association between unfavourable clinical outcome, development of vasospasm (VS), and the reduced ability of pressure autoregulation in patients following aneurysmal subarachnoid hemorrhage (aSAH). However, the detection of vasospasm was carried out only indirect by transcranial doppler sonography (TCD) or the methods used for detection of cerebral vasoreactivity are not sufficiently validated. Therefore, clinical outcome and the extent of angiographic VS was determined and correlated to the degree of impaired pressure autoregulation using a method that has also been extensively used for this purpose in other pathophysiologic conditions.
Methods: 33 patients suffering from aSAH were prospectively included in this trial. Proximal and global VS was determined for the vascular territory that was insoniated for autoregulatory testing using preoperative and day 8 ± 1 angiography. At least 3 dynamic tests of pressure autoregulation were performed 1 day prior and post, and on the day of angiography using Aaslid’s thigh cuff test. The resulting autoregulatory indices ([ARI] normal value 5 ± 1.1) were averaged for each hemisphere separately. Patient outcome was assessed using the extended Glasgow outcome scale (GOSE).
Results: Autoregulation data were available for 22 patients. Due to the limited bone window for transcranial doppler, only 40 hemispheres were amenable for analysis. The mean ARI around the day of angiography was 3.9 ± 2.3. The mean reduction of vessel diameter in the M1 segment of the middle cerebral artery (MCA) of both hemispheres was -23.3% ± 9.1%. Based on distal vessel segments (M2+), angiographic VS was not present in 10 hemispheres, it was mild in 15, moderate in 15, and severe in 4. Hemispheric ARI-values and anigographic data showed a significant correlation (-0.477, p = 0.002). The degree of angiographic vasospasm and low ARI-values correlated significantly with an unfavourable outcome (-0.512, p = 0.015; 0.677, p = 0.001).
Conclusions: Based on the present data, there is a significant correlation between low ARI-values indicating impaired pressure autoregulation, the degree of vessel constriction and an unfavourable outcome following aSAH. Analysis of ARI values from day 1+ following aSAH will further elicit the timing of impaired pressure autoregulation in aSAH patients.