Outcomes-based assessment of a new reference standard for delayed cerebral ischemia related to vasospasm in aneurysmal subarachnoid hemorrhage.
OBJECTIVE
The purpose is to perform outcomes-based assessment of a new reference standard for delayed cerebral ischemia (DCI) related to vasospasm.


METHODS
Retrospective study was performed with consecutive aneurysmal subarachnoid hemorrhage (A-SAH) patients between January 2002 and May 2009. A new reference standard for DCI was applied to the study population incorporating clinical and imaging criteria. Diagnostic accuracy was determined by chart diagnosis. Outcome measures for assessment included: permanent neurologic deficits, infarction, functional disability, treatment, and discharge status. Medical record review was performed by two blinded observers. Chi-square test calculated statistical significance between DCI and no DCI groups.


RESULTS
A total of 137 patients were included; 59% (81/137) classified as DCI and 41% (56/137) as no DCI by the reference standard. Overall accuracy is 96% (95% confidence interval 92-99) with 100% sensitivity, 92% specificity, 94% positive and 100% negative predictive values. Patients classified as DCI had 40% (32/81) permanent neurologic deficits and 57% (46/81) infarction compared to 0% (0/56) classified as no DCI. DCI patients had 33% (27/81) functional disability compared to 13% (7/56) classified as no DCI. Ninety-four percent (76/81) DCI patients received treatment compared to 0% (0/56) classified as no DCI. DCI group had 46% (37/81) discharged to rehabilitation facilities and 11% (9/81) mortality compared to 25% (14/56) and 2% (1/56), respectively, in no DCI group. There are statistically significant differences (P < .0001) between DCI and no DCI groups for all outcome measures.


CONCLUSIONS
This new reference standard has high diagnostic accuracy for DCI related to vasospasm. The outcomes-based assessment further supports its accuracy in correctly classifying A-SAH patients.
Department of Radiology, Weill Cornell Medical College/New York-Presbyterian Hospital, NY 10065, USA. pcs9001@med.cornell.edu
Pina C
PC
Sanelli
Nikesh
N
Anumula
Rachel
R
Gold
Elliott
E
Elias
Carl
C
Johnson
Joseph
J
Comunale
Apostolos J
AJ
Tsiouris
Alan Z
AZ
Segal
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000628:therapy; D002533:Cerebral Angiography; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D012015:Reference Standards; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000000981:diagnostic imaging* / Q000628:therapy; D014057:Tomography, X-Ray Computed; D020301:Vasospasm, Intracranial / Q000150:complications* / Q000000981:diagnostic imaging* / Q000628:therapy