New score predicts outcomes after intracranial aneurysm coiling
MedWire News: Researchers have developed a novel score, which they say predicts outcomes in patients undergoing coiling of ruptured intracranial aneurysms better than existing scores.
The three scores currently in use for predicting outcomes in patients with subarachnoid hemorrhage were developed in patients undergoing surgical clipping. These scores may not be appropriate for patients undergoing coiling, which is associated with different complications than clipping, say Vincent Degos (University of California, San Francisco, USA) and team.
"This led to the ABC score, which combines clinical and biological measurements and which was superior to the three pre-existing scores for predicting 1-year outcomes in a validation cohort," they write in Stroke.
The team developed the score in a cohort of 368 patients who underwent aneurysmal coiling in a single institution in 2003-2007. Of these, 17.4% died within 1 year and 69.8% made a full recovery, defined as a modified Rankin Scale score of 0-1.
Just three factors predicted 1-year mortality in this cohort. Admission troponin I and S100β levels greater than 0.5 µg/L raised mortality risk more than twofold and fourfold, respectively, and the risk declined with increasing admission Glasgow Coma Scale (GCS) score.
Degos et al combined these three factors into the ABC score, with high troponin I and S100β scoring 1 and 2 points, respectively, and 1, 2, and 3 points given for GCS scores of 14, 13, and less than 13, respectively. This gave a possible total of 6 points.
The sensitivity of the ABC score ranged from 94% at a threshold of 1 point to 13% at a threshold of 6 points. The corresponding specificities were 43% to 98%.
The ABC score had good overall discriminatory power (ability to discriminate between patients who did and did not die), with an area under the receiver operating characteristic (ROC) curve of 0.82, where 1.0 is perfect discrimination and 0.5 no better than chance.
Moreover, the discriminatory power of the ABC score was significantly better than that of current scores, at 0.79, 0.79, and 0.69 for the GCS, the World Federation of Neurosurgical Societies, and the Fisher score, respectively.
The researchers tested the score in a validation cohort of 158 patients from the same institution who underwent coiling during 2008-2009. In this cohort, the ABC score had an area under the ROC curve of 0.76 - still significantly better than those of the other three scores, which ranged from 0.67 to 0.69.
The ABC score also predicted full recovery at 1 year significantly better than did the other scores, at areas under the ROC curve of 0.82 versus 0.69-0.80 in the derivation cohort and 0.76 versus 0.67-0.68 in the validation cohort.
"A limitation of this study is that it was monocentric, because survival may be dependent on intensive care unit management," say Degos et al.
"However, the advantage of our study was that all patients were managed in highly standardized conditions that allowed us to identify clinically relevant independent risk factors. Nevertheless, a prospective and multicenter study featuring different intensive care unit therapeutic strategies should be conducted to confirm the value of this improved score."
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By Eleanor McDermid