Transcranial Doppler versus angiography in patients with vasospasm due to a ruptured cerebral aneurysm - A systematic review

Background and Purpose-Transcranial Doppler (TCD) is used for diagnosis of vasospasm in patients with subarachnoid hemorrhage due to a ruptured aneury sm. Our aim was to evaluate both the accuracy of TCD compared with angiogra phy and its usefulness as a screening method in this setting. Methods-A search (MEDLINE, EMBASE, Cochrane Library, bibliographies, hand s earching, any language, through January 31, 2001) was performed for studies comparing TCD with angiography. Data were critically appraised using a mod ified published 10-point score and were combined using a random-effects mod el. Results-Twenty-six reports compared TCD with angiography. Median validity s core was 4.5 (range 1 to 8). Meta-analyses could be performed with data fro m 7 trials. For the middle cerebral artery (5 trials, 317 tests), sensitivi ty was 67% (95% CI 48% to 87%), specificity was 99% (98% to 100%), positive predictive value (PPV) was 97% (95% to 98%), and negative predictive value (NPV) was 78% (65% to 91%). For the anterior cerebral artery (3 trials, 17 1 tests), sensitivity was 42% (11% to 72%), specificity was 76% (53% to 100 %), PPV was 56% (27% to 84%), and NPV was 69% (43% to 95%). Three of these 7 studies reported on the same patients, each on another artery, and for 4, data recycling could not be disproved. Other arteries were tested in only 1 trial each. Conclusions-For the middle cerebral artery, TCD is not likely to indicate a spasm when angiography does not show one (high specificity), and TCD may b e used to identify patients with a spasm (high PPV). For all other situatio ns and arteries, there is either lack of evidence of accuracy or of any use fulness of TCD. Most of these data are of low methodological quality, bias cannot not be ruled out, and data reporting is often uncritical.