Factors affecting survival rates for acute vertebrobasilar artery occlusions treated with intra-arterial thrombolytic therapy: A meta-analytical approach

OBJECTIVE: To determine whether recanalization, coma at presentation, or cl ot location in the basilar artery influences the relative mortality risk af ter intra-arterial thrombolytic therapy for acute vertebrobasilar artery oc clusions. METHODS: Studies were identified using the MEDLINE database for January 198 7 to November 1997. Series were included if they involved 10 or more patien ts with basilar or vertebrobasilar artery occlusions, used urokinase and/or recombinant tissue plasminogen activator, and were written in English. A f ixed-effect meta-analysis approach was used to estimate the risk of death w ith the aforementioned risk factors. Each study was weighted according to s ample size. Relative risks were calculated with 95% confidence intervals. RESULTS: As calculated from peer-reviewed published data, the relative mort ality risk for patients for whom recanalization was attempted but not achie ved was 2.34 (95% confidence interval, 1.48-3.71; n = 126). Coma at present ation was associated with a relative mortality risk of 1.95 (95% confidence interval, 1.26-2.99; n = 145). Clot locations in the distal one-third of t he basilar artery were shown to favor survival, compared with clots located in the proximal and/or middle portions of the basilar artery (relative ris k, 0.52; 95% confidence interval, 0.31-0.86; n = 126). CONCLUSION: The combined data suggest that coma at presentation has an inde pendent and adverse effect on survival rates. Complete recanalization, dist al clot location, and responsiveness at the time of presentation are statis tically significant factors for increased patient survival rates.