Heparin-induced thrombocytopenia and deep venous thrombosis are relatively frequent complications after aSAH. Early identification and targeted treatment are recommended, but further research is needed to identify the ideal screening paradigms. Class I, Level B Revised 1. For patients with an unavoidable delay in obliteration of aneurysm, a significant risk of rebleeding, and no compelling medical contraindications, short-term ( 72 hours) therapy with tranexamic acid or aminocaproic acid is reasonable to reduce the risk of early aneurysm rebleeding. Class IIa, Level B Revised 2. Determination of aneurysm treatment, as judged by both experienced cerebrovascular surgeons and endovascular specialists, should be a multidisciplinary decision based on characteristics of the patient and the aneurysm. Class I, Level C (Continued) for de novo aneurysms or late regrowth of a treated aneurysm, but the risks and benefits of this screen- ing require further study (Class IIb; Level of Evi- dence B). 7. After any aneurysm repair, immediate cerebrovas- cular imaging is generally recommended to identify remnants or recurrence of the aneurysm that may require treatment (Class I; Level of Evidence B). (New recommendation) Natural History and Outcome of aSAH Although the case fatality of aSAH remains high world- wide,5 mortality rates from aSAH appear to have declined in industrialized nations over the past 25 years.9,11,15,58,59 One study in the United States reported a decrease of 1% per year from 1979 to 1994.60 Others have shown that case fatality rates decreased from 57% in the mid-1970s to 42% in the mid-1980s,11 whereas rates from the mid-1980s to 2002 are reported to be anywhere from 26% to 36%.6,12,13,18,20,61,62 Mortality rates vary widely across published epidemiological studies, ranging from 8% to 67%.59 Regional variations become apparent when num- bers from different studies are compared. 