geoffrey modest medical blogs

background: stroke is common, but 20-40% of strokes and 50% of TIAs have no evident cause after work-up (called "cryptogenic"). since afib is a common and treatable cause of stroke (and the treatment of afib with anticoagulants is different from that of other strokes with antiplatelet agents), and since those with untreated afib have higher likelihood of recurrent stroke, it seems reasonable to look hard for afib. 2 recent articles in NEJM tried to assess this -- the CRYSTAL AF trial (see  stroke and cryptogenic afib1 nejm2014  in dropbox, or DOI: 10.1056/NEJMoa1313600) was an RCT of 441 patients >40yo (mean age 61.5) with cryptogenic stroke in prior 90 days (negative workup including 24-hr Holter) randomized to a long-term insertable cardiac monitor (ICM) vs conventional followup. primary endpoint was time to first detection of afib lasting >30 sec within 6 months. secondary endpt was time to first detection of afib with...

am acad of neurology just published new guidelines on stroke prevention in patients with nonvalvular atrial fib  (see  afib anticoag neuro guidelines 2014  in dropbox, or DOI 10.1212/WNL.0000000000000145). their findings:     --in patients with cryptogenic stroke, most studies used Holter monitoring, followed by serial EKGs, event monitors, etc, with monitoring duration from 24 hrs to 30d. pickup of nonvalvular afib (NVAF) was 0-23%, average 10.7%. increased pickup with increased duration of monitoring.     --INR goal for warfarin therapy is 2-3     --non-warfarin therapies: dabigatran is "probably more effective" than warfarin. hemorrhage risks similar, though less intracranial hemorrhage and more GI bleeds. rivaroxaban is "probably as effective as warfarin", no diff in risks of bleeds (also more GI and fewer intracranial). apixaban "likely more effective than warfarin", with decreased bleeding and reduced mortality. oral antic...