of Studies Risk of Bias Inconsistency Indirectness Imprecision Publication Bias Study Event Rates (%) Relative Effect CI) Estimation of Absolute Effects Time Frame Quality of Evidence With ASA Clopid With VKA With ASA Clopid With VKA CI) Death (critical outcome) median follow-up y RCT No serious limitations a No serious inconsistency No serious indirectness Imprecise b Undetected RR per c fewer death per (from fewer to more) Moderate Nonfatal stroke (critical outcome) median follow-up y; ischemic stroke and intracranial hemorrhage d RCT No serious limitations a No serious inconsistency No serious indirectness No serious imprecision Undetected e f RR CHADS points High per g fewer strokes per (from fewer to fewer) CHADS point per fewer strokes per (from fewer to fewer) CHADS points per fewer strokes per (from fewer to fewer) CHADS points per fewer strokes per (from fewer to fewer) Nonfatal major extracranial bleeds (important outcome) median follow-up y h RCT No serious limitations a No serious inconsistency No serious indirectness of patients were receiving VKA at study entry) Imprecise i Undetected RR per j fewer bleeds per (from fewer to more) Moderate www.chestpubs.org CHEST / 141 / 2 / FEBRUARY, 2012 SUPPLEMENT e547S Table Quality Assessment Summary of Findings No. of Studies Risk of Bias Inconsistency Indirectness Imprecision Publication Bias Study Event Rates (%) Relative Effect CI) Estimation of Absolute Effects Time Frame Quality of Evidence With ASA Clopid With VKA With ASA Clopid With VKA CI) Systemic embolism (important outcome) median follow-up y RCT No serious limitations a No serious inconsistency No serious indirectness No serious imprecision Undetected RR per k fewer systemic emboli per (from fewer to fewer) High Burden of treatment (important outcome) N/A No serious limitations No serious limitations No serious limitations No serious limitations N/A N/A N/A VKA . 