Female sex was inconsistently associated with stroke risk , whereas the evidence was inconclusive that either heart failure or coronary artery disease is independently predictive of stroke .
Conclusions : Four clinical features ( prior stroke/TIA , advancing age , hypertension , diabetes ) are consistent independent risk factors for stroke in atrial fibrillation patients .
Background : Absolute stroke rates vary widely among patients with nonvalvular atrial fibrillation .
To balance the benefits and risks of chronic antithrombotic prophylaxis , it is important to estimate the absolute risk of stroke for individual patients .
Pathophysiologic correlates of thromboembolism in nonvalvular atrial fibrillation: I. Reduced flow velocity in the left atrial appendage (The Stroke Prevention in Atrial Fibrillation [SPAF-III] study).
Stroke associated with atrial fibrillation ( AF ) is mainly due to embolism of thrombus formed during stasis of blood in the left atrial appendage ( LAA ) . Pathophysiologic correlates of appendage flow velocity as assessed by transesophageal echocardiography ( TEE ) in patients with AF have not been defined . To evaluate the hypothesis that reduced velocity is associated with spontaneous echocardiographic contrast and thrombus in the LAA and with clinical embolic events , we measured LAA flow velocity by TEE in 721 patients with nonvalvular AF entering the Stroke Prevention in Atrial Fibrillation ( SPAF-III ) study . Patient features , TEE findings , and subsequent cardioembolic events were correlated with velocity by multivariate analysis . Patients in AF during TEE displayed lower peak ante grade ( emptying ) flow velocity ( Anu(p ) ) than those with intermittent AF in sinus rhythm during TEE ( 33 cm/s vs 61 cm/s , respectively , P < .0001 ) . Anu(p ) < 20 cm/s was associated with dense spontaneous echocardiographic contrast ( P < .001 ) , appendage thrombus ( P < .01 ) , and subsequent cardioembolic events ( P < .01 ) . Independent predictors of Anu(p ) < 20 cm/s included age ( P = .009 ) , systolic blood pressure ( P < .001 ) , sustained AF ( P = .01 ) , ischemic heart disease ( P = .01 ) , and left atrial area ( P = .04 ) . Multivariate analysis found both Anu(p ) < 20 cm/s ( relative risk 2.6 , P = .02 ) and clinical risk factors ( relative risk 3.3 , P = .002 ) independently associated with LAA thrombus . LAA Anu(p ) is reduced in AF and associated with spontaneous echocardiographic contrast , appendage thrombus , and cardioembolic stroke . Systolic hypertension and aortic atherosclerosis , independent clinical predictors of stroke in patients with AF , also correlated with LAA Anu(p ) . Our results support the role of reduced LAA Anu(p ) in the generation of stasis , thrombus formation , and embolism in patients with AF , although other mechanisms also contribute to stroke
Female sex was inconsistently associated with stroke risk , whereas the evidence was inconclusive that either heart failure or coronary artery disease is independently predictive of stroke .
Conclusions : Four clinical features ( prior stroke/TIA , advancing age , hypertension , diabetes ) are consistent independent risk factors for stroke in atrial fibrillation patients .
Background : Absolute stroke rates vary widely among patients with nonvalvular atrial fibrillation .
To balance the benefits and risks of chronic antithrombotic prophylaxis , it is important to estimate the absolute risk of stroke for individual patients .