Risk factors for cerebral ischemic events in patients with atrial fibrillation on warfarin for stroke prevention.
OBJECTIVE
Patients with atrial fibrillation (AF) on treatment with oral anticoagulants may still suffer ischemic cerebrovascular events. The aim of this study was to evaluate the risk factors for cerebral ischemic events in warfarin-treated AF patients with an International Normalized Ratios (INR) above 1.8 on admission.


METHODS
In a case-control study, cases were consecutive patients with AF who were on warfarin and who were admitted to four Italian hospitals after an acute cerebrovascular ischemic event (ischemic stroke or transient ischemic attack) with an INR above 1.8. Controls were selected from a single anticoagulation clinic and were patients with AF on adequate warfarin treatment who did not suffer cerebrovascular events.


RESULTS
Cases were identified among 4785 consecutive patients with an ischemic cerebral event. 148 cases (3.1%, 21 with transient ischemic events and 127 with ischemic strokes) had AF and were taking warfarin with an INR above 1.8 on admission. On multivariate analysis, diabetes (OR 3.8; 95% CI 1.09-13.82, p=0.025), hyperlipidemia (OR 4.5; 95% CI 1.11-18.23, p=0.035) and carotid/vertebral atherosclerosis on ultrasound (OR 3.0; 95% CI 1.13-8.41, p=0.028) were independent predictors for ischemic cerebral events. The use of statins was inversely correlated with an ischemic event (OR 0.1; 95% CI 0.06-0.47. p=0.001).


CONCLUSIONS
Carotid/vertebral atherosclerosis, diabetes and hyperlipidemia are associated with an increased risk for ischemic events in patients with AF on adequate warfarin treatment. Statins significantly reduce the risk of ischemic events.
Paciaroni
Maurizio
M
Stroke Unit, Division of Cardiovascular Medicine, University of Perugia, UO Gravi Cerebrolesioni, S. Giovanni Battista Hospital, Foligno, Perugia, Italy. mpaciaroni@med.unipg.it
Agnelli
Giancarlo
G
Ageno
Walter
W
Caso
Valeria
V
Corea
Francesco
F
Lanari
Alessia
A
Alberti
Andrea
A
Previdi
Paolo
P
Fedele
Marta
M
Manina
Giorgia
G
Vedovati
Cristina
C
Venti
Michele
M
Billeci
Antonia M R
AM
Batta
Maurizio
M
Galli
Luca
L
Silvestrelli
Giorgio
G
D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use*; D050197:Atherosclerosis / Q000175:diagnosis* / Q000517:prevention & control; D001281:Atrial Fibrillation / Q000188:drug therapy*; D002545:Brain Ischemia / Q000175:diagnosis* / Q000517:prevention & control; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006949:Hyperlipidemias; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012306:Risk; D020521:Stroke / Q000517:prevention & control*; D014859:Warfarin / Q000009:adverse effects* / Q000627:therapeutic use*
D000925:Anticoagulants; D014859:Warfarin