Background: In atrial fibrillation (AF) patients stroke is nearly twice as likely to be fatal as non-AF patients and functional deficits are more likely to be severe among survivors. The incidence of stroke among AF patients is greatly reduced by oral anticoagulant treatment (OAT). However, fluctuation of anticoagulation levels is intrinsically related to OAT and often international normalized ratio (INR) is out of the therapeutic range.
Methods: Since the "anticoagulation history" is an ongoing process, we performed this prospective study in 578 AF patients to investigate the role of the whole quality of OAT and of INR levels at the occurrence of transient ischemic attack (TIA) or stroke on the severity of cerebral ischemia.
Results: During follow-up 13 patients had TIA and 18 had stroke (rate 1.67 x 100 pt/years). In relation to the quality of anticoagulant treatment, no significant differences were found in the time spent below and within the intended therapeutic range, between patients with and without TIA/stroke. Patients with TIA/stroke spent a longer time above the intended therapeutic range with respect to other patients, even if this difference was not confirmed at multivariate analysis. Forty-six percent of patients with TIA and 66% of patients with stroke had INR>or=2 at the occurrence of ischemic event.
Conclusion: The severity of stroke was not related to the whole quality of anticoagulation or to INR at the event.