It is estimated that nearly 20% of all cerebral infarctions in the total population are the result of a complication of atrial fibrillation (AF). While oral anticoagulation with vitamin K antagonists (AVKs) substantially reduces this risk, this requires regular monitoring of the international normalized ratio (INR) in order to achieve therapeutic levels (2,0-3,0). The aim of this study was to evaluate a group at high risk of cerebral infarction, among patients with AF undergoing long-term treatment with VKAs, taking into account the significance of therapeutic INR values. The analysed group consisted of 90 acute ischaemic stroke patients with paroxysmal or chronic “non-valvular” AF, receiving treatment with VKAs. As a result of the study, therapeutic INR values (≥ 2) were seen in thirty-five of these individuals (38,8%), while 55 (61,2%) showed non-therapeutic INR values. Moreover, there were no differences in demographics, vascular risk factors, biochemical and morphological blood parameters, mean CHA2DS2-VASc score and TOAST classification between either of the two groups. Furthermore, no additional factor that would increase their risk of cerebral infarction during the adequate treatment with VKAs was found. However, patients with non-therapeutic INR values had a statistically significantly higher frequency of concomitant moderate pathology of the bicuspid valve, p<0.05. Hence, a lack of proper control of INR can proved to be particularly dangerous for this subgroup of patients. Hence, this is a group with an elevated risk of cerebral infarction and therefore requires special oversight of VKA treatment or NOA treatment.
1. Bamford J, at al.: Classif ication and natural history of clinically identifiable subtypes of cerebral infarction. Lancet, 337,1521-1526,1993.
2. Conolly SJ.: Benefit of oral anticoagulant over antiplatelet therapy in atrial fibrillation depends on the quality of international normalized ratio control achieved by centres and countries as measured by time in therapeutic range. Circulation, 118, 2029-2037, 2008.
3. Crystal E, Connolly SJ: Role of oral anticoagulation in management of atrial fibrillation. Heart 20,813-817, 2004.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.