Thromboembolic (TE) and hemorrhagic (H) complications are the most significant causes of morbidity and mortality in patients treated with oral anticoagulants (OA) after implantation of artificial valvular prostheses. The risk of complications is dependent on recommended target INR ranges and quality of anticoagulation treatment. We studied 358 patients with a mean age 56.9 +/- 10.3 (who underwent 144 mitral, 172 aortic, 42 both artificial heart valve replacement). The follow up was averaged 36.7 +/- 12.1 month. Linearized incidents of TE events was 2.7%/pty, H events--4.15%/pty. The quality of anticoagulant treatment based on following parameters: averaged INR +/- SD, percentage measurements of INR within the target range 2.5-3.5, within the broad range 2-4 and under 2 and over 5. Average frequency of tests, SD/averaged INR X 100%--was similar in patients with TE and H complications and event free patients. Significant differences were found when a shorter period of time-3 months preceding the TE or H incident was analized compared with the average results of measurements of event free patients. The patients with TE and H complications have statistically significant higher fluctuation ratio than event free patients (respectively: 1.09 -/+ 0.71 and 1.71 -/+ 1.06 vs 0.5 -/+ 0.32, p = 0.04 and 0.02 )
Conclusions: 1. The risk of TE and H complications was dependent on high fluctuation of INR values in the period of 3 months before the event. 2. The worse control of measurements of INR in the period of 3 months before the event in comparison with yearly values within the recommended target ranges show, that TE and H complications are directly dependent on period of poor INR control.