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D-dimer and anticoagulation in patients with mechanical prosthetic heart valves. A 2-year follow-up
C Giansante1, N Fiotti, S Calabrese
1Institute of Clinical Medicine, University of Trieste, Italy. carlog@clmed.univ.trieste.it
Insights
D-dimer levels in mechanical heart valve patients are linked to anticoagulation control. Higher D-dimer indicates increased risk for vascular events, aiding in patient risk stratification.
Area of Science:
- Cardiology
- Hematology
- Biomarkers
Background:
- Optimal anticoagulation for mechanical heart valves remains debated.
- D-dimer is a marker for coagulation activation, detecting fibrin degradation products.
Purpose of the Study:
- To investigate D-dimer levels in patients with mechanical heart valves.
- To determine if D-dimer relates to anticoagulation control and predicts vascular or hemorrhagic events.
Main Methods:
- Measured D-dimer and INR in 142 patients with mechanical valves and 102 controls.
- Assessed time within therapeutic INR range over 8 months.
- Followed patients for 2 years for vascular and hemorrhagic events.
Main Results:
- Overall D-dimer levels were similar between patients and controls.
- Double valve replacement patients showed higher D-dimer.
- Inadequate anticoagulation (<75% time in range) correlated with higher D-dimer.
- High D-dimer tertile predicted thromboembolic events (5-fold risk).
Conclusions:
- D-dimer levels in mechanical heart valve patients reflect anticoagulation adherence.
- Elevated D-dimer is a significant predictor of vascular thromboembolic events.
- D-dimer testing can identify high-risk patients needing closer monitoring.
Abstract:
The best anticoagulation level in patients with mechanical heart valve prostheses is still being debated. D-dimer, which detects the presence of cross-linked fibrin degradation products, has been demonstrated to be a useful marker of coagulation activation. This study was designed to verify whether heart valve prostheses in anticoagulated patients are associated with abnormalities in D-dimer plasma levels, and if so, whether such levels are related to the anticoagulation level and/or whether they could be predictive of acute vascular or hemorrhagic events. In 132 patients with single and 10 with double mechanical valve replacement, international normalized ratio (INR) and D-dimer plasma levels were determined. The INR levels of the previous 8 months were reviewed to assess the time that each patient spent in the therapeutic range. The D-dimer plasma levels were compared with those obtained from 102 matched control subjects. The patients were then followed up for 2 years to record acute vascular and hemorrhagic events. For the entire group, D-dimer plasma levels in patients were the same as those in the control group. Patients with double valve replacement had higher D-dimer plasma levels than either monovalvular implant patients or control subjects. Patients who had spent < 75% of the time within the assigned anticoagulation range had higher values for D-dimer plasma levels (median, 270 vs 198 ng/mL, P = .02). The major determinants of D-dimer plasma levels were age (R2 = .07, P = .009) and the percentage of time spent below the predetermined INR level (R2 = .09, P = .001). During follow-up, 19 acute vascular and 16 hemorrhagic events occurred. High D-dimer tertile was the only parameter predicting the occurrence of thromboembolic events. In patients with mechanical heart valve prostheses, the D-dimer plasma level depended on the thoroughness of anticoagulation. Patients in the upper tertile of D-dimer values have an approximately 5-fold risk of vascular thromboembolic events. D-dimer determination can therefore be useful in detecting patients who are at a higher risk of severe vascular events.