Low molecular weight heparin after mechanical heart valve replacement achieved therapeutic anticoagulation on day 2 in 87% of patients compared to 9% with unfractionated heparin (P<0.0001).
Cohort (n=208)
Does subcutaneous low molecular weight heparin improve the achievement of therapeutic anticoagulation levels compared to unfractionated heparin in patients after mechanical heart valve replacement?
LMWH provides more rapid and reliable therapeutic anticoagulation compared to subcutaneous unfractionated heparin in the early postoperative period after mechanical heart valve replacement.
Absolute Event Rate: 87% vs 9%
p-value: p=<0.0001
BACKGROUND: Patients with mechanical heart valves require life-long anticoagulation. We report here the first large and comparative series of consecutive patients anticoagulated with low molecular weight heparin (LMWH) after mechanical heart valve replacement. METHODS AND RESULTS: In this comparative, nonrandomized study, 208 consecutive patients who underwent a single or double heart valve replacement with mechanical prostheses were anticoagulated subcutaneously with unfractionated heparin (UH) in the first period (n=106) and LMWH in the second phase (n=102) of the study. Baseline characteristics were similar in the 2 groups. The mean durations of UH and LMWH treatments were 13.6+/-0.5 and 14.1+/-0.6 days, respectively (not significant). On the second day of treatment, 87% of patients treated with LMWH had an anti-Xa activity within the range of efficacy (0.5 to 1 IU/mL), but only 9% of UH-treated patients had an activated partial-thromboplastin time value within the therapeutic range (1.5 to 2.5 times control, P<0.0001 between the 2 groups). On the last day of prescription, all LMWH-treated patients had anti-Xa activity above 0.5 IU/mL, but 19% were above 1 IU/mL. In the UH group, 27% of patients had an activated partial-thromboplastin time above 1.5 times control, but 62% were overanticoagulated. Two major bleedings occurred in each group, and one stroke occurred in the UH group. CONCLUSIONS: In this first comparative study, anticoagulation with LMWHs after mechanical heart valve replacement appears feasible, provides adequate biological anticoagulation, and compares favorably with UH anticoagulation. Randomized studies are now needed to further evaluate this new therapeutic approach.
Montalescot et al. (Tue,) conducted a cohort in Mechanical heart valve replacement (n=208). Low molecular weight heparin (LMWH) vs. Unfractionated heparin (UH) was evaluated on Therapeutic anticoagulation on the second day of treatment (anti-Xa activity 0.5-1 IU/mL for LMWH vs aPTT 1.5-2.5 times control for UH) (p=<0.0001). Low molecular weight heparin after mechanical heart valve replacement achieved therapeutic anticoagulation on day 2 in 87% of patients compared to 9% with unfractionated heparin (P<0.0001).