Optimal PT-INR after Prosthetic Valve Replacement: Queen Sirikit Heart Center’s Experience
Keywords:
anticoagulant, prosthetic valve replacement, PT-INR, warfarinAbstract
Background: Anticoagulant therapy after valve replacement using mechanical valve is indispensible forprevention of thromboembolism. On the other hand, hemorrhagic complications due to overdosed
anticoagulations also deteriorate the patients.
Objectives: The purpose of this study was to investigate the PT-INR value of the patients who underwent
mechanical valve replacement with anticoagulant-related complications compared with those who had no
complications. In addition, we aimed to identify the optimal PT-INR value not leading to either hemorrhagic
or thromboembolic complications.
Materials and Methods: From September 2007 to April 2008, a total of 432 patients who underwent
mechanical valve replacement with 962 postoperative follow-up visits were investigated for the PT-INR values
and anticoagulant-related complications. The patients were divided into 3 groups: Group I had no complication,
Group II had bleeding complications either minor (i.e. gingival bleeding, small subcutaneous ecchymosis or
minimal hematuria) or major (i.e. cerebral hemorrhage and large hematoma requiring surgical drainage), and
Group III had thromboembolic complications. In addition, Group II was redistributed into 3 subgroups: Group
IIa had the PT-INR < 2.50, Group IIb had the PT-INR between 2.50-3.50 and Group IIc had the PT-INR > 3.50.
Continuous variables were expressed as a mean + standard deviation. The P values < 0.05 were considered as
statistically significant.
Results: There were 209 males and 223 females with age ranged from 16 to 80 years (mean 48.87 ± 11.35).
The visit times ranged from 1 to 9 visits (mean 2.22 ± 1.27). Mean PT-INR values in Groups I, II and III were
2.57 ± 1.15 (n = 846), 4.09 ± 2.32 (n = 113) and 2.19 ± 1.73 (n = 3) respectively. The PT-INR in Group III showed
no difference from the other groups. However, the mean PT-INR in Group II was significantly higher than those
of Group I (p < 0.05). Among the hemorrhagic complication cases (n = 113), the mean PT-INR values in Groups
IIa, b and c were 1.72+0.50, 3.13+0.26 and 5.17+2.35, respectively. The PT-INR values in Groups IIb and IIc
were significantly higher than Group IIa (p < 0.05).
Conclusions: 1) The anticoagulant-related bleeding complications usually occurred when the PT-INR
values were high especially when > 3.50. 2) The thromboembolic complication could occur even when the PTINR
values were in the therapeutic range. 3) The optimal PT-INR value should not be higher than 3.50.
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