Analysis of factors for poor activated partial thromboplastin time control after dabigatran administration

In this study, we compared patients whose activated partial thromboplastin time (APTT) was prolonged excessively with those whose APTT was controlled within the normal range after dabigatran administration. We analyzed the factors for the APTT prolongation. We divided the patients into two groups: those whose APTTs prolonged to more than 65 s and those whose APTTs were less than 65 s after dabigatran administration. There were 130 patients from March 2011 to July 2013, and we analyzed the background features and laboratory data of these patients. Results showed that there were no significant differences in the patients' background and laboratory data except for the high-density lipoprotein cholesterol (HDL-C) level. However, details of the relationship between the APTT prolongation and the HDL-C level are currently unknown. We hypothesize that the reason for the APTT prolongation is the variability in such parameters as the time of blood drawing, internal time of dabigatran, individual variability, and blood concentration. Therefore, we consider that these parameters need to be carefully evaluated even if APTT does not show prolongation.