Hohlfelder et al reported an equation for predicting the change in INR after a change in the infusion rate of bivalirudin. The authors are from Brigham and Women's Hospital in Boston.
Patient selection: therapy with bivalirudin
Parameters:
(1) INR prior to starting bivalirudin
(2) INR after starting bivalirudin
(3) INR target after change in bivalirudin infusion (first specimen)
(3) bivalirudin weight-based infusion rate in mg per kg per hour at start of infusion
(4) bivalirudin weight-based infusion rate in mg per kg per hour after infusion change (0 if bivalirudin is discontinued)
(5) weight of the patient in kilograms
change in INR at start =
= (INR after starting) - (INR before starting)
change in INR after change =
= (INR after starting) - (INR after change)
change in INR after change =
= (change in INR after start) * (bivalirudin weight-based infusion after change) / (bivalirudin weight-based infusion at start)
In Figure 2 (after removal of outlier in Figure 1) the equation was:
change in INR after change =
= (change in INR after start) * (bivalirudin weight-based infusion after change) / (bivalirudin weight-based infusion at start) * 0.8527
