New anticoagulant drugs for treatment of venous thromboembolism and stroke prevention in atrial fibrillation

How to report results of prothrombin and activated partial thromboplastin times

“…Patients on DOAC display PT or APTT that are variably prolonged over the upper limit of the reference range [15]. The PT prolongation is more evident with rivaroxaban Table 1: International Society for Thrombosis and Hemostasis (ISTH) score system for diagnosis and monitoring of disseminated intravascular coagulation.…”

“…In all the other circumstances it can be used for results reporting, but it may fail to harmonize results obtained with different commercial thromboplastins. For instance, it was demonstrated that the INR fails to harmonize results across different thromboplastins when used to express PT results for patients with chronic liver disease, patients with disseminated intravascular coagulation (DIC) congenital deficiency of pro-coagulant factors, or for those on DOAC [15]. This is not surprising if one considers that the ISI (which is the mainstay of the calibration model) is determined by using plasmas from patients stabilized on VKA, and is therefore only dependent on the coagulation defect(s) induced by these drugs.…”

“…The system of calibration based on the revised Kirkwood model is still in place, and is the focus of continuous attention aimed at improving its reliability. One may guess that it will be the system of choice to monitor patients on treatment, at least until coumarin drugs will be replaced by the new generation of direct oral anti coagulants (DOAC) [14][15][16][17] that (allegedly) do not require dose-adjustment by laboratory testing.…”

The laboratory and the direct oral anticoagulants

“…Assessment of creatinine clearance is of paramount importance as DOAC are largely excreted via the kidney. 1 Therefore, even mild renal insufficiency may lead to drug accumulation during treatment, thus increasing the bleeding risk. Assessment of creatinine clearance is indicated not only before starting treatment but also at regular intervals during treatment, as kidney function may deteriorate rapidly, especially in the elderly.…”

“…Clinical trials have shown that DOAC, unlike vitamin K antagonists (VKA), are effective and safe when administered without dose adjustment based on laboratory testing. 1 However, it is a misconception to believe that the laboratory will not have a role in the management of patients treated with DOAC. This review is aimed at discussing:…”