Clinical Research Directory

External Multicenter Validation of the APTTO Model for Prolonged APTT Using Clot Waveform Analysis

Prolonged activated partial thromboplastin time (APTT) is a frequent laboratory finding that may reflect a broad spectrum of underlying conditions, ranging from benign laboratory abnormalities to clinically relevant hemostatic disorders. Clot waveform analysis (CWA), automatically generated during routine APTT testing by optical coagulation analyzers, provides additional quantitative and qualitative information on clot formation dynamics. The APTTO model is a previously developed two-step predictive algorithm based on CWA features designed to estimate the probability of a pathological cause of prolonged APTT and to differentiate lupus anticoagulant from intrinsic pathway factor deficiency or von Willebrand disease. Internal validation has demonstrated good discrimination and calibration. This multicenter observational study aims to perform an external validation of the APTTO model in independent patient cohorts, assessing its discrimination, calibration, and decision-analytic performance without model updating.

Goal-directed vs. Empirical Tranexamic Acid Administrationin Cardiovascular Surgery

The present study is a multi-center randomized prospective placebo-controlled non-inferiority trial. The study's primary objective is to compare the amounts of postoperative bleeding using two different TXA administration strategies: empirical TXA administration vs. viscoelastic test-based goal-directed TXA administration in cardiovascular surgery. The secondary objectives include comparing the incidents of hyper-fibrinolysis, thromboembolic complications, and postoperative seizures. Researchers assumed that goal-directed tranexamic acid (TXA) administration using viscoelastic field tests would not be inferior to the empirical TXA administration strategy in reducing postoperative bleeding and hyper-fibrinolysis. It also would be beneficial in lowering TXA-induced thromboembolic complications and seizures.