Is 10 min post heparin bolus ACT, alongside aPTT monitoring, predictive for CRRT filter survival?

Abstract

When using heparin anticoagulation for continuous renal replacement therapy (CRRT), the main challenge is to tailor the dosage to patient response. This study aimed to determine if the first activated thromboplastin time (aPTT) (measured after 3 hours post heparin bolus) can be a predictor for CRRT filter survival and if the first activated clotting time-low range (ACT-LR) (10 min post heparin bolus) can be predictive for subtherapeutic or therapeutic first aPTT. An unfractionated heparin (UF) anticoagulation protocol was used in CRRT and heparin monitoring was performed by aPTT and ACT-LR. Extracorporeal therapy was analyzed and filter survival was assessed for general risk factors, especially coagulation tests. For statistical analysis, Logrank tests, ROC curve analysis, and the Kaplan-Meier chart for survival evaluations were utilized. Using the pLogrank test, the overall survival for the CRRT procedure was 47.8 hours (p=0.04), and no clotting events occurred during the first 12 hours for all examined therapies. Multivariate analysis for filter survival prediction to estimate 48 hours of CRRT revealed statistical relevance for Age (<60 years), BMI (<25.9), and INR (>1.3), with negative statistical significance for lipids, triglycerides, and fibrinogen. aPTT (180 min) values greater than 57 sec were shown to be predictive of 48-hour filter survival, and similar findings were obtained for aPTT measured at 6 hours. ACT-LR samplesassessed 10 minutes after the initial heparin bolus was shown to be predictive of 48-hour filter survival (cutoff > 218 sec; p=0.04). When ACT prediction potential for therapeutic aPTT values was evaluated, ACT-LR 10 min (cut off > 200 sec.), ACT-LR 60 min (cut off > 186 sec.), and ACT-LR 180 min (cut off > 182 sec.) were found to be predictive. Based on this study and its sample size, ACT-LR can be a complimentary assessment to aPTT for monitoring anticoagulation with heparin on CRRT.