No Concluding Evidence on Optimal Activated Clotting Time for Non-cardiac Arterial Procedures

Heparin has a non-predictable effect in the individual patient. The activated clotting time (ACT) is used to measure the level of anticoagulation after administration of heparin. To date, appropriate heparin dose protocols and corresponding therapeutic ACT values have not been established in non-cardiac arterial procedures (NCAP). The aim of this review was to study the use of ACT monitoring during NCAP, and whether an optimal ACT could be determined based on the fewest arterial thrombo-embolic complications (ATEC) and bleeding complications.

This systematic review was performed in accordance with the PRISMA Guidelines. A systematic search was conducted in MEDLINE, EMBASE, and the Cochrane database. Any associations were evaluated between peri-procedural ACT levels and ATEC and bleeding complications detected during the same admission as the primary procedure or during 30 day follow up. Also, heparin dose protocols, peri-procedural target ACTs, different ACT devices, protamine use and pre-, peri-, and post-procedural anticoagulation therapy were evaluated.

In total, 21 studies with 3982 patients were included, on both open and endovascular NCAP. Four studies were primarily designed to correlate peak peri-procedural ACT with clinical outcomes; however, the definitions of the results and the clinical outcomes were too heterogeneous for analysis. There was major variability in all studied aspects of ACT measurement, heparin and protamine use, and in the type of procedures in the included studies. Overall methodological quality of the included studies was poor. No randomised controlled trials were found. Studies were at a high risk of bias.

This systematic review demonstrates a lack of data and no consensus in the literature concerning the optimal ACT, and the possible association with haemorrhagic complications and ATEC during NCAP.