Thorac Cardiovasc Surg 2019; 67(03): 191-202
DOI: 10.1055/s-0037-1609019
Original Cardiovascular
Georg Thieme Verlag KG Stuttgart · New York

Is 300 Seconds ACT Safe and Efficient during MiECC Procedures?

Adrian Bauer
1  Department of Cardiovascular Perfusion, MediClin Heart Center Coswig, Coswig, Saxony-Anhalt, Germany
2  Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
3  Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
,
Harald Hausmann
4  Department of Cardiothoracic and Vascular Surgery, MediClin Heart Center Coswig, Coswig, Saxony-Anhalt, Germany
,
Jan Schaarschmidt
1  Department of Cardiovascular Perfusion, MediClin Heart Center Coswig, Coswig, Saxony-Anhalt, Germany
,
Michal Szlapka
4  Department of Cardiothoracic and Vascular Surgery, MediClin Heart Center Coswig, Coswig, Saxony-Anhalt, Germany
,
Martin Scharpenberg
5  Competence Center for Clinical Trials Bremen, University of Bremen, Bremen, Germany
,
Thomas Eberle
6  Department of Anesthesia and Intensive Care Medicine, MediClin Heart Center Coswig, Coswig, Saxony-Anhalt, Germany
,
J. Michael Hasenkam
2  Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
3  Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
› Author Affiliations
Further Information

Publication History

26 August 2017

01 November 2017

Publication Date:
31 December 2017 (online)

Abstract

Introduction The recommended minimum activated clotting time (ACT) level for cardiopulmonary bypass (CPB) of 480 seconds originated from investigations with bubble oxygenators and uncoated extracorporeal circulation (ECC) systems. Modern minimal invasive ECC (MiECC) systems are completely closed circuits containing a membrane oxygenator and a tip-to-tip surface coating. We hypothesized that surface coating and the “closed-loop” design allow the MiECC to safely run with lower ACT levels and that an ACT level of 300 seconds can be safely applied without thromboembolic complications. The aim of this study was to investigate the potential risks during application of reduced heparin levels in patients undergoing coronary surgery.

Methods In this study, 68 patients undergoing coronary artery bypass grafting with MiECC were randomized to either the study group with an ACT target of 300 seconds or the control group with an ACT of 450 seconds. All other factors of MiECC remained unchanged.

Results The study group received significantly less heparin and protamine (heparin [international units] median [min–max], Red_AC: 32,800 [23,000–51,500] vs. Full_AC: 50,000 [35,000–65,000] p < 0.001; protamine [international units], Red_AC: 18,000 [10,000–35,000] vs. Full_AC: 30,000 [20,000–45,000] p < 0.001). The ACT in the study group was significantly lower at the start of MiECC (mean ± standard deviation: study group 400 ± 112 vs. control group 633 ± 177; p < 0.0001). Before termination of CPB the ACT levels were: study group 344 ± 60 versus control group 506 ± 80. In both groups, the values of the endogenous thrombin potential (ETP) decreased simultaneously. None of the study participants experienced thromboembolic complications.

Conclusion Since no evidence of increased thrombin formation (ETP) was found from a laboratory standpoint, we concluded that the use of MiECC with a reduced anticoagulation strategy seems possible. This alternative anticoagulation strategy leads to significant reduction in dosages of both heparin and protamine. We can confidently move forward with investigating this anticoagulation concept. However, to establish clinical safety of ACT below 300 seconds, we need larger clinical studies.