Biocompatibility Assessment of the CentriMag-Novalung Adult ECMO Circuit in a Model of Acute Pulmonary Hypertension

Abstract

Extracorporeal membrane oxygenation (ECMO) is rarely utilized in patients with severe pulmonary hypertension (PH) as a bridge to lung transplantation. In this study we assess the blood biocompatibility of the integrated Centrimag® Novalung ® ECMO system (veno arterial) in an acute model of PH. Severe PH (≥ 2/3 systemic) was induced in eight ovines through progressive ligation of the main pulmonary artery. System performance, platelet activation, thromboelastography parameters, fibrinogen, plasma free hemoglobin, and total plasma protein were measured at initiation, 3 and 6 hrs of support in the ECMO (N=4) and sham (N=4) groups. A stable ECMO flow (2.2 ± 0.1 L/min), low trans-membrane pressure gradient and steady blood O2 and CO2 levels were maintained. Platelet activation was low (< 4%) in both the groups whereas platelet responsiveness to agonist (platelet activating factor) was reduced in the sham group when compared to the ECMO group. There were no differences in the TEG parameters, fibrinogen concentration, plasma free hemoglobin (< 10 mg/dL) and plasma total protein between the two groups. The findings of low levels of platelet activation and plfHb suggest adequate blood biocompatibility of the integrated Centrimag® Novalung® circuit use for short term support in a model of PH.

Hemocompatibility of Axial Versus Centrifugal Pump Technology in Mechanical Circulatory Support Devices

“…provided the biocompatibility profile of an extracorporeal membrane oxygenation circuit including the CM adult pump. However, their setup also included an oxygenator and shares the same limitation regarding the limited numbers of enclosed biocompatibility markers . Other studies focused on the hydrodynamic properties and hemolysis of new pump systems.…”

“…In most cases, experimental models aiming at more detailed biocompatibility analysis include an oxygenator and therefore these investigations pay less attention to the impact of the pump itself . Furthermore, individual biocompatibility properties of different pump technologies are not compared in the same experimental model.…”

Assessment of Thrombelastography and Platelet Life Span in Ovines

“…The ovine is a frequently used preclinical animal model for the assessment of cardiovascular device function and biocompatibility . Adult ovines have hearts that are similar in size to the human heart for evaluation of implantable devices such as ventricular assist devices (VAD).…”

“…One of the primary endpoints of preclinical testing of blood contacting cardiovascular devices is to ensure adequate blood biocompatibility . Previously, flow cytometric assays to quantify activated ovine platelets have been reported and shown to be sensitive to blood pump complications and when there was subsequent evidence of thromboembolism .…”

“…Limited data exist describing the use of TEG in sheep. TEG was used as one parameter to assess the efficacy of anticoagulation in sheep as well as coagulation status following initiation of mechanical circulatory support . In another report, TEG was used to assess platelet function before and after burn and smoke inhalation injury .…”