A Novel Oxygenator-Right Ventricular Assist Device Circuit Using the SYNERGY Micropump as Right Heart Support in a Swine Model of Pulmonary Hypertension
Abstract
Objectives: As clinical experience with extracorporeal life support (ECLS) continues to grow, pulmonary hypertension (PH) remains a potential target for intervention and investigation. PH is a rare but severe, progressive disease that can lead to right heart failure and death. ECLS has the potential to ameliorate both the pulmonary and cardiac dysfunction associated with PH, and thus provide a life saving intervention in this disease.
Methods: In this study, we assessed the blood biocompatibility of the SYNERGY micropump in conjunction with a Quadrox D oxygenator in a novel oxygenator-right ventricular assist device (OxyRVAD) extracorporeal membrane oxygenation (ECMO) circuit in a swine model of acute PH. Four pigs were placed on OxyRVAD ECMO. PH was induced by banding the pulmonary artery. After banding, mean pulmonary artery pressure (mPAP) increased from 17 mmHg to 39 mmHg.
Results: All animals survived 6 hours without catastrophic biocompatibility issues. There were no significant differences in hemoglobin, plasma-free hemoglobin, or platelets from baseline. Platelet activation – assessed by plasma P-selectin – did not increase during the run. Indirect measurements of hemolysis were assessed by total bilirubin and lactate dehydrogenase. Total bilirubin did not change significantly. The average increase in lactate dehydrogenase was significant.Fibrinogen and D-dimer levels were significantly decreased from baseline.
Conclusion: OxyRVAD showed no catastrophic failures in this short-term test. Micropump OxyRVADs may have a role in the management of PH.
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Introduction
Extracorporeal life support (ECLS) is an important life-saving therapy for refractory cardiopulmonary failure. Technological advances as well as growing clinical experience continues to improve outcomes and extend the range of ECLS applications. Miniaturized pumps now allow for smaller, lighter systems, opening up possibilities for life-saving interventions with ECLS in mobile emergency, pediatric, bridge-to-transplant, and even combat environments. At the same time, novel circuit configurations allow for better physiologic optimization and broaden the scope of disease that can be managed effectively with ECLS.
In this study, we assess the hematologic biocompatibility of the SYNERGY (HeartWare International, Inc., Framingham, MA) miniature blood pump in conjunction with a Quadrox D oxygenator (Maquet, Inc., Rastatt, Germany) in a novel oxygenator/right ventricular assist device (OxyRVAD) circuit in an acute pulmonary hypertension (PH) model. Hemolysis and coagulation system effects remain the principle safety concerns with new pump and oxygenator technology in ECLS circuits. A prior study using the SYNERGY pump in a standard extracorporeal membrane oxygenation (ECMO) circuit in healthy swine found no discernable effect on measures of hemolysis or the coagulation system. We built on these results by testing the SYNERGY micropump in an animal PH model and with a novel ECLS circuit designed to optimize therapy for PH and right heart failure.Plasma-free hemoglobin (PFH), total hemoglobin, platelets, P-selectin, total bilirubin, lactate dehydrogenase, D-dimer, and fibrinogen were measured to assess blood biocompatibility.
Conclusion
The SYNERGY micropump Quadrox D oxygenator OxyRVAD system was successfully tested in a swine model of pulmonary hypertension with stable pump flows and without catastrophic hematologic issues. Low levels of hemolysis, platelet activation, and fibrinolysis demonstrate favorable biocompatibility of this system in this simulated condition. This study supports the idea of using micropump technology in combination with a gas oxygenator to alleviate the sequelae of PH and right heart failure.