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Updated: Apr 11, 2026
Procedure for Human Saphenous Veins Ex Vivo Perfusion and External Reinforcement
Published on: October 1, 2014
Counteracting negative venous line pressures to avoid arterial air bubbles: an experimental study comparing two
Anas Aboud1, Hendrikje Mederos-Dahms2, Kai Liebing3
1Department of Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr University Bochum, Georgstrasse 11, 32545, Bad Oeynhausen, Germany. aaboud@hdz-nrw.de.
Background:
Because of its low rate of clinical complications, miniaturized extracorporeal perfusion systems (MEPS) are frequently used in heart centers worldwide. However, many recent studies refer to the higher probability of gaseous microemboli formation by MEPS, caused by subzero pressure values. This is the main reason why various de-airing devices were developed for today's perfusion systems. In the present study, we investigated the potential benefits of a simple one-way-valve connected to a volume replacement reservoir (OVR) for volume and pressure compensation.
Methods:
In an experimental study on 26 pigs, we compared MEPS (n = 13) with MEPS plus OVR (n = 13). Except OVR, perfusion equipment was identical in both groups. Primary endpoints were pressure values in the venous line and the right atrium as well as the number and volume of air bubbles. Secondary endpoints were biochemical parameters of systemic inflammatory response, ischemia, hemodilution and hemolysis.
Results:
One animal was lost in the MEPS + OVR group. In the MEPS + OVR group no pressure values below -150 mmHg in the venous line and no values under -100 mmHg in right atrium were noticed. On the contrary, nearly 20% of venous pressure values in the MEPS group were below -150 and approximately 10% of right atrial pressure values were below -100 mmHg. Compared with the MEPS group, the bubble counter device showed lower numbers of arterial air bubbles in the MEPS + OVR group (mean ± SD: 13444 ± 5709 vs. 1 ± 2, respectively; p < 0.001). In addition, bubble volume was significantly lower in the MEPS + OVR group than in the MEPS group (mean ± SD: 1522 ± 654 μl vs. 4 ± 6 μl, respectively; p < 0.001). The proinflammatory cytokine interleukin-6 and biochemical indices of cardiac ischemia (creatine kinase, and troponin I) were comparable between both groups.
Conclusions:
The use of a miniaturized perfusion system with a volume replacement reservoir is able to counteract excessive negative venous line pressures and to reduce the number and volume of arterial air bubbles. This approach may lead to a lower rate of neurological complications.
Insights
Miniaturized extracorporeal perfusion systems (MEPS) with an oxygenator volume replacement reservoir (OVR) significantly reduce negative pressures and arterial air bubbles. This innovation may decrease neurological complications in cardiac surgery patients.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Perfusion Technology
Background:
- Miniaturized extracorporeal perfusion systems (MEPS) are widely used in cardiac surgery due to low complication rates.
- MEPS can generate gaseous microemboli from subzero pressure, necessitating de-airing devices.
- A simple one-way-valve connected to a volume replacement reservoir (OVR) was investigated for pressure and volume compensation.
Purpose of the Study:
- To evaluate the efficacy of an OVR in mitigating negative pressures within MEPS.
- To assess the impact of OVR on the formation of gaseous microemboli during extracorporeal perfusion.
- To compare the safety and effectiveness of MEPS with and without OVR in a preclinical model.
Main Methods:
- An experimental study was conducted on 26 pigs, divided into two groups: MEPS (n=13) and MEPS with OVR (n=13).
- Primary endpoints included monitoring pressure in the venous line and right atrium, and quantifying air bubble count and volume.
- Secondary endpoints involved analyzing biochemical markers for systemic inflammatory response, ischemia, hemodilution, and hemolysis.
Main Results:
- The MEPS + OVR group demonstrated no negative pressures below -150 mmHg (venous line) or -100 mmHg (right atrium), unlike the MEPS group.
- Arterial air bubble counts were drastically reduced in the MEPS + OVR group (1 ± 2 vs. 13444 ± 5709; p < 0.001).
- Bubble volume was also significantly lower in the MEPS + OVR group (4 ± 6 μl vs. 1522 ± 654 μl; p < 0.001), with comparable inflammatory and ischemic markers.
Conclusions:
- Integrating an OVR into MEPS effectively counteracts excessive negative pressures.
- The OVR system significantly reduces the number and volume of arterial air bubbles during perfusion.
- This approach holds promise for lowering the incidence of neurological complications associated with cardiac surgery.
