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Coronary endothelial damage during off-pump CABG related to coronary-clamping and gas insufflation
Y Okazaki1, K Takarabe, J Murayama
1Department of Thoracic and Cardiovascular Surgery, Saga Medical School, 5-1-1 Nabeshima, Saga City, 849-8501, Saga, Japan. okazaki@post.saga-med.ac.jp
Insights
Coronary artery bypass grafting (CABG) using non-elastic sutures and non-humidified gas causes endothelial injury. Elastic sutures and humidified gas, especially with heparin and dipyridamole, protect the coronary endothelium.
Area of Science:
- Cardiovascular Surgery
- Vascular Biology
- Surgical Innovation
Background:
- Off-pump coronary artery bypass grafting (CABG) is considered less invasive than conventional CABG.
- However, off-pump CABG techniques, such as coronary snaring and gas insufflation, may still cause coronary endothelial injury.
- Understanding these adverse effects is crucial for improving surgical outcomes.
Purpose of the Study:
- To evaluate the adverse effects of coronary snaring with looped sutures and gas insufflation on the coronary endothelium.
- To assess the protective efficacy of elastic sutures and humidified gas insufflation (with or without heparin and dipyridamole) against these injuries.
Main Methods:
- A canine model (n=36) was used to simulate coronary artery manipulation.
- Coronary arteries were incised and snared using non-elastic or elastic sutures.
- Insufflation with non-humidified or humidified carbon dioxide (with or without additives) was performed for 10 or 20 minutes.
- Endothelial damage was assessed using scanning electron microscopy and graded based on cell adhesion and delamination.
Main Results:
- Non-elastic sutures caused significantly more endothelial tears than elastic sutures (P<0.00001).
- Non-humidified gas insufflation led to greater endothelial cell damage and blood cell deposition compared to humidified gas (P=0.00005).
- Humidified gas with heparin and dipyridamole reduced blood cell deposition on the endothelium compared to simple humidified gas (P=0.00120).
Conclusions:
- Coronary snaring and gas insufflation during off-pump CABG can injure the coronary endothelium.
- Using elastic sutures and humidified gas significantly mitigates these adverse effects.
- Adding heparin and dipyridamole to humidified gas may offer further protection against endothelial damage.
Objective:
Although off-pump coronary artery bypass grafting (CABG) has been recognized less invasive than conventional CABG on cardiopulmonary bypass, off-pump CABG may be partly invasive especially to the coronary endothelium. The present study was designed to evaluate the adverse effects of coronary snaring with looped sutures and gas insufflation on the coronary endothelium. The protective efficacies on the coronary endothelium of coronary snaring with elastic sutures or humidified gas insufflation with/without heparin and dipyridamole-added were also tested.
Methods:
Thirty-six mongrel dogs were used. After systemic heparinization (150 U/kg), a 5 mm longitudinal coronary incision was made with looped non-elastic monofilament sutures or elastic sutures applied proximally and distally. The incised coronary artery was exposed to non-humidified carbon dioxide, humidified carbon dioxide with lactated Ringer solution, or humidified carbon dioxide with heparin and dipyridamole-added lactated Ringer solution for 10 or 20 min in each group. After gas insufflation, the incised coronary artery was repaired, then, the coronary was reperfused. Perfusion-fixation was done for observation of the coronary endothelium by scanning electron microscopy. The adverse effect on the endothelium was graded as follows: grade 1, appeared normal; grade 2, few blood cells deposited; grade 3, many blood cells deposited; grade 4, few endothelial cells delaminated with blood cells deposited; grade 5, many endothelial cells delaminated with blood cells deposited.
Results:
Non-elastic looping caused much more endothelial tears than elastic looping (P<0.00001). Non-humidified gas blowing for 20 min caused more endothelial cell damage than humidified gas blowing (P=0.00005). Non-humidified gas blowing for 10 min caused less damage than for 20 min (P=0.00326), but still caused more damage than humidified gas blowing (P=0.00253). Heparin and dipyridamole-added humidification reduced coronary endothelial area mottled by the deposited cells when compared with simple humidification (P=0.00120).
Conclusions:
Coronary snaring resulted in coronary endothelial injury, which was ameliorated by using elastic sutures instead of non-elastic sutures. Non-humidified gas insufflation made blood cells deposited and endothelial cells delaminated with time. Humidified gas insufflation attenuated these adverse effects. Heparin and dipyridamole-added humidification had potential advantage in terms of reducing deposited blood cells on the endothelium over simple humidification.