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Published on: September 15, 2023
Influence of intracoronary shunt size on coronary endothelial function during off-pump coronary artery bypass
Roland G Demaria1, Simon Fortier, Olivier Malo
1Department of Surgery and Research Center, Montreal Heart Institute, Montreal, Quebec, Canada.
Insights
Choosing the right intracoronary shunt size is crucial. Mismatched shunt sizes during coronary artery bypass surgery can cause endothelial dysfunction, impacting patient outcomes.
Area of Science:
- Cardiovascular Surgery
- Vascular Biology
- Surgical Devices
Background:
- Intracoronary shunts are used during off-pump coronary artery bypass surgery.
- Shunt insertion can lead to endothelial dysfunction in target arteries.
Purpose of the Study:
- To investigate the relationship between shunt-to-artery diameter ratio and endothelial dysfunction.
- To establish guidelines for optimal shunt size selection.
Main Methods:
- Swine models underwent implantation of 3-mm, 2-mm, and 1.25-mm shunts in the right coronary artery.
- Bleeding levels were quantified, and coronary rings were assessed for endothelium-dependent relaxations.
- Organ chambers were used to measure responses to serotonin and bradykinin, with non-instrumented arteries as controls.
Main Results:
- The 3-mm shunt (oversized) caused significant endothelial dysfunction (P <.005) with adequate hemostasis.
- The 2-mm shunt (congruent) led to decreased relaxation (P <.05) and intermittent bleeding.
- The 1.25-mm shunt (undersized) showed no significant dysfunction (P >.05) but resulted in continuous bleeding.
Conclusions:
- Intracoronary shunt use is linked to disadvantages based on size mismatch.
- No shunt size guarantees satisfactory hemostasis without potential complications.
- Selective use of intracoronary shunts is supported by these findings.
Objective:
The insertion of intracoronary shunts during off-pump coronary artery bypass surgery may induce severe endothelial dysfunction in the target arteries. The purpose of this study was to determine the role of the ratio of the shunt diameter to the target artery diameter in the development of endothelial dysfunction and to develop guidelines for selecting the most appropriate shunt size.
Methods:
Nine swine (25 +/- 4 kg) were used for this study. Three ClearView shunts 3 mm, 2 mm, and 1.25 mm in diameter were inserted proximally to distally via 3 arteriotomies into the right coronary artery to obtain oversizing with the 3-mm shunt, undersizing with the 1.25-mm shunt, and a satisfying congruence with the 2-mm shunt. The shunts were left in place for 15 minutes, and the levels of bleeding were quantified. Coronary rings upstream and downstream from the arteriotomies were then harvested and placed in organ chambers to study endothelium-dependent relaxations to serotonin and bradykinin. Noninstrumented coronary arteries served as controls.
Results:
A decrease of endothelium-dependent relaxation occurred with the 3-mm shunts (P <.005), which were associated with an adequate hemostasis. A decrease of endotheliumdependent relaxation occurred with the 2-mm shunts (P <.05), which were associated with intermittent bleeding, and no significant decrease of endothelium-dependent relaxation occurred with 1.25-mm shunts (P >.05), which were associated with continuous bleeding.
Conclusions:
Intracoronary shunts are associated with different disadvantages, depending on the mismatch to the target coronary artery, and whatever their size, shunts are not the ideal device for safely obtaining a satisfactory hemostasis. These results support our clinical attitude of the selective use of intracoronary shunts.
