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Intracoronary shunt prevents left ventricular function impairment during beating heart coronary revascularization
V Lucchetti1, F Capasso, M Caputo
1Department of Cardiac Surgery, Casa di Cura San Michele, Maddaloni, Italy.
Insights
Using an intracoronary shunt during coronary artery bypass surgery preserves left ventricular function by maintaining myocardial perfusion. This method is advisable for patients with unstable angina or poor ventricular function.
Area of Science:
- Cardiovascular Surgery
- Cardiac Anesthesia
- Echocardiography
Background:
- Beating heart coronary revascularization is a growing surgical technique.
- Temporary coronary artery occlusion is often necessary for anastomosis.
- Intracoronary shunts offer an alternative to maintain perfusion during occlusion.
Purpose of the Study:
- To monitor global left ventricular function and regional wall motion during coronary artery anastomosis.
- To compare the effects of using an intracoronary shunt versus no shunt on ventricular function.
Main Methods:
- Transesophageal echocardiography (TEE) was used in 40 patients undergoing coronary revascularization.
- Left ventricular wall motion score index (WMSI), left anterior descending (LAD) wall motion score (WMS), and ejection fraction (EF%) were measured.
- Measurements were taken preoperatively, during anastomosis construction with/without shunt, and after reperfusion.
Main Results:
- No significant changes in WMSI, WMS, or EF% were observed when an intracoronary shunt was used during anastomosis.
- A significant decline in these parameters was noted in patients not using a shunt.
- All measured parameters returned to baseline after reperfusion in the non-shunt group.
Conclusions:
- Coronary artery occlusion temporarily impairs left ventricular function, with full recovery upon reperfusion.
- Intracoronary shunts appear to prevent ventricular function deterioration by maintaining myocardial perfusion.
- Shunt use is recommended for patients with unstable angina, poor left ventricular function, or anticipated longer anastomosis times.
Objective:
Beating heart coronary revascularization is becoming increasingly popular world-wide. Temporary occlusion of the coronary artery is often required in order to perform the anastomosis. An alternative method to maintain perfusion is to use an intracoronary shunt. In this study, we monitored global left ventricular function and regional wall motion in the presence or absence of a shunt using transesophageal echocardiography (TEE).
Method:
Left ventricular wall motion score index (WMSI), wall motion score (WMS) in the left anterior descending (LAD) coronary artery territory, and ejection fraction (EF%) were measured by multiplane TEE during construction of the left internal mammary artery (LIMA)-LAD coronary artery anastomosis in 40 patients undergoing revascularization with or without the use of a shunt. WMSI was assessed preoperatively, 1, 3 and 6 min during the construction of the anastomosis and after 5 min of reperfusion. WMS was assessed at 6 min during anastomosis and after 5 min of reperfusion. EF% was calculated preoperatively, 5 min into the construction of the anastomosis, and 5 min after reperfusion.
Results:
During construction of the anastomosis, when the shunt was used, there were no changes in WMSI, WMS in the LAD territory or EF%. A significant decline in these parameters was seen in the group in which the shunt was not used, although on reperfusion all the values returned to baseline control.
Conclusion:
(i) occlusion of the LAD to perform the anastomosis results in temporary impairment in left ventricular function with complete recovery on reperfusion; (ii) the use of an intracoronary shunt presumably by maintaining myocardial perfusion prevents deterioration in ventricular function; (iii) from this data it seems therefore advisable to use an intracoronary shunt in patients with unstable angina, poor left ventricular function, or in cases in which a longer time to perform the anastomosis is anticipated.