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| Figure 15. Mid-esophageal Four Chamber |
Advantages
- Images entire LV.
- Shows and quantitates MR.
- Images RV and Tricuspid valve and regurgitation if any.
- Not obscured by lap under heart.
Disadvantages
- Multiplane probe needed.
- Requires several views.
- Foreshortening of the apex, poor imaging.
Transgastric views - LV short axis, two chamber and apical views. (Most familiar.)
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| Figure 16. Transgastric Two Chamber |
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| Figure 17. Transgastric Short Axis |
Advantages
- Familiarity (familiar views).
- Images three major distributions of the coronary arteries simultaneously.
- Multiplane probe not needed.
Disadvantages
- Images only one level of the heart (LV) at a time.
- CanŐt image mitral valve, tricuspid valve, right ventricle, MR, TR.
- Obscured by lap under the heart.
Impaired LV filling, increased mitral regurgitation due to:
- Pericardial retraction.
- Lap pad under heart.
- Compression-type stabilizer compressing the heart.
- Acute margin retraction for RCA graft.
Occluding the Vessel
- Regional wall motion abnormality (RWMA) usually appears within 15 seconds.
- May not appear if lesion is high grade and/or collateral circulation present. n RWMA in remote area possible if dependent on collateral flow from occluded vessel.
- Watch for deterioration in global function.
Reperfusion
RWMA usually improves within 15 seconds.
May not improve until graft is open, i.e., proximal graft completed.
Chest Closure
Appearance of new regional wall motion abnormalities should be a cause for concern.
- Consider possibility of a kinked graft.
- IMA or other arterial grafts spasm.
- Flawed grafts may be OK until heparin reversed.
- Reopen chest if RWMA persists.
| CONCLUSION |
Stabilizing devices have evolved into useful instruments to make beating heart surgery a reality for the majority of patients today. The future of beating heart surgery is upon us and to meet the challenge we need to share information and develop specific techniques to continue the evolution of anesthesia into the 21st century. A joint effort between the surgeon and the anesthesiologist during Beating Heart CAB is essential for continued successful outcomes.
* OPCAB is a trademark of Genzyme
** MIDCAB is a trademark of CardioThoracic System
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