Abstract
Minimally invasive cardiac surgery–coronary artery bypass grafting (MICS CABG) was developed to decrease morbidity associated with the standard median sternotomy approach. In experienced hands, this technique offers good graft patency rates and excellent clinical outcomes. This chapter describes the relevant anatomy, patient selection, operative techniques, and postoperative care for MICS CABG.
Keywords
coronary artery, bypass grafting, minimally invasive, MICS CABG
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Minimally Invasive Cardiac Surgery–Coronary Artery Bypass Grafting (MICS CABG)
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This technique enables revascularization with a similar configuration as that in a sternotomy technique, using left internal thoracic artery (LITA) harvesting and hand-sewn proximal and distal anastomoses under direct visualization. Complete revascularization is achieved in 95% of cases, allowing access to the anterior, lateral, and inferior walls of the heart, with or without the use of pump assistance.
Step 2
Preoperative Considerations
1
Indications
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These follow the current guidelines for coronary revascularization.
2
Contraindications
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Hemodynamic instability or acute ischemia
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Chest wall deformities and significant pleural adhesions
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Obesity
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Intolerance to single-lung ventilation
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Significant ascending aorta calcification, if aortic proximal anastomoses are planned
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Poor status of the femoral vessels for peripheral cardiopulmonary bypass (CPB) cannulation, whether planned or not
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Inadequate distal target size and quality. The right coronary artery and proximal posterior interventricular (PIV), posterolateral (PL), and proximal obtuse marginal (OM) targets are not easily accessible.
Step 3
Operative Technique
1
Anesthesia
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Paravertebral block is optional but may be preferred, especially for patients who are being planned for immediate extubation postoperatively.
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Single-lung ventilation is instituted either through a double-lumen endotracheal tube or through a bronchial blocker.
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Transesophageal echocardiography (TEE) may provide additional guidance if the patient develops instability. It can identify wall motion abnormalities and recovery. In the case of peripheral CPB cannulation, TEE must guide wire and cannula placement.
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Ensure that the endotracheal tube is still in the correct position after repositioning the patient.
2
Positioning
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The patient is placed in a semi–right lateral decubitus position ( Fig. 5.1 ). The right arm may be tucked at the patient’s side or extended to enable harvest of the right radial artery. The left arm is placed in a sling held above the patient’s head.
Figure 5.1
( A ) Patient positioning in MICS CABG. ( B ) Sterile draping in MICS CABG.
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The hips are placed in a nearly supine position to enable access to the groin in case of CPB, as well as to harvest the saphenous vein.
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External defibrillator pads are placed on the right anterior chest and the left back. Internal defibrillators will not fit through the small surgical access.
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The chest may be marked to identify the area of the LITA bed easily.
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Prepare the skin and place the sterile drapes in such a way that the sternum is easily accessible in case sternotomy conversion is needed.
3
Incision
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A 5-cm incision is made in the fifth intercostal space (ICS) at the left midclavicular line, usually located just below the nipple in this positioning.
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The fascia and muscles are transected layer by layer. The left lung should begin deflating at this stage.
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Palpation as to the location of the cardiac apex is done to check adequacy of the position. The apex should be around 2 cm caudal to the intercostal opening. This decision should be tailored based on the planned procedure; an incision that is placed too caudally will enable a relatively easy distal anastomosis, but will restrict access to the aorta for the proximal anastomoses and a more difficult mobilization of the proximal portion of the LITA. The ICS opening may be revised as needed.
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A retractor is placed and is spread gently. The pericardial fat is removed and the pericardium is opened. If a multivessel bypass and an aortic anastomosis are planned, the pericardium is opened from the diaphragmatic surface to the pericardial reflection on the aorta. The distal targets are inspected as a last feasibility check when using the MICS CABG approach.
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The LITA is harvested throughout its full length, from the bifurcation to the level of the subclavian vein. This is facilitated using ThoraTrak (Medtronic, Minneapolis) and Rultract (Rultract, Independence, OH) retractors ( Fig. 5.2 ). Other necessary accessories are headlights, long fine instruments, and long cautery blades. The LITA may be harvested in a skeletonized or nonskeletonized fashion. Adequate hemostasis is ensured at all times.
