How to Perform MIDCAB Using BIMA

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Step 1: Left Anterior Minithoracotomy 

The authors demonstrate how to perform a MIDCAB using bilateral internal mammary arteries under direct vision (1). 

The authors performed a left anterior minithoracotomy (6-8 cm) through the fourth intercostal space (2). Cutting into the skin along the natural groove of the pectoral muscle, marked the day before surgery, helped achieve the best aesthetic result. The coronary angiogram of the patient showed critical stenoses on the proximal RCA and mid LAD. 

It was of paramount importance to perform the incision as laterally as possible to have optimal access to both internal mammary arteries. Therefore, a CT thorax with contrast medium was recommended to figure out what the surgical view would be through the minithoracotomy and to exclude any possible intramyocardial course of the left anterior descending artery that could compromise the outcome of this approach (3). Possible contraindications to MIDCAB included severely depressed left ventricular function, peripheral arteries not suitable for cannulation when CPB was required, moderate to severe COPD due to single right lung ventilation, and previous left thoracotomy or lung adherences. 
 
Step 2: Left Internal Mammary Artery Harvesting 

Upon starting the single-lung ventilation, a rib spreader was applied. The surgeons usually use a Fehling retractor, which allows for good visualization of both mammary arteries. 

The surgeons began by harvesting the distal part of the LIMA for two important reasons: First, to reduce tension on the LIMA when applying the rib retractor, and second, because harvesting the distal part after using the retractor can be rather arduous. The Fehling retractor for MIDCAB contains a number of components to facilitate all steps of the procedure. The surgeons then switched to the Fehling retractor tool dedicated to internal mammary artery harvesting.  

First, the surgeons fastened the angulated rod to the surgical table. Next, they connected the blade guide arm to the horizontal bar of the angulated rod. Finally, they applied the dedicated blades to the retractor. One of the tricks for inserting and positioning the retractor is to fasten the two rotatable arms after applying the traction to the ribs. This allows for the best angulation of the retractor arms while avoiding excessive pressure and possible lesions on the skin. The traction achieved with the blade guide arm improves surgical vision by lifting the ribs. The surgeons progressively changed the blade from medium size to long size to better visualize the proximal part of the LIMA, always lifting the ribs with the traction of the blade guide arm. It is important to carefully position the retractor blades, avoiding any pressure on the LIMA and maximizing the view up to where the phrenic nerve crosses the LIMA. Whenever possible, the surgeons harvested the mammary artery using double clips and cuts. Thorough exposure of the mammary artery during harvesting was mandatory to avoid any injury that could be tricky to repair through the small incision. This is especially true when reaching the proximal part of the mammary artery, where the use of longer endoscopic instruments is required. The authors always use papaverine on the skeletonized mammary to improve possible vasospasm post harvesting. 
 
Step 3: Right Mammary Artery Harvesting

Once the LIMA harvesting was accomplished, the surgeons turned to the RIMA, starting with the repositioning of the blade retractor under the sternum. The LIMA was left under the blade and moved with a vessel loop around it if needed. Careful dissection of the right pleura was accomplished using a combination of electrocautery and traction with a peanut swab on a long instrument, such as curved Robert forceps. The Octopus Nuvo Stabilizer, positioned through subxiphoid access, was used as an essential tool to improve exposure toward the RIMA by pushing down the right lung. 

When the RIMA was clearly identified, dissection could be started in the usual way, opening the thoracic fascia just in front of the mammary artery. Long endoscopic instruments were required during this step, and gentle care was required to avoid excessive traction on the mammary branches. The repair of any injury on the mammary artery can be increasingly difficult when affecting the RIMA, which is far from the chest incision. The Octopus Nuvo Stabilizer can be repositioned further up as harvesting progresses toward the proximal RIMA to keep the best exposure. The authors carefully completed the harvest of the distal portion of the RIMA. 
 
Step 4: LIMA to LAD Anastomosis 

Once the harvesting of the mammary arteries was completed bilaterally, the pericardium could be opened to identify the coronary targets. The blade of the Fehling spreader can be swapped again in favor of the rib spreader, and stay sutures were carefully applied to the pericardium to provide a consistent, good quality exposure throughout the surgery. The LAD was stabilized in the usual way, using the Octopus s Nuvo Stabilizer, and the LIMA to LAD graft was easily completed. 

References

1. Kaushal K Tiwari, Vivek Wadhawa, Manish Jawarkar, Divyesh Rathod, Mausam Shah, Pratik Manek et al. Total arterial multivessels minimal invasive direct coronary artery bypass grafting via left minithoracotomy. Gen Thorac Cardiovasc Surg. 2021 Jan;69(1):8-13. doi: 10.1007/s11748-020-01412-4. Epub 2020 Jun 25.
2. Daniel Rams, Jakub Batko, Krzysztof Bartuś, Grzegorz Filip, Mariusz Kowalewski, Radosław Litwinowicz. Left Internal Mammary Artery Operative Topography for MIDCAB and TECAB Procedures. Innovations (Phila). 2022 Nov-Dec;17(6):499-505. doi: 10.1177/15569845221137578. Epub 2022 Dec 20.
3. Philippe-Primo R Caimmi, Rita Fossaceca, Marco Lanfranchi, Emmanouil I Kapetanakis, Alessandro Verde, Alessandro Panella et al. Cardiac angio-CT scan for planning MIDCAB. Heart Surg Forum. 2004 Apr 1;7(2):E113-6. doi: 10.1532/HSF98.200328101.

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