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| Comnaq artery bypass $refling |
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| Side-to-side sequential anasto~nosis - 'Diamond'-shaped side-to- side sequential anaston~osis |
Conventional CABG on Cardiopulmonary Bypass Chest is opened by midline incision and median sternotomy. Simul[aneously saphenous vein or radial artery is harvested. 'The pericardium is opened and aorta, left ventricle and target vessels for grafting are inspected. Using special sternal retractor, LIMA is harvested. After heparinisation distal end of LIMA is ligated and divided and flow checked. It is tucked away in a papaverine soaked gauze piece until it is to be anastomosed.
Ascending aorta is cannulated for arterial return. For venous return a two stage right atrio venous cannula is inserted though a purse string on the right atrial appendage. Cardiopulmonary bypass is instituted and patient cooled down to 28°C. Cardioplegia cannula is inserted into ascending aorta below the aortic cannula. A retrograde coronary sinus cannula is inserted through a purse string on the right atrium and the cannula is guided into the coronary sinus. It is then connected to a pressure monitor. Aorta is clamped and cold blood cardioplegia instilled into the aortic root. After heart is arestcd, rest of' the cardioplegia is administered through the coronaly sinus, taking care not to raise the pressure above 30 mm of Hg. Saphenous vein or radial artery ends are prepared for distal anastomosis cutting at an angle of 45" and tiimming the edges. Strategically placed stay sutures on the pericardium and wet sponges placed inside help to elevate and rotate the heart to expose target vessels. It is opened with a sharp scalpel blade. The length of the incision should match the size of the conduit.
Surgeons usually use 2.5 to 4 times magnification for surgery. Ideally the anastomosis made between the end of the conduit and the opened coronary artery should have a cobra hood appearance. Anastomosis is done with single 7 '0'double armed prolene suture taking special care at the heel and the toe. Patency of the graft and presence of any leak is checked by injection of heparinised blood through the conduit. If the same conduit is used for multiple grafting, the last one is an end to side anastomosis and Lhe others are side-to-side anastomoses (Sequential grafting). Care should be taken to get the correct length and lie of the conduit in sequential grafting. The last anastomosis done is usually LIMA to LAD and flow is established through the graft. All the distal anastomosis are checked for patency and bleeding. Aoi-tic cross clamp is released after de-airingof tlie aortic root. Proximal anastomosis of the conduit is done to the ascending aorta with a partial occlusion clamp. The length of each graft is measured with a full beating heart. This has to be accurate. Aortic punch is used to make circular holes in the ascending aorta on its partially occluded portion. Single 6 '0' double armed prolene suture is used. Before and after releasing the clamps, the conduits are deaired with a 25-gauge needle.
In another technique, the conduits to ascending aorta ailastornoses (proxinlal anastomoses) are done before going on bypass. This is tlie technique is used in cases of off pump coronary artery bypass grafts (OPCAB). The advantage of this technique is that full coronary flow is established to the inym .ar d' luln as so011 as the distal anastomosis is completed.
Total Arterial Re-vascnlarisation
In total artelial re-vascularisalio~~(TAR) end 01 the right internal mammary artery (RIMA) or radial arlery (RA) is anasloniosed to Lhe side of left internal mannary artery (LIMA) as a T or Y graft. This is done before cardio pulmonary bypass. 011 bypass, LIMA s anaston~osed to diagonal bra~ich as side-to-side ant1 to LAD as end-to-side graft. Then sequentiiil anastomoses between RIMA and OM], OM2 or OM3 are done as side-lo-side ani~~toll~oscs and it ends in PDA or KCA as UI cnd to side graft.
Some patients ]nay need ionolropic support of dopanline, dobu~amine or adrenaline. In spite of ionolropic support, if blootl pressure is low and I,A pressure is high, inserlion of intra aortic ballooli pump (IAUP) is indicated.After patient is weaned oi'l' cardio pulinonaly bypass, cannulae are removed and heparin is reversed with protarnine sulphate. Chest is closed with L W drains.Patients are taken off vel~tilator after a few hours or next morning and il' no colnplications intervene they sllollld be back in the ward next day. They are ready to go home in 9 to 10 days.
Endarterectomy is done as a selni open technique. 5-10mm long incision is nladc on the outer layers oi' the coronary artery and plain developed in 11ic thickened media of Ule vessel. By gentle dissection arid traction, the plane is extended dislally and a tapering spccirnen wit11 bmnclles is renloved as a single piece. Ti'the specimen breaks orf, tlie arteriotomy is extended and attenlpt is made to remove a tapering specimen. 'I'llc end of collduit is then ~~nastomosed to the corol~ary artery. In open technique, which is usually done for LAD, the cnlirc length of the arlery is laid open, atheromalous plaque is removed and a saphenous vcin patch plasty is done. On to the centre of the vcin patch, arterial graf is aliastornosed. Endarterectomy may lead to higher peri operative MI, graft ocdusion, an.l~ythmi:is, low cardiac output luid slightly increaser1 mortality. The consensus among surgeons is to avoid endarterectonly altogether.
Ascending aorta is cannulated for arterial return. For venous return a two stage right atrio venous cannula is inserted though a purse string on the right atrial appendage. Cardiopulmonary bypass is instituted and patient cooled down to 28°C. Cardioplegia cannula is inserted into ascending aorta below the aortic cannula. A retrograde coronary sinus cannula is inserted through a purse string on the right atrium and the cannula is guided into the coronary sinus. It is then connected to a pressure monitor. Aorta is clamped and cold blood cardioplegia instilled into the aortic root. After heart is arestcd, rest of' the cardioplegia is administered through the coronaly sinus, taking care not to raise the pressure above 30 mm of Hg. Saphenous vein or radial artery ends are prepared for distal anastomosis cutting at an angle of 45" and tiimming the edges. Strategically placed stay sutures on the pericardium and wet sponges placed inside help to elevate and rotate the heart to expose target vessels. It is opened with a sharp scalpel blade. The length of the incision should match the size of the conduit.
Surgeons usually use 2.5 to 4 times magnification for surgery. Ideally the anastomosis made between the end of the conduit and the opened coronary artery should have a cobra hood appearance. Anastomosis is done with single 7 '0'double armed prolene suture taking special care at the heel and the toe. Patency of the graft and presence of any leak is checked by injection of heparinised blood through the conduit. If the same conduit is used for multiple grafting, the last one is an end to side anastomosis and Lhe others are side-to-side anastomoses (Sequential grafting). Care should be taken to get the correct length and lie of the conduit in sequential grafting. The last anastomosis done is usually LIMA to LAD and flow is established through the graft. All the distal anastomosis are checked for patency and bleeding. Aoi-tic cross clamp is released after de-airingof tlie aortic root. Proximal anastomosis of the conduit is done to the ascending aorta with a partial occlusion clamp. The length of each graft is measured with a full beating heart. This has to be accurate. Aortic punch is used to make circular holes in the ascending aorta on its partially occluded portion. Single 6 '0' double armed prolene suture is used. Before and after releasing the clamps, the conduits are deaired with a 25-gauge needle.
In another technique, the conduits to ascending aorta ailastornoses (proxinlal anastomoses) are done before going on bypass. This is tlie technique is used in cases of off pump coronary artery bypass grafts (OPCAB). The advantage of this technique is that full coronary flow is established to the inym .ar d' luln as so011 as the distal anastomosis is completed.
Total Arterial Re-vascnlarisation
In total artelial re-vascularisalio~~(TAR) end 01 the right internal mammary artery (RIMA) or radial arlery (RA) is anasloniosed to Lhe side of left internal mannary artery (LIMA) as a T or Y graft. This is done before cardio pulmonary bypass. 011 bypass, LIMA s anaston~osed to diagonal bra~ich as side-to-side ant1 to LAD as end-to-side graft. Then sequentiiil anastomoses between RIMA and OM], OM2 or OM3 are done as side-lo-side ani~~toll~oscs and it ends in PDA or KCA as UI cnd to side graft.
Some patients ]nay need ionolropic support of dopanline, dobu~amine or adrenaline. In spite of ionolropic support, if blootl pressure is low and I,A pressure is high, inserlion of intra aortic ballooli pump (IAUP) is indicated.After patient is weaned oi'l' cardio pulinonaly bypass, cannulae are removed and heparin is reversed with protarnine sulphate. Chest is closed with L W drains.Patients are taken off vel~tilator after a few hours or next morning and il' no colnplications intervene they sllollld be back in the ward next day. They are ready to go home in 9 to 10 days.
Endarterectomy is done as a selni open technique. 5-10mm long incision is nladc on the outer layers oi' the coronary artery and plain developed in 11ic thickened media of Ule vessel. By gentle dissection arid traction, the plane is extended dislally and a tapering spccirnen wit11 bmnclles is renloved as a single piece. Ti'the specimen breaks orf, tlie arteriotomy is extended and attenlpt is made to remove a tapering specimen. 'I'llc end of collduit is then ~~nastomosed to the corol~ary artery. In open technique, which is usually done for LAD, the cnlirc length of the arlery is laid open, atheromalous plaque is removed and a saphenous vcin patch plasty is done. On to the centre of the vcin patch, arterial graf is aliastornosed. Endarterectomy may lead to higher peri operative MI, graft ocdusion, an.l~ythmi:is, low cardiac output luid slightly increaser1 mortality. The consensus among surgeons is to avoid endarterectonly altogether.
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