Explain the Techniques of Surgical Correction ?
Techniques of Surgical Correction proximal Dissection (De Bakey type I and IZ or Stanford A)
Monitoring lines are inserted in the right radial and left femoral arteries. TEE and Doppler of carotid artery will be very helpful. The light common femoral artery is exposed by a vertical incision. If there is dissection in hat, the channel through which there is forward flow is cannulated for arterial return. At times it may lead to obstruction of retrograde pel-fusion and so provision is made for cannulation of the ascending aorta, aortic arch, axillary artery or left ventricular apex. For CP bypass a venous cannula is passed to right atrium through right femoral vein. After median sternotomy and pericardiotomy cannulation of both venas cavae are done. If only the ascending aorta needs replacement, circulatory arrest is not required. Heart is vented through right superior pulmonary vein. A retrograde coronary sinus cannula is passed for cardioplegia administration. Aorta is clamped proximal to innominate artery and opened vertically. First opening is into the false lumen, which may contain clots. Intimal tear and true channel are visualised. This is opened and by direct cannulation of coronary ostia antegrade cardioplegia is given. Then aorta is transacted 4 to 5 cms above the aortic annulus. If dissection has extended to the annulus it can be fixed by interrupted 4 '0' prolene sutures. If coronary ostia are involved they can be raised as buttons with aortic wall and repaired with fine prolene sutures and then re-implanted into the ascending aortic graft. If dissection deep into coronaries exists, coronary artery bypass is indicated.
Two thin strips of PTFE or Dacron graft or pericardium - one inside and one outside the aorta are placed and interrupted sutures are taken through both strips and both layers of dissected aorta. The end of collagen impregnated Dacron graft is sutured to the newly created aortic cuff. Alternatively GRF (gelatin resorcinol formaldehyde) glue may be used between the two layers of dissected aorta and then graft anastomosed to its end. If the aortic valve is abnormal, a composite valve and graft (Bental procedure) will have to be done. In case of De Bakey type II dissection the aorta is transected below the clamp and innominate artery. End of the tube graft is then anastomosed to the cuff using thin strips of PTFE or gluteraldehyde treated pericardium 'for reinforcement. Alternatively, GRF glue can be used for sticking the two layers of dissection and the anastomosis to the graft done last. De-airing is done before removing the aortic clamp and heart is allowed to beat.