doi:10.1510/mmcts.2006.002006
Aortic arch replacement: the conventional ‘elephant trunk’ technique Marc A.A.M. Schepens* Department of Cardio-thoracic Surgery, St. Antonius Hospital, Koekoekslaan 1, 3435 CM Nieuwegein, The Netherlands Pathology of the aorta starting into the ascending aorta or aortic arch and extending downstream into the descending thoracic or thoracoabdominal aorta requiring surgical therapy, can be treated in two steps. At the first stage, via median sternotomy, the ascending aorta and arch are repaired, if necessary in combination with the aortic root or other cardiac interventions (such as bypass grafting or mitral valve repair). During this stage a free-floating extension of the arch prosthesis, the so-called elephant trunk, is left behind in the proximal descending aorta. Later, at the second stage via left thoracotomy, thoracophrenolaparatomy or endovascular repair, the descending aorta or thoracoabdominal aorta can be replaced. The most important advantage of leaving behind an elephant trunk is the avoidance of a difficult and hazardous dissection in the region of the distal aortic arch where arterial, venous, nervous, bronchial, gastro-intestinal and lymphatic structures cross. Doing so, the risk of damage to one of these structures can be completely avoided.
Keywords: Elephant trunk; Aorta; Aneurysm Introduction The first idea of the use of an elephant trunk was introduced by Hans Borst from Hannover in 1983 w1x, but already in 1975, Randall Griepp from Mount Sinai w2x described an original unfolding technique of the prosthesis using deep hypothermic circulatory arrest. Actually, total arch replacement is almost always performed using antegrade selective cerebral perfusion to protect the brain optimally w3,4x. Initially, however, these interventions were performed using only deep hypothermic circulatory arrest. Adequate protection of the central nervous system, brain and spinal cord, but also the distal organs such as kidneys and guts, is essential because during the period of the anastomosis between the elephant trunk * Corresponding author: Tel.: q31-30-6092047; fax: q31-306092120 E-mail: [email protected] 䉷 2007 European Association for Cardio-thoracic Surgery
and the proximal descending aorta, the circulation to the rest of the body is stopped and only the supraaortic vessels receive oxygenated blood. Therefore, it is essential to cool the patient down, at least to a rectal temperature of approximately 258C, to overcome ischemic problems with the distal organs including the spinal cord.
Surgical technique The illustrated example is a patient with a dilated ascending and descending aorta (chronic postdissection aneurysm) with only a mild dilatation of the aortic arch. There is a massive aortic valve incompetence. A preoperative CT-scan is shown in Photo 1. CO2 is applied into the pericardial sac at a flow rate of 5 l/min. The consecutive steps and the final result can be seen in Schematic 1. 1
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006 cannulation into the distal ascending aorta or proximal arch is possible after having verified that the aortic region chosen for the cannulation is free from atherosclerotic debris. In the illustrated example, we have cannulated directly the aortic arch. Step 2: Cooling and cardiac protection
Schematic 1. Preoperative situation. 2. Stage one of the repair. 3. Result after stage two.
After having started extracorporeal circulation (with a drain into the left ventricle through the right upper pulmonary vein to avoid left ventricular distention), cooling is started immediately. When the heart starts to fibrillate and there is no or only mild aortic valve incompetence, the ascending aorta is cross-clamped at the base of the innominate artery and one shot of cold, crystalloid cardioplegia is administered directly through the aortic root. Simultaneously the topical cooling is applied to the heart and the septal temperature is monitored by direct punction of the interventricular septum using a temperature probe which remains in situ during the complete repair. The amount of cardioplegia given depends on the temperature that the myocardium reaches. We aim to arrive at a septal temperature of 108C and this can be reached in most cases with only 1 l of cardioplegia w5x. When the aortic valve incompetence is greater than grade 1, we use selective cardioplegia (cold crystalloid) directly into both coronary ostia, again aiming at a septal temperature of 108C. In this way the heart is adequately protected. If the root needs further surgery, as in our example a root replacement with a biological conduit, this repair (valve resection, mobilisation of the coronary ostia upon buttons, resection of the aortic sinuses leaving a remnant on top of the annulus of about 5 mm) can be started during the cooling phase. Step 3: Arch phase – Cerebral protection
Photo 1. Preoperative CT image.
Step 1: Arterial and venous cannulation If no associated mitral valve surgery is planned, the right atrium is used for venous cannulation. There are different options for the placement of the arterial cannula. The common femoral artery can be used when there is no atherosclerosis or thrombus formation in the descending and/or abdominal aorta but it might be safer to use axillary or subclavian cannulation because these vessels are often free from atherosclerosis or dissection. However, in cases of a chronic postdissection aneurysm, the femoral artery remains a good option since, in these circumstances, there are almost no degenerative changes present. Also, direct 2
When the rectal temperature has reached 258C, the body is protected adequately to arrest the circulation and start the arch phase of the repair. The cannulae for antegrade cerebral perfusion are flushed to remove all air. Both the innominate artery and the common left carotid artery are snared or clamped (after having verified that the proximal parts of both arteries are free from atherosclerosis) to avoid air entering the supra-aortic arteries. This is done in Trendelenburg position. The arterial cannula is removed when distal ascending or aortic arch cannulation is used. When the femoral artery cannulation is used, the cannula may not be used anymore as an inflow cannula because when the trunk is in situ, retrograde flow from the groin may cause trunk collapse. In case the axillary artery is used for inflow, the cannula may
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
Video 1. Before the selective cannulae can be inserted into the ostia of the head vessels, the aortic arch must be opened after having stopped antegrade perfusion and after having removed the aortic clamp.
remain in position for later rewarming. The aortic clamp is removed (Video 1). The arch is emptied with the pump sucker and after having inspected the arch and origin of the arch vessels, the surgeon has to decide if an island technique or separate vessel technique is going to be used. The cannulae for selective cerebral perfusion are introduced into the left common carotid artery and the innominate artery (Video 2). The complete arch is resected (Video 3) except for the island including the origin of the innominate artery, the left common carotid and the left subclavian artery (sometimes also the origin of an aberrant left vertebral artery). The distal plane of resection is situated just beyond the origin of the left subclavian artery. This is the area where the left vagus nerve crosses the anterior aspect of the aorta. The use of a small cotton on a clamp is a useful instrument to dissect it bluntly from the aorta. The ligament of Botall should be identified realizing that the recurrent nerve runs around it and continues at the backside of the arch and left common carotid artery. In case of a large aneurysm the nerve may be unified within the aortic wall so that it is almost impossible to free it. In these circumstances it could be wise to divide the arch between the left carotid artery and the
Video 2. Insertion of the cannulae can be done with optimal visualisation of the ostia of the head vessels. This avoids dislodgement of calcium or debris into the brain.
Video 3. All aneurysmal aortic tissue is removed except a small rim for making the anastomosis.
subclavian artery and perform the anastomosis in this area to avoid the region of the vagus and recurrent nerve (of course the left subclavian has to be reimplanted then into the left common carotid artery). Very often the diameter of the aorta in the area of the left subclavian is somewhat smaller, reducing the discrepancy between the prosthesis and the aorta. It is wise to transect the aorta completely in a circular fashion and free a cuff of about 5 mm. In case of a chronic aortic dissection the intimal flap has to be resected as deep as possible into the descending aorta making one lumen from the dissected aorta (Video 4). Clots should be removed using a sucker realizing that no fragments may be lossed to prevent emboli. In case of an acute dissection the fragile aortic layers must be unified using Teflon or glue. Step 4: Preparation of the prosthesis A suitable prosthesis is chosen (it may be helpful to measure the size and the diameter of the proximal descending aorta using appropriate sizers). The proximal end of the prosthesis (later the ascending and arch part) is invaginated into the trunk part (Video 5). This means that the outer part is the trunk and the inner part the arch/ascending part. It may be helpful to mark the proximal end with a heavy stay suture;
Video 4. Resection of the web in a chronic dissected aorta is essential because otherwise the trunk can be placed into the true or false lumen. One should be very careful in resecting the web because damage to the outer aortic wall may lead to catastrophies.
3
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
Video 5. One simply invaginates one end of the prosthesis in the other. The result is a double-folded prosthesis with the outer part identified as the trunk part and the inner tube being the arch part.
this hangs out of the lumen of the folded prosthesis and will facilitate the later unfolding. Because the second stage procedure can be done using an endoprosthesis, it is wise to mark the lower end of the trunk with a number of metal clips making the catheterisation of the trunk easier. The length of the trunk certainly should exceed 5 cm, probably 10 to 15 cm is an ideal length. It is helpful to put a sump drain into the folded prosthesis to remove the blood continuously from the anastomotic region. Step 5: Insertion of the prosthesis into the descending aorta The complete infolded prosthesis is then inserted into the proximal descending aorta (Schematic 2) and this may be difficult in case there is only a mild dilatation (Video 6). The double fold is located just at the level of the aortic cuff. A prosthesis with an adaptable collar (Gelweave Plexus 4 TM, Vascutek Ltd, Scotland) can be helpful when the aorta is largely dilated also in this area or
Schematic 2. The insertion of the invaginated prosthesis into the descending thoracic aorta. Notice the island containing the arch vessels.
4
Video 6. The insertion of the double-folded prosthesis into the descending aorta should be done very carefully without causing damage to the wall of the aorta. It can be done using two forceps and gentle forward pressure on the prosthesis.
the aorta can be plicated at this level using a longitudinal incision. If one has decided to use the separate graft technique for the head vessels, the invagination of the graft on itself is almost impossible; then the predetermined length of the trunk should simply be inserted into the descending aorta. Step 6: Fixation of the trunk on the descending aorta Using a running prolene 4=0, mostly with a Teflon strip between the aorta and the graft, the prosthesis is secured to the proximal descending aorta (Video 7). This anastomosis is very delicate since it is really impossible at the end to reach the dorsal side of it. It is advised to use a nerve hook to tighten the suture line. Step 7: Unfolding of the prosthesis Then the prosthesis should be unfolded by traction on the inner part (Video 8) or the stay suture. This is the birth of the arch/ascending part (Schematic 3). If one is going to use glue on the first anastomosis, it should be applied now.
Video 7. This anastomosis between the graft and the aneurysm is the anchorage of the graft to the aorta. Therefore, it is essential to make it properly and without any leakage since the dorsolateral aspect can hardly be reached anymore. The use of prolene 4=0 allows for big and strong bites.
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
Video 8. Exertion of simple traction on the infolded prosthesis with two forceps will give birth to the arch part of the prosthesis since the dacron tube is fixed at the upper aortic rim.
Video 10. Reimplantation of the island can be done using running prolene 4=0 or 5=0 depending on the thickness of the aortic layers.
Schematic 3. Extraction of the prosthesis out of the descending aorta leaving the trunk behind.
Schematic 4. Construction of the anastomosis between the arch island and the arch part of the prosthesis.
Video 9. It is important to make holes in a woven prosthesis using the cautery because otherwise the edges will unravel. The length and width of the opening is adapted to that of the island containing the head vessels.
Step 8: Arch repair and connection of both prostheses together Afterwards an oval opening is made using cautery for the head vessels (Video 9) which are then reimplanted using prolene 4=0 or 5=0 (Video 10) depending on the quality of the tissue (Schematic 4). Again this suture line can be glued. Then the remaining portion of the proximal repair is performed at the level of the supracoronary area or on the graft inserted in the root (Schematic 5) as is done in this example. Mostly the main course of the arch part of the graft is horizontally, slightly downwards to the right side.
Because the main direction of the ascending prosthesis is always vertical, slightly towards the right upperside of the patient, it means that the connection between the ascending prosthesis and the arch prosthesis forms an angulation of approximately 908 (or a little less, sometimes however more). This makes it impossible to anastomose both prostheses in a circumference end-to-end fashion. One has to tailor this anastomosis individually in order to avoid kinking, often by resection of a small triangle at the front to obtain a congruent anastomosis. If both prosthetic parts are left too long, especially at the back side, kinking will be unavoidable. Therefore, we suggest to straighten them rather tightly. Precurved arch prostheses could potentially solve this problem, however, once pressurized they too lose most of the curvature. It is dangerous to restart body perfusion from the groin since the trunk may collapse causing inadequate perfusion to the brain vessels. Therefore, an arterial cannula is inserted directly into the prosthesis and antegrade perfusion is restarted. After deairing, the selective perfusion catheters can be removed. 5
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
Schematic 5. Construction of the proximal (supracoronary) anastomosis after having restarted antegrade flow through the side arm of the prosthesis.
Step 9 The completed repair is illustrated in Schematic 6 and the control CT-scan in Photo 2. Video 11 shows the final result.
Schematic 6. Completion of the repair.
Results We have analyzed our own results of 100 elephant trunk procedures w6x. The hospital mortality was 8% with three of the deaths (3%) due to rupture of the remote aneurysm. Safi found in his series that 2% of his patients died during the interval between step 1 and 2 w7x. Also Svensson reported a 2.1% interval mortality w8x. This finding demands for a second step within a few weeks after the first, certainly when the aneurysm of the descending or thoracoabdominal aorta is large. Transient and permanent neurologic deficit occurred in 4% and 2%, respectively. Only an emergent operation retained statistical significance as a factor contributing to postoperative neurologic deficit (after multivariate analysis). Hoarseness occurred in 17% in our series. Some surgeons advocate to perform a single operation in which the total aorta is repaired w9,10x but we think that this intervention is 6
Photo 2. CT-scan several weeks after the repair (red arrow: clip on the lower end of the trunk, green arrow: trunk)
much more demanding, especially for the ventilatory system.
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
w4x
w5x Video 11. Final result.
Conclusions Pathology of the aorta beginning in the ascending portion and extending all the way down into the descending or thoracoabdominal aorta (the megaaorta syndrome), can be dealt with using two surgical steps of which the first consists of repairing the ascending aorta and arch leaving a piece of prosthesis into the descending aorta to facilitate the second step. This surgical technique is an elegant way to avoid damage to vital structures at the second stage. The procedure demands not only for optimal cerebral protection but also for adequate protection of the distal organs such as spinal cord and kidneys.
References w1x Borst HG, Walterbusch G, Schaps D. Extensive aortic replacement using ‘‘elephant trunk’’ prosthesis. Thorac Cardiovasc Surg 1983;31:37–40. w2x Griepp RB, Stinson EB, Hollingsworth JF, Buehler D. Prosthetic replacement of the aortic arch. J Thorac Cardiovasc Surg 1975;70:1051–1063. w3x Dossche KM, Morshuis WJ, Schepens MA, Waanders FG. Bilateral antegrade selective cere-
w6x
w7x
w8x
w9x
w10x
bral perfusion during surgery on the proximal thoracic aorta. Eur J Cardiothorac Surg 2000;17: 462–467. Dossche KM, Schepens MAAM, Morshuis WJ, Muysoms FEE, Langemeijer JJ, Vermeulen FEE. Antegrade selective cerebral perfusion in operations on the proximal thoracic aorta. Ann Thorac Surg 1999;67:1904–1910. Schepens MA, Nochi A. Myocardial protection in major aortic surgery. In Salerno T, Ricci M, editors. Myocardial protection, Blackwell, 2004:193–195. Schepens MA, Dossche KM, Morshuis WJ, van den Barselaar PJ, Heijmen RH, Vermeulen FE. The elephant trunk technique: operative results in 100 consecutive patients. Eur J Cardiothorac Surg 2002;21:276–281. Safi HJ, Miller CC 3rd, Estrera AL, Huynh TT, Porat EE, Allen BS, Sheinbaum R. Staged repair of extensive aortic aneurysms: long-term experience with the elephant trunk technique. Ann Surg 2004;240:677–684. Svensson LG, Kim KH, Blackstone EH, Alster JM, McCarthy PM, Greenberg RK, Sabik JF, D’Agostino RS, Lytle BW, Cosgrove DM. Elephant trunk procedure: newer indications and uses. Ann Thorac Surg 2004;78:109–116. Rokkas CK, Kouchoukos NT. Single-stage extensive replacement of the thoracic aorta: the arch-first technique. J Thorac Cardiovasc Surg 1999;117:99–105. Svensson LG, Shahian DM, Davis FG, Entrup MH, Kimmel WA, McGrath DM, Jewel ER, Gray AW Jr. Replacement of entire aorta from aortic valve to bifurcation during one operation. Ann Thorac Surg 1994;58:1164–1166.
7
Aortic arch replacement: the conventional ‘elephant trunk’ technique Marc A.A.M. Schepens* Department of Cardio-thoracic Surgery, St. Antonius Hospital, Koekoekslaan 1, 3435 CM Nieuwegein, The Netherlands Pathology of the aorta starting into the ascending aorta or aortic arch and extending downstream into the descending thoracic or thoracoabdominal aorta requiring surgical therapy, can be treated in two steps. At the first stage, via median sternotomy, the ascending aorta and arch are repaired, if necessary in combination with the aortic root or other cardiac interventions (such as bypass grafting or mitral valve repair). During this stage a free-floating extension of the arch prosthesis, the so-called elephant trunk, is left behind in the proximal descending aorta. Later, at the second stage via left thoracotomy, thoracophrenolaparatomy or endovascular repair, the descending aorta or thoracoabdominal aorta can be replaced. The most important advantage of leaving behind an elephant trunk is the avoidance of a difficult and hazardous dissection in the region of the distal aortic arch where arterial, venous, nervous, bronchial, gastro-intestinal and lymphatic structures cross. Doing so, the risk of damage to one of these structures can be completely avoided.
Keywords: Elephant trunk; Aorta; Aneurysm Introduction The first idea of the use of an elephant trunk was introduced by Hans Borst from Hannover in 1983 w1x, but already in 1975, Randall Griepp from Mount Sinai w2x described an original unfolding technique of the prosthesis using deep hypothermic circulatory arrest. Actually, total arch replacement is almost always performed using antegrade selective cerebral perfusion to protect the brain optimally w3,4x. Initially, however, these interventions were performed using only deep hypothermic circulatory arrest. Adequate protection of the central nervous system, brain and spinal cord, but also the distal organs such as kidneys and guts, is essential because during the period of the anastomosis between the elephant trunk * Corresponding author: Tel.: q31-30-6092047; fax: q31-306092120 E-mail: [email protected] 䉷 2007 European Association for Cardio-thoracic Surgery
and the proximal descending aorta, the circulation to the rest of the body is stopped and only the supraaortic vessels receive oxygenated blood. Therefore, it is essential to cool the patient down, at least to a rectal temperature of approximately 258C, to overcome ischemic problems with the distal organs including the spinal cord.
Surgical technique The illustrated example is a patient with a dilated ascending and descending aorta (chronic postdissection aneurysm) with only a mild dilatation of the aortic arch. There is a massive aortic valve incompetence. A preoperative CT-scan is shown in Photo 1. CO2 is applied into the pericardial sac at a flow rate of 5 l/min. The consecutive steps and the final result can be seen in Schematic 1. 1
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006 cannulation into the distal ascending aorta or proximal arch is possible after having verified that the aortic region chosen for the cannulation is free from atherosclerotic debris. In the illustrated example, we have cannulated directly the aortic arch. Step 2: Cooling and cardiac protection
Schematic 1. Preoperative situation. 2. Stage one of the repair. 3. Result after stage two.
After having started extracorporeal circulation (with a drain into the left ventricle through the right upper pulmonary vein to avoid left ventricular distention), cooling is started immediately. When the heart starts to fibrillate and there is no or only mild aortic valve incompetence, the ascending aorta is cross-clamped at the base of the innominate artery and one shot of cold, crystalloid cardioplegia is administered directly through the aortic root. Simultaneously the topical cooling is applied to the heart and the septal temperature is monitored by direct punction of the interventricular septum using a temperature probe which remains in situ during the complete repair. The amount of cardioplegia given depends on the temperature that the myocardium reaches. We aim to arrive at a septal temperature of 108C and this can be reached in most cases with only 1 l of cardioplegia w5x. When the aortic valve incompetence is greater than grade 1, we use selective cardioplegia (cold crystalloid) directly into both coronary ostia, again aiming at a septal temperature of 108C. In this way the heart is adequately protected. If the root needs further surgery, as in our example a root replacement with a biological conduit, this repair (valve resection, mobilisation of the coronary ostia upon buttons, resection of the aortic sinuses leaving a remnant on top of the annulus of about 5 mm) can be started during the cooling phase. Step 3: Arch phase – Cerebral protection
Photo 1. Preoperative CT image.
Step 1: Arterial and venous cannulation If no associated mitral valve surgery is planned, the right atrium is used for venous cannulation. There are different options for the placement of the arterial cannula. The common femoral artery can be used when there is no atherosclerosis or thrombus formation in the descending and/or abdominal aorta but it might be safer to use axillary or subclavian cannulation because these vessels are often free from atherosclerosis or dissection. However, in cases of a chronic postdissection aneurysm, the femoral artery remains a good option since, in these circumstances, there are almost no degenerative changes present. Also, direct 2
When the rectal temperature has reached 258C, the body is protected adequately to arrest the circulation and start the arch phase of the repair. The cannulae for antegrade cerebral perfusion are flushed to remove all air. Both the innominate artery and the common left carotid artery are snared or clamped (after having verified that the proximal parts of both arteries are free from atherosclerosis) to avoid air entering the supra-aortic arteries. This is done in Trendelenburg position. The arterial cannula is removed when distal ascending or aortic arch cannulation is used. When the femoral artery cannulation is used, the cannula may not be used anymore as an inflow cannula because when the trunk is in situ, retrograde flow from the groin may cause trunk collapse. In case the axillary artery is used for inflow, the cannula may
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
Video 1. Before the selective cannulae can be inserted into the ostia of the head vessels, the aortic arch must be opened after having stopped antegrade perfusion and after having removed the aortic clamp.
remain in position for later rewarming. The aortic clamp is removed (Video 1). The arch is emptied with the pump sucker and after having inspected the arch and origin of the arch vessels, the surgeon has to decide if an island technique or separate vessel technique is going to be used. The cannulae for selective cerebral perfusion are introduced into the left common carotid artery and the innominate artery (Video 2). The complete arch is resected (Video 3) except for the island including the origin of the innominate artery, the left common carotid and the left subclavian artery (sometimes also the origin of an aberrant left vertebral artery). The distal plane of resection is situated just beyond the origin of the left subclavian artery. This is the area where the left vagus nerve crosses the anterior aspect of the aorta. The use of a small cotton on a clamp is a useful instrument to dissect it bluntly from the aorta. The ligament of Botall should be identified realizing that the recurrent nerve runs around it and continues at the backside of the arch and left common carotid artery. In case of a large aneurysm the nerve may be unified within the aortic wall so that it is almost impossible to free it. In these circumstances it could be wise to divide the arch between the left carotid artery and the
Video 2. Insertion of the cannulae can be done with optimal visualisation of the ostia of the head vessels. This avoids dislodgement of calcium or debris into the brain.
Video 3. All aneurysmal aortic tissue is removed except a small rim for making the anastomosis.
subclavian artery and perform the anastomosis in this area to avoid the region of the vagus and recurrent nerve (of course the left subclavian has to be reimplanted then into the left common carotid artery). Very often the diameter of the aorta in the area of the left subclavian is somewhat smaller, reducing the discrepancy between the prosthesis and the aorta. It is wise to transect the aorta completely in a circular fashion and free a cuff of about 5 mm. In case of a chronic aortic dissection the intimal flap has to be resected as deep as possible into the descending aorta making one lumen from the dissected aorta (Video 4). Clots should be removed using a sucker realizing that no fragments may be lossed to prevent emboli. In case of an acute dissection the fragile aortic layers must be unified using Teflon or glue. Step 4: Preparation of the prosthesis A suitable prosthesis is chosen (it may be helpful to measure the size and the diameter of the proximal descending aorta using appropriate sizers). The proximal end of the prosthesis (later the ascending and arch part) is invaginated into the trunk part (Video 5). This means that the outer part is the trunk and the inner part the arch/ascending part. It may be helpful to mark the proximal end with a heavy stay suture;
Video 4. Resection of the web in a chronic dissected aorta is essential because otherwise the trunk can be placed into the true or false lumen. One should be very careful in resecting the web because damage to the outer aortic wall may lead to catastrophies.
3
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
Video 5. One simply invaginates one end of the prosthesis in the other. The result is a double-folded prosthesis with the outer part identified as the trunk part and the inner tube being the arch part.
this hangs out of the lumen of the folded prosthesis and will facilitate the later unfolding. Because the second stage procedure can be done using an endoprosthesis, it is wise to mark the lower end of the trunk with a number of metal clips making the catheterisation of the trunk easier. The length of the trunk certainly should exceed 5 cm, probably 10 to 15 cm is an ideal length. It is helpful to put a sump drain into the folded prosthesis to remove the blood continuously from the anastomotic region. Step 5: Insertion of the prosthesis into the descending aorta The complete infolded prosthesis is then inserted into the proximal descending aorta (Schematic 2) and this may be difficult in case there is only a mild dilatation (Video 6). The double fold is located just at the level of the aortic cuff. A prosthesis with an adaptable collar (Gelweave Plexus 4 TM, Vascutek Ltd, Scotland) can be helpful when the aorta is largely dilated also in this area or
Schematic 2. The insertion of the invaginated prosthesis into the descending thoracic aorta. Notice the island containing the arch vessels.
4
Video 6. The insertion of the double-folded prosthesis into the descending aorta should be done very carefully without causing damage to the wall of the aorta. It can be done using two forceps and gentle forward pressure on the prosthesis.
the aorta can be plicated at this level using a longitudinal incision. If one has decided to use the separate graft technique for the head vessels, the invagination of the graft on itself is almost impossible; then the predetermined length of the trunk should simply be inserted into the descending aorta. Step 6: Fixation of the trunk on the descending aorta Using a running prolene 4=0, mostly with a Teflon strip between the aorta and the graft, the prosthesis is secured to the proximal descending aorta (Video 7). This anastomosis is very delicate since it is really impossible at the end to reach the dorsal side of it. It is advised to use a nerve hook to tighten the suture line. Step 7: Unfolding of the prosthesis Then the prosthesis should be unfolded by traction on the inner part (Video 8) or the stay suture. This is the birth of the arch/ascending part (Schematic 3). If one is going to use glue on the first anastomosis, it should be applied now.
Video 7. This anastomosis between the graft and the aneurysm is the anchorage of the graft to the aorta. Therefore, it is essential to make it properly and without any leakage since the dorsolateral aspect can hardly be reached anymore. The use of prolene 4=0 allows for big and strong bites.
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
Video 8. Exertion of simple traction on the infolded prosthesis with two forceps will give birth to the arch part of the prosthesis since the dacron tube is fixed at the upper aortic rim.
Video 10. Reimplantation of the island can be done using running prolene 4=0 or 5=0 depending on the thickness of the aortic layers.
Schematic 3. Extraction of the prosthesis out of the descending aorta leaving the trunk behind.
Schematic 4. Construction of the anastomosis between the arch island and the arch part of the prosthesis.
Video 9. It is important to make holes in a woven prosthesis using the cautery because otherwise the edges will unravel. The length and width of the opening is adapted to that of the island containing the head vessels.
Step 8: Arch repair and connection of both prostheses together Afterwards an oval opening is made using cautery for the head vessels (Video 9) which are then reimplanted using prolene 4=0 or 5=0 (Video 10) depending on the quality of the tissue (Schematic 4). Again this suture line can be glued. Then the remaining portion of the proximal repair is performed at the level of the supracoronary area or on the graft inserted in the root (Schematic 5) as is done in this example. Mostly the main course of the arch part of the graft is horizontally, slightly downwards to the right side.
Because the main direction of the ascending prosthesis is always vertical, slightly towards the right upperside of the patient, it means that the connection between the ascending prosthesis and the arch prosthesis forms an angulation of approximately 908 (or a little less, sometimes however more). This makes it impossible to anastomose both prostheses in a circumference end-to-end fashion. One has to tailor this anastomosis individually in order to avoid kinking, often by resection of a small triangle at the front to obtain a congruent anastomosis. If both prosthetic parts are left too long, especially at the back side, kinking will be unavoidable. Therefore, we suggest to straighten them rather tightly. Precurved arch prostheses could potentially solve this problem, however, once pressurized they too lose most of the curvature. It is dangerous to restart body perfusion from the groin since the trunk may collapse causing inadequate perfusion to the brain vessels. Therefore, an arterial cannula is inserted directly into the prosthesis and antegrade perfusion is restarted. After deairing, the selective perfusion catheters can be removed. 5
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
Schematic 5. Construction of the proximal (supracoronary) anastomosis after having restarted antegrade flow through the side arm of the prosthesis.
Step 9 The completed repair is illustrated in Schematic 6 and the control CT-scan in Photo 2. Video 11 shows the final result.
Schematic 6. Completion of the repair.
Results We have analyzed our own results of 100 elephant trunk procedures w6x. The hospital mortality was 8% with three of the deaths (3%) due to rupture of the remote aneurysm. Safi found in his series that 2% of his patients died during the interval between step 1 and 2 w7x. Also Svensson reported a 2.1% interval mortality w8x. This finding demands for a second step within a few weeks after the first, certainly when the aneurysm of the descending or thoracoabdominal aorta is large. Transient and permanent neurologic deficit occurred in 4% and 2%, respectively. Only an emergent operation retained statistical significance as a factor contributing to postoperative neurologic deficit (after multivariate analysis). Hoarseness occurred in 17% in our series. Some surgeons advocate to perform a single operation in which the total aorta is repaired w9,10x but we think that this intervention is 6
Photo 2. CT-scan several weeks after the repair (red arrow: clip on the lower end of the trunk, green arrow: trunk)
much more demanding, especially for the ventilatory system.
R.H. Anderson and M. Kanani / Multimedia Manual of Cardiothoracic Surgery / doi:10.1510/mmcts.2006.002006
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w5x Video 11. Final result.
Conclusions Pathology of the aorta beginning in the ascending portion and extending all the way down into the descending or thoracoabdominal aorta (the megaaorta syndrome), can be dealt with using two surgical steps of which the first consists of repairing the ascending aorta and arch leaving a piece of prosthesis into the descending aorta to facilitate the second step. This surgical technique is an elegant way to avoid damage to vital structures at the second stage. The procedure demands not only for optimal cerebral protection but also for adequate protection of the distal organs such as spinal cord and kidneys.
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