Ann Thorac Surg 2007;83:e6-e8
© 2007 The Society of Thoracic Surgeons
How To Do It
Modified Trifurcated Graft in Acute Type A Aortic Dissection With the Least Brain Ischemic Time
Chien-Chang Chen, MDa,*,
Shih-Rong Hsieh, MDb
a Division of Cardiovascular Surgery, Chi-Mei Hospital, Yungkang City, Taiwan
b Cardiovascular Center, Taichung Veterans General Hospital, Taichung City, Taiwan
Accepted for publication December 28, 2006.
* Address correspondence to Dr Chen, Division of Cardiovascular Surgery, Chi-Mei Hospital, 901 Chunghwa Rd, Yungkang City, Tainan County 710, Taiwan (Email: eadwine_chen{at}yahoo.com.tw).
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Abstract
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Cerebral ischemia, bleeding, and inadequate myocardial protection are the major concerns in doing aortic arch operation. The trifurcated graft technique as described by Spielvogel and associates was a useful technique in reducing the risk of postoperative neurologic complications. However, the cerebral ischemic time may be still too long in inexperienced hands. We recently encountered 3 patients of acute type A aortic dissection who needed aortic arch replacement. By modifying the procedure of the trifurcated graft technique and using a reversed sleeve graft technique, we greatly reduced the duration of cerebral and myocardial ischemia and made bleeding a minor problem.
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Introduction
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Aortic arch replacement is occasionally required in surgical repair of acute Standford type A aortic dissection. Cerebral ischemia, bleeding, and inadequate myocardial protection are the major causes of adverse outcome. Traditionally, the aortic arch is replaced as an island by using a single graft under hypothermic circulatory arrest. The disadvantages of this method include long brain ischemic time and high incidence of bleeding due to high anastomotic tension resulting from the large anastomotic caliber. In 2002, Spielvogel and associates [1] introduced the trifurcated graft technique accompanied by antegrade selective cerebral perfusion (ASCP) in aortic arch replacement. The technique reduced the hypothermic circulatory arrest time to 30 minutes but used the temperature of perfusate as low as 10°C. Moreover, grafts of three different sizes were needed [1]. Recently, we encountered three cases of acute type A aortic dissection requiring aortic arch replacement. We modified the procedure of the trifurcated graft technique and reduced the partial brain ischemic time to 15 minutes.
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Technique
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The patients underwent standard midline sternotomy. The cardiopulmonary bypass was established by using biarterial inflow from the side grafts of the right axillary and left femoral arteries and a single two-staged venous catheter in the right atrium (Edward lifesciences, Irvine, California). The nasopharyngeal temperature was lowered to 22°C. The left ventricle was vented from the right superior pulmonary vein. The three supra-aortic arteries were mobilized during lowering systemic temperature. The trifurcated graft was made with the following method: one of the branch limbs of the Ultramax Y-Graft (Atrium Medical, Hudson, New Hampshire) was partly cut and anastomosed to the main trunk at a 45-degree angle (Fig 1A). The right brachiocephalic artery was clamped softly on both sides with atraumatic clamps under transient decreased cardiopulmonary bypass arterial pressure. It was transected with the proximal stump oversewn. The first branch limb of the trifurcated graft was anastomosed to the right brachiocephalic artery without aortic cross-clamping (Fig 1A). After careful evacuation of air, the clamp was moved to the first branch limb. When the nasopharyngeal temperature reached 22°C, the second branch limb was anastomosed to the left common carotid artery (Fig 1B). This was the only period of partial brain ischemia that required ASCP from the right axillary artery. The flow of the ASCP was set at 14 to 18 mL · kg–1
· min–1, and the right radial arterial pressure was kept above 50 mm Hg.
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Fig 1. (A) The modified trifurcated graft: the first (a), second (b), and third (c) branch limb, and the main trunk (d). The right brachiocephalic artery was clamped and anastomosed to the first branch limb. The brain was fully protected by perfusion from the right axillary artery (black arrows) and left femoral artery (white arrows). (B) The left common carotid artery was anastomosed to the second branch limb. The antegrade selective cerebral perfusion from the right axillary artery was used during this anastomosis (black arrows). The white arrows indicate perfusion from left femoral artery. (C) Completion of the two anastomoses: the main trunk and the third branch limb were clamped (the latter not shown). Full brain perfusion was from the right axillary artery. Note that the aorta was not clamped (asterisk).
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After the anastomoses, the clamp was moved to the main trunk with an additional clamp on the third branch limb (Fig 1C). Lower body perfusion from left femoral artery ceased while the right axillary arterial inflow continued to perfuse the two reconstructed supra-aortic arteries. The ascending aorta and aortic arch were incised longitudinally after clamping the left subclavian artery to prevent flow steal. The intimal tear was completely excised. The myocardium was protected by intermittent retrograde or direct catheterized antegrade coronary perfusion. The left subclavian artery was preserved if the intimal tear or aneurysm did not extend beyond its orifice, and the aorta was transected between the orifices of the left subclavian and left common carotid arteries. Otherwise, the left subclavian artery and proximal descending aorta were transected, and the third branch limb of the trifurcated graft was end-to-end anastomosed to the left subclavian artery.
To reconstruct the main portion of the aorta, another straight Ultramax graft of suitable size was chosen according to the diameter of the distal aortic cut end. For clear surgical field, we used the "reversed sleeve graft" technique in distal aortic anastomosis [2]. Briefly, an inside-out reversed sleeve graft was made and folded along the longitudinal axis and then inserted into the distal aorta. The anastomosis was done using a 3-0 polypropylene running suture. After completion of the anastomosis, the reversed graft was pulled out from the aortic lumen (Fig 2). Resuspension of the aortic annulus and reconstruction of the proximal aorta were performed during rewarming. Finally, the main trunk of the trifurcated graft was end-to-side anastomosed to the straight graft (Fig 3).
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Fig 2. (A) The tube graft was reversed totally inside out with one end left in the reversed lumen. This reversed graft was folded longitudinally to reduce the size and to facilitate insertion. (B) The reversed graft was inserted into the distal aorta. The anastomosis was made by a 3-0 polypropylene running suture. (C) After completion of the anastomosis, the reversed graft was pulled out from the aortic lumen. The folded two-layer distal anastomosis provided a check-valve effect in sealing blood leak (black arrows).
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Fig 3. The trifurcated graft (a) was anastomosed to the straight graft (b). The left subclavian artery was (A) replaced or (B) preserved, depending on the extent of the aneurysm or the location of the intimal tear.
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Comment
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With the modified procedure of the trifurcated graft using biarterial inflow, only partial brain ischemia was necessary during anastomosing of the left common carotid artery. It could be easily limited to 15 minutes. Another advantage of the modification was the reduced ischemia of myocardium since the right brachiocephalic and left common carotid arteries were reconstructed without cross clamping the aorta. Moderate hypothermia at a rectal temperature of 25°C to 27°C has been recommended in ASCP [3]. In our practice, it was safe to protect the brain and spinal cord during anastomosing the left common carotid artery and distal aorta at a nasopharyngeal temperature of 22°C.
The safety of sequential clamping of the supra-aortic vessels during reconstruction of aortic arch with ASCP has been proved by several authors [3, 4]. Nevertheless, the sequential clamping should be done with the atraumatic clamps under transiently decreased cardiopulmonary bypass arterial pressure. It was important but easy to repair a leak immediately after anastomoses of the supra-aortic arteries because of great mobility and little wall tension of the anastomoses. The reversed sleeve graft technique provided a good surgical visual field in making distal aortic anastomosis and provided a check-valve effect in sealing blood leak. With careful measurement of the distal aortic diameter, a longer reversed sleeve graft could be inserted into the descending aorta for reconstruction of the main portion of the aorta. The modification was different from the original idea proposed by Spielvogel and coworkers [1] in that only two kinds of grafts and one graft-to-graft anastomosis were required in making the trifurcated graft. The size mismatch between the branch limb and right brachiocephalic artery could be solved by beveling one or both ends of them. Kinking usually resulted from a too-long graft but not from the beveled anastomotic angle. Surgeons should avoid the redundant branched limbs and main trunk of the trifurcated graft by measuring the lengths the trifurcated and straight grafts that have been distended with blood pressure.
We have successfully performed the modified technique in 3 patients. The first case was a 64-year-old man with acute type A dissection and a chronic aneurysm of the aortic arch and proximal descending aorta. The second and third cases were a 77-year-old woman and a 64-year-old woman with cardiac tamponade due to acute type A dissection in which the intimal tears were located in the aortic arches. The mean partial brain ischemic time for the 3 patients was 14 minutes (15, 15, and 12 minutes, respectively), and lower body ischemic time was 58 minutes (78, 55, and 40, respectively). The mean total bypass time was 236 minutes (205, 203, and 300, respectively). The mean durations of intensive care unit and hospital stay were 3.8 and 15.3 days, respectively. The first patient had permanent left recurrent laryngeal nerve palsy after operation. The other 2 patients had no complications. All 3 patients were alive after a mean follow-up period of 7 months.
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References
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- Spielvogel D, Strauch JT, Minanov OP, Lansman SL, Griepp RB. Aortic arch replacement using a trifurcated graft and selective cerebral antegrade perfusion Ann Thorac Surg 2002;74(Suppl):1810-1814.
- Hsieh SR, Verrier ED. A short wholly inside-out reversed vascular graft facilitating difficult aortic anastomosis Ann Thorac Surg 2005;80:1534-1536.[Abstract/Free Full Text]
- Panos A, Murith N, Bednarkiewicz M, Khatchatourov G. Axillary cerebral perfusion for arch surgery in acute type A dissection under moderate hypothermia Eur J Cardiothorac Surg 2006;29:1036-1040.[Abstract/Free Full Text]
- Kokotsakis J, Lazopoulos G, Milonakis M, et al. Right axillary artery cannulation for surgical management of the hostile ascending aorta Tex Heart Inst J 2005;32:189-193.[Medline]
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Abstract
Introduction
