MMCTS
(February 19, 2007). doi:10.1510/mmcts.2006.002014
Copyright © 2007 European Association for Cardio-thoracic Surgery
Procedure
Reconstruction of the intercostal arteries with small-branched grafts in patients with thoracoabdominal or descending aortic aneurysms
Yutaka Okita*,
Yujiro Kawanishi,
Keitaro Nakagiri,
Hiroshi Tanaka,
Masamichi Matsumori,
Mitsuru Asano,
Teruo Yamashita and
Kenji Okada
Division of Cardiovascular, Thoracic, and Pediatric Surgery, Department of Cardio-Pulmonary and Vascular Medicine, Kobe Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
* Corresponding author: * E-mail: yokita{at}med.kobe-u.ac.jp
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Summary
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An extent II thoracoabdominal aortic aneurysm of 60 mm diameter was exposed through the left 6th intercostal space and retroperitoneal approach. The partial cardiopulmonary bypass was initiated through the femoral arterial and venous cannulation. A knitted Dacron graft of 22 mm with four spatially orientated branches for the abdominal viscera and five branches for the intercostal arteries was utilized. The thoracoabdominal aorta was replaced with staged segmental aortic clamping. The proximal aorta, just distal to the left subclavian artery, was completely transected and anastomosed to the graft. The descending aorta was clamped at Th 10 level. The Th 8 and 9 intercostal arteries were clamped from the outside of the aorta. After opening the aorta, the left orifice of Th 8th and Th 9th intercostal arteries were anastomosed to the side branches of the graft, respectively. Similarly, the 10th and 11th intercostal arteries were reconstructed. After clamping the infra-renal portion of the abdominal aorta, four visceral arteries were perfused using an 8 French size balloon-tipped catheter. Each artery was anastomosed to the side branch of the graft. The distal anastomosis was performed and cardiopulmonary bypass was weaned-off.
Key Words: Thoracoabdominal aorta • Spinal cord ischemia • Reconstruction of the intercostal arteries • Postoperative paraplegia
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Introduction
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In surgery for descending aorta or thoracoabdominal aortic aneurysms, reconstruction of the intercostal artery is crucial to prevent postoperative paraplegia. However, conventional maneuver to reconstruct the intercostal arteries with the aortic patch method has a potential risk of future dilatation of residual aortic tissue. To avoid this problem, we have been reconstructing intercostal arteries with presewn branched grafts. The aim of this study is to report the early results of this technique.
Patients and methods
From October 1999 to December 2005, 147 patients underwent surgery for descending aorta (n=78) or thoracoabdominal aorta (n=69, Crawford extension type I (18); type II (22); type III (29); type IV (0)). Eighty-three patients had reconstruction of the intercostal arteries. Mean age was 64±13 years and 61 patients were male. Thirty-eight had aortic dissection, including two patients with acute type B dissection and 15 had ruptured aneurysms. Preoperative computed tomography (CT) scan or magnetic resonance (MR) angiography could detect the Adamkiewicz artery in 65 patients (Photo 1). The cerebrospinal fluid drainage (CSFD) was done in 42 patients and intraoperative motor evoked potentials were recorded in 40. Intercostal arteries from Th 7 to L2 were reconstructed with branched grafts in 80 patients. The distance between the individual grafts was dependent on the space of the intercostal arteries and the tortuosity of the aorta, however, preoperative measurement of the distance between the grafts was possible according to the X-ray, CT scan, MR angiography or aortography. In the majority of patients, at least three small grafts, 8 or 10 mm in diameter, for the intercostal arteries were presewn to the thoracic segment of the main graft before opening the aorta. Anastomosis of the intercostal arteries was achieved using inclusion technique with a 4-0 polypropylene suture. If right and left intercostal arteries were patent, both orifices were included in a single graft. Segmental-staged aortic clamping was liberally utilized under partial cardiopulmonary bypass. Each aortic segment, which contained less than three pairs of the intercostal arteries, were clamped and opened in tandem. We tried to clamp the intercostal arteries externally before the aortic opening to prevent ‘blood steal-phenomenon’ from the spinal cord caused by back bleeding from the intercostal arteries. Every reconstructed intercostal artery was immediately reperfused after anastomosis. There were only three patients who had reconstruction of the intercostal arteries with an aortic patch technique. Mild hypothermic partial cardiopulmonary bypass with tympanic temperature between 32–34°C was used in 61 patients, left heart bypass in 4, and deep hypothermic cardiopulmonary bypass with tympanic temperature below 20°C was used in 16.
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Photo 1 Preoperative magnetic resonance angiography clearly demonstrated the continuity of the Th 10 left intercostal artery, great radicular artery of Adamkiewicz, and anterior spinal artery.
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Surgical procedure
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The patient had an extent II thoracoabdominal aortic aneurysm of 60 mm diameter (Photo 2). The whole thoracoabdominal aorta was exposed through the left 6th intercostal space and retroperitoneal approach. The partial cardiopulmonary bypass was initiated through the femoral arterial and venous cannulation (Video 1, Schematic 1).
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Video 1 The cerebrospinal fluid drainage catheter was inserted from the lumbar vertebrae. The motor evoked potential was monitored with the left semi-recumbent position. The whole thoracoabdominal aorta was exposed through the left 6th intercostal space and retroperitoneal approach. The partial cardiopulmonary bypass was initiated through the femoral arterial and venous cannulation. The patient was cooled down to 32–33°C. A knitted Dacron graft of 22 mm with nine-side 8 mm-branches was utilized. This graft has four spatially orientated branches for the abdominal viscera and five branches for the intercostal arteries. The descending aorta was clamped distal to the left subclavian artery and mid-descending aorta. The aorta was opened and bleeding from the bronchial arteries or high intercostal arteries was stopped. The proximal aorta was completely transected and was dissected from the surrounding tissue, especially the esophagus. Special care was taken to prevent injuring the thoracic duct. Proximal anastomosis was performed using a 4-0 polypropylene monofilament suture (Prolene SH-1 needle) with a Teflon strip reinforcement. The edge of the Teflon strip was tightened by a compacting stitch to prevent suture hole bleeding.
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Schematic 1 The whole thoracoabdominal aorta was exposed through the left 6th intercostal space and retroperitoneal approach. The partial cardiopulmonary bypass was initiated through the femoral arterial and venous cannulation.
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A knitted Dacron graft of 22 mm with nine-side 8 mm-branches was utilized (Photo 3). This graft has four spatially orientated branches for the abdominal viscera and five branches for the intercostal arteries (Video 1). The descending aorta was clamped distal to the left subclavian artery and mid-descending aorta. The aorta was opened and bleeding from the bronchial arteries or high intercostal arteries was stopped (Schematic 2). The proximal aorta was completely transected and was dissected from the surrounding tissue. Proximal anastomosis was performed using a 4-0 polypropylene monofilament suture (Prolene SH-1 needle) with a Teflon strip reinforcement (Schematic 3, Video 1). The edge of the Teflon strip was tightened by a compacting stitch to prevent suture hole bleeding (Video 1). The descending aorta was clamped at Th 10 level. Before opening the aorta, Th 8 and 9 intercostal arteries were dissected and clamped from the outside of the aorta. This procedure may prevent spinal cord ischemia due to steal phenomenon which is easily induced by the back bleeding from the orifices of the intercostal arteries (Video 2). Five min after aortic clamping and watching the MEP, the aorta was opened. The left orifice of Th 8th intercostal artery was anastomosed to a side branch using a 4-0 poly-propylene monofilament suture (Prolene RB-1 needle) with inclusion technique. The graft clamp was transposed to perfuse this intercostal artery (Schematics 4 and 5, Video 2). The Th 9th intercostal artery was also reconstructed and was reperfused in a similar fashion (Video 2). The aorta was clamped at Th 12. The 10th and 11th intercostal arteries were clamped externally. The left orifice of the Th 11th intercostal artery was anastomosed and was reperfused (Video 2). The infra-renal portion of the abdominal aorta was clamped and opened. The back bleeding from the L1 lumbar artery was stopped using a 2 French size balloon catheter (Schematic 6). Four visceral arteries were perfused using an 8 French size balloon tipped catheter (Fuji Phycon). Each arterial flow was 200 ml/min (Video 3). The L1 lumbar artery was reconstructed also using 4-0 Prolene suture. Rewarming was started. The right renal artery was reconstructed in a similar manner (Video 4). The distal anastomosis was performed using 4-0 Prolene Sh-1 needle with a Teflon felt reinforcement (Video 5). The superior mesenteric artery was anastomosed with 4-0 Prolene. The celiac artery was reconstructed. Finally, the left renal artery was anastomosed using a button technique (Video 6). Cardiopulmonary bypass was weaned and hemostasis was achieved after protamine reversal (Schematic 7, Video 7). Postoperative CT was satisfactory (Photo 4).
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Schematic 2 The descending aorta was clamped distal to the left subclavian artery and mid-descending aorta. The aorta was opened and bleeding from the bronchial arteries or high intercostal arteries was stopped.
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Schematic 3 The proximal aorta was completely transected and proximal anastomosis was performed using a 4-0 polypropylene monofilament suture.
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Video 2 The descending aorta was clamped at the Th 10 level. Before opening the aorta, the Th 8 and 9 intercostal arteries were dissected and clamped from the outside of the aorta. This procedure may prevent spinal cord ischemia due to steal phenomenon which is easily induced by the back bleeding from the orifices of the intercostal arteries. The left orifice of the Th 8th intercostal artery was anastomosed to a side branch using 4-0 polypropylene monofilament suture (Prolene RB-1 needle) with inclusion technique. The graft clamp was transposed to perfuse this intercostal artery. The Th 9th intercostal artery was also reconstructed and was reperfused in a similar fashion. The aorta was clamped at Th 12. The 10th and 11th intercostal arteries were clamped externally. The left orifice of the Th 11th intercostal artery was anastomosed and was reperfused.
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Schematic 4 The descending aorta was clamped and the aorta was opened. The intercostal artery was anastomosed to a side branch using a 4-0 polypropylene monofilament suture with inclusion technique.
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Schematic 5 The graft clamp was transposed to perfuse this intercostal artery. The next intercostal artery was anastomosed and was reperfused.
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Video 3 Four visceral arteries were perfused using an 8 French size balloon tipped catheter (Fuji Phycon). Each arterial flow was 200 ml/min.
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Video 4 The L1 lumbar artery was reconstructed also using a 4-0 Prolene suture. Rewarming was started. The right renal artery was reconstructed in a similar manner.
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Video 5 The distal anastomosis was performed using a 4-0 Prolene Sh-1 needle with a Teflon felt reinforcement.
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Video 6 The superior mesenteric artery was anastomosed with a 4-0 Prolene. The celiac artery was reconstructed.
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Schematic 7 The visceral arteries were reconstructed and sometimes the left renal artery was connected separately.
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Video 7 Finally, the left renal artery was anastomosed using a button technique. Cardiopulmonary bypass was weaned and hemostasis was achieved after protamine reversal.
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Results
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The number of the reconstructed intercostal arteries was 2.8±1.5 (ranging from 1–5) in each patient. Early mortality was 5 (6.1%) and postoperative paraplegia occurred in 7 (9.0%). Postoperative angiography was performed in 51 patients, and 91 of 147 (62%) reconstructed grafts were patent (Photo 5). In CT scan, 145 of 204 (73%) reconstructed grafts were visualized (Photo 6). In 7 patients with paraplegia, postoperative image study demonstrated that 9 of 14 (64%, P=0.013) reconstructed grafts were occluded.
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Photo 5 Postoperative aortography. Black arrow: patent for the intercostal artery, white arrow: occluded graft.
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Photo 6 Postoperative computed tomography showing a patent graft (black arrow) for the intercostal artery (white arrow).
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Comments
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Revascularization of the intercostal arteries represents an important technical step during repair of descending or thoracoabdominal aneurysms. Several surgical techniques have been described, the most simple being an aortic patch anastomosis to the prosthetic graft. The main advantage of the patch technique is the reduced number of anastomoses [1]. However, isolated reimplantation of each intercostal artery might be necessary in large aneurysms, particularly if the ostia of the intercostal arteries are widely displaced from each other. Moreover, it has been reported that when a segment of aortic wall is left in situ to facilitate branch reconstruction, it becomes aneurysmal, particularly in patients with Marfan's syndrome [2]. Dardik et al. [3] reported a prevalence of patch aneurysm of 7.5% in 107 patients who underwent thoracoabdominal aneurysm repair. Lombardi et al. [4] reported three patients with patch aneurysm among 20 patients who required reoperation after previous thoracoabdominal aneurysm repair. Kouchoukos et al. [5] reported two incidences of patch aneurysm in Marfan patients. Carrel et al. [6] reported an alternative technique of separate revascularization of the visceral arteries in thoracoabdominal aneurysm repair. Similarly, Kouchoukos et al. [5] reported the usefulness of presewn 4-branched graft to the visceral artery reconstruction during thoracoabdominal aortic repair using deep hypothermic technique. However, no reports have been found to use the branched grafts for reconstruction of the intercostal arteries. We have been using a technique of reconstructing the intercostal arteries with an individual small graft for patients who required revascularization of the intercostal arteries.
The use of interposition grafts for the intercostal arteries could completely eliminate the diseased aortic tissue. And also it could reestablish the intercostal artery perfusion immediately after anastomosis by presewn side branches into the thoracic segment of the aortic graft. This maneuver could reduce duration of spinal cord ischemia with the concomitant use of staged clamping small segments of the aorta.
Other adjuncts for spinal cord protection participated important roles in the clinical setting. Recent advent of the MR image or CT has facilitated to identify the great radicular artery, the artery of Adamkiewicz. Yamada et al. [7] demonstrated the Adamkiewicz artery in the majority of the patients with descending or thoracoabdominal aortic aneurysm. Yoshioka et al. [8] demonstrated several intercommunicating collateral pathways between the critical intercostal arteries. These non-invasive new imaging techniques simplified the surgical procedure and prevented inadvertent injury to the vital intercostal arteries.
Concomitant use of intraoperative transcranial-stimulated motor evoked potential of the spinal cord also could detect the cord ischemia and identify the critical intercostal arteries in real time. The cerebrospinal fluid drainage could alleviate secondary compression of the spinal cord due to ischemic edema.
The major drawback of this technique is suboptimal patency of the reconstructed grafts being compared with patch technique, where almost all attached intercostal arteries should be patent. In our series, early patency of the reconstructed grafts was between 60 to 70% by angiography or CT scan. Moreover, more than half of the grafts were occluded in patients who had postoperative paraplegia. Several causes for this rather higher occlusion ratio of the grafts were analyzed, including graft twisting, deformity of the intercostal arteries, and blood vortex formation at the anastomosis of the graft to the intercostal arteries. More meticulous surgical technique and precise spatial orientation of the grafts were required to improve the outcome of this technique.
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Conclusion
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Early result of patients who underwent surgery for descending aorta or thoracoabdominal aortic aneurysms with reconstruction of the intercostal arteries using branched individual grafts was satisfactory. Although early patency of the reconstructed intercostal arteries was suboptimal, this technique can reduce the risk of future dilatation of aortic patch.
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References
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- Crawford ES, Crawford JL, Stowe CL, Safi HJ. Total aortic replacement for chronic aortic dissection occurring in patients with and without Marfan's syndrome. Ann Surg 1984;199:358–362.[Medline]
- Ingu A, Ando M, Okita Y, Yamada N, Kitamura S. Redo operation for thoracoaortic aneurysm after entire aortic replacement. Ann Thorac Surg 2001;72:1766–1777.[Abstract/Free Full Text]
- Dardik A, Perler BA, Roseborough GS, Williams GM. Aneurysmal expansion of the visceral patch after thoracoabdominal aortic replacement: an argument for limiting patch size? J Vasc Surg2001; 34
:405–409; discussion 410.[CrossRef][Medline]
- Lombardi JV, Carpenter JP, Pochettino A, Sonnad SS, Bavaria JE. Thoracoabdominal aortic aneurysm repair after prior aortic surgery. J Vasc Surg
2003; 38
:1185–1190.[CrossRef][Medline]
- Kouchoukos NT, Masetti P, Castner CF. Use of presewn multiple branched graft in thoracoabdominal aortic aneurysm repair. J Am Coll Surg 2005;201:646–649.[CrossRef][Medline]
- Carrel TP, Signer C. Separate revascularization of the visceral arteries in thoracoabdominal aneurysm repair. Ann Thorac Surg 1999;68:573–575.[Abstract/Free Full Text]
- Yamada N, Okita Y, Minatoya K, Tagusari O, Ando M, Takamiya M, Kitamura S. Preoperative demonstration of Adamkiewicz artery by magnetic resonance angiography in patients with descending or thoracoabdominal aortic aneurysms. Eur J Cardiothorac Surg 2000;18:104–111.[Abstract/Free Full Text]
- Yoshioka K, Niinuma H, Ohira A, Kawakami T, Kawazoe K. Three-dimensional demonstration of the artery of Adamkiewicz by multidetector-row computed tomography. Ann Thorac Surg 2004;78:719.[Free Full Text]
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Summary
Introduction
