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Successful endografting with simultaneous visceral artery bypass grafting for severely calcified thoracoabdominal aortic aneurysm
CASE REPORTS
Successful endografting with simultaneous visceral artery bypass grafting for severely calcified thoracoabdominal aortic aneurysm Yoshiko Watanabe, MD, Shin Ishimaru, MD, Satoshi Kawaguchi, MD, Taro Shimazaki, MD, Yoshihiko Yokoi, MD, Mikihiko Ito, MD, Yukio Obitsu, MD, and Mikio Ishikawa, MD, Tokyo, Japan We present two cases of severely calcified thoracoabdominal aortic aneurysm treated by means of endografting with a retrograde aortomesenteric bifurcated bypass graft reconstructing the celiac axis and superior mesenteric artery. To avoid spinal ischemia, we monitored evoked spinal cord potential and performed an occlusion test of the intercostal arteries using a retrievable stentgraft. No change in evoked spinal cord potential was noted, and no endoleaks or complications, including paraplegia, were observed. This procedure is a feasible and less-invasive treatment for severely calcified thoracoabdominal aortic aneurysms. (J Vasc Surg 2002;35:397-9.)
Prosthetic vascular graft repair of thoracoabdominal aortic aneurysms (TAAAs) continues to be associated with a high mortality rate (5%-17%1-4) and severe complications, including spinal cord ischemia (5%-20%1-4), despite such preventive methods as lumbar cerebrospinal fluid drainage,1 hypothermia,2,4 epidural cooling, distal aortic perfusion,1,3 and selective perfusion of the visceral arteries. The artery of Adamkiewicz, a major supplier of spinal perfusion, is known to originate from the T8 level to the L2 level with a high probability (about 80%5). The preservation of flow to the artery of Adamkiewicz is usually attempted in aortic replacement; however, its origin is so variable that no reliable method for flow preservation has been established. Additionally, severe calcification of the aortic wall is an obstacle to the reattachment of intercostal arteries. Although endograft repair is a less-invasive treatment for aortic disease,6-8 Mitchell reported that the rate of paraplegia in thoracic endografting was 3%.6 The inability to reattach the intercostal arteries is considered to be a serious drawback of endografting. To estimate spinal cord ischemia, we usually perform an occlusion test of the intercostal arteries with our retrievable stentgraft (“Retriever”) while monitoring evoked spinal cord potential (ESP9) before deciding to perform permanent endografting for From the Second Department of Surgery, Tokyo Medical University. Competition of interest: nil. Reprint requests: Yoshiko Watanabe, MD, The Second Department of Surgery, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160, Japan. Copyright © 2002 by The Society for Vascular Surgery and The American Association for Vascular Surgery. 0741-5214/2002/$35.00 + 0 24/4/119037 doi:10.1067/mva.2002.119037
the distal descending aortic disease.7 The Retriever can mimic the post-endografting state. No potential paraplegia has been detected in 60 patients undergoing this procedure. Thus, this occlusion test is considered to be a valuable method of monitoring the adequacy of spinal cord perfusion.7 In this report, two cases of severely calcified TAAA (Crawford type 1), in which successful endografting with simultaneous visceral artery bypass was achieved by using the occlusion-test, are described. CASE REPORTS Case 1. A 63-year-old man had a dilated aneurysm in the descending aorta (maximum diameter, 70 mm) extending from the distal thoracic aorta to the level of the superior mesenteric artery (SMA; Fig 1, A). Severe calcification of the descending thoracic aortic wall was detected. Because successful endografting requires landing zones of at least 2 cm at both ends for endografting, the stentgraft had to be deployed in the immediate suprarenal portion of the aorta. Reconstruction of the celiac axis (CA) and SMA was then planned as a combined procedure. Case 2. A 77-year-old woman had an aneurysm in the descending aorta (maximum diameter, 66 mm) extending from the proximal portion to the level of the SMA (Fig 1, B). Severe calcification of the aortic wall was also observed.
Surgical methods and results. The operations were performed after getting approval of the Ethics Committee of Tokyo Medical University and after informed consent was obtained. Permanent stentgrafts were constructed by using a selfexpanding Gianturco Z stent (Cook, Bloomington, Ind) covered with polyester graft fabric. The Retriever consisted of self-expanding stents connected with longitudinal stents. Each stent was collected in a bundle fixed to a pushing rod. The stent framework was lined with a polytetrafluoroethylene sheet.7 Because it is difficult to withdraw a Retriever that is very long, endografting was divided in two sections. 397
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398 Watanabe et al
A
B
A
Fig 1. Digital subtraction angiography and computed tomography scans revealing a TAAA classified as Crawford type 1 with severe calcification of the entire aortic wall. A, Case 1; B, case 2.
A
B
C
D
Fig 2. The endografting procedure. A, Access through the graft side limb anastomased on the main trunk of a bifurcated graft (case 2). B, First endografting. C, Occlusion test with the Retriever. D, Second endografting.
Mesenteric bypass grafting procedure. After an abdominal median incision was made, the elastic infrarenal aorta was used as the donor vessel of inflow for the retrograde visceral bypass graft (bifurcated woven graft; 12 × 6 mm for case 1, 16 × 8 mm for case 2). The CA and SMA were detached near their bases to prevent retrograde perfusion of the aneurysm sac and anastomosed in an end-to-end fashion to each graft limb. First endografting. A guidewire was introduced through the right brachial artery, in case 1 to the right femoral artery and in case 2 to the graft side limb that was anastomosed before the procedure to the main trunk of the bifurcated graft as an access conduit for endografting (Fig 2A). With the tug of wire technique,8 the delivery sheath was retracted from the femoral artery (case 1) or graft side branch (case 2). The first stentgraft was placed from the T3 to T6 level of the aorta (Fig 2B). Occlusion test of intercostal arteries. The Retriever was inserted into the target region of the second endo-
B
Fig 3. Digital subtraction angiography after endografting. Endografts were interplaced from the proximal descending aorta to just above the renal arteries. No endoleaks or collateral perfusion within the aneurysmal sac were observed. The CA and SMA were well enhanced through the bifurcated prosthetic graft.
grafting, also with the tug of wire method, and was expanded by withdrawing the sheath while the pushing rod was held at the same position7 (Fig 2C). No changes of ESP in amplitude or latency for 21 minutes were observed. The Retriever was then withdrawn. Second endografting. The second permanent stentgraft was placed from the T5 level to the immediate suprarenal portion of the aorta (Fig 2D). Neither endoleak nor collateral perfusion within the aneurysm sacs was observed with perioperative angiography (Fig 3). Results. Both patients were weaned from the respirator in the operating room. No complications occurred.
DISCUSSION Prosthetic graft replacement for TAAA is one of the most formidable and invasive procedures within the field of vascular surgery.1-4 Paraplegia is one of the most severe complications of this procedure. During TAAA replacement, aneurysm extent, cross-clamp duration, intraoperative and postoperative fluid shifts, and organ ischemia have been determined to affect the development of spinal ischemia. Aneurysm extension may result in the sacrifice of intercostal arteries,1 so intercostal arteries are often reconstructed. However, in cases in which there is a severely calcified aortic wall, reconstruction of branches would be technically difficult and entail a greater risk of embolism associated with the aortic clamp. Endografting can be used with visceral bypass grafting as a means of treating TAAA.10 This method can avoid thoracotomy, circulatory assist, and clamp of thoracic aorta and be safely performed only with a short crossclamp time downstream of the aorta. Postoperative lung disturbance can also be reduced. Furthermore, by accessing the area through the graft side limb, exposure of the femoral artery can be avoided without creating any problems in the delivery process. Although embolization and the inability to reperfuse intercostal arteries during endovascular repair remains a
JOURNAL OF VASCULAR SURGERY Volume 35, Number 2
significant concern, we believe that the probability of paraplegia in endografting may be lower than that in conventional replacement. If a critical portion of an intercostal artery or an entire intercostal artery is sacrificed, the spinal cord may escape ischemia when collateral perfusion is sufficiently abundant or when there is sufficient difference between interthecal pressure and arterial pressure reaching the anterior spinal artery. This is necessary for adequate flow to occur.1 Furthermore, intercostal arteries originating from the aneurysm sometimes become obstructed by vascular wall thrombosis before endografting. At this point, collateral circulation may be the main support of spinal flow. Earlier reports indicate that the length of the aorta excluded by the endograft and the interruption of lumbar collateral vessels resulting from earlier infrarenal aortic replacement may significantly impact the development of spinal ischemia.6 This suggests that it is important to estimate the adequacy of collateral spinal cord perfusion before endografting. We believe that permanent endografting should be carried out only for cases that have no remarkable change on ESP during the occlusion test. Endograft repair with visceral bypass grafting is a feasible and less-invasive treatment for TAAA and is not limited to use in severely calcified cases. We believe that the range of accepted indications for endografting, in combination with various other options, will be expanded in the future.
Watanabe et al
399
REFERENCES 1. Griepp RB, Ergin MA, Galla JD, Lansman S, Khan N, Quintana C, et al. Looking for the artery of Adamkiewicz: a quest to minimize paraplegia after operations for aneurysms of the descending thoracic and thoracoabdominal aorta. J Thorac Cardiovasc Surg 1996;112:1202-15. 2. Coselli JS. Thoracoabdominal aortic aneurysms: experience with 372 patients. J Card Surg 1994;9:638-47. 3. Schepens MA, Vermeulen FE, Morshuis WJ, Dossche KM, van Dongen EP, Ter Beek HT, et al. Impact of left heart bypass on the results of thoracoabdominal aortic aneurysm repair. Ann Thorac Surg 1999;67:1963-80. 4. Kouchoukos NT, Daily BB, Rokkas CK, Murphy SF, Bauer S, Abboud N. Hypothermic bypass and circulatory arrest for operations on the descending thoracic and thoracoabdominal aorta. Ann Thorac Surg 1995;60:67-77. 5. Kieffer E, Richard T, Chiras J, Godet G, Cormie E. Preoperative spinal cord arteriography in aneurysmal disease of the descending thoracic and thoracoabdominal aorta: preliminary results in 45 patients. Ann Vasc Surg 1989;3:34-46. 6. Mitchell RS, Miller DC, Dake MD, Semba CP, Moore KA, Sakai T. Thoracic aortic aneurysm repair with an endovascular stent graft: the “first generation.” Ann Thorac Surg 1999;67:1971-80. 7. Ishimaru S, Kawaguchi S, Koizumi, N, Obitsu Y, Ishikawa M. Preliminary report on prediction of spinal cord ischemia in endovascular stent graft repair of thoracic aortic aneurysm by retrievable stent graft. J Thorac Cardiovasc Surg 1998;115:811-8. 8. Kawaguchi S, Ishimaru S, Shimazaki T, Yokoi Y, Koizumi N, Obitsu Y, et al. Clinical results of endovascular stent graft repair for fifty cases of thoracic aortic aneurysms. Jpn J Thorac Cardiovasc Surg 1998;46:971-5. 9. Matsui Y, Goh K, Shiiya N, Murashita T, Miyama M, et al. Clinical application of evoked spinal cord potentials elicited by direct stimulation of the cord during temporary occlusion of the thoracic aorta. J Thorac Cardiovasc Surg 1994;107:1519-27. 10. Quinones-Baldrich WJ, Panetta TF, Vescera CL, Kashyap VS. Repair of type IV thoracoabdominal aneurysm with a combined endovascular and surgical approach. J Vasc Surg 1999;30:555-60.
Submitted Mar 5, 2001; accepted Jul 18, 2001.
Successful endografting with simultaneous visceral artery bypass grafting for severely calcified thoracoabdominal aortic aneurysm Yoshiko Watanabe, MD, Shin Ishimaru, MD, Satoshi Kawaguchi, MD, Taro Shimazaki, MD, Yoshihiko Yokoi, MD, Mikihiko Ito, MD, Yukio Obitsu, MD, and Mikio Ishikawa, MD, Tokyo, Japan We present two cases of severely calcified thoracoabdominal aortic aneurysm treated by means of endografting with a retrograde aortomesenteric bifurcated bypass graft reconstructing the celiac axis and superior mesenteric artery. To avoid spinal ischemia, we monitored evoked spinal cord potential and performed an occlusion test of the intercostal arteries using a retrievable stentgraft. No change in evoked spinal cord potential was noted, and no endoleaks or complications, including paraplegia, were observed. This procedure is a feasible and less-invasive treatment for severely calcified thoracoabdominal aortic aneurysms. (J Vasc Surg 2002;35:397-9.)
Prosthetic vascular graft repair of thoracoabdominal aortic aneurysms (TAAAs) continues to be associated with a high mortality rate (5%-17%1-4) and severe complications, including spinal cord ischemia (5%-20%1-4), despite such preventive methods as lumbar cerebrospinal fluid drainage,1 hypothermia,2,4 epidural cooling, distal aortic perfusion,1,3 and selective perfusion of the visceral arteries. The artery of Adamkiewicz, a major supplier of spinal perfusion, is known to originate from the T8 level to the L2 level with a high probability (about 80%5). The preservation of flow to the artery of Adamkiewicz is usually attempted in aortic replacement; however, its origin is so variable that no reliable method for flow preservation has been established. Additionally, severe calcification of the aortic wall is an obstacle to the reattachment of intercostal arteries. Although endograft repair is a less-invasive treatment for aortic disease,6-8 Mitchell reported that the rate of paraplegia in thoracic endografting was 3%.6 The inability to reattach the intercostal arteries is considered to be a serious drawback of endografting. To estimate spinal cord ischemia, we usually perform an occlusion test of the intercostal arteries with our retrievable stentgraft (“Retriever”) while monitoring evoked spinal cord potential (ESP9) before deciding to perform permanent endografting for From the Second Department of Surgery, Tokyo Medical University. Competition of interest: nil. Reprint requests: Yoshiko Watanabe, MD, The Second Department of Surgery, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160, Japan. Copyright © 2002 by The Society for Vascular Surgery and The American Association for Vascular Surgery. 0741-5214/2002/$35.00 + 0 24/4/119037 doi:10.1067/mva.2002.119037
the distal descending aortic disease.7 The Retriever can mimic the post-endografting state. No potential paraplegia has been detected in 60 patients undergoing this procedure. Thus, this occlusion test is considered to be a valuable method of monitoring the adequacy of spinal cord perfusion.7 In this report, two cases of severely calcified TAAA (Crawford type 1), in which successful endografting with simultaneous visceral artery bypass was achieved by using the occlusion-test, are described. CASE REPORTS Case 1. A 63-year-old man had a dilated aneurysm in the descending aorta (maximum diameter, 70 mm) extending from the distal thoracic aorta to the level of the superior mesenteric artery (SMA; Fig 1, A). Severe calcification of the descending thoracic aortic wall was detected. Because successful endografting requires landing zones of at least 2 cm at both ends for endografting, the stentgraft had to be deployed in the immediate suprarenal portion of the aorta. Reconstruction of the celiac axis (CA) and SMA was then planned as a combined procedure. Case 2. A 77-year-old woman had an aneurysm in the descending aorta (maximum diameter, 66 mm) extending from the proximal portion to the level of the SMA (Fig 1, B). Severe calcification of the aortic wall was also observed.
Surgical methods and results. The operations were performed after getting approval of the Ethics Committee of Tokyo Medical University and after informed consent was obtained. Permanent stentgrafts were constructed by using a selfexpanding Gianturco Z stent (Cook, Bloomington, Ind) covered with polyester graft fabric. The Retriever consisted of self-expanding stents connected with longitudinal stents. Each stent was collected in a bundle fixed to a pushing rod. The stent framework was lined with a polytetrafluoroethylene sheet.7 Because it is difficult to withdraw a Retriever that is very long, endografting was divided in two sections. 397
JOURNAL OF VASCULAR SURGERY February 2002
398 Watanabe et al
A
B
A
Fig 1. Digital subtraction angiography and computed tomography scans revealing a TAAA classified as Crawford type 1 with severe calcification of the entire aortic wall. A, Case 1; B, case 2.
A
B
C
D
Fig 2. The endografting procedure. A, Access through the graft side limb anastomased on the main trunk of a bifurcated graft (case 2). B, First endografting. C, Occlusion test with the Retriever. D, Second endografting.
Mesenteric bypass grafting procedure. After an abdominal median incision was made, the elastic infrarenal aorta was used as the donor vessel of inflow for the retrograde visceral bypass graft (bifurcated woven graft; 12 × 6 mm for case 1, 16 × 8 mm for case 2). The CA and SMA were detached near their bases to prevent retrograde perfusion of the aneurysm sac and anastomosed in an end-to-end fashion to each graft limb. First endografting. A guidewire was introduced through the right brachial artery, in case 1 to the right femoral artery and in case 2 to the graft side limb that was anastomosed before the procedure to the main trunk of the bifurcated graft as an access conduit for endografting (Fig 2A). With the tug of wire technique,8 the delivery sheath was retracted from the femoral artery (case 1) or graft side branch (case 2). The first stentgraft was placed from the T3 to T6 level of the aorta (Fig 2B). Occlusion test of intercostal arteries. The Retriever was inserted into the target region of the second endo-
B
Fig 3. Digital subtraction angiography after endografting. Endografts were interplaced from the proximal descending aorta to just above the renal arteries. No endoleaks or collateral perfusion within the aneurysmal sac were observed. The CA and SMA were well enhanced through the bifurcated prosthetic graft.
grafting, also with the tug of wire method, and was expanded by withdrawing the sheath while the pushing rod was held at the same position7 (Fig 2C). No changes of ESP in amplitude or latency for 21 minutes were observed. The Retriever was then withdrawn. Second endografting. The second permanent stentgraft was placed from the T5 level to the immediate suprarenal portion of the aorta (Fig 2D). Neither endoleak nor collateral perfusion within the aneurysm sacs was observed with perioperative angiography (Fig 3). Results. Both patients were weaned from the respirator in the operating room. No complications occurred.
DISCUSSION Prosthetic graft replacement for TAAA is one of the most formidable and invasive procedures within the field of vascular surgery.1-4 Paraplegia is one of the most severe complications of this procedure. During TAAA replacement, aneurysm extent, cross-clamp duration, intraoperative and postoperative fluid shifts, and organ ischemia have been determined to affect the development of spinal ischemia. Aneurysm extension may result in the sacrifice of intercostal arteries,1 so intercostal arteries are often reconstructed. However, in cases in which there is a severely calcified aortic wall, reconstruction of branches would be technically difficult and entail a greater risk of embolism associated with the aortic clamp. Endografting can be used with visceral bypass grafting as a means of treating TAAA.10 This method can avoid thoracotomy, circulatory assist, and clamp of thoracic aorta and be safely performed only with a short crossclamp time downstream of the aorta. Postoperative lung disturbance can also be reduced. Furthermore, by accessing the area through the graft side limb, exposure of the femoral artery can be avoided without creating any problems in the delivery process. Although embolization and the inability to reperfuse intercostal arteries during endovascular repair remains a
JOURNAL OF VASCULAR SURGERY Volume 35, Number 2
significant concern, we believe that the probability of paraplegia in endografting may be lower than that in conventional replacement. If a critical portion of an intercostal artery or an entire intercostal artery is sacrificed, the spinal cord may escape ischemia when collateral perfusion is sufficiently abundant or when there is sufficient difference between interthecal pressure and arterial pressure reaching the anterior spinal artery. This is necessary for adequate flow to occur.1 Furthermore, intercostal arteries originating from the aneurysm sometimes become obstructed by vascular wall thrombosis before endografting. At this point, collateral circulation may be the main support of spinal flow. Earlier reports indicate that the length of the aorta excluded by the endograft and the interruption of lumbar collateral vessels resulting from earlier infrarenal aortic replacement may significantly impact the development of spinal ischemia.6 This suggests that it is important to estimate the adequacy of collateral spinal cord perfusion before endografting. We believe that permanent endografting should be carried out only for cases that have no remarkable change on ESP during the occlusion test. Endograft repair with visceral bypass grafting is a feasible and less-invasive treatment for TAAA and is not limited to use in severely calcified cases. We believe that the range of accepted indications for endografting, in combination with various other options, will be expanded in the future.
Watanabe et al
399
REFERENCES 1. Griepp RB, Ergin MA, Galla JD, Lansman S, Khan N, Quintana C, et al. Looking for the artery of Adamkiewicz: a quest to minimize paraplegia after operations for aneurysms of the descending thoracic and thoracoabdominal aorta. J Thorac Cardiovasc Surg 1996;112:1202-15. 2. Coselli JS. Thoracoabdominal aortic aneurysms: experience with 372 patients. J Card Surg 1994;9:638-47. 3. Schepens MA, Vermeulen FE, Morshuis WJ, Dossche KM, van Dongen EP, Ter Beek HT, et al. Impact of left heart bypass on the results of thoracoabdominal aortic aneurysm repair. Ann Thorac Surg 1999;67:1963-80. 4. Kouchoukos NT, Daily BB, Rokkas CK, Murphy SF, Bauer S, Abboud N. Hypothermic bypass and circulatory arrest for operations on the descending thoracic and thoracoabdominal aorta. Ann Thorac Surg 1995;60:67-77. 5. Kieffer E, Richard T, Chiras J, Godet G, Cormie E. Preoperative spinal cord arteriography in aneurysmal disease of the descending thoracic and thoracoabdominal aorta: preliminary results in 45 patients. Ann Vasc Surg 1989;3:34-46. 6. Mitchell RS, Miller DC, Dake MD, Semba CP, Moore KA, Sakai T. Thoracic aortic aneurysm repair with an endovascular stent graft: the “first generation.” Ann Thorac Surg 1999;67:1971-80. 7. Ishimaru S, Kawaguchi S, Koizumi, N, Obitsu Y, Ishikawa M. Preliminary report on prediction of spinal cord ischemia in endovascular stent graft repair of thoracic aortic aneurysm by retrievable stent graft. J Thorac Cardiovasc Surg 1998;115:811-8. 8. Kawaguchi S, Ishimaru S, Shimazaki T, Yokoi Y, Koizumi N, Obitsu Y, et al. Clinical results of endovascular stent graft repair for fifty cases of thoracic aortic aneurysms. Jpn J Thorac Cardiovasc Surg 1998;46:971-5. 9. Matsui Y, Goh K, Shiiya N, Murashita T, Miyama M, et al. Clinical application of evoked spinal cord potentials elicited by direct stimulation of the cord during temporary occlusion of the thoracic aorta. J Thorac Cardiovasc Surg 1994;107:1519-27. 10. Quinones-Baldrich WJ, Panetta TF, Vescera CL, Kashyap VS. Repair of type IV thoracoabdominal aneurysm with a combined endovascular and surgical approach. J Vasc Surg 1999;30:555-60.
Submitted Mar 5, 2001; accepted Jul 18, 2001.