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A Complex Thoracoabdominal Aneurysm in a Loeys-Dietz Patient: An Open, Hybrid, Anatomic Repair

2010; Elsevier BV; Volume: 90; Issue: 6 Linguagem: Inglês

10.1016/j.athoracsur.2010.08.077

1552-6259

Eugénio Neri, Giulio Tommasino, Enrico Tucci, Antonio Benvenuti, Carmelo Ricci,

Aortic aneurysm repair treatments

We report the successful treatment of a life-threatening thoracoabdominal aneurysm in a young patient affected by type I Loeys-Dietz syndrome. To overcome anatomic and surgical difficulties, we used an original strategy and a specially designed surgical tool. The clinical and technical aspects of this approach are presented. We report the successful treatment of a life-threatening thoracoabdominal aneurysm in a young patient affected by type I Loeys-Dietz syndrome. To overcome anatomic and surgical difficulties, we used an original strategy and a specially designed surgical tool. The clinical and technical aspects of this approach are presented. Dr Neri discloses that he has a financial relationship with Siena Collared Grafts.Loeys-Dietz syndrome (LDS) is an autosomal-dominant disorder that is caused by mutations in the genes encoding transforming growth factor β receptor 1 or 2 and is characterized by vascular and skeletal manifestations. LDS is subdivided according to the presence (type I) or absence (type II) of craniofacial involvement. The natural history of LDS is marked, at an early age, by aggressive arterial aneurysms and a high incidence of aortic dissection or rupture at aortic diameters that ordinarily are not predictive of these events.A 25-year-old man with type I LDS [1Williams J.A. Loeys B.L. Nwakanma L.U. et al.Early surgical experience with Loeys-Dietz: a new syndrome of aggressive thoracic aortic aneurysm disease.Ann Thorac Surg. 2007; 83: S757-S763Abstract Full Text Full Text PDF PubMed Scopus (208) Google Scholar] was referred to our institution in March 2010 for a large aneurysm of the thoracoabdominal aorta measuring more than 80 mm in diameter (Fig 1). His medical history was complex, including the surgical closure of a patent ductus arteriosus at a young age.In 2005 he underwent a valve-sparing operation for an aortic root aneurysm, and in May 2009 he experienced an acute type B aortic dissection extending to both external iliac arteries. A computed tomography scan during the early (30-day) follow-up for the aortic dissection showed that the diameter of the proximal descending aorta had rapidly increased to 70 mm.In June 2009 he was scheduled for thoracic endovascular aneurysm repair, with the goal to promote thrombosis of the proximal false channel and to exclude the aneurysm. Two Zenith TX2 thoracic graft components (Cook Inc, Brisbane, Australia), each overlapping the other by 4 cm, were deployed, starting from the left subclavian artery to the distal one-third of the descending thoracic aorta. This procedure successfully excluded the proximal descending aortic aneurysm. The patient was admitted again 2 weeks after this procedure, this time for a diverticular perforation with subsequent laparoscopic colonic resection.A computed tomography scan in September 2009 indicated a further increased diameter of the false channel, and as such, a second endovascular procedure was planned to exclude the false channel above the level of the visceral arteries. This procedure entailed the placement of a 40-mm Zenith device distal to the previous grafts. This procedure was unsuccessful: the graft crossed the true channel and redirected the flow into the false channel; there was no malperfusion of the visceral arteries because of the multiple reentries in the abdominal aorta and at the level of the left common iliac artery. No further therapy was offered, and he was monitored for progression of the false channel size.A few days after discharge, he was readmitted as an emergency with acute abdominal pain resulting from gangrenous volvulus of the small intestine. This required a median laparotomy bowel resection and multiple reexplorations.The rapid progression of the aortic diameter had by then reached 80 mm at the level of the diaphragm, and so he was reevaluated for operative intervention. When we examined this patient for the first time, we were concerned that an operation might be problematic for two main reasons: the presence of multiple stent grafts into the descending aorta and severe mitral regurgitation. An untreated severe mitral regurgitation could represent a contraindication to an aortic operation. The surgical approach to the mitral valve was very complex because of the complete displacement of the heart into the left hemithorax caused by a severe pectus excavatum (Fig 1).We rejected a hybrid procedure involving visceral debranching, extraanatomic revascularization, and endovascular stent grafting of the thoracic aorta due to the multiple abdominal interventions that would be needed. Conventional treatment of the descending aorta was considered very high risk because it would have required the removal of the thoracic stent grafts, with the consequence that the proximal anastomosis would have to have been made at the distal arch level. Moreover, distal arch exposure was extremely complex because of his chest wall deformity, heart displacement, and previous operations. Meanwhile, the thoracic stent grafts effectively excluded the proximal aneurysm, so we sought a solution that would make use of the stent grafts already in place.For this patient, we designed and manufactured a special surgical tool (Fig 2 A, B) to crimp the distal end of the thoracic stent graft in vivo: the stent graft could be reopened inside a conventional surgical graft to perform an open hybrid anatomic repair.Fig 2This diagram illustrates the surgical tool designed to obtain the in vivo crimping of the thoracic stent graft already in place. The tool consists of (A) a 10-mm stainless steel tube and (B) a trumpet-shaped funnel (50-mm diameter) capable of being split and disengaged from the tube once the graft is loaded and crimped. The parts are kept together by a heavy silk suture. (C) The thoracic stent graft contained inside of the tube could be passed and released inside of a branched Siena collared graft, thus obtaining continuity between the surgical and the endovascular grafts.View Large Image Figure ViewerDownload (PPT)The patient, who had previously refused a traditional operation with an extensive aortic replacement, was informed about this alternative strategy, and consented to the operation. The Institutional Review Board gave its consent for the operation to take place under compassionate indication.Before the procedure was scheduled, the patient was treated in an authorized center with percutaneous edge-to-edge mitral repair using the MitraClip System (Evalve Inc, Menlo Park, CA), which effectively reduced the mitral regurgitation and enabled the next step of treatment.The operation on the thoracic aorta was performed with the patient in a right anterolateral decubitus position. A cerebrospinal fluid drainage system was put in place after the induction of anesthesia. Intraoperative transesophageal echocardiography was used to assess mitral valve competence and ventricular filling and to correctly guide the venous cannula into the right atrium. The aorta was exposed through a thoracoabdominal incision at the level of the eighth intercostal space, with a retroperitoneal approach to the abdominal segment.After full heparinization, the right atrium was cannulated through the left femoral vein (Cardiosmart Ltd, Fribourg, Switzerland). The left axillary artery was exposed under the lateral border of the pectoralis major and cannulated for arterial return; another cannula was inserted into the left femoral artery and connected to a second limb of the arterial line. Visceral perfusion was assured by a dedicated line with a 4-branched delivery system.Full moderate hypothermic (32°C) cardiopulmonary bypass was instituted, and the distal thoracic aorta containing the stent grafts was clamped; a distal clamp was placed at the aortoiliac bifurcation. The aorta was incised, the intimal flap was resected, and the visceral arteries were perfused selectively. Two very small pairs of intercostal arteries were ligated. The caudal end of the stent graft was identified, and the distal stent was captured using a heavy monofilament suture pulled into a tourniquet. This allowed the thoracic stent graft to be passed through our specialized surgical tool featuring a detachable funnel shape on its proximal end (Fig 2A). This tool recompacted the remaining 4 distal stents of the 40-mm thoracic stent graft.A 32-mm Siena collared graft (Vascutek Terumo, Renfrewshire, Scotland) with 4 branches was selected; the compacted end of the TSG was released inside the proximal end of the Siena graft (Fig 2B). Four stitches of 2-0 braided suture with pledgets were passed through both grafts to reinforce the connection. The collar of the Siena graft was trimmed to fit the size of the aortic aneurysm and anastomosed to its wall using a running 3-0 polypropylene suture. This was made to confine, inside the excluded aneurysm, the hybrid junction between the graft and the thoracic stent graft, thus avoiding external bleeding from stent graft oozing. The remaining operation was conducted in a conventional fashion using the 4 branches of the Siena graft to individually reimplant the visceral vessels. The distal anastomosis was performed at the level of the aortoiliac bifurcation.The patient's postoperative course was uneventful, and he was discharged on postoperative day 18. The predischarge CT angiography showed full aneurysm exclusion and good flow through all visceral vessels (Fig 3).Fig 3A postoperative computed tomography scan shows the hybrid repair of the thoracoabdominal aorta. The hybrid junction is confined inside the excluded aneurysm by suturing the graft collar to the aortic aneurysm (white arrow). No distortion or fracture of the metal structure of thoracic stent graft was observed after cross clamping.View Large Image Figure ViewerDownload (PPT)CommentComplex aortic lesions resulting from dissection or degenerative aneurysms are often difficult to manage and require patient-tailored strategies. The conventional open repair of thoracoabdominal aneurysms and dissections remains complex and demanding and is associated with significant morbidity and mortality. The introduction and development of stent graft technologies has expanded the surgical horizon, thus permitting new forms of treatment for challenging cases.Hybrid procedures involving visceral debranching are gaining an important role in the treatment of complex aortic lesions; however, complex situations such as those in our patient exist: for this reason, these types of procedures are mainly reserved for patients with severe comorbidities, including advanced age [2Younes H.K. Davies M.G. Bismuth J. et al.Hybrid thoracic endovascular aortic repair: pushing the envelope.J Vasc Surg. 2010; 51: 259-266Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar]. We share the concern about use of thoracic stent grafts in patients with genetic aortic aneurysm syndromes [3Nordon I.M. Hinchliffe R.J. Holt P.J. et al.Endovascular management of chronic aortic dissection in patients with Marfan syndrome.J Vasc Surg. 2009; 50: 987-991Abstract Full Text Full Text PDF PubMed Scopus (90) Google Scholar], although in this patient it could be justified by his severe comorbidities.The approach used in this particular case allowed us to offer an anatomic repair whilst limiting the extent of resection to the lower thoracoabdominal segment. This approach is reproducible and may represent a solution for patients with secondary evolution of aneurysm after thoracic endovascular aneurysm repair, especially in the case of chronic dissection; it is plausible that this will become a common problem in the near future.However, it seems reasonable to use this new hybrid anatomic approach on extensive lesions of the thoracoabdominal aorta, using thoracic stent grafts to treat the proximal thoracic aorta and completing the procedure in an open fashion, thus limiting the surgical replacement to the lower portion of the aorta. This staged approach might reduce the incidence of spinal cord injury [4Etz C.D. Zoli S. Mueller C.S. et al.Staged repair significantly reduces paraplegia rate after extensive thoracoabdominal aortic aneurysm repair.J Thorac Cardiovasc Surg. 2010; 139: 1464-1472Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar].Although we did not experience this problem, caution is required in presence of stainless steel stent grafts, which differently from nitinol stent grafts, might be deformed by cross clamping. The use of a soft-bite clamp and the possibility to institute total circulatory arrest to control the aorta are advisable. Dr Neri discloses that he has a financial relationship with Siena Collared Grafts. Dr Neri discloses that he has a financial relationship with Siena Collared Grafts. Dr Neri discloses that he has a financial relationship with Siena Collared Grafts. Loeys-Dietz syndrome (LDS) is an autosomal-dominant disorder that is caused by mutations in the genes encoding transforming growth factor β receptor 1 or 2 and is characterized by vascular and skeletal manifestations. LDS is subdivided according to the presence (type I) or absence (type II) of craniofacial involvement. The natural history of LDS is marked, at an early age, by aggressive arterial aneurysms and a high incidence of aortic dissection or rupture at aortic diameters that ordinarily are not predictive of these events. A 25-year-old man with type I LDS [1Williams J.A. Loeys B.L. Nwakanma L.U. et al.Early surgical experience with Loeys-Dietz: a new syndrome of aggressive thoracic aortic aneurysm disease.Ann Thorac Surg. 2007; 83: S757-S763Abstract Full Text Full Text PDF PubMed Scopus (208) Google Scholar] was referred to our institution in March 2010 for a large aneurysm of the thoracoabdominal aorta measuring more than 80 mm in diameter (Fig 1). His medical history was complex, including the surgical closure of a patent ductus arteriosus at a young age. In 2005 he underwent a valve-sparing operation for an aortic root aneurysm, and in May 2009 he experienced an acute type B aortic dissection extending to both external iliac arteries. A computed tomography scan during the early (30-day) follow-up for the aortic dissection showed that the diameter of the proximal descending aorta had rapidly increased to 70 mm. In June 2009 he was scheduled for thoracic endovascular aneurysm repair, with the goal to promote thrombosis of the proximal false channel and to exclude the aneurysm. Two Zenith TX2 thoracic graft components (Cook Inc, Brisbane, Australia), each overlapping the other by 4 cm, were deployed, starting from the left subclavian artery to the distal one-third of the descending thoracic aorta. This procedure successfully excluded the proximal descending aortic aneurysm. The patient was admitted again 2 weeks after this procedure, this time for a diverticular perforation with subsequent laparoscopic colonic resection. A computed tomography scan in September 2009 indicated a further increased diameter of the false channel, and as such, a second endovascular procedure was planned to exclude the false channel above the level of the visceral arteries. This procedure entailed the placement of a 40-mm Zenith device distal to the previous grafts. This procedure was unsuccessful: the graft crossed the true channel and redirected the flow into the false channel; there was no malperfusion of the visceral arteries because of the multiple reentries in the abdominal aorta and at the level of the left common iliac artery. No further therapy was offered, and he was monitored for progression of the false channel size. A few days after discharge, he was readmitted as an emergency with acute abdominal pain resulting from gangrenous volvulus of the small intestine. This required a median laparotomy bowel resection and multiple reexplorations. The rapid progression of the aortic diameter had by then reached 80 mm at the level of the diaphragm, and so he was reevaluated for operative intervention. When we examined this patient for the first time, we were concerned that an operation might be problematic for two main reasons: the presence of multiple stent grafts into the descending aorta and severe mitral regurgitation. An untreated severe mitral regurgitation could represent a contraindication to an aortic operation. The surgical approach to the mitral valve was very complex because of the complete displacement of the heart into the left hemithorax caused by a severe pectus excavatum (Fig 1). We rejected a hybrid procedure involving visceral debranching, extraanatomic revascularization, and endovascular stent grafting of the thoracic aorta due to the multiple abdominal interventions that would be needed. Conventional treatment of the descending aorta was considered very high risk because it would have required the removal of the thoracic stent grafts, with the consequence that the proximal anastomosis would have to have been made at the distal arch level. Moreover, distal arch exposure was extremely complex because of his chest wall deformity, heart displacement, and previous operations. Meanwhile, the thoracic stent grafts effectively excluded the proximal aneurysm, so we sought a solution that would make use of the stent grafts already in place. For this patient, we designed and manufactured a special surgical tool (Fig 2 A, B) to crimp the distal end of the thoracic stent graft in vivo: the stent graft could be reopened inside a conventional surgical graft to perform an open hybrid anatomic repair. The patient, who had previously refused a traditional operation with an extensive aortic replacement, was informed about this alternative strategy, and consented to the operation. The Institutional Review Board gave its consent for the operation to take place under compassionate indication. Before the procedure was scheduled, the patient was treated in an authorized center with percutaneous edge-to-edge mitral repair using the MitraClip System (Evalve Inc, Menlo Park, CA), which effectively reduced the mitral regurgitation and enabled the next step of treatment. The operation on the thoracic aorta was performed with the patient in a right anterolateral decubitus position. A cerebrospinal fluid drainage system was put in place after the induction of anesthesia. Intraoperative transesophageal echocardiography was used to assess mitral valve competence and ventricular filling and to correctly guide the venous cannula into the right atrium. The aorta was exposed through a thoracoabdominal incision at the level of the eighth intercostal space, with a retroperitoneal approach to the abdominal segment. After full heparinization, the right atrium was cannulated through the left femoral vein (Cardiosmart Ltd, Fribourg, Switzerland). The left axillary artery was exposed under the lateral border of the pectoralis major and cannulated for arterial return; another cannula was inserted into the left femoral artery and connected to a second limb of the arterial line. Visceral perfusion was assured by a dedicated line with a 4-branched delivery system. Full moderate hypothermic (32°C) cardiopulmonary bypass was instituted, and the distal thoracic aorta containing the stent grafts was clamped; a distal clamp was placed at the aortoiliac bifurcation. The aorta was incised, the intimal flap was resected, and the visceral arteries were perfused selectively. Two very small pairs of intercostal arteries were ligated. The caudal end of the stent graft was identified, and the distal stent was captured using a heavy monofilament suture pulled into a tourniquet. This allowed the thoracic stent graft to be passed through our specialized surgical tool featuring a detachable funnel shape on its proximal end (Fig 2A). This tool recompacted the remaining 4 distal stents of the 40-mm thoracic stent graft. A 32-mm Siena collared graft (Vascutek Terumo, Renfrewshire, Scotland) with 4 branches was selected; the compacted end of the TSG was released inside the proximal end of the Siena graft (Fig 2B). Four stitches of 2-0 braided suture with pledgets were passed through both grafts to reinforce the connection. The collar of the Siena graft was trimmed to fit the size of the aortic aneurysm and anastomosed to its wall using a running 3-0 polypropylene suture. This was made to confine, inside the excluded aneurysm, the hybrid junction between the graft and the thoracic stent graft, thus avoiding external bleeding from stent graft oozing. The remaining operation was conducted in a conventional fashion using the 4 branches of the Siena graft to individually reimplant the visceral vessels. The distal anastomosis was performed at the level of the aortoiliac bifurcation. The patient's postoperative course was uneventful, and he was discharged on postoperative day 18. The predischarge CT angiography showed full aneurysm exclusion and good flow through all visceral vessels (Fig 3). CommentComplex aortic lesions resulting from dissection or degenerative aneurysms are often difficult to manage and require patient-tailored strategies. The conventional open repair of thoracoabdominal aneurysms and dissections remains complex and demanding and is associated with significant morbidity and mortality. The introduction and development of stent graft technologies has expanded the surgical horizon, thus permitting new forms of treatment for challenging cases.Hybrid procedures involving visceral debranching are gaining an important role in the treatment of complex aortic lesions; however, complex situations such as those in our patient exist: for this reason, these types of procedures are mainly reserved for patients with severe comorbidities, including advanced age [2Younes H.K. Davies M.G. Bismuth J. et al.Hybrid thoracic endovascular aortic repair: pushing the envelope.J Vasc Surg. 2010; 51: 259-266Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar]. We share the concern about use of thoracic stent grafts in patients with genetic aortic aneurysm syndromes [3Nordon I.M. Hinchliffe R.J. Holt P.J. et al.Endovascular management of chronic aortic dissection in patients with Marfan syndrome.J Vasc Surg. 2009; 50: 987-991Abstract Full Text Full Text PDF PubMed Scopus (90) Google Scholar], although in this patient it could be justified by his severe comorbidities.The approach used in this particular case allowed us to offer an anatomic repair whilst limiting the extent of resection to the lower thoracoabdominal segment. This approach is reproducible and may represent a solution for patients with secondary evolution of aneurysm after thoracic endovascular aneurysm repair, especially in the case of chronic dissection; it is plausible that this will become a common problem in the near future.However, it seems reasonable to use this new hybrid anatomic approach on extensive lesions of the thoracoabdominal aorta, using thoracic stent grafts to treat the proximal thoracic aorta and completing the procedure in an open fashion, thus limiting the surgical replacement to the lower portion of the aorta. This staged approach might reduce the incidence of spinal cord injury [4Etz C.D. Zoli S. Mueller C.S. et al.Staged repair significantly reduces paraplegia rate after extensive thoracoabdominal aortic aneurysm repair.J Thorac Cardiovasc Surg. 2010; 139: 1464-1472Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar].Although we did not experience this problem, caution is required in presence of stainless steel stent grafts, which differently from nitinol stent grafts, might be deformed by cross clamping. The use of a soft-bite clamp and the possibility to institute total circulatory arrest to control the aorta are advisable. Complex aortic lesions resulting from dissection or degenerative aneurysms are often difficult to manage and require patient-tailored strategies. The conventional open repair of thoracoabdominal aneurysms and dissections remains complex and demanding and is associated with significant morbidity and mortality. The introduction and development of stent graft technologies has expanded the surgical horizon, thus permitting new forms of treatment for challenging cases. Hybrid procedures involving visceral debranching are gaining an important role in the treatment of complex aortic lesions; however, complex situations such as those in our patient exist: for this reason, these types of procedures are mainly reserved for patients with severe comorbidities, including advanced age [2Younes H.K. Davies M.G. Bismuth J. et al.Hybrid thoracic endovascular aortic repair: pushing the envelope.J Vasc Surg. 2010; 51: 259-266Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar]. We share the concern about use of thoracic stent grafts in patients with genetic aortic aneurysm syndromes [3Nordon I.M. Hinchliffe R.J. Holt P.J. et al.Endovascular management of chronic aortic dissection in patients with Marfan syndrome.J Vasc Surg. 2009; 50: 987-991Abstract Full Text Full Text PDF PubMed Scopus (90) Google Scholar], although in this patient it could be justified by his severe comorbidities. The approach used in this particular case allowed us to offer an anatomic repair whilst limiting the extent of resection to the lower thoracoabdominal segment. This approach is reproducible and may represent a solution for patients with secondary evolution of aneurysm after thoracic endovascular aneurysm repair, especially in the case of chronic dissection; it is plausible that this will become a common problem in the near future. However, it seems reasonable to use this new hybrid anatomic approach on extensive lesions of the thoracoabdominal aorta, using thoracic stent grafts to treat the proximal thoracic aorta and completing the procedure in an open fashion, thus limiting the surgical replacement to the lower portion of the aorta. This staged approach might reduce the incidence of spinal cord injury [4Etz C.D. Zoli S. Mueller C.S. et al.Staged repair significantly reduces paraplegia rate after extensive thoracoabdominal aortic aneurysm repair.J Thorac Cardiovasc Surg. 2010; 139: 1464-1472Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar]. Although we did not experience this problem, caution is required in presence of stainless steel stent grafts, which differently from nitinol stent grafts, might be deformed by cross clamping. The use of a soft-bite clamp and the possibility to institute total circulatory arrest to control the aorta are advisable. A special word of gratitude goes to Massimiliano Grassini, who manufactured with mastery the surgical tool: drawings are freely available upon request under the principle of “open design.” Special thanks to Jonathon Hargreaves, Donna Male, and Jamie Shields from Vascutek Terumo for manuscript editing and illustrations.