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Partial descending thoracic aortic replacement for chronic Type B dissection
HOW-TO-DO-IT
How-To-Do-It
Partial descending thoracic aortic replacement for chronic Type B dissection Benjamin M. Robinson, MPhil a , David Martin, MBBS b , Ramesh Velu, FRACS b and Sumit Yadav, FRACS a,∗ a
Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, QLD, Australia b Department of Vascular Surgery, The Townsville Hospital, Townsville, QLD, Australia
Repair of chronic Type B aortic dissection can be technically challenging. Here we describe a technique for the partial replacement of the descending thoracic aorta that minimises operative risk and avoids full replacement of the thoracoabdominal aorta. This approach can be considered when there is heterogeneous perfusion of abdominal viscera by the true and false lumens of the chronically dissected aorta. (Heart, Lung and Circulation 2012;21:740–742) © 2012 Published by Elsevier Inc on behalf of Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Keywords. Aortic dissection; Descending aortic replacement; Hypothermic circulatory arrest; Thoracic; Chronic Type B
Introduction
A
32 year-old woman presented with chronic, Stanford Type B dissection. Her acute event had occurred seven months prior to surgery, secondary to preeclampsia. The dissection began at the left subclavian artery origin, partially involving this vessel and extended to the terminal aorta without involving the iliac arteries. Fig. 1 demonstrates the degree of aneurysmal degeneration in the proximal descending thoracic aorta and the heterogeneous perfusion of the abdominal aortic branches by true and false lumen. The dissection flap is also well illustrated. There was significant effacement of the true lumen of the proximal descending aorta as seen in axial section (Fig. 2). This image corresponds with the distal extent of subsequent replacement. In the abdomen, the true aortic lumen supplied the celiac trunk, right renal artery and SMA. The left renal artery and IMA were supplied by the false lumen. Transthoracic echocardiography demonstrated a structurally normal aortic valve without stenosis or regurgitation. The transaortic sinus and ascending aorta were dilated at 3.7 cm and 3.1 cm respectively. The sinotubular junction (2.6 cm) and the aortic arch were normal. The patient had no other signs of Marfan syndrome, nor family history of aortopathy. ANA, anti-dsDNA, anti-ENA, ANCA and hepatitis screens were negative.
Received 22 October 2011; received in revised form 14 April 2012; accepted 25 April 2012; available online 31 May 2012 ∗
Corresponding author at: Cardiac Institute, 100 Angus Smith Drive, Douglas 4814, Australia. E-mail address: sumit [email protected] (S. Yadav).
Interval CT scans demonstrated progressive dilatation of the proximal descending aorta, with a transverse diameter in the axial plane increasing from 30 to 55 mm over six months. The distal descending thoracic aorta and the abdominal aorta remained relatively stable. Endoluminal treatment approaches were considered. Options include coverage of the primary entry tear or treating of the full extent of the affected aorta, using branches or fenestrations to supply vital abdominal branches. Limited stent grafting may expose the thoracic false lumen to continued perfusion and expansion [1,2]. While complicated endoluminal interventions for chronic thoraco-abdominal dissection risk organ malperfusion requiring further complex intervention. Either approach would have required a concurrent debranching procedure to ensure an adequate proximal landing zone. Given the patient’s youth, fitness and these technical considerations an open surgical approach was agreed.
Surgical Technique The patient was anaesthetised with a double lumen endotracheal tube and placed in the right lateral decubitius position, with the pelvis rotated to allow access to the left femoral vessels. External defibrillator pads were applied and the patient was monitored with transoesphageal echocardiography (TOE). A 5 cm incision was made in the line of the anterior border of the left sternocleidomastoid and the left common carotid artery was dissected out. Heparin was administered (300 mg/kg) and an 8 mm Propaten vascular graft (Gore, Flagstaff, AZ, USA) was anastamosed to the side of this vessel, which allowed arterial perfusion via a 20 Fr cannula (EOPA, Medtronic, Minneapolis,
© 2012 Published by Elsevier Inc on behalf of Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ).
1443-9506/04/$36.00 http://dx.doi.org/10.1016/j.hlc.2012.04.017
Robinson et al. Partial descending thoracic aortic replacement
741
Figure 2. Axial CT scan at the level of distal aortic graft anastamosis. An arrow indicates the false aortic lumen. The smaller true lumen lies medially.
Figure 1. Reconstructed coronal section of CT aortogram. The dissection flap can be seen extending to the terminal abdominal aorta. The proximal descending aorta progressively dilated following the initial dissection.
MN, USA). This graft was maintained at a length adequate for use as a common carotid to left subclavian bypass graft if required. Venous cannulation was undertaken via the left femoral vein (Biomedicus 23 Fr, Medtronic). Cannula position was confirmed by TOE. A left posterolateral thoracotomy was then performed through the fourth intercostal space and single lung ventilation commenced. The left ventricle was vented through the left inferior pulmonary vein (DLP 20 Fr, Medtronic) and cardiopulmonary bypass was established. The patient was cooled to 15 ◦ C and circulation was arrested. The proximal left common carotid was clamped and anterograde cerebral perfusion was maintained via this vessel. The aorta was then opened and the left subclavian was divided just distal to its origin. A 26 mm Gelweave aortic graft (Vascutek-Terumo, Inchinnan, Scotland) with an 8 mm side arm was anastamosed to the aortic arch distal to the left common carotid origin, after which full cardiopulmonary bypass flow was recommenced. With the graft clamped, the distal anastamosis was done at the level of the seventh thoracic vertebra after a 3 cm fenestration was made in the septum between the true and false aortic lumens (Fig. 3). In the completion of this step the smaller aortic true lumen was plicated proximal to the fenestration. The graft clamp was released to allow distal perfusion and placed on the sidearm, which was then anastamosed end-to-end with the left subclavian artery. It was possible
to complete this anastamosis in the chest. Carotid to subclavian bypass was not required. The patient was then rewarmed and cardiopulmonary bypass was weaned. Protamine was administered and Bioglue (CryoLife, Kennesaw, GA, USA) was used at the anastamosis sites. The graft to the left common carotid in the neck was then divided and closed as a patch over the arteriotomy. Two 28 Fr intercostal drains were placed to the left hemithorax, to the apex and base. The left lung was reventilated and the thoracotomy was closed in the usual fashion. Postoperative CT aortogram demonstrated good perfusion of the true and false aortic lumens distal to the graft. The patient was discharged on the eighth post-operative day, with no neurological, renal or gut sequelae.
Discussion Patients with acute non-complicated Type B dissection are traditionally managed conservatively. They remain at risk of complication due to aneurysmal degeneration of the false lumen. The diameter of the aneurysm is a key determinant of the probability of rupture [3]. Therefore close follow-up of chronic Type B dissection is mandatory. Size related criteria for repair of descending thoracic aortic aneurysms include rapid expansion of greater than 0.5 cm/year or a maximal diameter greater than 5.5 cm [4]. The patient in this case met both criteria, within six months of the acute event, despite optimal antihypertensive therapy and heart rate control. The evolution of management of Type B aortic dissections has seen a rise in the use of endografts. The potential advantages of this method include that it does not require thoracotomy, aortic cross clamp or cardiopulmonary bypass. Perioperative morbidity and hospital stay may be shorter. Not all patients are suitable to for
HOW-TO-DO-IT
Heart, Lung and Circulation 2012;21:740–742
742 HOW-TO-DO-IT
Robinson et al. Partial descending thoracic aortic replacement
Heart, Lung and Circulation 2012;21:740–742
restoration of left subclavian artery flow. Our distal anastamotic technique and large fenestration created between the two lumens of the residual native aorta allowed adequate perfusion of all abdominal viscera. It also allows reinforcement of a thin walled lumen by its incorporation with the septum in the anastomotic suture line. A potential shortcoming of this repair is that the false lumen of the residual thoracic and abdominal aorta remains necessarily patent. It is therefore at risk of further aneurysmal degeneration [6]. The patient will therefore be followed closely, initially with six-monthly CT scans. Importantly, the partial repair described here does not preclude future replacement of the remaining native aorta if required.
Acknowledgement We would like to thank Mr. Kieran Sturgeon CN, for his illustrative work.
References
Figure 3. Detail of anastamosis of distal graft to residual native thoracic aorta, drawn as cutaway to demonstrate fenestration in the septum between lumens and plication of the smaller true aortic lumen.
this approach. Contraindications to endovascular repair include the absence of a graft landing zone, landing zone dimension wider than available grafts and a lack of suitable vascular access sites, often due to atherosclerosis [4]. The operative risks of open thoracoabdominal aortic replacement are high. Svensson et al. [5] reported perioperative mortality of 8% in 1509 patients undergoing thoracoabdominal aortic operations over a 30-year period. Significant morbidity included paraplegia or paraparesis, renal failure and gastrointestinal complications. Here we present a technique that allowed open replacement of the expanding, at risk portion of the thoracic aorta, while avoiding the high degree of morbidity of associated with the replacement of the full thoracoabdominal aorta. We used hypothermic circulatory arrest and continuous antegrade cerebral perfusion to minimise the risk of neurological complication. Redundancies were incorporated into the operative strategy to allow two options for the
[1] Resch TA, Delle M, Falkenberg M, Ivancev K, Konrad P, Larzon T, et al. Remodeling of the thoracic aorta after stent grafting of type B dissection: a Swedish multicenter study. J Cardiovasc Surg (Torino) 2006;47:503–8. [2] Sayer D, Bratby M, Brooks M, Loftus I, Morgan R, Thompson M. Aortic morphology following endovascular repair of acute and chronic type B aortic dissection: implications for management. Eur J Vasc Endovasc Surg 2008;36:522–9. [3] Juvonen T, Ergin MA, Galla JD, Lansman SL, McCullough JN, Nguyen K, et al. Risk factors for rupture of chronic type B dissections. J Thorac Cardiovasc Surg 1999;117:776–86. [4] Hiratzka LF, Bakris GL, Beckman JA, Bersin RM, Carr VF, Casey Jr DE, et al. ACCF/AHA/AATS/ACR/ASA/SCA/ SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation 2010;121:e266–369. [5] Svensson LG, Crawford ES, Hess KR, Coselli JS, Safi HJ. Experience with 1509 patients undergoing thoracoabdominal aortic operations. J Vasc Surg 1993;17:357–68, discussion 68–70. [6] Onitsuka S, Akashi H, Tayama K, Okazaki T, Ishihara K, Hiromatsu S, et al. Long-term outcome and prognostic predictors of medically treated acute type B aortic dissections. Ann Thorac Surg 2004;78:1268–73.
How-To-Do-It
Partial descending thoracic aortic replacement for chronic Type B dissection Benjamin M. Robinson, MPhil a , David Martin, MBBS b , Ramesh Velu, FRACS b and Sumit Yadav, FRACS a,∗ a
Department of Cardiothoracic Surgery, The Townsville Hospital, Townsville, QLD, Australia b Department of Vascular Surgery, The Townsville Hospital, Townsville, QLD, Australia
Repair of chronic Type B aortic dissection can be technically challenging. Here we describe a technique for the partial replacement of the descending thoracic aorta that minimises operative risk and avoids full replacement of the thoracoabdominal aorta. This approach can be considered when there is heterogeneous perfusion of abdominal viscera by the true and false lumens of the chronically dissected aorta. (Heart, Lung and Circulation 2012;21:740–742) © 2012 Published by Elsevier Inc on behalf of Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Keywords. Aortic dissection; Descending aortic replacement; Hypothermic circulatory arrest; Thoracic; Chronic Type B
Introduction
A
32 year-old woman presented with chronic, Stanford Type B dissection. Her acute event had occurred seven months prior to surgery, secondary to preeclampsia. The dissection began at the left subclavian artery origin, partially involving this vessel and extended to the terminal aorta without involving the iliac arteries. Fig. 1 demonstrates the degree of aneurysmal degeneration in the proximal descending thoracic aorta and the heterogeneous perfusion of the abdominal aortic branches by true and false lumen. The dissection flap is also well illustrated. There was significant effacement of the true lumen of the proximal descending aorta as seen in axial section (Fig. 2). This image corresponds with the distal extent of subsequent replacement. In the abdomen, the true aortic lumen supplied the celiac trunk, right renal artery and SMA. The left renal artery and IMA were supplied by the false lumen. Transthoracic echocardiography demonstrated a structurally normal aortic valve without stenosis or regurgitation. The transaortic sinus and ascending aorta were dilated at 3.7 cm and 3.1 cm respectively. The sinotubular junction (2.6 cm) and the aortic arch were normal. The patient had no other signs of Marfan syndrome, nor family history of aortopathy. ANA, anti-dsDNA, anti-ENA, ANCA and hepatitis screens were negative.
Received 22 October 2011; received in revised form 14 April 2012; accepted 25 April 2012; available online 31 May 2012 ∗
Corresponding author at: Cardiac Institute, 100 Angus Smith Drive, Douglas 4814, Australia. E-mail address: sumit [email protected] (S. Yadav).
Interval CT scans demonstrated progressive dilatation of the proximal descending aorta, with a transverse diameter in the axial plane increasing from 30 to 55 mm over six months. The distal descending thoracic aorta and the abdominal aorta remained relatively stable. Endoluminal treatment approaches were considered. Options include coverage of the primary entry tear or treating of the full extent of the affected aorta, using branches or fenestrations to supply vital abdominal branches. Limited stent grafting may expose the thoracic false lumen to continued perfusion and expansion [1,2]. While complicated endoluminal interventions for chronic thoraco-abdominal dissection risk organ malperfusion requiring further complex intervention. Either approach would have required a concurrent debranching procedure to ensure an adequate proximal landing zone. Given the patient’s youth, fitness and these technical considerations an open surgical approach was agreed.
Surgical Technique The patient was anaesthetised with a double lumen endotracheal tube and placed in the right lateral decubitius position, with the pelvis rotated to allow access to the left femoral vessels. External defibrillator pads were applied and the patient was monitored with transoesphageal echocardiography (TOE). A 5 cm incision was made in the line of the anterior border of the left sternocleidomastoid and the left common carotid artery was dissected out. Heparin was administered (300 mg/kg) and an 8 mm Propaten vascular graft (Gore, Flagstaff, AZ, USA) was anastamosed to the side of this vessel, which allowed arterial perfusion via a 20 Fr cannula (EOPA, Medtronic, Minneapolis,
© 2012 Published by Elsevier Inc on behalf of Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ).
1443-9506/04/$36.00 http://dx.doi.org/10.1016/j.hlc.2012.04.017
Robinson et al. Partial descending thoracic aortic replacement
741
Figure 2. Axial CT scan at the level of distal aortic graft anastamosis. An arrow indicates the false aortic lumen. The smaller true lumen lies medially.
Figure 1. Reconstructed coronal section of CT aortogram. The dissection flap can be seen extending to the terminal abdominal aorta. The proximal descending aorta progressively dilated following the initial dissection.
MN, USA). This graft was maintained at a length adequate for use as a common carotid to left subclavian bypass graft if required. Venous cannulation was undertaken via the left femoral vein (Biomedicus 23 Fr, Medtronic). Cannula position was confirmed by TOE. A left posterolateral thoracotomy was then performed through the fourth intercostal space and single lung ventilation commenced. The left ventricle was vented through the left inferior pulmonary vein (DLP 20 Fr, Medtronic) and cardiopulmonary bypass was established. The patient was cooled to 15 ◦ C and circulation was arrested. The proximal left common carotid was clamped and anterograde cerebral perfusion was maintained via this vessel. The aorta was then opened and the left subclavian was divided just distal to its origin. A 26 mm Gelweave aortic graft (Vascutek-Terumo, Inchinnan, Scotland) with an 8 mm side arm was anastamosed to the aortic arch distal to the left common carotid origin, after which full cardiopulmonary bypass flow was recommenced. With the graft clamped, the distal anastamosis was done at the level of the seventh thoracic vertebra after a 3 cm fenestration was made in the septum between the true and false aortic lumens (Fig. 3). In the completion of this step the smaller aortic true lumen was plicated proximal to the fenestration. The graft clamp was released to allow distal perfusion and placed on the sidearm, which was then anastamosed end-to-end with the left subclavian artery. It was possible
to complete this anastamosis in the chest. Carotid to subclavian bypass was not required. The patient was then rewarmed and cardiopulmonary bypass was weaned. Protamine was administered and Bioglue (CryoLife, Kennesaw, GA, USA) was used at the anastamosis sites. The graft to the left common carotid in the neck was then divided and closed as a patch over the arteriotomy. Two 28 Fr intercostal drains were placed to the left hemithorax, to the apex and base. The left lung was reventilated and the thoracotomy was closed in the usual fashion. Postoperative CT aortogram demonstrated good perfusion of the true and false aortic lumens distal to the graft. The patient was discharged on the eighth post-operative day, with no neurological, renal or gut sequelae.
Discussion Patients with acute non-complicated Type B dissection are traditionally managed conservatively. They remain at risk of complication due to aneurysmal degeneration of the false lumen. The diameter of the aneurysm is a key determinant of the probability of rupture [3]. Therefore close follow-up of chronic Type B dissection is mandatory. Size related criteria for repair of descending thoracic aortic aneurysms include rapid expansion of greater than 0.5 cm/year or a maximal diameter greater than 5.5 cm [4]. The patient in this case met both criteria, within six months of the acute event, despite optimal antihypertensive therapy and heart rate control. The evolution of management of Type B aortic dissections has seen a rise in the use of endografts. The potential advantages of this method include that it does not require thoracotomy, aortic cross clamp or cardiopulmonary bypass. Perioperative morbidity and hospital stay may be shorter. Not all patients are suitable to for
HOW-TO-DO-IT
Heart, Lung and Circulation 2012;21:740–742
742 HOW-TO-DO-IT
Robinson et al. Partial descending thoracic aortic replacement
Heart, Lung and Circulation 2012;21:740–742
restoration of left subclavian artery flow. Our distal anastamotic technique and large fenestration created between the two lumens of the residual native aorta allowed adequate perfusion of all abdominal viscera. It also allows reinforcement of a thin walled lumen by its incorporation with the septum in the anastomotic suture line. A potential shortcoming of this repair is that the false lumen of the residual thoracic and abdominal aorta remains necessarily patent. It is therefore at risk of further aneurysmal degeneration [6]. The patient will therefore be followed closely, initially with six-monthly CT scans. Importantly, the partial repair described here does not preclude future replacement of the remaining native aorta if required.
Acknowledgement We would like to thank Mr. Kieran Sturgeon CN, for his illustrative work.
References
Figure 3. Detail of anastamosis of distal graft to residual native thoracic aorta, drawn as cutaway to demonstrate fenestration in the septum between lumens and plication of the smaller true aortic lumen.
this approach. Contraindications to endovascular repair include the absence of a graft landing zone, landing zone dimension wider than available grafts and a lack of suitable vascular access sites, often due to atherosclerosis [4]. The operative risks of open thoracoabdominal aortic replacement are high. Svensson et al. [5] reported perioperative mortality of 8% in 1509 patients undergoing thoracoabdominal aortic operations over a 30-year period. Significant morbidity included paraplegia or paraparesis, renal failure and gastrointestinal complications. Here we present a technique that allowed open replacement of the expanding, at risk portion of the thoracic aorta, while avoiding the high degree of morbidity of associated with the replacement of the full thoracoabdominal aorta. We used hypothermic circulatory arrest and continuous antegrade cerebral perfusion to minimise the risk of neurological complication. Redundancies were incorporated into the operative strategy to allow two options for the
[1] Resch TA, Delle M, Falkenberg M, Ivancev K, Konrad P, Larzon T, et al. Remodeling of the thoracic aorta after stent grafting of type B dissection: a Swedish multicenter study. J Cardiovasc Surg (Torino) 2006;47:503–8. [2] Sayer D, Bratby M, Brooks M, Loftus I, Morgan R, Thompson M. Aortic morphology following endovascular repair of acute and chronic type B aortic dissection: implications for management. Eur J Vasc Endovasc Surg 2008;36:522–9. [3] Juvonen T, Ergin MA, Galla JD, Lansman SL, McCullough JN, Nguyen K, et al. Risk factors for rupture of chronic type B dissections. J Thorac Cardiovasc Surg 1999;117:776–86. [4] Hiratzka LF, Bakris GL, Beckman JA, Bersin RM, Carr VF, Casey Jr DE, et al. ACCF/AHA/AATS/ACR/ASA/SCA/ SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation 2010;121:e266–369. [5] Svensson LG, Crawford ES, Hess KR, Coselli JS, Safi HJ. Experience with 1509 patients undergoing thoracoabdominal aortic operations. J Vasc Surg 1993;17:357–68, discussion 68–70. [6] Onitsuka S, Akashi H, Tayama K, Okazaki T, Ishihara K, Hiromatsu S, et al. Long-term outcome and prognostic predictors of medically treated acute type B aortic dissections. Ann Thorac Surg 2004;78:1268–73.