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Aortic arch aneurysms; Surgical experience A Bhan, M.Ch., M Hote, M.Ch., R Sharma, M.Ch., P Saxena, M.D., S Sharma, M.D., P Venugopal, M.Ch. Cardiothaoracic Centre, All India Institute of Medical Sciences, New Delhi Abstract Background: Several recent modifications in technical, operative and perfusion techniques have enabled good operative results and final outcome for patients with aneurysms of the aortic arch. Although surgical procedures for this disease still remain a formidable challenge, availability of improved prosthetic grafts, myocardial protection techniques, brain protection protocols and better blood bank facilities ensure minimal postoperative morbidity and mortality. Methods: Records of 28 patients operated between January 1994 and January 2001 for aneurysms of the aortic arch were analysed. The study group includes patients with isolated aortic arch aneurysms or with concomitant involvement of the ascending and/or descending thoracic aorta. There were 22 males and 6 females, with an age range of 9-78 years. The mean age at operation was 45.5 years. Etiology included myxomatous degeneration (Marfan’s) in 10; myxomatous degeneration (NonMarfan’s) in 11; atherosclerosis in 6 and traumatic in 1 patient. Graft replacement of the transverse aortic arch with reimplantation of arch vessels was done for 6 patients; Bentall’s procedure with hemiarch replacement for 3 patients; Bentall’s procedure with arch replacement and vessel reimplantation for 4 patients; supracoronary replacement of the ascending aorta plus hemiarch repair in 2 patients; graft replacement of the distal arch alone in 11 patients and ascending, transverse and descending thoracic aorta repair using the elephant trunk technique in 2 patients. Results: Early hospital mortality was seen in 2 patients with 1 late death. Postoperative complications seen were hemorrhage requiring reoperation in 3 patients, pulmonary insufficiency in 1 patient, renal dysfunction in 1 patient, neurological morbidity in 2 patients and wound sepsis in 2 patients. Mean postoperative hospital stay was 11.4 days. Followup to the present date was completed for all survivors the range being 2-72 months (mean 29.2 months). Majority of the patients reported significant improvement in their symptoms. Conclusion: With sufficient technical skill and precautions, operative treatment for aneurysms of the aortic arch can be carried out with acceptable mortality and morbidity rates. (Ind J Thorac Cardiovasc Surg, 2002; 18: 154–159) Key words: Arch aneurysms, Retrograde cerebral perfusion, Deep hypothermic circulatory arrest.
Introduction Pioneering efforts by Cooley, DeBakey, Bahnson and Spencer in the early 1950’s1,2 saw inception of surgical treatment of aneurysms of the transverse aortic arch. However it was not until recently that these operations could be carried out with low morbidity and mortality. Several multidisciplinary advances in the 1980’s made
Address for correspondence: Anil Bhan Additional Professor Department of Cardiothoracic and Vascular Surgery All India Institute of Medical Sciences Ansari Nagar, New Delhi 110029, INDIA Tel. : 91-11-6561123 Ext. 4835, 4843 Fax: 91-11-6862663 E-mail :
[email protected] ©IJTCVS 097091341841202/018
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the current excellent results possible. These included widespread use of deep hypothermia and circulatory arrest, open distal anastomosis technique, reliable methods of cerebral protection, availability of superior prosthetic grafts that enable hemorrhage free, durable replacement of the diseased aorta. The present report is an overview of our 7 year experience with aneurysms involving the aortic arch. Methods Between January 1994 and January 2001, 28 patients (22 males and 6 females) underwent surgery for treatment of aortic arch aneurysms at the All India Institute of Medical Sciences, New Delhi. The mean age of these patients was 45.5 years (range 9-78 years); the mean size of the aneurysm being 7.15 centimetres.
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The anatomical types of aneurysms seen in our series were [Table 1]:- saccular aneurysm involving whole of the transverse aortic arch (Cooley’s type A) in 6 patients (21.4%), saccular aneurysm of the distal aortic arch alone in 11 patients (39.3%), fusiform aneurysm involving ascending aorta and the transverse aortic arch (Cooley’s type B) in 7 patients (25%), fusiform aneurysm of ascending aorta, transverse arch and extending to the proximal descending thoracic aorta (Cooley’s type C) in 2 patients (7.1%) and extensive involvement of whole of the thoracic aorta (Cooley’s type D) in 2 patients (7.1 %) (See Figure). This method of classification is based on the segment of thoracic aorta involved.9 Majority of the patients were in the age group of 5060 years (14 patients, 50%) 10 patients (35.7%) were less than 40 years old. Our youngest patient was 9 years old; the oldest being 78 years of age. The etiology of aneurysms as determined by histopathological studies and the clinical findings was predominantly myxomatous degeneration (Marfan’s or NonMarfan’s) in 21 patients (71.4%), atherosclerotic degeneration in 6 patients (21.4%) and post-traumatic in 1 patient (3.6%) [Table 2]. Only mild or occasional symptoms attributed to the aneurysm were noted in 12 patients (42.9%), 5 patients (17.6%) had symptoms of airway compression and/or hoarseness of voice. Pain was the mode of presentation in 5 patients (17.6%) and 6 were asymptomatic (21.4%) with incidental diagnoses. However on examination 18 patients (64.3%) were found to be in NYHA class III
Table 1. Preoperative data for 28 patients undergoing surgical treatment for aortic arch aneurysms. Patient Characteristics
No. of Patients
Sex Male Female
22 06
Extent of Aneurysm Cooley’s Type A Type B Type C Type D Distal arch
06 07 02 02 11
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In patients with Cooley’s type A extensive aneurysm of the aortic arch the standard median sternotomy approach is used. Cardiopulmonary bypass is instituted using memberane oxygenators, with a femoral arterial cannula and the venous cannulae being placed in the right atrium. All the patients underwent operations under deep hypothermia and circulatory arrest. F or all these patients retrograde cerebral perfusion is used as Table 3. Preoperative symptoms Symptoms
No. of patients
Asymptomatic Mild Symptoms Airway compression (Dyspnoea) Hoarseness of Voice Back pain Pre-op NYHA class III
6 12 3 5 5 18
Table 4. Associated risk factors Risk Factors
No. of patients
Diabetes Mellitus Hypertention Renal Dysfunction COPD Angina Emergency/Semiurgent Surgery
Operative Procedure
No. of patients
Myxomatous Degeneration (Marfan’s) Myxomatous Degeneration (Non Marfan’s) Atherosclerotic Traumatic
Operative technique
6 8 2 2 2 5
Table 5. Operative procedures performed
Table 2. Etiology of aneurysms Etiology
[Table 3 ]. Important risk factors noted are mentioned in table 4. One patient was operated as an emergency case. He had acute deterioration of symptoms because of left bronchial compression and acute respiratory insufficiency. Others underwent elective or semiemergency surgery. Depending on the type of aneurysm, appropriate reparative surgery was performed [Table 5]. 2 patients had associated coronary artery disease and underwent concomitant coronary artery bypass procedure.
10 11 06 01
Aortic arch replacement + arch vessel reimplantation Bentall Procedure + hemiarch Repair Bentall procedure + arch replacement Supracoronary ascending aorta replacement + hemiarch reapir Distal aortic arch replacement Total replacement of – ascending, transverse & descending thoracic aorta (Elephant trunk technique)
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No. of patients 6 3 4 2 11
2
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an adjunct to ensure adequate cerebral perfusion. Methyl prednisolone is added to the pump and ice packs are applied to the head for topical cooling. 20 mL/kg of crystalloid cardioplegic solution is instilled in antegrade or retrograde manner. The patient is cooled to 18 degrees Celsius, aneurysm sac is incised longitudinally, underlying contents (thrombi etc.) are evacuated. Using a Hemashield double velour prosthetic graft, the distal anastomosis is performed first using a posterior buttressing layer of teflon felt strip, with continuous running 3-0 polypropelene suture. The posterior suture line is reinforced with 4 or 5 interrupted pledgetted hemostatic sutures. The arch vessels are reimplanted on the superior aspect of the prosthetic graft using continuous running 4-0 prolene suture. The graft is clamped and circulation reestablished from the femoral arterial cannula. All the suture lines made are tested for any 1eakages and repaired accordingly. Subsequently the proximal anastomosis made to the ascending aorta as the patient is being rewarmed. Air is completely evacuated from the aorta, graft and the arch vessels. For patients with distal arch aneurysms a posterolateral thoracotomy approach was used. 9 of these patients were done under deep hypothermic circulatory arrest and 2 patients with left heart bypass technique. For deep hypothermic circulatory arrest cannulation was done in the femoral artery and femoral vein in 7 patients. In last 2 patients we have used a long venous Carpentier cannula (Medtronic DLP Carpentier Bicaval femoral cannula cat. No. 58729) for the venous return. The mean duration of total circulatory arrest in our series of patients was 48 +/- 6.4 minutes (range 34-66 minutes). For the left heart bypass the inflow cannula was put into the left atrial body and the distal cannula into the normal segment of descending thoracic aorta. The clamp was put on the arch between the 1eft common carotid and the left subclavian artery. One important anaesthetic consideration here was the use of double lumen endotracheal tube in all these patients for elective single lung ventilation. Retrograde cerebral perfusion (RCP) is technically difficult in this subgroup of patients. Only one patient who had left superior venacava associated with distal arch aneurysm could be given retrograde cerebral perfusion. The repair involves incising into the aneurysmal sac, evacuation of the contents inside and repair of the defect using a prosthetic woven dacron patch material. The vital structures are taken care of. In all the distal arch aneurysm patients we have used the aneurysm sac for wrap up. Patients with Cooley’s type B aneurysms have involvement of the ascending aorta with/without
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involvement of the aortic sinuses (and thereby of the coronary arteries) with variable extension into the transverse arch. Under deep hypothermic circulatory arrest and retrograde cerebral perfusion support, the entire aortic root and ascending aorta is replaced using a composite graft (St. Jude Medical aortic valved conduit). Simultaneously the coronary arteries are reimplanted into the prosthetic graft (the modified Bentall procedure).3,4 The coronary arteries have been dissected beforehand for a distance of I -1.5 centimetres on the epicardium and they are harvested at their origin from the ascending aorta thus preparing the coronary buttons. These buttons are sutured to the graft using continuous running 5-0 polypropelene suture, with care to make a tension-free anastomosis. The distal anastomosis is then done using a tapered end of the tube graft to the inferior surface of the transverse arch. In 2 patients, the supracoronary segment of aorta was replaced with extension into the arch (hemiarch procedure). For Cooley’s type C aneurysms the same standard steps are used for surgical approach and cardiopulmonary bypass. For the ascending aorta, the modified Bentall or the Wheat procedure is performed. For management of the arch part of aneurysm, the distal anastomosis is performed first. The arch vessels are then anastomosed on the superior aspect of the graft. A third end-to-end anastomosis is then done to unite the grafts placed for the ascending aorta and the arch. 2 patients in our series had type D aneurysms that involved ascending, transverse and descending thoracic aorta extending into the abdominal aorta. These extensive lesions were dealt with by a staged sternotomy and left thoracotomy approach. With the median sternotomy incision, we replace the ascending, transverse and the proximal descending thoracic aorta. The repair is done using the elephant trunk technique5 in which 5-6 centimetres of the distal end of prosthetic tube graft is left “hanging” into the proximal descending thoracic- aorta. This part of the graft is used in the second stage sugery for replacement of the descending thoracic and abdominal aorta using the left thoracoabdominal approach. Results Operative mortality : Early hospital mortality was seen in 2 patients (7.1%). One patient with a large distal arch aneurysm had an acute avulsion of the graft from the calcified segment of aorta in the early postoperative period. As a result, he had acute severe hemorrhage for which he was immediately reexplored but died of
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Fig. 1. Cooley’s classification of aortic aneurysms depending on the area of involvement
massive bleeding. Another patient had a 12cm diameter distal arch aneurysm with localised dissection rupturing into the airway preoperatively. He died because of uncontrolled hemorrhage from the airway and failure to maintain adequate ventilation. There was 1 late death seen in a patient 4 years after surgery who died of acute decompensation of heart secondary to cor pulmonale. He was a known case of chronic obstructive airway disease. Morbidity : 3 patients (10.7%) underwent reoperation for bleeding.1 patient with chronic obstructive pulmonary disease developed postoperative pulmonary insufficiency and could be weaned off the ventilator only after tracheostomy on 7th day of surgery. One 72 year old patient developed right sided hemiparesis in the early postoperative period which recovered gradually over the next 3 weeks. This patient had a saccular aneurysm mainly on the under surface of the aorta with multiple clots in the sac. He had hoarseness of voice preoperatively which has not recovered. Another patient developed hoarseness of voice in the postoperative period which improved significantly after injection of teflon paste.1 patient with preoperative renal insufficiency (serum creatinine 2.4 mg %) developed acute renal shutdown and recovered with dialysis after 72 hours. Septic wound complications were seen in 2 patients, necessitating their prolonged hospital stay. No surviving patient had myocardial infarction. The postoperative period was uneventful for 19 patients (67.9%). Average post operative stay on ventilator was for 32 hours [Table 6]. Follow up : Of the 26 survivors, all have had complete scheduled followup (mean followup duration -29.2 months) uptill the date of the present study (but for 1 late death). We request patient visits at 1 month, 3 months, 6 months and subsequently every 12 months. 4 of 5 patients who had preoperative hoarseness of voice
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reported complete recovery. All 5 patients who had severe boring pain noted complete absence of the same 3 months after surgery. 16 out of 18 patients who were in class III preoperatively had functional class improvement by l or 2 grades, all these patients currently being in class I or II. In 2 patients no improvement in functional class was seen. No patient has reported any cardiovascular or cerebrovascular event. Prosthetic valve function: No patient has any reported prosthetic valve dysfunction. They are being maintained on routine anticoagulation to keep the prothrombin time between 1.5-2.5 times normal. Followup studies : In patients who have undergone Bentall procedure with arch/hemiarch replacement, routine serial followup echocardiographic examinations reveal preservation of the left ventricular function and end-diastolic volume. 3 patients were studied postoperatively with CT scan and/or MRI. 2 of them showed no surgery related complications at any of the anastomotic sites. 1 patient operated for Bentall procedure and arch replacement shows development of descending thoracic aorta aneurysm and awaits surgery. Discussion Aortic arch surgery marks an end to the challenge of cardiac surgery. Natural history of large ascending aortic and arch aneurysms6 is sufficiently dismal so as to warrant operative treatment in almost all patients. Good results have been obtained for extensive operations for aortic arch aneurysms in the last decade. Factors that make this possible include improved myocardial and neurological protection, availability of better prosthetic graft materials, better blood bank facilities and improved surgical skill and experience. Hypothermic circulatory arrest technique popularised in 1975 by Griepp and colleagues enables a dry operative field with excellent exposure. This facilitates a good technical repair of the aortic Table 6. Post-operative complications and outcome. Events
No. of patients
Early Post-operative deaths Late follow up death NYHA functional class improvement (class III -> I/II) Post-operative hoarseness of voice Neurologic incidents (right hemiparesis) Re-exploration (Bleeding) Renal dysfuntion Prolonged ventilatory support (pulmonary insufficiency)
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2 1 16 (of 18 patients) 1 3 1 1 1 (7 days)
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aneurysms. In addition, hypothermia reduces metabolic requirement of all vital organs to minimal levels, enabling tolerance of total circulatory arrest for the requisite period of time. It provides adequate cerebral protection if the arrest period is kept less than 60 minutes.7 However some disadvantages accompany its use, including necessity of prolonged bypass times with alteration in blood elements causing troublesome hemorrhagic complications. Neurologic protection is ensured by use of retrograde cerebral perfusion. This technique provides oxygenated blood to the brain during times of total circulatory arrest and flushes out air and debris from the arch vessels. Several series have documented reduced incidence of temporary and permanent neurologic sequelae. Our experience with the use of this technique is described in detail elsewhere8. Blood conservation techniques assume importance today to avoid the spreading menace of Hepatitis and HIV viruses; and the risk of disseminated intravascular coagulation following massive transfusion. Use of autologous blood, cell saving devices, blood products and hemostatic agents in the pump (aprotinin and eaminocaproic acid) have been useful in minimising the need for blood transfusions. Availability of collagen impregnated grafts (Hemashield double velour grafts) reduces transgraft blood loss. In addition there is reduced occurance of long term complications related to the anastomotic suture lines. Several new surgical techniques reduce early and late postoperative complications. Use of the modified Bentall operation (button technique) avoiding creation of a Cabrol fistula minimises false aneurysm formation at the anastomotic site. There should be no tension or kinking at the coronary button suture line. Posterior teflon felt buttressing of suture line and reinforcement with interrupted pledgetted sutures minimises bleeding. Exclusion techniques for graft anastomosis avoids kinking of the graft, enables proper inspection of bleeding suture lines and reduces the incidence of pseudoaneurysm formation and dissection in the long term. Complete tubular replacement of whole of the diseased aorta is accepted to be a better anatomical corrective procedure. Patch aortoplasty should be limited to small saccular aneurysm involving only a part of the aortic wall circumference. For aneurysms involving the descending thoracic aorta, use of elephant trunk procedure enables early second stage surgery. Through a posterolateral thoracotomy approach, minimal dissection is needed at the previous anastomotic site to reach to the distal
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end of the prosthetic graft. Regular followup of the patient is essential. This is brought out by the frequent association seen between ascending and/or aortic arch aneurysm with aneurysmal disease of the distal thoracic aorta. We have achieved a 30 day operative mortality of 7.1%, which favours favourably with other series [Table 7]. Galloway, Colvin and Spencer reported mortality of 17.9 % between 1978-1982 and 12.3% between 1983-1988 in their series of 165 patients. Cooley et al compared 2 methods of hypothermic circulatory arrest and reported a mortality of 50 % in patients undergoing operations under deep hypothermic circulatory arrest (18 degrees Celsius).9,10 This high rate was attributed to uncontrolled hemorrhage and cerebral or cardiac complications associated with prolonged bypass times. In their other group using moderate hypothermia (22-26 degree Celsius), the reported mortality was 10 %. In this surgical cohort of patients, they used moderate hypothermia, pre- prepared prosthetic grafts (treated with autologous plasma) and open distal anastomotic technique; all these leading to a gratifying reduction in mortality mainly by reducing the hemorrhagic complications. In another of their later series for distal arch aneurysms, the inhospital mortality was 6%.14 Our relatively new series beginning in 1994 mirrors the use of latest operative and supplemental techniques which have given consistently good results despite extensive use of deep hypothermic circulatory arrest.11,12 Aortic arch surgery being a major surgical insult, these operations are associated with considerable morbidity. The incidence of various complications as noted in our series (breeding -10.7%; renal dysfunction3.5%; pulmonary insufficiency -3.5% and neurological sequelae -3.5%) is relatively low.13,14 Cooley et al reported significant morbidity in their series of 60 patients. Griepp has reported that the incidence of temporary neurologic dysfunction rises linearly with age of patient and the duration of hypothermic circulatory arrest. However, permanent neurologic injury is a result of thromboembolic events and is not related to the method of cerebral protection used. We believe retrograde Table 7. Comparative results S. Series No. 1. 2. 3.
4.
Period of study
No. of patients
Early mortality
Neurological complications
Laas, Jurmann 1980-1991 et al13 Cooley et al (9) 1976-1982 Ergin, Griepp et al10 1985-1992
130
4.2%
60
13.9% (198791->8%) 23%
200
15%
Bhan et al
28
7.1%
1994-2001
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16% Temporary-19% Permanent-7% 3.5%
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cerebral protection affords significant protection and makes a dramatic impact on observed postoperative neurologic function.15,16 The present study gives only short and mid-term results for patients surgically treated for aortic arch aneurysms. The low mortality and morbidity rates, minimal late cardiovascular and neurological events, significant improvement from the preoperative NYHA functional class and its continued maintenance are pointers towards adopting an aggressive approach to the surgical management for this disease. Further longterm studies with special emphasis on followup anatomical investigations (CT scan and MRI) are indicated to establish freedom from long term complications at the anastomotic sites. With the present available technical expertise and good results to show with, surgical treatment for aortic arch aneurysms, though technically demanding, can be accomplished with excellent benefit to the patients. References 1. Cooley DA, DeBakey ME. Surgical considerations of intrathoracic aneurysms of the aorta and great vessels. Ann Surg 1952; 135: 660–80. 2. Bahnson HT : Definitive treatment of saccular aneurysms of the aorta with excision of the sac and aortic suture. Surg Gynaec Obstet 1953; 96, 383–401. 3. Bentall HH, DeBono A. A technique for complete replacement of the ascending aorta. Thorax 1968; 23: 338–39. 4. Cabrol C, Parie A : Long term results with total replacement of the ascending aorta and reimplantation of the coronary arteries. J Thorac Cardiovasc Surg 1986; 91: 17, 25.
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5. Borst HG, Walterbusch G, Schaps D. Extensive aortic replacement using the “elephant-trunk” prosthesis. J Thorac Cardiovasc Surg 1983; 31 : 37–40. 6. Presler V, McNamara JJ. Thoracic aortic aneurysms: natural history and treatment. J Thorac Cardiovasc Surg 1980; 79: 489–98. 7. Griepp RB,Stinson EB, Hollingsworth JF,Buehler D.Prosthetic replacement of the aortic arch. J Thorac Cardiovasc Surg 1975; 70: 1051–63. 8. Manoj Kumar SP, Bhan A, Chaudhary SK,.Sharma R, Makhija N, Venugopal P. Profound Hypothermic Circulatory Arrest in management of aortic aneurysms, Indian Heart Journal, 2000; 52, 1: 60–64. 9. Cooley DA Duncan JM. Resection of aortic arch aneurysms: A comparison of hypothermic techniques in 60 patients. Ann Thorac Surg 1983, 36 : 1, 19–26. 10. Ergin MA, O’Connor I, Guinto R, Griepp RB. Experience with profound hypothermia and circulatory arrest in the treatment of aneurysms of aortic arch. J Thorac Cardiovasc Surg 1982; 84 : 649–55. 11. Galloway AC, Colvin SB, LaMendola CL,Hurwitz JB, Grossi EA, Spencer FC et al. Ten year operative experience with 165 aneurysms of the ascending aorta and transverse arch. Circulation 1980; 80 (Suppl. I) 1–249–56. 12. Stowe CL, Rucker M : Surgical management of ascending and aortic arch disease, refined techniques with improved results. Ann Thorac Surg 1998, 66: 388–95. 13. Laas J, Jurmann MJ, Heinemann M, Borst HG : Advances in aortic arch surgery. Ann Thorac Surg 1992; 53: 227–32. 14. Kay GL, Cooley DA, Reardon MJ : Surgical repair of aneurysms involving the distal aortic arch. J Thorac Cardiovasc Surg 1986; 91: 397–04. 15. Crawford ES, Svensson LG, Cosselli JS, Safi HJ, Hess KR. Surgical treatment of aneurysm and/or dissection of the ascending aorta, transverse aortic arch and ascending aorta with transverse aortic arch. J Thorac Cardiovasc Surg 1989; 98: 659–74. 16. Deeb GM,Jenkins E,Bolling SF: Retrograde cerebral perfusion during hypothermic circulatory arrest reduces neurologic morbidity. J Thorac Cardiovasc Surg 1995; 109 : 259–68.
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