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Surgery for complex coarctation of the aorta
International Journal of Cardiology 97 (2004) 67 – 73 www.elsevier.com/locate/ijcard
Surgery for complex coarctation of the aorta Rachel Massey, Darryl F. Shore* Department of Cardiac Surgery and Adult Congenital Heart Program, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK Available online 11 November 2004
Abstract The application of improved surgical techniques to correct coarctation in the neonate and infant may in the longterm reduce the incidence of recoarctation in the adult. In addition, in many cases, catheter-based intervention offers an alternative to reoperation and the role of catheter-based intervention is likely to be extended with the introduction of improved technology. However, surgery is likely to be required in coarctation and recoarctation in the adult in some cases, particularly those with hypoplasia of the aortic arch, aneurysms of the ascending aorta and those with intracardiac pathology. Operation for primary coarctation in the adult can be performed through a left thoracotomy without significant postoperative morbidity. However, this is not the case with recoarctation where reoperation through a left thoracotomy has resulted in a high incidence of postoperative complications including residual coarctation, false aneurysm and recurrent laryngeal nerve palsy. Repair through a median sternotomy offers an alternative surgical approach to recoarctation which avoids these complications and allows concomitant procedures for problems associated with arteriopathy, aortic valve disease and other associated intracardiac anomalies. The approach to coarctation and recoarctation in the adult should be tailored to individual patients and made after careful discussion with interventional cardiologists. D 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Aorta; Complex coarctation; Surgery
1. Introduction When Crawford performed the first surgical correction of coarctation in 1944 it was widely believed that his would represent definitive management. This has proved not to be the case and 50 years later its management still remains a surgical challenge. Questions remain about the best surgical technique with no one technique clearly superior or applicable in all cases of coarctation. What appeared to be a simple lesion has proved over time to be complex with great variability and morphology, in association with multiple cardiac abnormalities. A distinction is often made between infantile and adult forms. In practice, this is not a useful distinction. When coarctation is diagnosed for the first time in the adult the coarctation usually, but not invariably, consists of a discrete narrowing beyond the origin of the left subclavian artery. Conversely, there is great variability in the * Corresponding author. Tel.: +44 0207 351 8211. E-mail address: [email protected] (D.F. Shore). 0167-5273/$ - see front matter D 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2004.08.009
anatomy when coarctation is diagnosed in the neonate and infant. Although the discrete form can exist in this age group there is great variability in the presence and severity of arch hypoplasia, the length and size of the aortic isthmus, the involvement of the origin of the left subclavian artery and the presence of an anomalous right subclavian, for example. The discrete form is caused by a shelf-like process on the posterior aortic wall which projects into the aortic lumen and is continuous with the ductus arteriosus. It is made up of thickened aortic media and intima and at the time of ductal closure, ectopic ductal tissue pulls the shelf in towards the ductal orifice causing narrowing [1]. Hypoplasia of the aortic arch is frequently associated with proximal valvar or septal defects which result in a decreased flow into the ascending aorta and aortic arch, although hypoplasia usually of a minor degree can occur with isolated coarctation [2]. The term complex coarctation is usually used to describe coarctation when associated with other important cardiac lesions, most commonly these are bicuspid aortic valve,
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VSD, subvalvular aortic stenosis, secundum ASD. Less commonly, it is associated with Turner’s syndrome, and congenital cerebral artery aneurysm [1,2]. In addition, aortic medial abnormalities may be present which some consider part of a generalised arteriopathy [2]. These become increasingly important as age progresses, both in terms of the propensity to develop ascending aorta aneurysms and to the thinning and weakening of the aortic wall, which may occur in the segments of the aorta close to the coarctation. This has implications for the selection of the surgical technique.
2. Surgical management of coarctation in the neonate Surgical options to date for repair of coarctation include excision with end-to-end anastomosis, subclavian flap repair and patch aortoplasty. With rare exceptions, interposition grafts are reserved for older children or adults. Subclavian flap procedures have the advantage of using autologous tissue with the capacity for growth and provide tension-free repair with limited dissection and only a partial scar. The potential disadvantages of this technique are that ductal tissue is retained and maybe a substrate for recoarctation. The approach does nothing to directly address associated tubular hypoplasia, although there is evidence that if the coarctation is adequately relieved the hypoplasia of the arch may regress by the increased flow across it. Resection with end-to-end anastomosis has the advantage of removing all ductal tissue. In neonatal coarctation, the isthmus of the aorta is often hypoplastic, so that in practice the anastomosis is made between the descending aorta distal to the coarctation and the underneath of the aortic arch between the left common carotid and the left subclavian. In extended end-to-end anastomosis, the incision on the underneath of the aortic arch is made more proximally and addresses the problem of aortic arch hypoplasia when present. Both the end-to-end and the extended end-to-end anastomosis carry the potential disadvantage of including a circumferential scar and suture line tension, although in practice the latter can usually be overcome by extensive mobilisation of the descending aorta and the head and neck vessels and liberating them from their pericardial attachment. The advantages of patch aortoplasty is that it provides a tension-free scar with limited dissection; however, ductal issue is retained. When used in neonates it has been associated with a high rate of recoarctation [3,4]. There is also an apparent increase in the incidence of postoperative aneurysm formation at the site of repair although this may be associated with excision of the coarctation shelf [5]. Many studies have compared these operations with the incidence of recoarctation and aneurysm formation postoperatively. Recoarctation may occur with all surgical techniques and no single technique is clearly superior [1,3,4]. Instead, etiology of recoarctation is multifactorial,
with age at primary operation perhaps being the most important predictive factor of recoarctation [6]. Patch aortoplasty is associated with an increased incidence of postoperative aneurysm formation, and is also associated with a high recoarctation rate when the operation is performed in infants [3,4].
3. Management of complex coarctation or recoarctation in the adult As eluded to previously, because of a number of issues involved, the surgical management of coarctation or recoarctation in the adult population should be considered a complex surgical challenge.
4. Considerations in the management of coarctation or recoarctation in the adult (1)
(2)
(3)
(4)
The anatomy of obstruction. This may be either discrete, as is usually the case in primary coarctation in the adult. Longer segments of narrowing or hypoplasia of the aortic arch in the adult population is usually associated with recoarctation [2]. Pathology of the aortic wall. The abnormalities of the aortic media previously referred to, may lead to the presence of ascending aortic aneurysms which may require surgical management in their own right. The presence of a thin and weak aortic wall adjacent to the site of coarctation or recoarctation may have implications in terms of postoperative complications [7]. Collateral circulation. The collateral circulation is important in two respects. Large intercostal vessels may enter the descending aorta adjacent to the site of coarctation. These vessels are often friable and aneurysmal. Techniques for surgical repair which require cross clamp of the descending aorta demands that at least some of these vessels must be dissected and divided or temporarily occluded. This can be hazardous as if these vessels are damaged, it can lead to profuse haemorrhage. The other important aspect of this collateral circulation is in its ability to sustain adequate perfusion of the descending aorta during aortic cross clamping. An important aspect of coarctation repair in this age group is in the assessment of the need to provide additional means of descending aortic perfusion. Aneurysm formation (Fig. 1). True or false aneurysms may occur at the site of previous coarctation repair. The use of patch aortoplasty is associated with an increased incidence of aneurysm formation [4,5]. These may be discovered on routine assessment or screening or may present following rupture. The presence and the size of the aneurysm, and whether it has ruptured will all influence the surgical approach.
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Fig. 1. Three-dimensional reconstruction following gadolinium enhancement with cardiac MRI in a patient with previous surgical repair of CoA. Note significant aneurysm formation in the descending intrathoracic aorta distal to the repair.
(5)
The presence of an aneurysm of the ascending aorta may demand surgical management to coincide with repair of coarctation. Associated malformations. The commonly associated malformations are aortic valve disease, subvalvar aortic stenosis, mitral valve disease and coronary artery disease [8]. Patients with previously repaired coarctation may require reoperation for recoarctation or a haemodynamically significant associated malformation, or a combination of the two. The influence of associated malformations on the surgical approach to coarctation or recoarctation is discussed in more detail later.
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have been introduced to address these issues. They negate the need to mobilise the aorta, do not require mobilisation or dissection of collateral vessels and avoid the need to place sutures in the aortic wall close to the site of coarctation where it is at its most friable. In addition, they allow the use of an aortic side clamp as opposed to complete aortic cross clamping, and therefore reduce the risk of postoperative paraplegia which is increased in adults. They also reduce the need for a heparinised shunt or cardiopulmonary bypass to augment distal aortic perfusion. In primary repair of coarctation in adults, the left subclavian artery is often equal in size to the aortic arch and therefore the proximal end of the graft can be placed on the left subclavian artery. In 1995, Grinder et al. described 16 patients with coarctation of the aorta treated with bypass graft. In 14 of these 16 patients, the proximal end of the graft was placed on the left subclavian artery and in two the graft was interposed between the ascending and the descending aorta. There was no incidence of recurrent laryngeal phrenic nerve or spinal injury, although one patient developed an infected false aneurysm [9]. Recoarctation of the aorta is more commonly associated with hypoplasia of the aortic arch. In order to address this problem, the proximal end of any interposition graft must be placed more proximally. This can be difficult through a left thoracotomy, particularly in large-chested individuals. The need to clamp the aorta proximal to the left common carotid artery necessitates the use of bypass and direct cannulation and perfusion of the left common carotid artery. In order to overcome these difficulties, a bypass graft can be interposed between the ascending and the descending aorta using a side-biting clamp. In 1999, Daebritz et al. described five cases in whom an anatomically positioned ascending-todescending aorta bypass graft was performed via a left posterolateral thoracotomy for reoperation of aortic coarctation without the use of cardiopulmonary bypass. There were no operative deaths and no measurable postoperative pressure gradients [10].
6. Aneurysm formation after surgical repair 5. Surgical technique for repair of coarctation/ recoarctation in the adult Traditionally, surgical approach to coarctation and recoarctation in the adult has been through a left thoracotomy. More recently, there has been interest in repair through a median sternotomy and this will be discussed in some detail later. The surgical options in adults with primary coarctation are different and some surgical options are not suitable at all. Excision with end-to-end anastomosis and interposition grafting are possible options. However, these approaches can be technically difficult due to an extensive collateral circulation and advanced aortic wall arteriopathy, making dissection and mobilisation of the aorta difficult. In recent years, a number of additional surgical techniques
Some studies suggest that approximately 9% of coarctation repairs are complicated by aneurysm formation and that mortality from rupture of these aneurysms if left untreated is as high as 36% [5]. What predisposes a patient’s formation of these aneurysms is not well understood. The type of primary repair, presence of associated cardiac lesions and the patient’s age at primary repair have all been sited as possible factors. Von Kodolitsch et al. looked at predictors for aneurysm formation and found 25 patients with previous coarctation and late aneurysm formation. Of the 25 aneurysms, eight were aneurysms of the ascending aorta whereas 17 were aneurysms occurring at the site of coarctation repair. Operations were performed for dissection (n=2), for rapid aneurysm progression (n=2), and aneurysm
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rupture (n=3), and for aortic root dilatation (n=3). The remaining patients underwent elective repair. To try and stratify the risks for the development of late aneurysm, the study involved a consecutive control group of 74 patients who underwent successful coarctation repair during the same period. They studied 16 variables including age at surgical correction, gender, position of the coarctation in relation to the ductus, the surgical technique at primary operation and any previous coarctation repairs. In addition, close attention was paid to pre- and postoperative systolic and diastolic blood pressure and pressure gradients across the segment and the subsequent need for postoperative betablockers. Their results indicated that type A aneurysm was associated with advanced age at primary operation ( p=0.044), bicuspid aortic valve ( p=0.02) and a high preoperative pressure gradient of 74F21 mm Hg in patients with type A aneurysm versus 52F27 mm Hg in controlled subjects. However, multivariate analysis indicated only a bicuspid aortic valve as an independent predictor of type A aneurysm. Their data also suggested that patch aortoplasty ( pV0.0005) and age at primary operation ( pb0.004) were independent predictors of aneurysms occurring at the site of coarctation repair. Thirteen and a half years of age was established as a threshold for increased risk of post surgical aneurysm formation ( pV0.005). Seventy-five percent (18 out of 25 of the patients) with late aneurysm had had primary coarctation repair beyond 13.5 years of age [5]. Aneurysms after patch aortoplasty can be divided into either true aneurysms, which seem to develop opposite the patch, or false aneurysms which arise from suture lines. Mc Griffin et al. argue that development of true aneurysms after coarctation repair by synthetic patch aortoplasty is due to the aortic wall stress profile following repair. Maximal aortic stress is concentrated opposite the patch hence the development of true aneurysms here. Patch stiffness is also thought to have an important role with lower stiffness (i.e., subclavian patch) leading to higher aortic wall stress for the same patch geometry as a synthetic patch repair [11]. Heikkinen et al. looked at morphological and histopathological aspects of aneurysms after patch aortoplasty for coarctation . They analysed 14 speciments and found 13 displayed medionecrosis, 11 retraction of a foreign body and intimal thickening in 3 [12]. Opinion on the etiology of aneurysm formation after patch aortoplasty remains divided. Bromberg et al. [13] concluded that suture material and surgeon had no bearing on late aneurysm formation and that previous coarctation resection and use of PTFE grafts appeared to have a protective effect. In contrast, De Santo et al. [14] found that resection of the intima predisposes to aneurysm formation opposite the aortotomy and should be avoided. Bogaert et al. screened 85 patients with MRI looking for aneurysm following patch aortoplasty, 12F2 years after operation. They established that all 33 patients with aneurysm had hypoplastic transverse aortic arches and concluded that aneurysm formation at the site of a repair
is highly related to hypoplasia of the aortic arch ( pb0.001). This is in direct contrast with Von Kodolitsch et al. [5] and Bogaert et al. [15] who found no association with local aneurysm and a hypoplastic transverse arch. The surgical management of aneurysm occurring at the site of coarctation repair with or without recoarctation is difficult and attention should be first directed towards their prevention. For this reason, we have stopped using patch aortoplasty for the surgical correction of adult coarctation or recoarctation. When aneurysms do occur, protocol for postoperative follow-up must ensure their identification. Arguably, small aneurysms can be followed by repeated magnetic resonance imaging but large aneurysms, those showing rapid progression in size and those producing symptoms, have a high mortality as being associated with rupture. It is possible that in the future some of these aneurysms will be suitable for treatment by stent implantation. Of seven aneurysms treated surgically in this institution between 1970 and 1998, four presented with rupture [16].
7. Spinal cord protection Despite recent advances in operative technique and improvements in postoperative care, risks of spinal cord injury following coarctation repair are estimated at 0.5–5% and appear to increase with age [1]. Our current policy is to accept a perfusion pressure of no less than 50 mm Hg in the descending aorta at any stage during repair. Where the collateral circulation is inadequate to meet such criteria this can be achieved by means of a heparinised Gott shunt or by the use of partial cardiopulmonary bypass established by pulmonary artery to descending aorta or by femorofemoral bypass. Left heart bypass from left atrium to descending aorta can also be used. Femorofemoral bypass with hypothermia allowing for periods of circulatory arrest has been reserved for those cases of ruptured aneurysm where dissection at the aneurysm site may lead to haemorrhage and circulatory collapse. In such cases, an attempt is always made during thoracotomy to establish proximal control before dissection of the aneurysm itself. Ideally reliable detection of spinal cord ischaemia should be operational (regardless of surgical procedure) at a reversible stage, thus allowing appropriate intervention and therefore preventing paraparesis. Cerebrospinal fluid pressure (CSFP) measurements are well established as a means for detecting increased ischaemic risk as increased CSFP leads to vascular compression. In addition, other studies have shown that recording changes in somatosensory evoked potentials (SEP) perioperatively indicates ischaemic change. Maintaining a spinal cord perfusion pressure (SCPP) of N40 mm Hg defined as a pressure difference between the distal aortic pressure and the cerebrospinal fluid pressure, has been clinically shown to be valuable in preventing ischaemia. Wada et al.
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looked at elective repair of the descending thoracic and thoracoabdominal aorta in 82 patients with mixed aortic disease, all of whom had a temporary bypass shunt or partial cardiopulmonary bypass during the aortic cross clamping at normothermia. They monitored SEP, mean distal aortic pressure (MDAP), CSFP, perioperatively. Sixty of the patients had no ischaemic change in SEP. In 17 patients with significant ischaemic changes of SEP, SEP recovered by increasing SCPP to more than 40 mm Hg either by increasing the MDAP or by decreasing the CSFP. Complete loss of SEP was associated with paraplegia in two cases. They drew three conclusions. First, that SEP, MDAP and CSFP should be monitored during aortic cross clamping. Second, that maintaining SCPP at more than 40 mm Hg by increasing MDAP or withdrawal of SCSF is valuable for prevention of paraplegia, and lastly, that femoral vein to femoral artery pressure is useful to control the distal aortic perfusion pressure during cross clamping [17]. These findings are controversial and are of limited practical value in the majority of surgical centres but may eventually be of great value in elective aortic surgery. In complex coarctation or recoarctation in adults in whom the risk of spinal cord injury and paraplegia is highest, partial cardiopulmonary bypass with hypothermia, or on some occasions deep hypothermia, with circulatory arrest is often the most practical surgical option.
8. Repair of coarctation/recoarctation in adults through a left thoracotomy Since 1988, several authors have reported their experience with repair of complex coarctation through a median sternotomy. This was performed either to avoid the complications associated with repair through a rethoracotomy or to deal with associated valvar heart disease or coronary artery disease concomitantly. We retrospectively analysed the results of repair of coarctation or recoarctation through a left thoracotomy using a variety of techniques between 1970 and 1998. Sixty-five patients were included. Their age range was 16–58 years of age with a mean age of 27.8 years and a mean follow-up of 9.7 years. There were 38 men and 27 women [16]. There were 45 primary repairs of coarctation and 20 reoperations. Of these, 17 patients underwent a second operation, 2 a third and 1 a fourth operation. Seven procedures were performed for aneurysm formation at the site of coarctation repair. These all proved to be false aneurysms. Fourteen of the redo operations were performed for recoarctation. The mean age of the patients undergoing reoperation was 28.5F1.8 versus 27.5F2.4 years for primary repair. Of the patients undergoing reoperations, 14 were female and 6 were male ( pV0.01). The surgical techniques employed included
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end-to-end anastomosis in 11, an interposition graft in 12, a bypass graft in 12, and a patch repair in 30. The results were analysed in terms of early and late mortality and complications analysed included reexploration for bleeding, recurrent laryngeal nerve palsy, persistent gradient of more than 20 mm Hg and false aneurysm formation. There was no early mortality. The late mortality was 4.5%, three deaths occurring at 10, 14 and 19 years after surgery. One late death was unrelated and two occurred following surgery for aortic valve disease [16]. Five out of 65 patients had evidence of recoarctation defined as a resting gradient of 20 mm Hg. Recoarctation was not associated with any particular technique. False aneurysm occurred in 3 out of 45 patients undergoing primary repair and 4 out of 20 patients undergoing reoperation. The difference was not statistically significant. False aneurysm was not commoner in any single group but together patch aortoplasty and bypass grafts had a higher incidence than end-to-end anastomosis and interposition grafts ( pV0.01). Recurrent laryngeal nerve palsy occurred in 6 out of 65 patients. Five of those six patients were in the group undergoing reoperation [16]. Three out of 45 patients (or 7%) of those undergoing primary operation had one or other complication as opposed to 15 out of 20 (or 75%) of those undergoing reoperation. Since analysing these data we have elected to perform repair of recoarctation when not associated with aneurysm formation, through a median sternotomy. This technique is also preferred where concomitant procedures are indicated [16].
9. Repair of coarctation through a median sternotomy A posterior pericardial approach is performed via median sternotomy and with the aid of hypothermic cardiopulmonary bypass. After institution of bypass the heart undergoes cephalad retraction (Fig. 2) and a longitudinal posterior pericardial incision exposes the descending thoracic aorta. After application of a sidebiting clamp, an end-to-side anastomosis of the graft to the descending aorta is performed. The graft is then passed posterior to the inferior vena cava and anterior to the oesophagous, and anastomosed to the right hand side of the ascending aorta. Several authors have reported repair of coarctation through a posterior pericardial approach [18,19]. Connelly et al. performed extra anatomical posterior pericardial repairs in 18 patients between 1985 and 2000. Twelve patients had had previous surgery, 10 having had previous repair of coarctation. The surgical procedure was performed as described above. Nine of the 18 patients had associated aortic valve disease, five with aortic stenosis and four with aortic regurgitation. Three patients had coronary artery bypass surgery. The outcome of surgery was good
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Fig. 2. Repair of complex CoA with and ascending to descending aortic bypass graft. Note cephalad retraction of the heart for placing the distal part of the anastomosis.
with no operable deaths, no paraplegia and graft patency at follow-up, mean of 45 months after surgery [18]. In addition, Powell et al. [20], Pethig et al. [21] and Morris et al. [22] used a similar approach to combine coarctation repair with aortic valve repair, mitral valve surgery and CABG with equal success. We have used this approach in six cases, 5 with recoarctation, 2 combined with aortic valve replacement, and in 1 patient with primary repair of coarctation combined with replacement of the ascending aorta (Bental procedure). One patient developed postcardiotomy syndrome postoperatively, but there were no other complications. No patient had a significant gradient postoperatively, although postoperative magnetic resonance imaging showed turbulance at the right-angled end-to-side anastomosis at the descending aorta [16]. The effect of such energy loss at the right-angled anastomosis and the presence of long noncompliant bypass grafts on systemic blood pressure are unknown.
aortic valve and the incidence of ascending aorta and aortic arch pathology after coarctation repair. One hundred and twenty-four adult patients after surgical correction of aortic coarctation were studied. During follow-up, 28 patients (or 23%) developed recoarctation requiring reoperation in 10 and balloon dilatation in 18 patients. During the same period, 27 (or 22%) of patients required reintervention (25 had surgery, 2 had balloon dilatation) for aortic stenosis or regurgitation. Of the 97 patients without aortic valve intervention, 23 patients had evidence of aortic stenosis and 28 had evidence of aortic regurgitation. Aortic valve disease was therefore observed in 63% of their patients during follow-up. In addition, dilatation of the ascending aorta was found in 35 patients, most commonly associated with a bicuspid aortic valve, and aortic arch hypoplasia was found in 12 patients [7]. Attenhofer Jost et al. reviewed the clinical, echocardiographic and cardiac catheterisation data, criteria for reoperation and surgical procedures performed, and outcome in 43 patients who underwent 54 reoperations after previous coarctation repair at their institution between 1972 and 1996. Twenty-two of these 54 operations were for recoarctation, 22 had aortic valve surgery, 12 surgery on the left ventricular outflow tract, 6 underwent surgery for aneurysmal enlargement of the aorta, 5 mitral valve surgery and 2 coronary artery bypass grafting. They emphasized the importance of individualized management in patients with recoarctation and additional pathology and advocated the use of an ascending descending aorta bypass graft through a posterior pericardial approach in selected cases [8] (Fig. 3).
10. Reoperation for associated anomalies after coarctation repair After operation, the prevalence of recoarctation is variously reported to be between 3% and 41% [7,8]. However, in addition to the need for reintervention for recoarctation there is an increasing need for reoperation for associated anomalies as follow-up increases. The most common lesions requiring reoperation are aortic valve replacement, subvalvar aortic stenosis, aneurysms of the ascending aorta, coronary artery disease and mitral valve disease [7]. Roos Hesselink et al. investigated the incidence of aortic stenosis and regurgitation related to a bicuspid
Fig. 3. Three-dimensional cardiac MRI in the same patient with Fig. 2 demonstrating long bypass graft and effective relief of complex CoA with long sever arch hypoplasia.
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11. Summary The advent of catheter-based intervention has transformed the management of the adult with coarctation and recoarctation, and it is likely that with improved technology more cases will be amenable to catheter based management, even those with evidence of aneurysm formation at the site of coarctation repair. However, surgery will still be required in some cases, particularly those with hypoplasia of the aortic arch, aneurysms of the ascending aorta and intracardiac pathology. In our experience, reoperation in the adult for recoarctation through a left thoracotomy has resulted in significant postoperative morbidity and complete relief of recoarctation is difficult through this approach when there is associated aortic arch hypoplasia. In the adult, repair of coarctation and recoarctation through a median sternotomy has in our hands, as in others, proved a safe and effective alternative approach and can readily be combined with additional intracardiac procedures and replacement of an aneurysmal ascending aorta. In the future, the application of improved surgical technique to correct coarctation in the neonate and infant may reduce the incidence of recoarctation in the adult. Recently, Bakker suggested that we may now be at the point at which it is the modulation of the healing process after repair of coarctation which will lead to a further reduction in the incidence of recoarctation and consequent late hypertension. In an experimental model, they found that the topical application of vascular endothelial growth factor to the anastomotic site resulted in enhanced healing, less fibrosis and cellular infiltrate and no focal dystrophic medial calcification [23]. However, even if in the future we were able to achieve this end, patients who have had repair of coarctation will still require reoperation for problems associated with arteriopathy and associated intracardiac anomalies.
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[6] Brouwer R, Erasmus ME, Ebels T, Eijgelaar A. Influence of age in survival, late hypertension and recoarctation in elective coarctation repair. Including longterm results after elective aortic coarctation repair with a follow-up from 25–44 yrs. J Thorac Cardiovasc Surg 1994;66:525 – 31. [7] Roos-Hesselink JW, Scholzel BE, Heijdra RJ, Spitaels SE, Meijboom FJ, Boersma E, et al. Aortic valve and aortic arch pathology after coarctation. Heart 2003;89:1074 – 7. [8] Attenhofer Jost, Schaff H, Connolly H, et al. Spectrum of reoperations after aortic coarctation: importance of an individualised approach because of coexistant cardiovascular disease. Mayo Clin Proc 2002; 77:646 – 53. [9] Grinda JM, Mace L, Dervanian P, Folliguet TA, Neveux JY. Bypass grafts for complex forms of isthmic aortic coarctation in adults. Ann Thorac Surg 1995;60:1299 – 302. [10] Daebritz S, Fausten B, Sachweh J, Muhler E, Franke A, Messmer BJ. Anatomically positioned aorta ascending–descending bypass grafting via left posterolateral thoracotomy for reoperation of aortic coarctation. Eur J Cardio-thorac Surg 1999;16(5):519 – 23. [11] McGriffin DC, McGriffin PB, Galbraith AJ, Cross RB. Aortic wall stress profile after repair of coarctation of the aorta. Is it related to subsequent true aneurysm formation? J Thorac Cardiovasc Surg 1992;104(4):924 – 31. [12] Heikkinen L, Sariola H, Salo J, Ala-Kulju K. Morphological and histopathological aspects of aneurysms after patch aortoplasty for coarctation. Ann Thorac Surg 1990;50(6):946 – 8. [13] Bromberg BI, Beekman RH, Rocchini AP, Snider AR, Bank ER, Heidelberger K, et al. Aortic aneurysm after patch aortoplasty repair of coarctation: a prospective analysis of prevalence, screening tests and risks. J Am Soc Cardiol 1989;14(3):734 – 41. [14] De Santo A, Bills RG, King H, Waller B, Brown JW. Pathogenesis of aneurysm formation opposite prosthetic patches used for coarctation repair. An experimental study. J Thorac Cardiovasc Surg 1987; 94(5):720 – 3. [15] Bogaert J, Gewillig M, Rademakers F, Bosmans H, Verschakelen J, Denen W, et al. Transverse arch hypoplasia predisposes to aneurysm formation at the repair site after patch aortoplasty for coarctation of the aorta. J Am Coll Cardiol 1995;26(2):521 – 7. [16] Barron DJ, Somerville J, de Leval MR, Shore DF. Surgical management of recurrent coarctation of the aorta in adults (1970–1988). Presented at the Society of Cardiothoracic Surgeons Annual Meeting, Nottingham, 1999. [17] Wada T, Yao H, Miyamoto T, Mukai S, Yamamura M. Prevention and detection of spinal cord injury during thoracic and thoracoabdominal aortic repairs. Ann Thorac Surg 2001;72:80 – 5. [18] Connolly H, Schaff HV, Izhar U, Dearani JA, Warnes CA, Orszulak TA. Posterior pericardial ascending to descending aortic bypass. Circulation 2001;104(12 Suppl. 1):I133 – 7. [19] Izhar U, Schaff HV, Mullany CJ, Daly RC, Orszulak TA. Posterior pericardial approach for ascending–descending aortic bypass through a median sternotomy. Ann Thorac Surg 2000;70:31 – 7. [20] Powell WR, Adams PR, Cooley DA. Repair of coarctation of the aorta associated with intracardiac repair. Texas Heart Inst J 1983; 10(4):409 – 13. [21] Pethig K, Wahlers T, Tager S, Borst HG. Total simultaneous repair of coarctation and intracardiac pathology in adult patients. Ann Thorac Surg 1996;61:1724 – 6. [22] Morris RJ, Samuels LE, Brockman SK. Total simultaneous repair of coarctation and intracardiac pathology in adult patients. Ann Thorac Surg 1998;65:1698 – 702. [23] Backer CL. Coarctation the search for the Holy Grail. J Thorac Cardiovasc Surg 2003;126(2):329 – 31.
Surgery for complex coarctation of the aorta Rachel Massey, Darryl F. Shore* Department of Cardiac Surgery and Adult Congenital Heart Program, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK Available online 11 November 2004
Abstract The application of improved surgical techniques to correct coarctation in the neonate and infant may in the longterm reduce the incidence of recoarctation in the adult. In addition, in many cases, catheter-based intervention offers an alternative to reoperation and the role of catheter-based intervention is likely to be extended with the introduction of improved technology. However, surgery is likely to be required in coarctation and recoarctation in the adult in some cases, particularly those with hypoplasia of the aortic arch, aneurysms of the ascending aorta and those with intracardiac pathology. Operation for primary coarctation in the adult can be performed through a left thoracotomy without significant postoperative morbidity. However, this is not the case with recoarctation where reoperation through a left thoracotomy has resulted in a high incidence of postoperative complications including residual coarctation, false aneurysm and recurrent laryngeal nerve palsy. Repair through a median sternotomy offers an alternative surgical approach to recoarctation which avoids these complications and allows concomitant procedures for problems associated with arteriopathy, aortic valve disease and other associated intracardiac anomalies. The approach to coarctation and recoarctation in the adult should be tailored to individual patients and made after careful discussion with interventional cardiologists. D 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Aorta; Complex coarctation; Surgery
1. Introduction When Crawford performed the first surgical correction of coarctation in 1944 it was widely believed that his would represent definitive management. This has proved not to be the case and 50 years later its management still remains a surgical challenge. Questions remain about the best surgical technique with no one technique clearly superior or applicable in all cases of coarctation. What appeared to be a simple lesion has proved over time to be complex with great variability and morphology, in association with multiple cardiac abnormalities. A distinction is often made between infantile and adult forms. In practice, this is not a useful distinction. When coarctation is diagnosed for the first time in the adult the coarctation usually, but not invariably, consists of a discrete narrowing beyond the origin of the left subclavian artery. Conversely, there is great variability in the * Corresponding author. Tel.: +44 0207 351 8211. E-mail address: [email protected] (D.F. Shore). 0167-5273/$ - see front matter D 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2004.08.009
anatomy when coarctation is diagnosed in the neonate and infant. Although the discrete form can exist in this age group there is great variability in the presence and severity of arch hypoplasia, the length and size of the aortic isthmus, the involvement of the origin of the left subclavian artery and the presence of an anomalous right subclavian, for example. The discrete form is caused by a shelf-like process on the posterior aortic wall which projects into the aortic lumen and is continuous with the ductus arteriosus. It is made up of thickened aortic media and intima and at the time of ductal closure, ectopic ductal tissue pulls the shelf in towards the ductal orifice causing narrowing [1]. Hypoplasia of the aortic arch is frequently associated with proximal valvar or septal defects which result in a decreased flow into the ascending aorta and aortic arch, although hypoplasia usually of a minor degree can occur with isolated coarctation [2]. The term complex coarctation is usually used to describe coarctation when associated with other important cardiac lesions, most commonly these are bicuspid aortic valve,
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VSD, subvalvular aortic stenosis, secundum ASD. Less commonly, it is associated with Turner’s syndrome, and congenital cerebral artery aneurysm [1,2]. In addition, aortic medial abnormalities may be present which some consider part of a generalised arteriopathy [2]. These become increasingly important as age progresses, both in terms of the propensity to develop ascending aorta aneurysms and to the thinning and weakening of the aortic wall, which may occur in the segments of the aorta close to the coarctation. This has implications for the selection of the surgical technique.
2. Surgical management of coarctation in the neonate Surgical options to date for repair of coarctation include excision with end-to-end anastomosis, subclavian flap repair and patch aortoplasty. With rare exceptions, interposition grafts are reserved for older children or adults. Subclavian flap procedures have the advantage of using autologous tissue with the capacity for growth and provide tension-free repair with limited dissection and only a partial scar. The potential disadvantages of this technique are that ductal tissue is retained and maybe a substrate for recoarctation. The approach does nothing to directly address associated tubular hypoplasia, although there is evidence that if the coarctation is adequately relieved the hypoplasia of the arch may regress by the increased flow across it. Resection with end-to-end anastomosis has the advantage of removing all ductal tissue. In neonatal coarctation, the isthmus of the aorta is often hypoplastic, so that in practice the anastomosis is made between the descending aorta distal to the coarctation and the underneath of the aortic arch between the left common carotid and the left subclavian. In extended end-to-end anastomosis, the incision on the underneath of the aortic arch is made more proximally and addresses the problem of aortic arch hypoplasia when present. Both the end-to-end and the extended end-to-end anastomosis carry the potential disadvantage of including a circumferential scar and suture line tension, although in practice the latter can usually be overcome by extensive mobilisation of the descending aorta and the head and neck vessels and liberating them from their pericardial attachment. The advantages of patch aortoplasty is that it provides a tension-free scar with limited dissection; however, ductal issue is retained. When used in neonates it has been associated with a high rate of recoarctation [3,4]. There is also an apparent increase in the incidence of postoperative aneurysm formation at the site of repair although this may be associated with excision of the coarctation shelf [5]. Many studies have compared these operations with the incidence of recoarctation and aneurysm formation postoperatively. Recoarctation may occur with all surgical techniques and no single technique is clearly superior [1,3,4]. Instead, etiology of recoarctation is multifactorial,
with age at primary operation perhaps being the most important predictive factor of recoarctation [6]. Patch aortoplasty is associated with an increased incidence of postoperative aneurysm formation, and is also associated with a high recoarctation rate when the operation is performed in infants [3,4].
3. Management of complex coarctation or recoarctation in the adult As eluded to previously, because of a number of issues involved, the surgical management of coarctation or recoarctation in the adult population should be considered a complex surgical challenge.
4. Considerations in the management of coarctation or recoarctation in the adult (1)
(2)
(3)
(4)
The anatomy of obstruction. This may be either discrete, as is usually the case in primary coarctation in the adult. Longer segments of narrowing or hypoplasia of the aortic arch in the adult population is usually associated with recoarctation [2]. Pathology of the aortic wall. The abnormalities of the aortic media previously referred to, may lead to the presence of ascending aortic aneurysms which may require surgical management in their own right. The presence of a thin and weak aortic wall adjacent to the site of coarctation or recoarctation may have implications in terms of postoperative complications [7]. Collateral circulation. The collateral circulation is important in two respects. Large intercostal vessels may enter the descending aorta adjacent to the site of coarctation. These vessels are often friable and aneurysmal. Techniques for surgical repair which require cross clamp of the descending aorta demands that at least some of these vessels must be dissected and divided or temporarily occluded. This can be hazardous as if these vessels are damaged, it can lead to profuse haemorrhage. The other important aspect of this collateral circulation is in its ability to sustain adequate perfusion of the descending aorta during aortic cross clamping. An important aspect of coarctation repair in this age group is in the assessment of the need to provide additional means of descending aortic perfusion. Aneurysm formation (Fig. 1). True or false aneurysms may occur at the site of previous coarctation repair. The use of patch aortoplasty is associated with an increased incidence of aneurysm formation [4,5]. These may be discovered on routine assessment or screening or may present following rupture. The presence and the size of the aneurysm, and whether it has ruptured will all influence the surgical approach.
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Fig. 1. Three-dimensional reconstruction following gadolinium enhancement with cardiac MRI in a patient with previous surgical repair of CoA. Note significant aneurysm formation in the descending intrathoracic aorta distal to the repair.
(5)
The presence of an aneurysm of the ascending aorta may demand surgical management to coincide with repair of coarctation. Associated malformations. The commonly associated malformations are aortic valve disease, subvalvar aortic stenosis, mitral valve disease and coronary artery disease [8]. Patients with previously repaired coarctation may require reoperation for recoarctation or a haemodynamically significant associated malformation, or a combination of the two. The influence of associated malformations on the surgical approach to coarctation or recoarctation is discussed in more detail later.
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have been introduced to address these issues. They negate the need to mobilise the aorta, do not require mobilisation or dissection of collateral vessels and avoid the need to place sutures in the aortic wall close to the site of coarctation where it is at its most friable. In addition, they allow the use of an aortic side clamp as opposed to complete aortic cross clamping, and therefore reduce the risk of postoperative paraplegia which is increased in adults. They also reduce the need for a heparinised shunt or cardiopulmonary bypass to augment distal aortic perfusion. In primary repair of coarctation in adults, the left subclavian artery is often equal in size to the aortic arch and therefore the proximal end of the graft can be placed on the left subclavian artery. In 1995, Grinder et al. described 16 patients with coarctation of the aorta treated with bypass graft. In 14 of these 16 patients, the proximal end of the graft was placed on the left subclavian artery and in two the graft was interposed between the ascending and the descending aorta. There was no incidence of recurrent laryngeal phrenic nerve or spinal injury, although one patient developed an infected false aneurysm [9]. Recoarctation of the aorta is more commonly associated with hypoplasia of the aortic arch. In order to address this problem, the proximal end of any interposition graft must be placed more proximally. This can be difficult through a left thoracotomy, particularly in large-chested individuals. The need to clamp the aorta proximal to the left common carotid artery necessitates the use of bypass and direct cannulation and perfusion of the left common carotid artery. In order to overcome these difficulties, a bypass graft can be interposed between the ascending and the descending aorta using a side-biting clamp. In 1999, Daebritz et al. described five cases in whom an anatomically positioned ascending-todescending aorta bypass graft was performed via a left posterolateral thoracotomy for reoperation of aortic coarctation without the use of cardiopulmonary bypass. There were no operative deaths and no measurable postoperative pressure gradients [10].
6. Aneurysm formation after surgical repair 5. Surgical technique for repair of coarctation/ recoarctation in the adult Traditionally, surgical approach to coarctation and recoarctation in the adult has been through a left thoracotomy. More recently, there has been interest in repair through a median sternotomy and this will be discussed in some detail later. The surgical options in adults with primary coarctation are different and some surgical options are not suitable at all. Excision with end-to-end anastomosis and interposition grafting are possible options. However, these approaches can be technically difficult due to an extensive collateral circulation and advanced aortic wall arteriopathy, making dissection and mobilisation of the aorta difficult. In recent years, a number of additional surgical techniques
Some studies suggest that approximately 9% of coarctation repairs are complicated by aneurysm formation and that mortality from rupture of these aneurysms if left untreated is as high as 36% [5]. What predisposes a patient’s formation of these aneurysms is not well understood. The type of primary repair, presence of associated cardiac lesions and the patient’s age at primary repair have all been sited as possible factors. Von Kodolitsch et al. looked at predictors for aneurysm formation and found 25 patients with previous coarctation and late aneurysm formation. Of the 25 aneurysms, eight were aneurysms of the ascending aorta whereas 17 were aneurysms occurring at the site of coarctation repair. Operations were performed for dissection (n=2), for rapid aneurysm progression (n=2), and aneurysm
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rupture (n=3), and for aortic root dilatation (n=3). The remaining patients underwent elective repair. To try and stratify the risks for the development of late aneurysm, the study involved a consecutive control group of 74 patients who underwent successful coarctation repair during the same period. They studied 16 variables including age at surgical correction, gender, position of the coarctation in relation to the ductus, the surgical technique at primary operation and any previous coarctation repairs. In addition, close attention was paid to pre- and postoperative systolic and diastolic blood pressure and pressure gradients across the segment and the subsequent need for postoperative betablockers. Their results indicated that type A aneurysm was associated with advanced age at primary operation ( p=0.044), bicuspid aortic valve ( p=0.02) and a high preoperative pressure gradient of 74F21 mm Hg in patients with type A aneurysm versus 52F27 mm Hg in controlled subjects. However, multivariate analysis indicated only a bicuspid aortic valve as an independent predictor of type A aneurysm. Their data also suggested that patch aortoplasty ( pV0.0005) and age at primary operation ( pb0.004) were independent predictors of aneurysms occurring at the site of coarctation repair. Thirteen and a half years of age was established as a threshold for increased risk of post surgical aneurysm formation ( pV0.005). Seventy-five percent (18 out of 25 of the patients) with late aneurysm had had primary coarctation repair beyond 13.5 years of age [5]. Aneurysms after patch aortoplasty can be divided into either true aneurysms, which seem to develop opposite the patch, or false aneurysms which arise from suture lines. Mc Griffin et al. argue that development of true aneurysms after coarctation repair by synthetic patch aortoplasty is due to the aortic wall stress profile following repair. Maximal aortic stress is concentrated opposite the patch hence the development of true aneurysms here. Patch stiffness is also thought to have an important role with lower stiffness (i.e., subclavian patch) leading to higher aortic wall stress for the same patch geometry as a synthetic patch repair [11]. Heikkinen et al. looked at morphological and histopathological aspects of aneurysms after patch aortoplasty for coarctation . They analysed 14 speciments and found 13 displayed medionecrosis, 11 retraction of a foreign body and intimal thickening in 3 [12]. Opinion on the etiology of aneurysm formation after patch aortoplasty remains divided. Bromberg et al. [13] concluded that suture material and surgeon had no bearing on late aneurysm formation and that previous coarctation resection and use of PTFE grafts appeared to have a protective effect. In contrast, De Santo et al. [14] found that resection of the intima predisposes to aneurysm formation opposite the aortotomy and should be avoided. Bogaert et al. screened 85 patients with MRI looking for aneurysm following patch aortoplasty, 12F2 years after operation. They established that all 33 patients with aneurysm had hypoplastic transverse aortic arches and concluded that aneurysm formation at the site of a repair
is highly related to hypoplasia of the aortic arch ( pb0.001). This is in direct contrast with Von Kodolitsch et al. [5] and Bogaert et al. [15] who found no association with local aneurysm and a hypoplastic transverse arch. The surgical management of aneurysm occurring at the site of coarctation repair with or without recoarctation is difficult and attention should be first directed towards their prevention. For this reason, we have stopped using patch aortoplasty for the surgical correction of adult coarctation or recoarctation. When aneurysms do occur, protocol for postoperative follow-up must ensure their identification. Arguably, small aneurysms can be followed by repeated magnetic resonance imaging but large aneurysms, those showing rapid progression in size and those producing symptoms, have a high mortality as being associated with rupture. It is possible that in the future some of these aneurysms will be suitable for treatment by stent implantation. Of seven aneurysms treated surgically in this institution between 1970 and 1998, four presented with rupture [16].
7. Spinal cord protection Despite recent advances in operative technique and improvements in postoperative care, risks of spinal cord injury following coarctation repair are estimated at 0.5–5% and appear to increase with age [1]. Our current policy is to accept a perfusion pressure of no less than 50 mm Hg in the descending aorta at any stage during repair. Where the collateral circulation is inadequate to meet such criteria this can be achieved by means of a heparinised Gott shunt or by the use of partial cardiopulmonary bypass established by pulmonary artery to descending aorta or by femorofemoral bypass. Left heart bypass from left atrium to descending aorta can also be used. Femorofemoral bypass with hypothermia allowing for periods of circulatory arrest has been reserved for those cases of ruptured aneurysm where dissection at the aneurysm site may lead to haemorrhage and circulatory collapse. In such cases, an attempt is always made during thoracotomy to establish proximal control before dissection of the aneurysm itself. Ideally reliable detection of spinal cord ischaemia should be operational (regardless of surgical procedure) at a reversible stage, thus allowing appropriate intervention and therefore preventing paraparesis. Cerebrospinal fluid pressure (CSFP) measurements are well established as a means for detecting increased ischaemic risk as increased CSFP leads to vascular compression. In addition, other studies have shown that recording changes in somatosensory evoked potentials (SEP) perioperatively indicates ischaemic change. Maintaining a spinal cord perfusion pressure (SCPP) of N40 mm Hg defined as a pressure difference between the distal aortic pressure and the cerebrospinal fluid pressure, has been clinically shown to be valuable in preventing ischaemia. Wada et al.
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looked at elective repair of the descending thoracic and thoracoabdominal aorta in 82 patients with mixed aortic disease, all of whom had a temporary bypass shunt or partial cardiopulmonary bypass during the aortic cross clamping at normothermia. They monitored SEP, mean distal aortic pressure (MDAP), CSFP, perioperatively. Sixty of the patients had no ischaemic change in SEP. In 17 patients with significant ischaemic changes of SEP, SEP recovered by increasing SCPP to more than 40 mm Hg either by increasing the MDAP or by decreasing the CSFP. Complete loss of SEP was associated with paraplegia in two cases. They drew three conclusions. First, that SEP, MDAP and CSFP should be monitored during aortic cross clamping. Second, that maintaining SCPP at more than 40 mm Hg by increasing MDAP or withdrawal of SCSF is valuable for prevention of paraplegia, and lastly, that femoral vein to femoral artery pressure is useful to control the distal aortic perfusion pressure during cross clamping [17]. These findings are controversial and are of limited practical value in the majority of surgical centres but may eventually be of great value in elective aortic surgery. In complex coarctation or recoarctation in adults in whom the risk of spinal cord injury and paraplegia is highest, partial cardiopulmonary bypass with hypothermia, or on some occasions deep hypothermia, with circulatory arrest is often the most practical surgical option.
8. Repair of coarctation/recoarctation in adults through a left thoracotomy Since 1988, several authors have reported their experience with repair of complex coarctation through a median sternotomy. This was performed either to avoid the complications associated with repair through a rethoracotomy or to deal with associated valvar heart disease or coronary artery disease concomitantly. We retrospectively analysed the results of repair of coarctation or recoarctation through a left thoracotomy using a variety of techniques between 1970 and 1998. Sixty-five patients were included. Their age range was 16–58 years of age with a mean age of 27.8 years and a mean follow-up of 9.7 years. There were 38 men and 27 women [16]. There were 45 primary repairs of coarctation and 20 reoperations. Of these, 17 patients underwent a second operation, 2 a third and 1 a fourth operation. Seven procedures were performed for aneurysm formation at the site of coarctation repair. These all proved to be false aneurysms. Fourteen of the redo operations were performed for recoarctation. The mean age of the patients undergoing reoperation was 28.5F1.8 versus 27.5F2.4 years for primary repair. Of the patients undergoing reoperations, 14 were female and 6 were male ( pV0.01). The surgical techniques employed included
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end-to-end anastomosis in 11, an interposition graft in 12, a bypass graft in 12, and a patch repair in 30. The results were analysed in terms of early and late mortality and complications analysed included reexploration for bleeding, recurrent laryngeal nerve palsy, persistent gradient of more than 20 mm Hg and false aneurysm formation. There was no early mortality. The late mortality was 4.5%, three deaths occurring at 10, 14 and 19 years after surgery. One late death was unrelated and two occurred following surgery for aortic valve disease [16]. Five out of 65 patients had evidence of recoarctation defined as a resting gradient of 20 mm Hg. Recoarctation was not associated with any particular technique. False aneurysm occurred in 3 out of 45 patients undergoing primary repair and 4 out of 20 patients undergoing reoperation. The difference was not statistically significant. False aneurysm was not commoner in any single group but together patch aortoplasty and bypass grafts had a higher incidence than end-to-end anastomosis and interposition grafts ( pV0.01). Recurrent laryngeal nerve palsy occurred in 6 out of 65 patients. Five of those six patients were in the group undergoing reoperation [16]. Three out of 45 patients (or 7%) of those undergoing primary operation had one or other complication as opposed to 15 out of 20 (or 75%) of those undergoing reoperation. Since analysing these data we have elected to perform repair of recoarctation when not associated with aneurysm formation, through a median sternotomy. This technique is also preferred where concomitant procedures are indicated [16].
9. Repair of coarctation through a median sternotomy A posterior pericardial approach is performed via median sternotomy and with the aid of hypothermic cardiopulmonary bypass. After institution of bypass the heart undergoes cephalad retraction (Fig. 2) and a longitudinal posterior pericardial incision exposes the descending thoracic aorta. After application of a sidebiting clamp, an end-to-side anastomosis of the graft to the descending aorta is performed. The graft is then passed posterior to the inferior vena cava and anterior to the oesophagous, and anastomosed to the right hand side of the ascending aorta. Several authors have reported repair of coarctation through a posterior pericardial approach [18,19]. Connelly et al. performed extra anatomical posterior pericardial repairs in 18 patients between 1985 and 2000. Twelve patients had had previous surgery, 10 having had previous repair of coarctation. The surgical procedure was performed as described above. Nine of the 18 patients had associated aortic valve disease, five with aortic stenosis and four with aortic regurgitation. Three patients had coronary artery bypass surgery. The outcome of surgery was good
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Fig. 2. Repair of complex CoA with and ascending to descending aortic bypass graft. Note cephalad retraction of the heart for placing the distal part of the anastomosis.
with no operable deaths, no paraplegia and graft patency at follow-up, mean of 45 months after surgery [18]. In addition, Powell et al. [20], Pethig et al. [21] and Morris et al. [22] used a similar approach to combine coarctation repair with aortic valve repair, mitral valve surgery and CABG with equal success. We have used this approach in six cases, 5 with recoarctation, 2 combined with aortic valve replacement, and in 1 patient with primary repair of coarctation combined with replacement of the ascending aorta (Bental procedure). One patient developed postcardiotomy syndrome postoperatively, but there were no other complications. No patient had a significant gradient postoperatively, although postoperative magnetic resonance imaging showed turbulance at the right-angled end-to-side anastomosis at the descending aorta [16]. The effect of such energy loss at the right-angled anastomosis and the presence of long noncompliant bypass grafts on systemic blood pressure are unknown.
aortic valve and the incidence of ascending aorta and aortic arch pathology after coarctation repair. One hundred and twenty-four adult patients after surgical correction of aortic coarctation were studied. During follow-up, 28 patients (or 23%) developed recoarctation requiring reoperation in 10 and balloon dilatation in 18 patients. During the same period, 27 (or 22%) of patients required reintervention (25 had surgery, 2 had balloon dilatation) for aortic stenosis or regurgitation. Of the 97 patients without aortic valve intervention, 23 patients had evidence of aortic stenosis and 28 had evidence of aortic regurgitation. Aortic valve disease was therefore observed in 63% of their patients during follow-up. In addition, dilatation of the ascending aorta was found in 35 patients, most commonly associated with a bicuspid aortic valve, and aortic arch hypoplasia was found in 12 patients [7]. Attenhofer Jost et al. reviewed the clinical, echocardiographic and cardiac catheterisation data, criteria for reoperation and surgical procedures performed, and outcome in 43 patients who underwent 54 reoperations after previous coarctation repair at their institution between 1972 and 1996. Twenty-two of these 54 operations were for recoarctation, 22 had aortic valve surgery, 12 surgery on the left ventricular outflow tract, 6 underwent surgery for aneurysmal enlargement of the aorta, 5 mitral valve surgery and 2 coronary artery bypass grafting. They emphasized the importance of individualized management in patients with recoarctation and additional pathology and advocated the use of an ascending descending aorta bypass graft through a posterior pericardial approach in selected cases [8] (Fig. 3).
10. Reoperation for associated anomalies after coarctation repair After operation, the prevalence of recoarctation is variously reported to be between 3% and 41% [7,8]. However, in addition to the need for reintervention for recoarctation there is an increasing need for reoperation for associated anomalies as follow-up increases. The most common lesions requiring reoperation are aortic valve replacement, subvalvar aortic stenosis, aneurysms of the ascending aorta, coronary artery disease and mitral valve disease [7]. Roos Hesselink et al. investigated the incidence of aortic stenosis and regurgitation related to a bicuspid
Fig. 3. Three-dimensional cardiac MRI in the same patient with Fig. 2 demonstrating long bypass graft and effective relief of complex CoA with long sever arch hypoplasia.
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11. Summary The advent of catheter-based intervention has transformed the management of the adult with coarctation and recoarctation, and it is likely that with improved technology more cases will be amenable to catheter based management, even those with evidence of aneurysm formation at the site of coarctation repair. However, surgery will still be required in some cases, particularly those with hypoplasia of the aortic arch, aneurysms of the ascending aorta and intracardiac pathology. In our experience, reoperation in the adult for recoarctation through a left thoracotomy has resulted in significant postoperative morbidity and complete relief of recoarctation is difficult through this approach when there is associated aortic arch hypoplasia. In the adult, repair of coarctation and recoarctation through a median sternotomy has in our hands, as in others, proved a safe and effective alternative approach and can readily be combined with additional intracardiac procedures and replacement of an aneurysmal ascending aorta. In the future, the application of improved surgical technique to correct coarctation in the neonate and infant may reduce the incidence of recoarctation in the adult. Recently, Bakker suggested that we may now be at the point at which it is the modulation of the healing process after repair of coarctation which will lead to a further reduction in the incidence of recoarctation and consequent late hypertension. In an experimental model, they found that the topical application of vascular endothelial growth factor to the anastomotic site resulted in enhanced healing, less fibrosis and cellular infiltrate and no focal dystrophic medial calcification [23]. However, even if in the future we were able to achieve this end, patients who have had repair of coarctation will still require reoperation for problems associated with arteriopathy and associated intracardiac anomalies.
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