Keywords
graft interposition for repair of coarctation - recurrence of coarctation - development
of anastomotic aneurysms and pseudoaneurysms - endovascular stenting for recurrent
coarctation - hybrid approach for repair of late complications - ascending to descending
aorta bypass grafting through right thoracotomy off-pump
Introduction
Isolated coarctation of the aorta (CO-A) comprises a significant percentage of congenital
heart diseases.[1] It is usually diagnosed and treated when discovered, most often during infancy or
childhood, and more rarely in adulthood. Initial surgical repair is then performed
through a left thoracotomy and consists of either resection of the stenotic site with
end-to-end anastomosis or left subclavian artery (SCA) onlay patch aortoplasty. Less
common techniques include Dacron or Goretex (polytetrafluoroethylene) patch angioplasty
without resection, or interposition graft when the segment of coarcted aorta is too
long to allow resection and end-to-end anastomosis.[2] Since 1982, transcatheter balloon dilatation became an acceptable alternative to
surgery, and subsequently balloon expandable endovascular stents were used successfully
either primarily or to manage failed percutaneous transluminal angioplasty.
Despite technical success, neither initial surgical intervention nor endovascular
stenting (EVS) appears to be curative as late recurrence of coarctation and/or development
of aneurysms (ANs) or pseudoaneurysms (PANs) frequently prompt reintervention.[3]
We hereby present such a patient whose management required more than a single intervention
to treat his complex anatomy, and we discuss the therapeutic alternatives under similar
circumstances.
Case Presentation
A 64-year-old male patient presented to his primary care physician complaining of
a dry cough and recurrent bouts of bronchitis as well as frequent orthostatic dizziness.
At the age of 20 years, he had undergone repair of CO-A through a left thoracotomy
using an interposition Dacron graft between the left SCA and the mid thoracic aorta.
His chest radiograph raised suspicion of AN of the thoracic aorta. Computed tomographic
angiogram then confirmed the presence of two large anastomotic PANs at both ends of
the graft ([Fig. 1]) as well as an occluded right SCA, stenosis of the left vertebral artery, and bovine
origin of the carotid arteries ([Fig. 2]).
Fig. 1 Computed tomographic findings. Upper panel, lateral view: proximal (upper arrow)
and distal (lower arrow) large anastomotic pseudoaneurysms of the left subclavian
to aorta bypass graft. Lower panel, frontal view: arrow points to large distal graft
pseudoaneurysm.
Fig. 2 Proximal (upper arrow) and distal (lower arrow) pseudoaneurysms of left subclavian
to aorta bypass graft. Occluded right subclavian artery. Bovine origin of carotids.
Stenosis of the origin of the left vertebral artery.
In view of this complex anatomy, the decision was made to use a hybrid approach to
address these findings. In a first stage, a right carotid artery to right SCA bypass
was done using a short segment of Goretex graft ([Fig. 3]). Next, using single lung ventilation, a right posterolateral thoracotomy was performed
and the chest entered through the fifth intercostal space. With the diaphragm retracted
inferiorly, the pericardium, posterior to the phrenic nerve, was gently lifted with
a long clamp, thus allowing exposure of the distal most portion of the thoracic aorta,
medial to the inferior vena cava (IVC). After heparinization, the aorta was partially
clamped and a 22 mm Hemashield graft anastomosed in an end-to-side fashion to an appropriate
aortotomy using a continuous suture of 5–0 Prolene ([Fig. 4]). The graft was then brought posteriorly to the IVC and anteriorly to the right
hilum, then anastomosed in an end-to-side similar fashion to the partially occluded
ascending aorta through a vertical pericardial opening ([Figs. 5], [6]).
Fig. 3 First-stage surgery: right carotid to subclavian artery bypass graft.
Fig. 4 Right posterolateral thoracotomy and off-pump anastomosis of distal graft to supradiaphragmatic
aorta.
Fig. 5 Proximal graft anastomosis to ascending aorta.
Fig. 6 Completed extra-anatomic ascending aorta to descending aorta bypass graft through
right thoracotomy and off pump.
The immediate postoperative course was uneventful, and 5 days later, the patient was
brought to the hybrid operating room for completion angiogram. This confirmed patency
of the extra-anatomic graft as well as the presence of a 4 cm proximal left SCA anastomotic
PAN with close extension to the left vertebral artery origin, and a 4.5 cm distal
anastomotic PAN. EVS of the proximal PAN was done using a 16 × 80 mm covered Medtronic
stent deployed across the origin of the left vertebral artery ([Fig. 7]).The distal PAN was excluded using a 26 × 100 mm covered Medtronic stent extending
from the level of the coarctation to the insertion of the extra-anatomic bypass graft
([Fig. 8]). Completion angiogram confirmed patency of the latter and occlusion of the left
SCA to thoracic aorta graft as well as of both anastomotic PANs ([Fig. 9]). The postoperative course was uneventful and the patient remains asymptomatic 2
years later and will be followed up on a yearly basis.
Fig. 7 Upper panel: angiographic finding of the proximal anastomotic pseudoaneurysm (arrow).
Lower panel: endovascular stenting of the proximal anastomotic pseudoaneurysm with
16 × 80 mm Medtronic covered stent graft deployed across the origin of the left vertebral
artery.
Fig. 8 Upper panel: angiographic finding of the distal anastomotic pseudoaneurysm (arrow).
Lower panel: endovascular stenting of distal anastomotic pseudoaneurysm with 24 ×
100 mm long Medtronic stent graft from level of coarctation to the insertion of the
ascending-to-descending thoracic aorta bypass graft.
Fig. 9 Completion angiogram shows a patent extra-anatomic ascending to descending aorta
bypass graft (arrow), occluded left subclavian to thoracic aorta bypass graft, and
occluded proximal and distal pseudoaneurysms.
Discussion
Late complications after surgical repair of CO-A are not uncommon, the most frequent
being recurrence of the coarctation and development of anastomotic ANs and PANs. The
latter are the result of suture line disruption between a prosthetic patch—used for
aortic augmentation—or a tube graft and the aorta, or of the progressive occurrence
of fusiform widening of the aorta. There is also an increased risk of such complications
after balloon angioplasty, usually occurring early after the intervention, in contrast
to their late occurrence after surgical repair of the CO-A.
Left alone, recurrent CO-A ultimately leads to severe hypertension with its associated
significant complications. Similarly, conservative management of AN and PAN complicating
surgery for CO-A can also be fatal due to a documented high risk of rupture.[4]
[5]
[6] Thankfully, several therapeutic options have become available in the prevention
and management of such complications.
With increasing patient demand for less invasive options and the development of sophisticated
percutaneous technologies, it is now well established that stent implantation carries
lower morbidity and mortality compared with surgery for recurrent isolated CO-A. This
is particularly so in high-risk patients with coronary artery disease, ventricular
dysfunction, or other significant comorbidities. An additional advantage of EVS is
the fact that it requires a much shorter hospitalization, causes less postprocedure
pain, and allows earlier return to full activities. EVS has also recently emerged
as the least invasive approach to treat thoracic aortic ANs and dissections and has
thus also grown in popularity in the treatment of anastomotic AN and PAN after CO-A
repair, either primarily[7] or in combination with surgical repair, the so-called hybrid solution.[8]
[9]
[10] Despite very encouraging early results, there remain, however, several early and
late complications of endovascular interventions,[11] namely stent migration, aortic rupture and, at times, difficulty achieving a satisfactory
proximal seal without occluding the left SCA. Although often well tolerated, occlusion
of this artery may occasionally cause limb ischemia necessitating reimplantation of
the left SCA or a carotid to subclavian bypass graft. Interestingly, somatic growth
in children with coarctation frequently necessitates further vascular interventions,
thus limiting the indication for stenting at a young age.
Surgical reintervention, when indicated, is more challenging. Despite improvements
in surgical techniques, it carries a significant morbidity and mortality, particularly
when traditional redo left thoracotomy is the chosen approach as this involves the
difficult tasks of releasing extensive lung adhesions while avoiding bleeding and
major air leaks, mobilizing the thoracic aorta extensively to cross-clamp it above
and below the AN, and avoiding phrenic and recurrent laryngeal nerves as well as thoracic
duct injuries and preventing the rare occurrence of a devastating spinal cord ischemia.
For all those reasons, most surgical reinterventions today avoid left chest re-entry
and, instead, aim at creating an extra-anatomic ascending aorta to descending aorta
(EA AS-DA) bypass graft.[12]
[13] This is usually achieved through a median sternotomy and cardiopulmonary bypass,
thereby facilitating elevation of the heart and completion of the distal anastomosis
to the supradiaphragmatic thoracic aorta through a posterior retrocardiac pericardial
rent. This approach has the advantage of also addressing the management of more proximal
aortic arch anomalies as well as the repair of coexistent intracardiac anomalies.
Less frequently, and using the same sternotomy approach extending to the upper abdomen
and without the need for cardiopulmonary bypass, the extra-anatomic graft is extended
from the ascending aorta to the supraceliac abdominal aorta.[14] Although achieving excellent results with low morbidity and mortality, the sternotomy
approach does not address the issue of AN and PAN complicating coarctation repair.
It is indicated mostly in cases of recurrent CO-A with or without concomitant intracardiac
pathology as well as in acquired coarctation after repair of traumatic transection
of the descending aorta.
A valid alternative approach to tackle recurrent CO-A without concomitant intracardiac
pathology is through an off-pump right posterolateral thoracotomy[15]
[16]
[17] as described in our case report. Through virgin territory and with the beating heart
untouched, an EA AS-DA bypass graft can easily be sutured in place, thus avoiding
both sternotomy and cardiopulmonary bypass with their many potential complications.
Unfortunately, both surgical approaches, sternotomy and right thoracotomy alone, fail
to address the issue of post coarctation repair of AN and PAN. Because there is no
single recipe for the management of these complex cases, the selection of the appropriate
technique of repair in each patient's case requires careful evaluation by a multidisciplinary
team and a tailored approach. Thus arose the need in our case for a hybrid approach
combining both an EA AS-DA bypass around the recoarctation and an EVS of the aneurysmal
dilatation or PAN formation as in our case report.
Discussion
While initial surgical repair of CO-A in infancy remains the gold standard, reintervention
at a later age is often necessary due to the frequent recurrence of the coarctation
and/or the formation of ANs or PANs secondary to delayed suture line disruption.
Presently, it appears that EVS is ideally suited—and very successful—in most cases
of isolated re-CO-A and in some cases of AN or PAN formation.[7]
[18] In more complex situations, surgical intervention becomes necessary, whether by
sternotomy—particularly when there are concomitant arch or intracardiac anomalies
that need to be corrected simultaneously—or right thoracotomy, with creation of an
EA AS-DA bypass graft. Irrespective of the surgical approach, surgery alone often
fails to address the associated AN or PAN. In these cases, a hybrid approach combining
both surgery and EVS in a single or staged approach offers a significant advantage
in converting an incomplete and risky surgical procedure into a safe and effective
one as this case report demonstrates.
There are currently no clear guidelines and no single method to deal with the management
of the late complications of surgery for isolated CO-A. Thus, careful evaluation of
each case by a multidisciplinary team should allow the selection of the most appropriate
therapeutic approach: EVS in most cases of isolated recurrence of the coarctation,
surgical approach in more complex cases, or a combination of both, the hybrid approach.
Irrespective of the type of repair, and even after successful intervention, all patients
undergoing CO-A repair will need lifelong clinical and imaging follow-up to detect
and treat potential late complications, not the least being hypertension, congestive
heart failure, and coronary artery disease occurrence.
