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Address for reprints: M. Doss, MD, Department of Thoracic and
Cardiovascular Surgery, J.W. Goethe University Frankfurt am Main, Theodor Stern
Kai 7, 60599, Frankfurt am Main, Germany
Management of extensive thoracic aortic disease may present an
immense technical challenge. The choice of surgical access and subsequent
exposure determines whether a single-stage or a 2-stage approach can be
adopted.
Methods
Fifteen patients with extensive thoracic aortic disease underwent
resection of the ascending aorta, the aortic arch, and varying segments of the
descending aorta. Four patients had concomitant coronary artery bypass grafting
and 3 patients had aortic valve reconstruction. All patients were treated with a
single-stage approach via a bilateral anterior thoracosternotomy (clamshell
incision).
Results
There was 1 hospital death (6.6%). Two patients required reoperation
for bleeding (13.3%). Two patients needed mechanical ventilation for more than
48 hours. Three patients suffered a stroke (20%). Two patients (13.3%) had
transient neurologic dysfunction. None of the patients had renal failure. There
were no wound infections in this group.
Conclusion
The single-stage approach, via a clamshell incision, is a safe and
effective procedure for patients who require treatment of extensive thoracic
aortic disease and concomitant cardiac lesions.
The optimal surgical treatment of patients with extensive thoracic aortic
disease involving the ascending aorta, aortic arch, and descending aorta is not
clearly established. Some of these patients also require concomitant treatment of
coronary artery or heart valve disease. Conventionally, a 2-stage approach is
adopted to gain access to all parts of the thoracic aorta and cardiac structures.
This, however, exposes the patient to the risk of 2 major procedures. The elephant
trunk technique is a means to facilitate the second surgical procedure;
nevertheless, associated mortality for both stages still remains high, and
especially ruptures in the interval between the stages represent an avoidable
additional risk.
Alternatively, a single-stage approach via transverse thoracosternotomy (clamshell
incision) can be performed.
We present our experiences with a single-stage repair of extensive thoracic
aortic disease, using the clamshell incision.
Methods
Between January 1998 and May 2000, 15 patients with extensive thoracic
aortic disease were treated at our institution via a clamshell incision in a
single-stage approach. The mean age of these patients was 66.5 ± 7.6
years. There were 7 men and 8 women. Nine patients underwent replacement of the
entire thoracic aorta; 3 patients had replacement of the ascending aorta and
aortic arch; 3 patients had replacement of the aortic arch and descending
thoracic aorta.
The underlying pathology was atherosclerotic aortic aneurysm in 13 cases
with a diameter greater 5.5 cm, type B dissection in 1 case, and type A
dissection with a thrombosed false lumen extending into the descending aorta in
2 cases. Four patients had concomitant coronary artery disease requiring
myocardial revascularization. Another 3 patients had additional aortic valve
disease that was treated by aortic valve reconstruction.
The indications for operation were progressive enlargement of the involved
aortic segment, documented by computed tomography or magnetic resonance imaging
in all patients, and the presence of symptoms. All elective patients had
preoperative cardiac catheterization and echocardiography. A demographic survey
of all patients’ concomitant comorbidities is provided in Table 1.
TABLE 1Concomitant diseases of patients undergoing clamshell
incision
Surgical access to the chest was gained through a bilateral anterior
thoracotomy and transverse sternotomy in the fourth or fifth intercostal
space (Figure 1). The incision was extended from the medioclavicular line on
the right to the anterior axillary line on the left. The internal thoracic
arteries were both ligated or dissected when needed. Then the heart and the
entire thoracic aorta were exposed and dissected. To establish
cardiopulmonary bypass, the right subclavian artery (n = 9), the femoral
artery (n = 2), or direct cannulation (n = 4) of the aortic arch was used
for arterial return, and the right atrial appendage was cannulated for
venous return. During circulatory arrest, retrograde cerebral perfusion (n =
3), at 18°C rectal temperature, and antegrade cerebral perfusion (n =
12), at 22°C rectal temperature, were applied.
Figure 1Intraoperative view. The clamshell incision provides excellent
exposure of the entire thoracic aorta and cardiac structures.
For patients who had concomitant coronary artery bypass grafting,
exposure of the 3 major arterial systems was possible by widely incising the
pericardium. The left internal thoracic artery was dissected when needed.
The aortic root was also accessible, if aortic valve reconstruction was
indicated.
The clamshell approach was chosen in patients in whom the underlying
pathology would conventionally require a staged repair via 2 separate
incisions, or technical difficulties at the distal arch anastomoses due to
sclerosis or dissection were anticipated. With increasing experience, we
employed this technique for patients in whom we anticipated technical
problems in exposure via a median sternotomy.
Indications for the clamshell incision were an aortic aneurysm of the
complete thoracic aorta; a combination of aortic aneurysms of the complete
aortic arch and the ascending or descending aorta; severely diseased other
segments; a combination of aortic aneurysms of the complete aortic arch or
descending aorta; and coronary heart disease or aortic valve disease.
Further indications were a combination of an acute type A dissection with an
entry tear in the descending aorta and coronary heart disease; a type A
dissection extending into the descending thoracic aorta with a thrombosed
false lumen in the aortic arch; a combination of a type B dissection and an
ascending aortic aneurysm; a distal arch aneurysm with left lateral
dislodgement of the proximal descending aorta; and dilatation of the
proximal descending or ascending aorta in the presence of severe sclerosis
combined with a descending aortic aneurysm.
Results
In all cases, we obtained good exposure of the chest cavity, which enabled
us to successfully treat all pathologies of the entire thoracic aorta and
concomitant cardiac lesions in 1 session. The mean bypass time was 191 ±
51 minutes and the mean crossclamping time was 90 ± 41 minutes. Mean
circulatory arrest or low flow time was 26 ± 17.5 minutes.
Morbidity
Two patients (13.3%) required reexploration for bleeding. In all cases,
the hemorrhages were easily controllable. The mean postoperative blood loss,
via chest tubes, was 1250 ± 506 mL. All patients were weaned from
mechanical ventilation. Two patients with preexisting respiratory
insufficiency were ventilated for more than 48 hours. None required
tracheotomy.
The mean intensive care unit stay was 7.5 days. None of the patients
developed renal failure requiring temporary hemofiltration or hemodialysis.
There were no cases of left recurrent laryngeal nerve injury.
A total of 5 patients had neurologic dysfunctions postoperatively.
Three patients (20%) had a stroke, 1 early on postoperative day 9 and 2 late
postoperatively. Transient neurologic dysfunction occurred in 2 patients
(13.3%) and resolved completely before discharge. None of the patients had
evidence of spinal cord ischemic injury.
There were no deep wound infections, and postoperative pain was
controlled by oral analgesics. The mean duration of postoperative hospital
stay was 23 ± 14 days.
Mortality
There was 1 hospital death (6.6%). This patient had undergone
replacement of the ascending aorta, aortic arch, and descending thoracic
aorta. After an initial uneventful postoperative course that included
extubation, she had a stroke and died on postoperative day 9. A computed
tomography scan was performed that showed signs of cerebral edema and brain
stem infarction. There were no signs of intracranial hemorrhage.
Discussion
The clamshell incision has been used widely for the performance of
bilateral lung transplantation.
This approach provides excellent exposure of
the entire thoracic aorta, venae cavae, the heart, and both pleural spaces. We
have adopted this technique in our effort to treat patients with extended
thoracic aortic disease and patients requiring replacement of the descending
thoracic aorta and concomitant cardiac surgery, in 1 session.
We feel that the conventional 2-stage approach bears a number of
disadvantages. It is used because a median sternotomy does not allow for
adequate exposure of the descending thoracic aorta and distal arch. Therefore,
surgeons are forced to make a number of compromises, such as a second painful
incision, dissection through dense adhesions from the previous procedure,
application of an aortic clamp near the proximal anastomotic site with the
increased risk of bleeding, or repeated hypothermic circulatory arrest and
repeated anesthesia.
The difficulties encountered at the distal suture line were addressed by
introducing the elephant trunk technique, which allowed for technically easier
graft-to-graft anastomoses. Therefore, the second stage of the operation was
facilitated. However, the interval between the stages remains a cause of
concern, as recent literature suggests that there is a mortality of 10% in this
period among patients on the waiting list.
The need for a second operation brings the avoidable risk of 2 major
procedures. For instance, staged replacement of the entire thoracic aorta is
associated with a mortality rate of 7% to 16%, a neurologic sequelae rate of 9%
to 60%, respiratory insufficiency rate of 32%, and a renal failure rate of 10%,
per session.
describe an additional incidence of pulmonary
complications in 32%, renal insufficiency in 16%, cardiac complications in 29%,
and encephalopathy in 6% of their patients. Furthermore, the need for repeated
general anesthesia, a second extracorporeal circulation, and circulatory arrest
have to be considered.
The foremost advantage of the clamshell incision is that its superior
exposure of all relevant thoracic structures enables surgeons to treat complex
thoracic diseases in 1 session, thereby avoiding the additional perioperative
mortality and morbidity of a second procedure. Our encouraging experiences in
the treatment of extensive aortic disease in pediatric cases via this incision
prompted us to employ this technique in concomitant complex cardiac and aortic
lesions. In all of these cases, excellent exposition of the cardiac structures
and thoracic aorta was obtained, enabling us to treat these children in 1
session.
The transverse thoracotomy is a single symmetric incision, giving a good
cosmetic result with 2 incisions and a good quality of life. Although it causes
more pain than a median sternotomy, it is certainly better tolerated than a
poster lateral thoracotomy.
Women especially benefit from this incision,
as the scar is partially hidden by the breasts; multiple chest scars and the
occurrence of breast asymmetry are avoided.
A number of disadvantages of the clamshell incision have been described.
The incision requires the ligation of both internal thoracic arteries, which is
a downside of the procedure. Griepp and Ergin
describe a serious deleterious effect on
pulmonary function in their group of patients after transverse thoracotomy, with
55% respiratory insufficiency compared with 32% for the staged approach. Our
respiratory insufficiency rate was 13.3%.
In our experience, the clamshell incision has no additional risk of
respiratory insufficiency, especially considering the good results obtained with
this incision in bilateral lung transplantation, where an increased risk of
respiratory insufficiency would indeed be deleterious. Furthermore, higher
postoperative bleeding rates and a higher perioperative mortality of up to 55%
versus 13% for the staged approach are described in the literature.
Two of our patients needed
reexploration for bleeding. This rate is comparable to reexploration rates for
single replacement of the descending thoracic aorta via poster lateral
thoracotomy.
who
describe a low mortality rate, no respiratory insufficiency, and a low
reoperation rate for bleeding in their experience with the clamshell incision.
Our in-hospital mortality of 6.6% shows that the approach alone does not
necessarily explain the high rates of mortality described by other authors for
this technique.
In conclusion, we would like to state that the clamshell incision gives
superior exposure of the entire thoracic aorta and the heart. Thus, extended
aortic replacement and combined cardiac procedures can be performed safely, in a
single-stage approach. Our encouraging results from using this technique need to
be confirmed by larger series.
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