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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3734_Библиотеки_им_академика_М_И_Перельмана
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50%
5.0 to 5.9 cm
4.0 to 4.9 cm
300 179 165 136102 76
* at Risk
Diagnosis andManagement ofRuptured Thoracic Aortic Aneurysms
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449
Fig. 1 Kaplan-Meier
cumulative hazard function
of rupture or dissection.
Five-year hazard estimates
are illustrated for patients
as a function of initial
aneurysm size (p=0.006)
Fig. 2 Ruptured
descending thoracic
aneurysm
45%
40%
35%
30%
25%
20%
15%
10%
5%
Cumulative Incidence of Rupture or Dissection
0%
Years
0
12345
t6.0 cm
3.5 to 3.9 cm
Diagnosis
Rupture of TAA may be suggested by clinical presentation but the diagnosis must
be conrmed by cross-sectional imaging. The modality of choice is computed
tomographic (CT) angiography due to the rapidity of image acquisition and highly
detailed imaging resolution. While it may be difcult to get an unstable patient to
the scanner, the imaging is absolutely necessary for identifying the cause and location of rupture, and for operative planning.
The etiology of rTAA is most often from aortic aneurysmal disease or aortic
dissection (Figs.2 and 3). A smaller proportion of ruptured aortas are due to blunt
force trauma and rapid deceleration injuries causing tearing and pseudoaneurysm
formation at the aortic isthmus. CT can clearly identify whether aortic dissection
is present and it can give a sense of the chronicity of the dissection if present. It
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Fig. 3 Ruptured type B
aortic dissection
C. Lau et al.
characterizes the location and nature of the ruptured area, which is important
information for planning the operation. Knowledge of the location of rupture is
clearly of utmost importance to determine whether sternotomy, thoracotomy or
endovascular approach is appropriate. The extent of aorta that is involved or aneurysmal will also dictate the amount of aorta that is replaced and specic technique
that is used.
Aside from cross-sectional imaging of the aorta, a baseline echocardiogram documenting the ventricular function and any valvular pathology is helpful for risk
stratication. Valvular pathology may require additional valve repair or replacement
while regional wall motion abnormalities may imply a potential need for concomitant coronary artery bypass grafting. Usually the luxury of a cardiac catheterization
to identify coronary disease and anatomy is not available due to the urgency of the
need for surgical intervention.
Surgical Management
Ruptured TAA located in the ascending aorta are usually associated with an acute
type A aortic dissection while ruptured aneurysms of the descending or thoracoabdominal aorta are comprised of a mix of pure aneurysmal disease, acute dissection,
and chronic dissection. While rTAA of the ascending aorta are almost exclusively
approached with open surgical repair via a sternotomy, ruptured descending thoracic aneurysm (DTA) may be repaired with either endovascular or open surgical
techniques, depending on the situation.
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Ruptured Ascending/Arch Aneurysm
The available data on ruptured ascending aortas is limited. A majority of patients
with ruptured ascending aortas likely die in the eld due to cardiac tamponade. The
data that is available is difcult to compare due to differing denitions of “rupture.”
Rupture may be dened as bloody pericardial effusion, presence of cardiac tamponade physiology, or evidence of frank blood or clot in the pericardium. In our experience, rupture may also occur on the aortic wall adjacent to another structure such as
the pulmonary artery, thus containing the blood in the epicardial tissues. Those with
ruptured ascending aortas who survive to surgery have usually sealed or contained
the rupture. The sternotomy and pericardiotomy often actually improve hemodynamics by relieving some degree of tamponade physiology.
In these cases, the priority is to get the patient on cardiopulmonary bypass in
order to decrease the impulse pressure, which reduces the risk of worsening rupture.
Secondly, if the rupture is located in the ascending aorta or aortic root, crossclamping and cardioplegic arrest will resolve the rupture issues. Aortic arch ruptures
require repair with hypothermic circulatory arrest, which we routinely perform with
adjunctive retrograde cerebral perfusion [6], although selective antegrade cerebral
perfusion may be substituted depending on surgeon and institutional preferences.
Rupture dened as bloody pericardial effusion has not been found to be a risk factor for in-hospital mortality but may have some detrimental effect on long-term survival [7]. However, in an analysis of the International Registry of Acute Aortic
Dissection database, 18% of patients with type A dissection had cardiac tamponade
and the mortality in this group was signicantly higher than in those without cardiac
tamponade (44% versus 20%, p<0.001). Additionally, periaortic hematoma is found
in 45% of patients with cardiac tamponade and this itself is an independent predictor
of mortality in patients with aortic dissection [2]. The presence of cardiac tamponade
warrants emergent surgical intervention in order to prevent the later sequelae of prolonged low cardiac output, such as vasoplegia, renal failure, and hepatic failure.
Ruptured Descending/Thoracoabdominal Aorta
The management of ruptured DTA depends heavily on a number of factors including the etiology of the rupture, the experience and expertise of the operating surgeon
and institution, the appropriateness of the aortic anatomy for thoracic endovascular
aortic repair (TEVAR), and the availability of the appropriate implants. The need to
proceed rapidly with repair limits these options. While some centers are equipped
for expedient open aortic surgery, others may only have endovascular repair options
available. Aneurysmal involvement of the visceral segment of the thoracoabdominal
aorta further limits endovascular options. Endovascular repair in the visceral segment currently requires custom-made branched or fenestrated grafts that are not
available on an emergent basis. Off-the-shelf options are not widely available at this
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time. Most centers do not have the resources and experience required to offer reasonable outcomes with both open repair and endovascular repair. There is a clear
volume-outcome relationship at both the center and the surgeon level [8, 9].
Therefore, surgeons should use the approach that they are most familiar, whether
that is endovascular or open repair. If the aortic anatomy precludes that approach
then they should send the patient to a center experienced in the matter. At our center,
we perform open aortic repair on all patients presenting with ruptured DTA with
inadequate TEVAR landing zones or TAAA with involvement of the visceral branch
vessels [10]. We employ TEVAR for ruptured aneurysms isolated to the DTA with
adequate proximal and distal landing zones. In the setting of ruptured aneurysm
with aortic dissection, we often perform open aortic repair rather than TEVAR due
to the difculty of permanently sealing off false lumen ow due to the inevitable
presence of downstream fenestrations that perpetuate false lumen ow.
C. Lau et al.
Aneurysm Versus Dissection
Consideration must be given to the primary aortic pathology causing the ruptured
aorta, whether it is due to degenerative aneurysm, acute dissection, or chronic dissection. Degenerative aneurysms may be approached with either open surgical repair or
TEVAR depending on the anatomy of the aneurysm and landing zones. Acute dissections with rupture may benet from a TEVAR approach due to the fragile nature of
acutely dissected aorta and the difculty of open surgery in this setting. However,
TEVAR may be more applicable in aortas that are not severely aneurysmal. With a
rupture, one must be sure that the primary tear is covered and that there is complete
obliteration of the false lumen in the area of the rupture to ensure that there is no
perfusion to the ruptured area. With chronic aortic dissection and rupture, we would
not recommend an endovascular approach. The indications for TEVAR have been
expanding and some groups have had early success with TEVAR for chronic type B
aortic dissections when anatomic criteria are appropriate (suitable proximal and distal landing zones, visceral vessels originating from the true lumen, absence of
extremely small true lumen, presence of large proximal entry tear, and absence of
connective tissue disorder) [11]. In follow up studies, reverse aortic remodeling and
false lumen thrombosis have been seen in 86–91% of patients [12]. However, in the
setting of aortic rupture, acute obliteration of false lumen ow cannot be guaranteed
due to the stiff nature of the intimal septum and continued blood loss through the
area of rupture may be possible. In this setting we prefer open surgical repair.
Open Repair
Open surgical repair is a versatile method of treating rTAA that can be used for all
types of aortic anatomy, including aneurysms extending into the aortic arch and/or
involving the visceral segment and abdominal aorta. However, it remains a
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formidable surgical challenge with morbidity and mortality that remain signicantly
higher than in elective situations [10]. Historical data from the Nationwide Inpatient
Sample from 1988–1998 showed that open repair of rTAAA carried a 53% mortality
but this sample included low-volume centers and both surgical technique and critical care have improved signicantly since that time [13]. In contemporary singlecenter series, operative mortality ranges from 12% to 26% [10, 14–18]. However,
centers with less experience who decide to attempt repair given the near certain risk
of death without surgery likely contribute to the overall poor nationwide results.
Our algorithm for treating rTAAA is based on that we have described for intact
TAAA [19] and modied according to the hemodynamic stability of the patient and
the anatomy of the aneurysm. In unstable patients we skip the preoperative lumbar
spinal drain and proceed straight to surgery. We perform a 5th–6th interspace thoracotomy and obtain proximal control immediately. Care is taken not to mobilize the
lung off of the aneurysm aggressively because the rupture is often contained by the
mediastinal tissues or lung itself. If proximal control is not attainable then cooling
for circulatory arrest is initiated, usually via femoral cannulation. If proximal control is obtained, we almost exclusively use a clamp-and-sew technique for unstable
patients in order to proceed as rapidly as possible. A lumbar spinal drain is then
placed postoperatively in the operating room for spinal cord protection.
In stable patients, attempt is made to place a preoperative lumbar spinal drain
given the strong evidence showing a reduction in spinal cord injury and minimal
adverse effects of drainage [20, 21]. Hypothermic circulatory arrest is utilized when
proximal control is lacking. When proximal control is attainable either between the
left common carotid artery and left subclavian artery or distal to the left subclavian
artery, then repair is completed with mild hypothermia with or without left heart
bypass support. Simpler repairs such degenerative aneurysms limited to the thoracic
aorta are repaired with a clamp-and-sew technique. Complex repairs, such as extent
II TAAA or aortic dissections are repaired with the support of left heart bypass due
to the increased time necessary to perform the repair and the increased risk of spinal
cord injury. In these cases there is often an abundance of patent intercostal arteries
that require time-consuming ligation. Left heart bypass is initiated from the left
inferior pulmonary vein to the distal aorta or femoral artery. The proximal anastomosis is performed on partial bypass and then bypass is discontinued to perform an
open distal anastomosis often with reimplantation of one to two sets of intercostal
arteries in the lower thoracic region.
Using these techniques, our group recently reported on the repair of 100 consecutive rTAAA with an operative mortality of 14% [10], which represents an
improvement from 18.5% in our prior series [22]. Improvement in surgeon experience, surgical technique, and perioperative care likely contributed to the improvements in outcomes. However, the results in the rupture group still remained over
threefold worse than in the intact aneurysm group, which had a mortality of only
4.2% (p=0.01) (Fig.4). Additionally, the incidence of major postoperative adverse
events was signicantly higher in the rupture group. Myocardial infarction (7.0% vs
0.8%, P<0.004), respiratory failure (19% vs 5.7%, P <0.001), and the need for
postoperative dialysis (11% vs 4.2%, P= 0.01) were all more prevalent in those
presenting with rupture. Fortunately, spinal cord injury was not more common (5%
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Cumulative Survival
Rupture
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C. Lau et al.
1.0
0.8
Groups
Intact
Rupture
Intact-censored
Rupture-censored
p:<0.001
0.6
0.4
0.2
0.0
575
100
.00
309 236 189
1.00 2.00 3.00 4.00 5.00
Number at risk:
3236
154
27
23
124
Intact
21
Time (Years)
Survival
Intact 94.0% (92.0%-96.0%)
30 days (95% CI)
73.5% (64.3%-82.7%)
3- Year (95% CI)
71.2% (66.5%-75.9%)
56.0% (44.2%-67.8%)
5- Year (95% CI)
59.5% (53.8%-65.2%)
47.5% (35.0%-60.0%)Rupture
Fig. 4 Kaplan-Meier survival curves, rupture versus intact, in the unmatched series. CI, Condence
interval
vs 2.4%, P=0.16). Similar to ndings from other groups, the 5-year survival was
lower (47.5% vs 59.5%, P<0.001) than for our nonruptured group [10].
Endovascular Repair
TEVAR has become a viable alternative to open surgical repair and it is being used
with increasing frequency for rTAA. A majority of patients with rTAA present to
hospitals that do not perform open DTA/TAAA repair in high volume and lack the
infrastructure to achieve optimal results with open surgery. However, a growing
number of surgeons have learned and developed endovascular skills, making successful treatment with TEVAR a possibility for a larger number of patients, even in
a smaller hospital center. Potential advantages of TEVAR are the minimally invasive nature of the procedure, avoidance of thoracotomy incisions, more rapid recovery, and lower incidence of respiratory complications. While one might expect a
minimally invasive endovascular procedure to have signicantly better outcomes
compared to open aortic repair, in reality, the incidence of major postoperative
adverse events is quite similar, with the exception of reduced pulmonary complications. However, the trade-off is a high incidence of endoleaks, increased need for
re-intervention, and poorer long-term survival [3, 23–31] (Fig.5).
Freedom From Reintervention
Time (months)
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1.0
0.8
0.6
0.4
0.2
DTAR n=34
TEVAR n=35
0.0
0
Fig. 5 A Kaplan-Meier analysis describing the need for reintervention in any aortic segment. This
analysis suggests that the need for aortic reintervention at any aortic segment (treated, adjacent, or
remote) is signicantly higher in the TEVAR group. Freedom from reintervention at 4years was
87.4% for DTAR vs 61.2% for TEVAR (P=0.037). In this analysis, if patients were deemed to be
nonoperative, or refused further intervention, the date at which point the need for reintervention
was identied was used as the time of treatment failure
22
11 654
12 24
DTAR
p=0.037
TEVAR
16 13 9
36 48
In our practice, we employ TEVAR for rTAA when the anatomy is ideal. These
are patients with aneurysm and rupture isolated to the DTA, who have adequate
proximal and distal landing zones and reasonable iliofemoral arterial access. If debranching of the arch will be necessary to obtain an adequate proximal landing zone,
our preference is open repair. We also exclude chronic dissections from TEVAR
while acute complicated type B dissections are approached with endovascular repair
when anatomically feasible.
Operative mortality associated with TEVAR for rTAA has varied widely from
3% to 48% [3, 23–31] highlighting the importance of operator and institutional
experience as well as the high-risk nature of these patients regardless of the repair
methods chosen. The incidences of stroke and spinal cord injury were similar to
most open surgical series, ranging from 0–11% and 4–26%, respectively [23–31].
The rate of endoleaks with TEVAR is quite prominent, occurring in approximately
16–18% of patients in a majority of series resulting in need for re-intervention in up
to 24% of cases [23, 25, 26, 28, 29, 31]. The need for re-interventions in those surviving the initial procedure remains disappointing and negates the early mortality
benet of TEVAR in rTAAs in large data sets where late survival is actually worse
with TEVAR then open repair [3].
Although pulmonary complications are less common with TEVAR than open
surgery, in the setting of rTAA, it is still a common complication occurring in at
least 18% of patients partly due to the presence of retained hemothorax [23, 32].
Undrained blood in the thorax may contribute to respiratory complications. At a
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C. Lau et al.
minimum, the presence of hemothorax should indicate a thoracostomy tube and
nearly a quarter of patients may require a thoracic drainage procedure [23]. If chest
tube drainage fails to evacuate clotted blood, this could lead to brothorax.
Traumatic Aortic Rupture
One entity particularly well-suited for TEVAR rather than open repair is traumatic
aortic rupture (Fig.6). A majority of these patients have suffered from blunt force
trauma causing injury at the isthmus of the aorta and have signicant other associated traumatic injuries. Obtaining proximal aortic control can be hazardous during
open repair due to the location of injury near the crossclamp site. Additionally, the
higher amount of heparin necessary could worsen other injuries. TEVAR is wellsuited since a majority of these patients have normal-sized aortas and landing zones
are usually not an issue, although some patients will require coverage of the left
subclavian artery. Direct comparisons between open repair and TEVAR for traumatic aortic rupture favor TEVAR in this situation [33, 34].
Comparison ofOpen Versus Endovascular Repair
ofRuptured DTA
Comparisons between open repair and TEVAR for rTAA are skewed by confounding factors that affect patient selection. Thus, comparisons of the two groups are
often not between evenly matched patient cohorts with similar risk factors and
Fig. 6 Traumatic aortic
rupture with pseudoanuerysm
at the aortic isthmus after
blunt trauma
Diagnosis andManagement ofRuptured Thoracic Aortic Aneurysms
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anatomy. For example, patients with favorable anatomy and thus lesser risk, such as
a mid-descending aneurysm with normal proximal and distal landing zones, are
more likely to be repaired by TEVAR.Older patients, who may be higher risk would
also be considered for TEVAR in order to avoid a risky open procedure, even if
landing zones are suboptimal. Some difcult anatomies, such as distal arch aneurysm or perivisceral aneurysms, are not candidates for routine TEVAR and these
higher risk patients can only be repaired by open surgery. These anatomic risk factors are often not captured even when patients are matched for baseline characteristics in studies. Despite this, a risk adjusted study from the US nationwide Inpatient
Sample found that that the odds of mortality, complications, and failure to rescue
were similar for TEVAR and open repair. Additionally, results of TEVAR were similar in smaller compared to larger hospitals but the results of open repair were poorer
in smaller hospitals, where open repair expertise may have been lacking [35]
(Table1).
Single-center studies comparing open repair to TEVAR have often found TEVAR
to be associated with a lower operative mortality and more favorable discharge disposition [16, 36]. However, other series from centers experienced in open repair
have reported operative mortality as low as 14%, which is favorable compared to
most TEVAR series [10]. A recent meta-analysis reported lower operative mortality
with TEVAR (19% versus 33%, p=0.016) but TEVAR was associated with a signicant number of aneurysm-related deaths in follow-up, largely due to stent-graft
related complications such as endoleak [17]. A study of the Medicare database
showed similar ndings. There was lower operative mortality with TEVAR compared to open repair (28.4% vs 45%, P<0.001). However, this survival advantage
disappeared by 1.5years after the procedure, due to aortic events and need for reintervention [3] (Fig.7).
Table 1 Backward stepwise regression: nal iterations of subgroup analysis
Predictor Outcome Group OR
Smaller (vs larger) hospital Mortality OAR 2.39 1.13 5.09 0.023
Smaller (vs larger) hospital Mortality TEVAR 1.00 0.30 3.30 0.997∗
Renal comorbidity Mortality TEVAR 10.81 3.54 32.99 <0.001
CI Condence interval; OAR open aortic repair; FTR failure to rescue; TEVAR thoracic endovascular aortic repair
∗Represents P value when covariate was excluded, not nal iteration
95% CI
P valueLower Upper
Complications OAR 3.96 1.78 8.79 0.001
FTR OAR 51.11 9.73 268.35 <0.001
Complications TEVAR 0.58 0.21 1.56 0.283∗
FTR TEVAR 1.05 0.21 5.16 0.951∗
FTR TEVAR 309.54 47.97 1997.15 <0.001
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Proportion Surviving
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C. Lau et al.
a
Survival Following Thoracic Aneurysm Repair
1.00
Survival Following Thoracic Aneurysm Repair
b
1.000.750.50
Intact
Ruptured
Intact
0.75
0.50
Ruptured
Proportion Surviving
0.250.00
Number at risk
Intact / Open
Intact / TEVAR
Rupt / Open
Rupt / TEVAR
012
11565
2433
1008
299
NB: Standard Errors all <0.10 at 5 years: Intact open=0.008, Intact TEVAR=0.02 Ruptured open=0.01, Reptured TEVAR=0.05
log rank p<0.001
log rank p=0.001
Ye ars Following Repair
8762
6975
1495
816
386
313
113
Open
TEVAR
Open
TEVAR
60
log rank p<0.001
345
5305
423
250
33
Propensity-Matched Survival Following Thoracic aneurysm Repair
c
1.000.750.500.250.00
Proportion Surviving
log rank p=NS
3753
256
171
20
2483
Open
TEVAR
Open
TEVAR
143
116
9
Open
log rank =0.007
TEVAR
0.250.00
Adjusted analyses representing male, non-black patients under age 75,
0123
NB: Standard Errors all <0.10 at 5 years: Intact open=0.008, Intact TEVAR=0.02 Ruptured open=0.01, Reptured TEVAR=0.05
with Charison score<2, performed after 2003
Year Following Repair
45
Number at risk
Intact / Open 550
Intact / TEVAR
550 364
012
Ye ars Following Repair
382
274
187
3 4
158
68
42
27
Fig. 7 (a) Unadjusted 5-year survival in thoracic aneurysms by procedure type and diagnosis. (b)
Adjusted 5-year survival in thoracic aneurysms by procedure type and diagnosis. Results represent
male, nonblack patients <75years of age with a Charlson score < 2 performed after 2003. (c)
Propensity-matched 5-year survival in thoracic aneurysms by procedure type. These patients represent a randomly selected, propensity-matched sample of low-risk patients who are at equal likelihood of undergoing either open repair or thoracic endovascular repair (TEVAR)
Conclusions
The answer to the question of whether open aortic repair or TEVAR is the preferred method for repairing rTAA is not straightforward. Fortunately, the results
of both techniques are improving with experience. Surgeons experienced in either
open aortic repair or TEVAR can achieve excellent results using their respective
techniques. Thus the ideal repair technique in any single situation is the one with
which the surgeon and institution has the best chance of success. With open aortic
repair, experienced centers achieve results comparable to TEVAR but with excellent long- term durability. With TEVAR, even smaller, less experienced centers
can achieve good results but long-term durability may be compromised due to
endograft-related complications.
Conicts of Interest No conicts of interest to report.
Funding No outside funding received.
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