Keywords
atherosclerosis - peripheral vascular disease - thoracobifemoral bypass
Introduction
The management of complete obstruction of the abdominal aorta at the renal artery
level poses a formidable surgical challenge. Traditionally, the descending thoracic
aorta (DTA) has been employed as an inflow source, primarily in cases of graft failure,
infection, or intra-abdominal pathologies precluding a standard abdominal aortic approach.
While endovascular techniques have emerged as effective treatments for symptomatic
aortoiliac occlusive disease (AIOD), they exhibit lower mortality and morbidity compared
with open surgery. However, the primary patency rates of endovascular approaches are
inferior to those of surgical grafts.[1]
Surgical intervention remains the preferred choice, especially for cases of AIOD originating
at the juxtarenal level and extending to the bilateral iliac arteries. Aortofemoral
bypass (AFB) may encounter technical challenges and increased postoperative risks
due to inadequate anastomotic areas and severe calcification.[2]
[3] Although extensive endarterectomy can create sufficient anastomotic space, residual
calcification and abnormal arterial walls postendarterectomy pose significant challenges
to successful anastomosis. Moreover, aortic cross-clamping, both suprarenal and infrarenal,
in this pathological region may result in complications affecting visceral organs
and the kidneys. Extra-anatomic bypass or thoracofemoral bypass (TFB) serves as a
viable alternative to mitigate these complications.[4]
[5]
While the long-term results of extra-anatomic bypass vary across published series,
TFB is commonly reserved as a secondary surgical option following failures of open
aortic revascularization and aortofemoral graft infections.[4] However, considering the challenges posed by pararenal aortic neck calcification
or thrombus hindering the safe construction of the proximal anastomosis of AFB, TFB
can also be contemplated as a primary surgical option.[5]
[6] In our institution, we have adopted TFB as the initial treatment for severe AIOD,
and in this study, we aim to present the outcomes of cases treated with TFB and share
our surgical experience spanning the past 10 years.
The utilization of the DTA as an alternative inflow source for AIOD was introduced
in 1961 by Stevenson et al and Blaisdell et al.[7]
[8] Initially employed as a remedial reconstruction for aortic graft failure, graft
infection, or other intra-abdominal catastrophes, bypass grafting from the DTA to
the iliac or femoral arteries has evolved over time. The purpose of this study is
to report early results (30 days) encompassing 90 DTA to femoral artery bypass grafting
procedures performed at our institution.
Materials and Methods
A total of 90 patients with AIOD underwent descending thoracic aortobifemoral bypass
as primary procedure at S.M.S. Medical College and Group of Hospitals, Jaipur (Rajasthan)
between August 2012 and August 2022. Demographic information and procedural details
were extracted from hospital records. Angiography, available for all patients, was
performed and subsequently reviewed ([Fig. 1]).
Fig. 1 Preoperative computed tomography image.
Medical conditions, indications for surgery, and any prior vascular interventions
were comprehensively assessed through hospital records. Prior to the operation, complete
angiography of the aortoiliac and lower extremity vessels was conducted using standard
techniques. Additionally, coronary angiography was systematically performed in all
patients to exclude the presence of coronary artery disease.
For patients with suspected limited pulmonary reserve or documented severe pulmonary
disease—a potential contraindication to the procedure—pulmonary function tests and
baseline arterial blood gas measurements were obtained. DTA to femoral artery bypass
grafting served as the primary procedure for patients without previous direct aortoiliac
or extra-anatomic reconstructions.
The criteria for selecting patients for primary repair included (1) severe atherosclerotic
disease or complete occlusion of the infrarenal aorta with relative contraindications
to direct aortic reconstruction (e.g., prior intra-abdominal sepsis, multiple abdominal
operations, radiation, or colostomy) and (2) severe atherosclerotic disease or complete
occlusion of the infrarenal aorta, wherein the DTA was deemed the preferred source
of inflow by the operating surgeon based on the severity of occlusive disease in the
infrarenal aortic segment.
Surgery was indicated in all patients presented with vascular symptoms like disabling
intermittent claudication, chronic nonhealing ulcers, and rest pain. Computed tomography
(CT) angiography revealed infrarenal aortic stenosis, juxtarenal aortic occlusion,
and stenosis of the common and external iliac arteries in all cases ([Fig. 1]).
Considering the absence of a suitable site for aortic cross-clamping, abdominal aortobifemoral
bypass was deemed hazardous. The BARD IMPRA expanded polytetrafluoroethylene vascular
graft, along with the Vascutech graft, were employed for bypass surgery ([Fig. 2]).
Fig. 2 Intraoperative image.
Surgical Technique
Patients underwent general anesthesia with continuous hemodynamic monitoring during
the surgical procedure. Although not mandatory, a double-lumen endotracheal tube was
considered advantageous. The patient was positioned with the left hemithorax elevated
at an angle of 30 to 45 degrees, and the pelvis was maintained as flat as possible
to facilitate access to both groins. Adequate preparation and draping were performed
on the chest, abdomen, and both groins.
An anterolateral thoracotomy was conducted through the 7th intercostal space. The
proximal anastomosis of a bifurcated graft was executed in an end-to-side fashion
at the lower DTA, as illustrated in [Fig. 2]. Subsequently, the graft limbs were guided through a tunnel between the rectus abdominis
muscle and peritoneum to a short midline incision at the level of the umbilicus. Each
limb of the graft was then drawn through a subcutaneous tunnel to reach the respective
sides of the groin, where anastomosis to each common femoral artery was performed.
In the postoperative period, thorough assessments were conducted to evaluate distal
pulsations, primary patency, warmth of the foot, symptom relief, wound infection,
healing of ulcers, and the occurrence of complications. Additionally patients were
counseled for smoking cessation and vascular protective measures. Follow-up CT angiography
was systematically performed to assess the vascular graft's performance. [Fig. 3] depicts a CT angiography revealing a normal flow pattern in the graft.
Fig. 3 Postoperative image.
Results
Ninety patients underwent this surgery in S.M.S. Hospital, Jaipur during study period.
Out of 90 patients, 83 (92.22%) were males and 7 (7.78%) were female. The age range
spans from 51 to 77 years, with an average age of 58.62 ± 6.647 years. Among 90 study
participants, 82 (91.11%) had coronary artery disease (CAD), whereas 90 (100.00%)
suffered from hypertension. Diabetes mellitus (DM) affected 54 patients (60.00%),
and hyperlipidemia was prevalent in 86 patients (95.56%). Additionally, 14 patients
(15.56%) had renal disease, 7 (7.78%) had undergone prior intra-abdominal surgery,
and 1 (1.11%) had a history of prior thoracic surgery. Pulmonary disease was observed
in 38 patients (42.22%) ([Table 1]).
Table 1
Baseline variables of study participants
|
Variable
|
n
|
%
|
|
Sex
|
|
|
|
Male
|
83
|
92.22
|
|
Female
|
7
|
7.78
|
|
Age
|
|
|
|
Range (y)
|
51–77
|
|
Mean ± SD (y)
|
58.62 ± 6.647
|
|
Associated morbidities
|
|
|
|
CAD
|
82
|
91.11
|
|
Hypertension
|
90
|
100.00
|
|
DM
|
54
|
60.00
|
|
Hyperlipidemia
|
86
|
95.56
|
|
Renal disease
|
14
|
15.56
|
|
Prior intra-abdominal surgery
|
7
|
7.78
|
|
Prior thoracic surgery
|
1
|
1.11
|
|
Pulmonary disease
|
38
|
42.22
|
Abbreviations: CAD, coronary artery disease; DM, diabetes mellitus.
Average duration of surgery falls within the range of 2.5 to 4.5 hours, with a mean
duration of 3.33 hours and a standard deviation of 0.537. Blood loss during surgery
was 100 to 500 mL, with an average of 290 mL and a standard deviation of 97.65.
Postoperative findings revealed that the extubation time after surgery spans from
6 to 12 hours, with an average time of 8.74 hours and a standard deviation of 1.608.
Intensive care unit stays ranged from 3 to 5 days, with an average stay of 3.64 days
and a standard deviation of 0.724. Reexploration after surgery was required in 3 (3.33%)
cases. Rare postoperative complications included renal failure, myocardial infarction,
peritonitis, fever, wound complications, and mortality, each occurring in 1.11% of
the cases ([Table 2]).
Table 2
Intra- and postoperative findings of study participants
|
Outcome
|
Range/number
|
Mean ± SD/%
|
|
Intraoperative findings
|
|
Avg duration of surgery
|
2.5–4.5 h
|
3.33 ± 0.537
|
|
Blood loss
|
100–500 mL
|
290 ± 97.65
|
|
Graft used
|
|
|
|
PTFA
|
49
|
54.44
|
|
Vascutech
|
41
|
45.56
|
|
Postoperative findings
|
|
Postoperative extubation time
|
6–12 h
|
8.74 ± 1.608
|
|
ICU stay
|
3–5 d
|
3.64 ± 0.724
|
|
Reexploration
|
3
|
3.33
|
|
Renal failure
|
1
|
1.11
|
|
MI
|
1
|
1.11
|
|
Peritonitis
|
1
|
1.11
|
|
Fever
|
6
|
6.67
|
|
Wound complications
|
5
|
5.56
|
|
Mortality
|
3
|
3.33
|
Abbreviations: Avg, average; ICU, intensive care unit; MI, myocardial infarction;
PTFA, polytetrafluoroethylene; SD, standard deviation.
Among the 90 patients we performed concomitant coronary artery bypass grafting (CABG)
(left internal mammary artery to left anterior descending artery) via thoracotomy
in two patients during the same procedure.
Thirty-day follow-up of 87 individuals remaining after early mortality of three patients.
Data revealed a 100% graft patency rate. All grafts remained open and functional during
this period. There were only three immediate postoperative mortalities. These positive
findings in graft patency and the absence of subsequent mortality underscore the favorable
short-term outcomes and effectiveness of the surgical interventions performed on the
individuals in this cohort ([Table 3]).
Table 3
Findings of 30-day follow-up of surviving study participants
|
30-day follow-up
|
n (out of 87)
|
%
|
|
Graft patency
|
87
|
100
|
|
Mortality
|
0
|
0
|
Discussion
Several notable limitations characterize this study, foremost among them being its
retrospective design and the absence of randomization, primarily due to the infrequent
occurrence of the condition under investigation. Consequently, drawing unequivocal
conclusions from a single-center experience is challenging. Nevertheless, this study
stands out among the limited existing literature by presenting a substantial number
of cases where the TFB procedure was chosen as the primary treatment for specific
patients. A major limitation of our study is the 30-day endpoint follow-up, whereas
these patients required prolonged follow-up for optimal results. The study's significance
is further underscored by its comprehensive follow-up results and the wealth of surgical
expertise accumulated over approximately 10 years.
In the current landscape where endovascular approaches are increasingly favored for
AIODs, the durability of open surgical reconstruction remains a pivotal consideration.
Our study identifies specific scenarios warranting careful consideration for the utilization
of open TFB, including severe circumferential juxtarenal/suprarenal aortic calcification,
failed AFB, or an initial endovascular approach lacking favorable anatomy for direct
reconstruction. This paper underscores the procedure's low perioperative morbidity,
mortality, and favorable patency rates, supporting its application not only as an
alternative but also as a primary revascularization option in select cases.[9]
The presented study encompasses a 10-year experience involving 90 TFB procedures conducted
at a single institution, representing a substantial accumulation of clinical data.
Traditionally reserved for cases of aortic graft failure or infection or as an alternative
when a direct transabdominal aortic approach is unfeasible, bypass grafting from the
descending thoracic to femoral arteries has yielded satisfactory results in prior
publications, with patency rates ranging from 76 to 86% at 5 years.[10]
While DTA-to-iliofemoral artery bypass grafting is firmly established as a secondary
procedure, its role as a primary operation remains contentious. In carefully selected
patients with challenging abdominal conditions, where the infrarenal aorta's approach
is complicated, primary DTA-to-iliofemoral artery bypass grafting emerges as a preferable
alternative.[11]
It is imperative to contextualize historical series, considering that patients undergoing
revascularization for AIOD via direct AFB grafting several decades ago often presented
with less severe atherosclerotic disease and a lower prevalence of limb-threatening
ischemia.
The utilization of the DTA as an inflow source for primary aortoiliac reconstruction
offers several advantages over conventional direct aortic repair. Notably, the DTA
typically exhibits minimal atherosclerotic disease, rendering it more suitable for
proximal anastomosis than the abdominal aorta.
While AFB grafting remains the standard surgical treatment for AIOD, alternative procedures
such as axillofemoral bypass or thoracobifemoral bypass are considered when abdominal
aortic surgery is contraindicated due to severe inflow site disease. In this context,
thoracobifemoral bypass holds major advantages over axillofemoral bypass, offering
superior inflow, requiring a shorter graft length, providing enhanced graft protection
from infection and mechanical trauma, and demonstrating a superior patency rate.
Our series presented unique considerations, such as the concurrent recommendation
of CABG followed by TFB in patients with coronary artery disease. Simultaneous CABG
via thoracotomy approach and TFB were performed in select cases, with one postoperative
mortality due to myocardial infarction.[12]
[13]
In contrast to other series, our study adopted a distinct graft tunneling approach,
directing the graft anteriorly through the anterior aspect of the diaphragm to a short
midline incision, then to both femoral arteries. All patients in our series demonstrated
good distal pulses, and the operative mortality rate was notably low at 3.33%, with
one mortality attributed to myocardial infarction.
Graft failure or occlusion, reported in 4 to 30% of cases over 3 to 5 years in other
series, was managed effectively in our series through embolectomy, resulting in good
distal flow and favorable patient recovery. Overall, our series demonstrated superior
inflow and more reliable patency with thoracobifemoral bypass, recommending its consideration
in selected patients where conventional approaches to the abdominal aorta are deemed
hazardous ([Tables 1] and [2]).
Conclusion
In individuals presenting with total aortic lesions at the juxtarenal level, both
AFB and endovascular interventions may pose technical challenges and carry substantial
morbidity risks, primarily attributed to the nature and location of the occlusive
lesions. In light of these considerations, TFB emerges as a comprehensive primary
revascularization approach for patients with this specific lesion profile. Our study
provides evidence supporting the efficacy of TFB as an initial treatment option in
carefully selected patients with juxtarenal total aortic occlusion.
Despite the inherent complexity of the surgical technique involved in TFB, our findings
reveal that it can deliver favorable outcomes when chosen as the primary treatment
in this subset of patients. Notably, TFB exhibits a favorable safety profile, with
acceptable rates of mortality and morbidity.
