In
situ reconstruction with cryopreserved arterial allograft in mycotic
aneurysms or aortoiliac prosthetic grafts infection: a multi-institutional
experience
(PDF version)
Wei
Zhou,1 Thomas T. Terramani,1 Peter
H. Lin,1 Ruth L. Bush,1 John H.
Matsuura,2 Mitchell Cox,1 Alan B.
Lumsden1
1.
MD, Division of Vascular Surgery & Endovascular Therapy, Michael
E. DeBakey Department of Surgery, Baylor College of Medicine, Houston,
TX, USA.
2.
MD, Division of Vascular Surgery, Department of Surgery, Emory University
School of Medicine and Atlanta Medical Center, Department of Surgery,
Atlanta, GA, USA.
Correspondence:
Peter H. Lin
Michael E. DeBakey Department of Surgery
Baylor College of Medicine
Houston VAMC - 20002 Holcomb Blvd (112)
Houston, TX 77030, USA
Phone: +1 (713) 794.7895
E-mail: plin@bcm.tmc.edu
ABSTRACT
Objective:
Aortic prosthetic graft infection remains a highly fatal surgical complication. Recent studies with cryopreserved allografts in the treatment of vascular graft infection suggest improved clinical outcomes. The purpose of this study was to evaluate the efficacy of cryopreserved aortic allografts in the treatment of infected prosthetic grafts or mycotic aneurysms.
Methods:
Clinical data of all patients who underwent in situ aortic reconstruction
with cryopreserved allografts for either infected aortic prosthetic
graft or mycotic aneurysms from 1999 to 2003 were reviewed. Relevant
clinical variables and treatment outcomes were analyzed.
Results: A total of 18 patients (14 men; overall mean age
62 ± 12 years, range 41-72 years) were identified during
this study period. Treatment indications include 12 primary aortic
graft infections (67%), four mycotic aneurysms (22%), and two aortoenteric
erosions (11%). Transabdominal and thoracoabdominal approaches were
used in 14 (78%) and four patients (22%), respectively. Staphylococcus
aureus was the most commonly identified organism (n = 11, 61%).
Although there was no intraoperative death, the 30-day operative
mortality was 17% (3/18). There were nine (50%) non-fatal complications
including local wound infection (n = 3), lower extremity deep venous
thrombosis (n = 2), amputation (n = 2), and renal failure requiring
hemodialysis (n = 2). The average length of their hospital stay
was 16.4 ± 7 days. During a mean follow-up period of 8.3
months, reoperation for allograft revision was necessary in one
patient due to graft thrombosis. The overall treatment mortality
rate was 22% (4/18).
Conclusions:
In situ aortic reconstruction with cryopreserved allografts
is an acceptable treatment modality in patients with infected aortic
prosthetic graft or mycotic aneurysms. Our study showed that mid-term
graft-related complications such as reinfection or aneurysmal degeneration
remained uncommon.
Key
words: aortic graft infection, mycotic aneurysm, surgical treatment,
cryopreserved graft.
J
Vasc Br 2005;4(2):123-8
Infected
aortic prosthetic graft remains one of the most serious complications
of aortic surgery and presents significant treatment challenges.1
The standard surgical management of total graft excision and extra-anatomic
bypass is associated with substantial morbidity, mortality, and rate
of limb loss.1,2 Aortic allograft has been used as a conduit for arterial
reconstruction since the 1950s, when DeBakey and Cooley reported resection
and homograft replacement for occlusive and aneurysmal diseases of the
aorta in 1954.3,4 During the 1960s and 1970s, arterial allografts lost
popularity due to concerns of potential risk of later deterioration,
availability, and preservation. However, recent studies have demonstrated
cryopreserved allograft replacement as an effective and durable alternative
for aortic prosthetic graft infection with improved outcomes.5-9 Most
reports on in situ aortic allograft reconstruction are from Europe,
while studies conducted in the U.S. are scattered and controversial.
We herein reviewed our experiences and evaluated the outcomes of cryopreserved
allograft replacement for infected aortic prosthetic graft and mycotic
aneurysms.
MATERIAL
AND METHODS
From January 1999 to December 2003, hospital records of all patients who were admitted to the affiliated hospitals of Baylor College of Medicine and Emory University School of Medicine for mycotic aortic aneurysms or suspected aortic prosthetic graft infections were retrospectively reviewed. The four affiliated hospitals included the Methodist Hospital, Houston Veteran Affair Medical Center, Emory University Hospital, and Atlanta Medical Center. Patients who underwent surgical intervention for infected aortic grafts or mycotic aneurysms were further evaluated. Those who had intraoperatively confirmed infections and treated with in situ cryopreserved allograft replacement were included in the study. Data were collected with respect to risk factors, preoperative clinical presentations, operative findings, hospital courses, and follow-up evaluations. Types of organisms identified, allograft- related complications, and long-term outcomes were recorded. Patients who had concomitant thoracic graft infections or isolated groin infections without intra-abdominal extensions were excluded from the study.
All cryopreserved
allografts were obtained from Cyolife® (CryoLife, Inc, Kennesaw, GA,
USA) stored at -180 °C to -196 °C and thawed at 37 °C to 42 °C. Matching
of blood and tissue compatibility between the cryografts and recipients
was not attempted.
RESULTS
Over a
4-year period, a total of 18 patients met the selection criterion. There
were 14 men (78%) and four women, with a mean age of 62 years (range,
41-72 years). All patients had multiple medical comorbidities, including
coronary artery disease (n = 10), hypertension (n = 16), diabetes mellitus
(n = 8), and peripheral vascular disease (n = 14). Twelve patients had
long standing histories of tobacco usage (Table 1).
 Table
1 - Patient demographics and presentation
 |
| Total
patients (n) |
18 |
|
| Patient
characteristics |
Age
(range) |
62
(41-72) |
|
Male gender (n, %) |
14
(78%) |
|
Co-morbidities
|
Coronary
artery disease (n, %) |
10
(56%) |
|
Hypertension (n, %) |
16
(89%) |
|
Diabetes mellitus (n, %) |
8
(44%) |
|
Smoking (n, %) |
12
(67%) |
|
Peripheral vascular disease (n, %) |
14
(78%) |
Treatment
indications
|
Primary
aortic graft infection (n, %) |
12
(67%) |
|
Aortoenteric erosion (n, %) |
2
(11%) |
|
Mycotic aneurysms (n, %) |
4
(22%) |
| Concomitant
groin infection (n, %) |
14
(78%) |
| Interval
from original surgery (months) |
90
(4-180) |
|
Treatment
indications included primary graft infection (n = 12, 67%), mycotic
aneurysms (n = 4, 22%), and aortoenteric erosion (n = 2, 11%). Concomitant
groin infections were presented in all patients with infected aortic
grafts (n = 14). The primary diagnostic modality was an abdominal computer
tomography (CT) scan showing evidence of intraabdominal infections in
all patients and the diagnosis was further confirmed by intraoperative
tissue cultures. The average interval from the original aortic surgeries
to the presence of prosthetic graft infection was 90 months, ranging
from 4 months to 15 years in those patients who presented infected aortic
prosthetic grafts.
All patients
were treated with intravenous antibiotics and operative management of
graft excision followed by in situ cryopreserved allograft replacement
(Table 2). Positive bacterial cultures were confirmed in all the explanted
aortic prosthesis or the aneurysmal sac tissue. Staphylococcus aureus
was the most commonly identified organism, found in 11 patients
(61%). The average operating time was 267 minutes (range, 3-5.5 hours)
with a 100% technical success rate. The average stay in intensive care
was 6 days and the average length of the hospital stay was 16.7 days
(range, 9-24 days). All patients received intravenous antibiotics postoperatively
followed by long-term oral antibiotics.
Table
2 - Treatment strategies and outcomes
|
| Operative
approach |
Transabdominal
(n, %) |
14
(78%) |
| Thoracoabdominal
(n, %) |
4
(22%) |
| Presence
of Staphylococcus aureus (n, %) |
11
(61%) |
| Operating
time (minutes) |
267
± 53 |
| ICU
stay (days) |
6
± 4 |
| Hospital
stay (days) |
16.7
(9-24) |
| Follow-up
(months) |
8.3
(3-18) |
|
Perioperative
complications
|
Local
wound infection (n, %)
|
3
(17%) |
| Deep
vein thrombosis (n, %) |
2
(11%) |
|
Amputation (n, %) |
2
(11%) |
|
Acute renal failure (n, %) |
2
(11%) |
| Late
complication |
Graft
thrombosis (n, %) |
1
(5.6%) |
| 30-day
mortality (n, %) |
3
(17%) |
| Overall
mortality (n, %) |
4
(22%) |
|
ICU =
intensive care unit.
Although
there was no intraoperative death, the 30-day operative mortality rate
was 17%, secondary to multi-organ failure as the result of sepsis (n
= 3). In addition, there were 50% non-lethal procedure-related complications,
including local wound infection (n = 3), lower extremity deep venous
thrombosis (n = 2), renal failure requiring hemodialysis (n = 2), and
amputation (n = 2). All patients were available for follow-up with a
mean period of 8.3 months (range, 3-18 months). One patient required
allograft revision for graft thrombosis (6%) and one died as a result
of colocutaneous fistula complications that led to the overall treatment
mortality rate of 22% (4/18). There was no evidence of aneurysmal dilatation
or disruption on follow-up CT scan evaluations.
Although there was no intraoperative death, the 30-day operative mortality rate was 17%, secondary to multi-organ failure as the result of sepsis (n = 3). In addition, there were 50% non-lethal procedure-related complications, including local wound infection (n = 3), lower extremity deep venous thrombosis (n = 2), renal failure requiring hemodialysis (n = 2), and amputation (n = 2). All patients were available for follow-up with a mean period of 8.3 months (range, 3-18 months). One patient required allograft revision for graft thrombosis (6%) and one died as a result of colocutaneous fistula complications that led to the overall treatment mortality rate of 22% (4/18). There was no evidence of aneurysmal dilatation or disruption on follow-up CT scan evaluations.
DISCUSSION
Aortic prosthetic graft is a rare complication of aortic surgery, occurring in 1 to 2% of patients and the complication rate has been consistent, despite the advances in antibiotics, graft material, and surgical techniques.1 The standard management of total graft excision and extra-anatomic bypass is associated with substantial morbidities and significant mortality rates ranging from 25 to 75% in reported series.1,2 Cryopreserved allograft replacement is an attractive alternative that has been adopted successfully in Europe, while data from the U.S. are scattered and controversial. Our study confirms cryopreserved allograft replacement as an effective strategy for infected aortic prosthetic grafts and mycotic aneurysms.
There are multiple factors contributing to aortic prosthetic graft infection including contamination at the time of implantation, extending infection from the adjacent tissues, seeding from distal sources via hematologous routine, or erosion into adjacent organs. Manifestation of graft infection may vary widely from days to years depending upon the etiologies of the infection and the physical condition of the patient. The average interval between the original aortic surgeries and the presence of graft infection in our patients was 90 months ranging from 4 months to 15 years. The patient may present with a variety of symptoms, mostly nonspecific, including recurrent fever and chills, groin infection, pulsatile mass or generalized abdominal pain. Rarely, the patients may have gastrointestinal bleeding in the presence of aortoenteric fistula. In the presence of nonspecific symptoms, additional imaging studies are particularly useful in assisting in the diagnosis and operative planning. The most common imaging methods used to evaluate aortic graft infections or aneurysms are ultrasonography, CT scan, and magnetic resonance imaging (MRI).10,11 Late aortic graft infections are best evaluated initially by a CT scan or a MRI. CT findings include ectopic gas, perigraft fluid, perigraft inflammatory changes, anastomotic pseudoaneurysm, and thickening of the adjacent bowel. The MRI offers the additional advantage of T2-weighted images to identify perigraft inflammation and minute quantities of perigraft fluid. Sonographic findings of a graft infection include perigraft fluid and pseudoaneurysms. The imaging for infection within a 3-month postoperative period is less diagnostic because of persistent perigraft fluid and inflammatory changes up to 3 months after surgery. Suspected early graft infections often require urgent operative exploration for diagnosis.10,11 Due to late presentations of graft infection in our patients, CT scans were particularly informative in confirming the presence of aortic prosthetic graft infection and aiding the operative planning. The presence of sacccular aneurysms on CT scans combined with symptoms of infection and positive blood cultures helped identify the mycotic aneurysms in four of our patients.
Treating infected aortic prosthetic graft is extremely challenging. The standard therapeutic option of total graft excision and extra-anatomic bypass is associated with significant mortality and complication rates. O'Hara et al. reviewed their 25 year-experience and demonstrated 0.77% of incidence of aortic graft infection.1 Despite aggressive surgical treatment including graft excision with and without extra-anatomic bypass in 89% of their patients, they yielded 30-day and 1-year survival of 72 and 42%, respectively. In addition, 27% of the treated patients required major amputation in their series. Similarly, Quinones-Baldrich et al. treated 45 patients with aortic graft infection, including 36 patients who underwent extra-anatomic bypasses.12 They reported a 30-day mortality rate of 24%, 3-year primary axillo-femoral bypass graft patency rate of 43% and an amputation rate of 34% at 5 years. Their study also suggested that infection in the extra-anatomic bypass graft was the most common cause of recurrent sepsis and the leading cause of late amputations. Nonetheless, the study conducted by Yeager et al. has demonstrated improved overall results. They treated 60 aortic prosthetic graft infections with total excision and extra-anatomic bypass and achieved 30-day mortality and 5-year primary axillo-femoral bypass patency rates of 13 and 73%, respectively.2 Despite improved results in some reports, standard surgical treatment of total graft excision and extra-anatomic bypass continues to be associated with substantial complication and mortality rates with potential risk of aortic stump blow out.
The disappointing
results of standard surgical treatment have kindled interests in evaluating
alternative approaches, such as partial or complete graft preservation,
autogenous veins reconstruction, or antibiotic-bonded prostheses. Calligaro
et al. investigated partial or complete graft preservation in nine patients
and achieved an acceptable perioperative survival rate of 89%.13 However,
five of the nine patients had limited infection involving the groin
only and one of whom had a recurrence that required total excision 6
months later. Additionally, Clagett et al. described using autogenous
superficial femoral-popliteal vein (SFPV) as a reconstruction conduit
in 41 patients with infected aortic prosthetic grafts and achieved an
excellent result of 100% perioperative survival.14 Nevertheless, they
encountered significant perioperative complications associated with
vein harvesting including amputation (5%), compartment syndrome (12.3%),
and pulmonary embolism (2.4%). Antibiotic-bonded prosthesis as replacement
conduits has been studied as well, with variable success. Koshiko et
al. evaluated the efficacy and duration of the antibacterial activity
of rifampicin-gelatin grafts in a canine model15 and concluded that
rifampicin-gelatin grafts were valid for Staphylococcus epidermidis
(S. epidermidis) infection, whereas there was no efficacy against
more virulent strains of bacteria such as methicillin-resistant Staphylococcus
aureus (MRSA) and Escherichia coli (E. coli). Hayes and associates
treated 11 patients with major aortic graft infections by total graft
excisions and in situ replacements with a rifampicin-bonded prosthesis.
They demonstrated a 30-day mortality of 18.2%, but only one of the two
patients infected with MRSA survived after 30 days.16
In situ
allograft reconstruction was first described as an effective alternative
in treating infected aortic prosthesis in 1991.5 Since then, multiple
studies have confirmed the efficacy of using allograft replacement for
the treatment of prosthetic aortic graft infection.7-9,17 Teebken et
al. treated 42 patients with in situ cryopreserved allograft reconstruction
and achieved a 30-day mortality rate of 14%.7 A multi-centered study
conducted in Belgium involving 90 patients further confirmed cryopreserved
aortic allograft replacement as a promising technique in managing aortic
prosthetic graft infections.17 Kieffer et al. reviewed their extensive
experience of treating 179 patients using in situ allograft replacement
and compared the results in patients who received fresh allograft versus
patients who received cyopreserved allografts.6 They achieved an overall
early postoperative mortality rate of 20.1% and a 1-year average survival
rate of 73%. The allograft-related mortality rate was only 2.2% in their
study and all allograft-related deaths and complications were in patients
who received fresh allografts. Their observation was confirmed by Litzler
et al., who compared cryopreserved to fresh allografts on dogs that
were infected with Staphylococcus aureus and concluded greater
bacterial resistance from cryopreserved allografts than fresh grafts.18
However, Chiesa et al. did not find a significant difference between
fresh and cyopreserved allograft aortic reconstruction.19 In addition,
Knosalla et al. examined the efficacy of allograft replacement in dogs
that were implanted with S. epidermidis infected aortic prosthetic
graft and concluded that cryopreserved aortic allografts were more resistant
to reinfection than synthetic grafts after in situ replacement of an
infected prosthetic graft. However, the antibiotic loading of the cryopreserved
aortic allograft appears to be essential in obtaining optimal therapeutic
effects20 while the study by Rowe et al. failed to demonstrate superior
results of cryopreserved allografts over collagen-impregnated Dacron
grafts.21 Furthermore, allograft-related complications of degeneration
and rupture have been reported by some authors22 but not others.23
Studies on allograft reconstruction for infected aortic prosthesis in the U.S. are scattered. Noel et al. reported the experience of in situ aortic reconstruction using cryopreserved aortic allografts on 56 patients in 31 institutions and demonstrated a 30-day mortality rate of 13% with 4% graft-related mortality. They concluded that in situ aortic reconstruction with an cryopreserved aortic allograft in an infected field carried a high mortality rate and proper caution should be taken even though most deaths were not the result of allograft failure.24 Our experience in treating 18 patients showed no perioperative mortality and an overall mortality rate of 22%. We did not encounter any incidence of allograft infection, degeneration, or disruption over a follow-up mean of 8.3 months. However, we observed one graft thrombosis that required an allograft revision and a 50% non-lethal complication rate including deep venous thrombosis, local wound infection, renal failure, and amputation. Even though allograft-related complications were uncommon in our mid-term evaluation, long-term follow-up is warranted to identify the potential complications of graft infection, thrombosis, or aneurysmal changes.
In conclusion,
aortic prosthetic graft is a devastating and potentially lethal complication
of aortic surgery that presents significant treatment challenges. Total
graft excision followed by in situ cryopreserved allograft reconstruction
is an effective alternative with satisfactory mid-term outcomes.
REFERENCES
1.
O'Hara PJ, Hertzer NR, Beven EG, Krajewski LP. Surgical management of
infected abdominal aortic grafts: review of a 25-year experience. J
Vasc Surg 1986;3:725-31.
2.
Yeager RA, Taylor Jr. LM, Moneta GL, et al. Improved results with conventional
management of infrarenal aortic infection. J Vasc Surg 1999;30:76-83.
3. Debakey ME, Creech Jr. O, Cooley DA. Occlusive disease
of the aorta and its treatment by resection and homograft replacement.
Ann Surg 1954;140:290-310.
4. Cooley DA, Debakey ME. Ruptured aneurysms of abdominal
aorta; excision and homograft replacement. Postgrad Med 1954;16:334-42.
5. Bahnini A, Ruotolo C, Koskas F, Kieffer E. In situ
fresh allograft replacement of an infected aortic prosthetic graft:
eighteen months' follow-up. J Vasc Surg 1991;14:98-102.
6. Kieffer E, Gomes D, Chiche L, Fleron MH, Koskas F,
Bahnini A. Allograft replacement for infrarenal aortic graft infection:
early and late results in 179 patients. J Vasc Surg 2004;39:1009-17.
7. Teebken OE, Pichlmaier MA, Brand S, Haverich A. Cryopreserved
arterial allografts for in situ reconstruction of infected arterial
vessels. Eur J Vasc Endovasc Surg 2004;27:597-602.
8.
Vogt PR, Turina MI. Management of infected aortic grafts: development
of less invasive surgery using cryopreserved homografts. Ann Thorac
Surg 1999;67:1986-98.
9. Vogt PR, Brunner-LaRocca HP, Lachat M, Ruef C, Turina
MI. Technical details with the use of cryopreserved arterial allografts
for aortic infection: influence on early and midterm mortality. J Vasc
Surg 2002;35:80-6.
10.
Modrall JG, Clagett GP. The role of imaging techniques in evaluating
possible graft infections. Semin Vasc Surg 1999;12:339-47.
11. Orton DF, LeVeen RF, Saigh JA, et al. Aortic prosthetic
graft infections: radiologic manifestations and implications for management.
Radiographics 2000;20:977-93.
12. Quinones-Baldrich WJ, Hernandez JJ, Moore WS. Long-term
results following surgical management of aortic graft infection. Arch
Surg 1991;126:507-11.
13. Calligaro KD, Veith FJ, Yuan JG, Gargiulo NJ, Dougherty
MJ. Intra-abdominal aortic graft infection: complete or partial graft
preservation in patients at very high risk. J Vasc Surg 2003;38:1199-205.
14. Clagett GP, Valentine RJ, Hagino RT. Autogenous
aortoiliac/femoral reconstruction from superficial femoral-popliteal
veins: feasibility and durability. J Vasc Surg 1997;25:255-70.
15. Koshiko S, Sasajima T, Muraki S, et al. Limitations
in the use of rifampicin-gelatin grafts against virulent organisms.
J Vasc Surg 2002;35:779-85.
16. Hayes PD, Nasim A, London NJ, et al. In situ replacement
of infected aortic grafts with rifampicin-bonded prostheses: the Leicester
experience (1992 to 1998). J Vasc Surg 1999;30:92-8.
17.
Verhelst R, Lacroix V, Vraux H, et al. Use of cryopreserved arterial
homografts for management of infected prosthetic grafts: a multicentric
study. Ann Vasc Surg 2000;14:602-7.
18. Litzler PY, Thomas P, Danielou E, et al. Bacterial
resistance of refrigerated and cryopreserved aortic allografts in an
experimental virulent infection model. J Vasc Surg 1999;29:1090-6.
19.
Chiesa R, Astore D, Frigerio S, et al. Vascular prosthetic graft infection:
epidemiology, bacteriology, pathogenesis and treatment. Acta Chir Belg
2002;102:238-47.
20.
Knosalla C, Goeau-Brissonniere O, Leflon V, et al. Treatment of vascular
graft infection by in situ replacement with cryopreserved aortic allografts:
an experimental study. J Vasc Surg 1998;27:689-98.
21.
Rowe NM, Impellizzeri P, Vaynblat M, et al. Studies in thoracic aortic
graft infections: the development of a porcine model and a comparison
of collagen-impregnated dacron grafts and cryopreserved allografts.
J Thorac Cardiovasc Surg 1999;118:857-65.
22.
Lehalle B, Geschier C, Fieve G, Stoltz JF. Early rupture and degeneration
of cryopreserved arterial allografts. J Vasc Surg 1997;25:751-2.
23.
Locati P, Novali C, Socrate AM, et al. The use of arterial allografts
in aortic graft infections. A three year experience on eighteen patients.
J Cardiovasc Surg (Torino) 1998;39:735-41.
24.
Noel AA, Gloviczki P, Cherry Jr. KJ, et al. Abdominal aortic reconstruction
in infected fields: early results of the United States cryopreserved
aortic allograft registry. J Vasc Surg 2002;35:847-52.
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