Abdominal aortic aneurysms infected with salmonella: Problems of treatment Prasert Trairatvorakul, M D , FACS, 1 Suthus Sriphojanart, M D , 1 and B o o n m e e Sathapatayavongs, M D , M R C P , 2 Bangkok, Thailand Seven patients with abdominal aortic aneurysms infected with salmonella organisms were surgically treated between 1985 and 1988. Salmonella culture was obtained from the wall of the aneurysm in every patient, and in five patients it was identified as Salmonella typhimurium. S. choleraesuis and salmonella group D (isolated from this patient but not speciated) were found in the other two remaining patients. Three patients underwent aneurysmal resection with axillofemoral bypass grafting, and three patients were treated by aneurysmal resection with in situ graft; two of this group had the wall and infective periaortic tissue excised. One patient died during the operation as a result of rupture of the aneurysm. Therapeutic doses of antibiotic drugs were given to all of the patients. Although two of the patients in the first group (with the axillofemoral bypass graft) died and the remaining patient had very compficated postoperative course, all the patients in the second group (with in situ graft) survived. We think that in situ graft placement after an extensive debridement of the aneurysmal wall and infected periaortic tissue together with more effective and adequate antibiotic therapy for at least 6 weeks after the operatio n is a satisfactory method of surgical treatment of this condition. However, graft infection is still a possibility, therefore regular follow-up is needed. (J VASe SUinG 1990; 12:16-9.)
A review of the English-language literature in 1984 revealed that the bacteriology of mycotic aneurysms has undergone a change in pattern. Before 1965 salmonella organisms were the most common, being present in 38% of the aneurysms, whereas after 1965 the most common organisms were staphylococci, which were found in 30% and salmonellas in only 10%. This same review also noted that the abdominal aorta was one of the most common sites of mycotic aneurysms (31%).1 Rupture of the aorta, resulting from either salmonella suppurative aortitis or salmonella mycotic aneurysm was consistently fatal before 1970. 2.4 After that, more reports of successful treatment of this condition were published, s8 In Thailand, a tropical country, salmonella infection is still common and sometimes causes some epidemiologic concern by its sporadic outbreaks. Within 3 years we had the chance to treat seven patients who had abdominal aortic aneurysms infected with salmonella organisms, and while treating the patients we were confronted with many problems From the Departments of Surgery~ and Medicine,2 Faculty of Medicine, Ramathibodi Hospital, Mahidol University. Reprint requests: Prasert Trairatvorakul, MD, Department of Surgery, Ramathibodi Hospital, Rama VIRd., Bangkok 10400, Thailand. 24 / 1 / 19944
16
that required further study to choose the best alternatives for the patients. PATIENTS AND METHOD Seven consecutive patients with abdominal aortic aneurysms infected with salmonella organisms were treated at Ramathibodi Hospital, Bangkok, Thailand, between 1985 and 1988. A summary o f c l i n i c ~ features of all the cases is presented in Table I. The{e were five men and two women, and the age range was between 53 and 75 years, with a mean age of 64 years. Fever was present in all patients, and abdominal pain and abdominal mass were the next most common complaints. Although correct diagnosis was made before operation in only five out of seven patients, four patients were considered to have delayed diagnosis (patients 1, 2, 5, and 6). Hemocultures were positive for salmonella organisms in only two patients. Cultures from the wall of the aneurysms were positive for salmonella organisms in all patients. The most prominent species was Salmonella typhimurium, which was found in five patients. Broad spectrum antibiotic therapy was given as soon as the diagnosis was made, and the condition was treated as a semiemergency, that is, elective surgery was performed as soon as possible, unless there were signs of rupture or threatened rupture of the aneurysm.
Volume 12 Number 1 Jff 1990
Aortic aneurysms infected with salmonella 17
Table I. Summary of clinical features of patients Diagnosed Case Sex/Age
preoperatively
No.
(yr)
Symptom
1
M/67
Fever; abdominal pain; mass
Yes
Duration Pathologic organism
Site of culture
S. typhimurium Aneurysm; Ruptured Resection blood
2
F/58
Fever; abdominal pain; mass
Yes
S. typhimurium Aneurysm
3
M/75
No
S. choleraesuis Aneurysm
4
F/59
Fever; abdominal & back pain Fever; back pain; mass
Yes
S. typhimurium Aneurysm
5
M/70
Fever; back pain; diarrhea
Yes
S. group D
6
M/53
Yes
7
M/67
Fever; abdominal pain; mass Fever; abdominal pain; diarrhea;
No
Operative finding Operation Complication Multiple infected and organ AAA; - A x B i F ; failure aortoabdomiduo&noperinal fisneal retula section Aortitis Resection Aortowith and uodenal leakage AxBiF fistula 2 and anmonths eurysm after operation Leaking In situ None infected graft AAA AAA
Resection and AxBiF
Aneurysm; Aortitis In siva blood with graft leakage and aneurysm S. typhimurium Aneurysm Ruptured Explorinfected atory AAA laparotomy S. typhimurium Aneurysm; AAA In situ urine; with graft stool periaortic adhesion
Result
offollow-up (too)
Died 2 weeks after operation
--
Died 2 months after operation
--
Alive
12
ThromAlive bosed graft; emphysematous pyelonephritis Prolonged Alive intestinal ileus
24
22
Died
Prolonged resplratory insufficicncy
Alive
13
mass
AAA, abdominal aortic aneurysm; AxBif, axillobifemoral bypass.
Resection and axillofemoral bypass reconstruction was performed in three patients (patients 1, 2, and 4). In patient 1 there was also extensive necrosis of the sigmoid colon and rectum, and this necessitated abdominoperineal resection. Two patients (patients 3 and 5) had complete removal of aneurysmal wall and most of the infected periaortic tissue and in situ graft. One patient (patient 7) had most of the aneurysmal wall left intact to cover the in situ graft, since preoperative diagnosis of salmonella infection was not yet made. The remaining one patient (patient 6) bled before the surgery, and emergency laparotomy was done but failed to save the patient's life. When a diagnosis of salmonellosis was made, our choice of antibiotics were cotrimoxazole, ampicillin, cefuroxime, and ceftriaxone, alone or in combina-
tion. The antibiotic therapy was given for at least 6 weeks after the operation. It has been proposed that a single bactericidal agent used to achieve a mininaal serum bactericidal capacity of 1 : 8 should be optimal if proper surgical drainage has been achieved. 8 We adopted this antibiotic regime in three of four patients who survived. Serum bactericidal activity of the antibiotic was monitored both at the peak or maximum serum concentration and at the trough or minimum serum concentration, as determined by the pharmacokinetic property of the antibiotic (Table II). Serum bactericidal activity was done by serially diluting the patient's serum, and each dilution was tested against the organism isolated from the same patient. The greatest dilution of serum that killed at
18
lournal of VASCULAR SURG..V~Y
Trairatvorakul, Sriphojanart, and Sathapatayavongs
DISCUSSION
Table II. Summary of serum bactericidal activity in three survival cases Reciprocal of serum bactericidal titer [SBT] at Case No.
3 4
7
Antibiotic regimen (dose x frequency~day)
Ceftriaxone [1 gm × 1] Ampicillin [2 gm × 6] + Ceftriaxone [1 gm × 2] Ampicillin [2 gm x 6]
Peak
Trough
64
8
>512
>512
32
8
least 99.9% of the initial inoculum is defined as the serum bactericidal activity.9 RESULTS Of those who had aneurysmal resection and axillofemoral bypass grafting (patients 1, 2, and 4), one died 2 weeks after the operation as a result of multiple organ failure. This patient had rupture of the aneurysm before the surgery. He also had an extensive necrosis of the sigmoid colon and rectum necessitating an abdominoperineal resection. Another patient from this group died 2 months after the operation because of massive hemorrhage from the fistula between the aortic stump and the duodenum. The only surviving patient in this group had serious complications, one after the other, after the surgery. She had emphysematous pyelonephritis, which required a nephrectomy, and then she developed thrombosis of the bypass graft requiring a thrombectomy (Table I). All three patients who underwent in situ graft placement survived, with a duration of follow-up between 1 and 2 years (patients 3, 5, and 7) (Table I). The first two patients who had extensive removal of the aneurysm and the infected periaortic tissue as recommended in most of the literature concerning this condition had 12 and 22 months of follow-up, respectively. The last patient in this group had almost all of the aneurysm wall left intact, which was used to cover the in situ graft because preoperative diagnosis of salmonella infection was not made. This patient survived and had 13 months of follow-up. One patient died during the surgery (patient 6). Diagnosis was not made until the time of surgery, which had to be done urgently because of rupture of the aneurysm. The patient went into profound hypovolemic shock, and we were unable to replace the blood lost in time.
Three different types of vascular lesions produced by salmonella organisms are diffuse suppurative arteritis with rupture and development of false aneurysm, focal arteritis with rupture and aneurysm formarion, and secondary infection superimposed on preexisting arteriosclerotic aneurysm. 2 Judging from the operative finding, we think that two of our patients (patients 2 and 5) probably had arteriosclerosis and diffuse artcritis of the aortic wall, which ruptured and developed into a false aneurysm, and the remaining patients had superimposed infection on arteriosclerotic aortic aneurysm. The timing of surgery is important. The significance of early diagnosis and early treatment of the infected aneurysm before its rupture cannot be over;~ emphasized. Patient 1 and patient 6 should be a~J example of the urgency of the condition, whereas patient 3 and patient 5 were fortunate enough to have a slow leak as a warning, and early surgery saved their lives. Most vascular surgeons recommend generous resection of the infected aorta, wide debridement of the retroperitoneum, and vascular bypass grafting through clean tissue plane, and the most popular one is axillofemoral bypass grafting. 4-8'1° It is generally believed that placement of synthetic vascular graft in the septic bed will eventually lead to anastomotic failure as a result of unrelenting retroperitoneal infection. 3'6'1°-1s It is interesting to note that in a recent review of the experience of Chan et al.14 on in situ graft replacement for mycotic aneurysm of the aorta (21 thoracic and suprarenal and 1 infrarenal abdominal aortic aneurysm), 19 of 22 patients st~r~ vived (four patients had salmonella mycotic aneurysms). ~4 There have also been many reports of successful in situ vascular bypass grafting for abdominal aortic aneurysms infected with salmonella organisms.a,s,s, ~sa7 In our three patients who were treated with in situ bypass surgery, with or without wide excision of the infected aorta and periaortic tissue, no infection reoccurred. Patient 7 demonstrated even one step further, because much of the aneurysmal wall was left intact and was used to cover the graft. The success of treatment in this patient seems to bring out more the significance of proper and prolonged antibiotic therapy and the usefulness of monitoring serum bactericidal activity. On the other hand all our patients who were treated by resection of the aneurysm and extraanatomic bypass grafting did not do very well. One patient died of recurrent infection and another one o~ multiple organ failure. The only one who survive~~
Volume 12 Number 1 Jul; 990
developed several complications, including thrombosis of the graft requiring a thrombectomy. Although theoretically this operation seems sound, it .has many disadvantages. There is a blind end of the aorta, which in one of our patients developed into a fistula communicating with the duodenum producing a fatal hemorrhage. The graft is extraanatomic, longer and subject to outside pressure, and vulnerable to thrombosis. In our experience the in situ bypass group yielded better result. In an attempt to find the best alternative for res'toration of blood flow after the resection of the abdominal aortic aneurysm infected by salmonella organisms, we reviewed the English-language literature on abdominal aortic salmonellosis. We found a total o~ 21 reports in which resection of aneurysms were fbdowed either by in situ or extraanatomic bypass ~grafting. 1-s'13,ls'17.27 There seemed to be a turnaround of the result of in situ grafting after 1970. Since that year, there have been reports of 12 patients who had in situ grafting and survived (including our three patients). On the other hand two out of eight patients died after extraanatomic bypass grafting. However, 'a closer look revealed that among the 12 patients with the in situ graft who survived, four did develop graft infection requiring graft removal and extraanatomic bypass grafting. In our estimation effective antibiotics together with more adequate administration have contributed 'a great deal to the success of the in situ graft. By monitoring the serum bactericidal activity the titer was not allowed to fall below 1 : 8, particularly in the trough period in which the serum antibiotic concentr ;:ion was at its minimum during the course of the treatment. We feel that this method of administration, together with extensive removal of aneurysm and periaortic infective tissue is the key to successful treatment. The authors gratefiflly acknowledge Professor Sira Bunyaratavej for his assistance in the preparation o f this manuscript. REFERENCES 1. Brown SL, Busuttil RW, Baker JD, Machleder HI, Moore WS, Barker WF. Bacteriologic and surgical determinants of survival in patients with mycotic aneurysms. J Vase Suv,a 1984;1:541-7. 2. Sower ND, Whelan TJ. Suppurative arteritis due to Salmonella. Surgery 1962;52:851-9. 3. Meade RH III, Moran JM. Salmonella arteritis-preoperative diagnosis and cure of Salmonella typhimurium aortic aneurysm. N Engl J Med 1969;281:310-2. 4. Mundth ED, Darling C, Alvarado RH, Buckley MJ, Linton RR, Austen WG. Surgical management of mycotic aneurysms and the complications of infection in vascular reconstructive surgery. Am J Surg 1969;117:460-70.
Aortic aneurysms infected with salmonella
19
5. Finseth F, Abbott WM. One-stage operative therapy for salmonella mycotic abdominal aortic aneurysm. Ann Surg 1973;179:8-11. 6. Wilson SE, Gordon HE, Van Wagenen P. Salmonella arteriffs. Arch Surg 1978;113:1163-6. 7. Mendelowitz DS, Ramstedt R, Yao JST, Bergan JJ. Abdominal aortic salmonellosis.Surgery 1979;85:514-9. 8. Parsons R, Gregory J, Palmer DL. Salmonella infection of the abdominal aorta. Rev Infect Dis 1983;5:227-31. 9. Wolfson ]S, Swartz MN. Serum bactericidalactivityas a monitor of antibiotic therapy. N Engl J Med 1985;312:968-75. 10. Iarrett F, Darling RC, Mundth ED, Experience with infected aneurysms of the abdominal aorta. Arch Surg 1975;110: 1281-6. 11. Carter SC, Cohen CA, Whelan TJ. Clinical experience with management of the infected Dacron graft. Ann Surg 1963; 158:249-55. 12. MarmickJA. Complications of peripheral arterial surgery and their management. Am J Surg 1968;116:387-93. 13. Reichle FA, Tyson R_R, Soloff LA, Lantsch EV, Rosemond GP. Salmonellosis and aneurysm of the distal abdominal aorta. Case report with a review. Ann Surg 1970;171:21928. 14. Chan FY, Crawford ES, Coselli JS, Sail HJ, Williams TW. In sire prosthetic graft replacement for mycotic aneurysm of the aorta. Ann Thorac Surg 1989;47:193-203. 15. James EC, GillespieJT. Aortic mycotic abdominal aneurysm involving all visceral branches: Excision and dacron graft replacement. 1 Cardiovasc Surg 1977;18:353-6. 16. lohansen K, Devin J. Mycotic aortic aneurvsm. Arch Surg 1983;118:583-8. 17. Wilda CC, Tan L, Cheong FW. Case report: computed tomography and ultrasotmd diagnosis of mycotic aneurysm of the abdominal aorta due to Salmonella. Clin Radiol 1987; 38:325-6. 18. Black PH, Kunz LI, Swartz MN. Salmonellosis: a review of some unusual aspects. N Engl J Med 1960;262:811-7. 19. Hyde RD, Davis PKB. Infection of an aortic aneurysm with Salmonella choleraesuis. Br Med J 1962;1:30-1. 20. Morris GC, Crawford ES, Cooley DA, De Bakey ME. Revascularisationof the celiac and superior mesenteric arteries. Arch Surg 1962;84:95-107. 21. Ohma K. Mucoffsk aorta aneurysme ved salmonellae med ruptur til duodenum. Nord Med 1965;73:10-1. 22. Dixon RH, Lowicki EM. Salmonellosisassociated with abdominal aortic aneurysm. South Med J 1966;59:1403. 23. DeMuth WE, McConaghie RJ. Salmonella infection in ruptured abdominal aortic aneurysm. Arch Surg 1967;95: 193-7. 24. Porschen RK, Hale D, Goodman Z. Misdiagnosedsalmonella septicemia and endarteriffs due to a lactose-fermenting strain. Am J Clin Pathol 1977;68:416-9. 25. DavisOG, Thorbum JD, Powell P. Cryptic mycotic abdominal aortic aneurysms. Am J Surg 1978;136:96-101. 26. Humphrey RW, Vercoutere AL, Abu-Dalu J. Ruptured mycotic salmonella aortic aneurysm treated with combined cefotaxime antibiotic and staged surgical management. Angiology 1983;34:674-8. 27. Ljungberg B, Braconier JH. Abdominal aortiffs and infected aneurysms due to salmonella. Scand J Infect Dis 1986; 18:401-6.
A review of the English-language literature in 1984 revealed that the bacteriology of mycotic aneurysms has undergone a change in pattern. Before 1965 salmonella organisms were the most common, being present in 38% of the aneurysms, whereas after 1965 the most common organisms were staphylococci, which were found in 30% and salmonellas in only 10%. This same review also noted that the abdominal aorta was one of the most common sites of mycotic aneurysms (31%).1 Rupture of the aorta, resulting from either salmonella suppurative aortitis or salmonella mycotic aneurysm was consistently fatal before 1970. 2.4 After that, more reports of successful treatment of this condition were published, s8 In Thailand, a tropical country, salmonella infection is still common and sometimes causes some epidemiologic concern by its sporadic outbreaks. Within 3 years we had the chance to treat seven patients who had abdominal aortic aneurysms infected with salmonella organisms, and while treating the patients we were confronted with many problems From the Departments of Surgery~ and Medicine,2 Faculty of Medicine, Ramathibodi Hospital, Mahidol University. Reprint requests: Prasert Trairatvorakul, MD, Department of Surgery, Ramathibodi Hospital, Rama VIRd., Bangkok 10400, Thailand. 24 / 1 / 19944
16
that required further study to choose the best alternatives for the patients. PATIENTS AND METHOD Seven consecutive patients with abdominal aortic aneurysms infected with salmonella organisms were treated at Ramathibodi Hospital, Bangkok, Thailand, between 1985 and 1988. A summary o f c l i n i c ~ features of all the cases is presented in Table I. The{e were five men and two women, and the age range was between 53 and 75 years, with a mean age of 64 years. Fever was present in all patients, and abdominal pain and abdominal mass were the next most common complaints. Although correct diagnosis was made before operation in only five out of seven patients, four patients were considered to have delayed diagnosis (patients 1, 2, 5, and 6). Hemocultures were positive for salmonella organisms in only two patients. Cultures from the wall of the aneurysms were positive for salmonella organisms in all patients. The most prominent species was Salmonella typhimurium, which was found in five patients. Broad spectrum antibiotic therapy was given as soon as the diagnosis was made, and the condition was treated as a semiemergency, that is, elective surgery was performed as soon as possible, unless there were signs of rupture or threatened rupture of the aneurysm.
Volume 12 Number 1 Jff 1990
Aortic aneurysms infected with salmonella 17
Table I. Summary of clinical features of patients Diagnosed Case Sex/Age
preoperatively
No.
(yr)
Symptom
1
M/67
Fever; abdominal pain; mass
Yes
Duration Pathologic organism
Site of culture
S. typhimurium Aneurysm; Ruptured Resection blood
2
F/58
Fever; abdominal pain; mass
Yes
S. typhimurium Aneurysm
3
M/75
No
S. choleraesuis Aneurysm
4
F/59
Fever; abdominal & back pain Fever; back pain; mass
Yes
S. typhimurium Aneurysm
5
M/70
Fever; back pain; diarrhea
Yes
S. group D
6
M/53
Yes
7
M/67
Fever; abdominal pain; mass Fever; abdominal pain; diarrhea;
No
Operative finding Operation Complication Multiple infected and organ AAA; - A x B i F ; failure aortoabdomiduo&noperinal fisneal retula section Aortitis Resection Aortowith and uodenal leakage AxBiF fistula 2 and anmonths eurysm after operation Leaking In situ None infected graft AAA AAA
Resection and AxBiF
Aneurysm; Aortitis In siva blood with graft leakage and aneurysm S. typhimurium Aneurysm Ruptured Explorinfected atory AAA laparotomy S. typhimurium Aneurysm; AAA In situ urine; with graft stool periaortic adhesion
Result
offollow-up (too)
Died 2 weeks after operation
--
Died 2 months after operation
--
Alive
12
ThromAlive bosed graft; emphysematous pyelonephritis Prolonged Alive intestinal ileus
24
22
Died
Prolonged resplratory insufficicncy
Alive
13
mass
AAA, abdominal aortic aneurysm; AxBif, axillobifemoral bypass.
Resection and axillofemoral bypass reconstruction was performed in three patients (patients 1, 2, and 4). In patient 1 there was also extensive necrosis of the sigmoid colon and rectum, and this necessitated abdominoperineal resection. Two patients (patients 3 and 5) had complete removal of aneurysmal wall and most of the infected periaortic tissue and in situ graft. One patient (patient 7) had most of the aneurysmal wall left intact to cover the in situ graft, since preoperative diagnosis of salmonella infection was not yet made. The remaining one patient (patient 6) bled before the surgery, and emergency laparotomy was done but failed to save the patient's life. When a diagnosis of salmonellosis was made, our choice of antibiotics were cotrimoxazole, ampicillin, cefuroxime, and ceftriaxone, alone or in combina-
tion. The antibiotic therapy was given for at least 6 weeks after the operation. It has been proposed that a single bactericidal agent used to achieve a mininaal serum bactericidal capacity of 1 : 8 should be optimal if proper surgical drainage has been achieved. 8 We adopted this antibiotic regime in three of four patients who survived. Serum bactericidal activity of the antibiotic was monitored both at the peak or maximum serum concentration and at the trough or minimum serum concentration, as determined by the pharmacokinetic property of the antibiotic (Table II). Serum bactericidal activity was done by serially diluting the patient's serum, and each dilution was tested against the organism isolated from the same patient. The greatest dilution of serum that killed at
18
lournal of VASCULAR SURG..V~Y
Trairatvorakul, Sriphojanart, and Sathapatayavongs
DISCUSSION
Table II. Summary of serum bactericidal activity in three survival cases Reciprocal of serum bactericidal titer [SBT] at Case No.
3 4
7
Antibiotic regimen (dose x frequency~day)
Ceftriaxone [1 gm × 1] Ampicillin [2 gm × 6] + Ceftriaxone [1 gm × 2] Ampicillin [2 gm x 6]
Peak
Trough
64
8
>512
>512
32
8
least 99.9% of the initial inoculum is defined as the serum bactericidal activity.9 RESULTS Of those who had aneurysmal resection and axillofemoral bypass grafting (patients 1, 2, and 4), one died 2 weeks after the operation as a result of multiple organ failure. This patient had rupture of the aneurysm before the surgery. He also had an extensive necrosis of the sigmoid colon and rectum necessitating an abdominoperineal resection. Another patient from this group died 2 months after the operation because of massive hemorrhage from the fistula between the aortic stump and the duodenum. The only surviving patient in this group had serious complications, one after the other, after the surgery. She had emphysematous pyelonephritis, which required a nephrectomy, and then she developed thrombosis of the bypass graft requiring a thrombectomy (Table I). All three patients who underwent in situ graft placement survived, with a duration of follow-up between 1 and 2 years (patients 3, 5, and 7) (Table I). The first two patients who had extensive removal of the aneurysm and the infected periaortic tissue as recommended in most of the literature concerning this condition had 12 and 22 months of follow-up, respectively. The last patient in this group had almost all of the aneurysm wall left intact, which was used to cover the in situ graft because preoperative diagnosis of salmonella infection was not made. This patient survived and had 13 months of follow-up. One patient died during the surgery (patient 6). Diagnosis was not made until the time of surgery, which had to be done urgently because of rupture of the aneurysm. The patient went into profound hypovolemic shock, and we were unable to replace the blood lost in time.
Three different types of vascular lesions produced by salmonella organisms are diffuse suppurative arteritis with rupture and development of false aneurysm, focal arteritis with rupture and aneurysm formarion, and secondary infection superimposed on preexisting arteriosclerotic aneurysm. 2 Judging from the operative finding, we think that two of our patients (patients 2 and 5) probably had arteriosclerosis and diffuse artcritis of the aortic wall, which ruptured and developed into a false aneurysm, and the remaining patients had superimposed infection on arteriosclerotic aortic aneurysm. The timing of surgery is important. The significance of early diagnosis and early treatment of the infected aneurysm before its rupture cannot be over;~ emphasized. Patient 1 and patient 6 should be a~J example of the urgency of the condition, whereas patient 3 and patient 5 were fortunate enough to have a slow leak as a warning, and early surgery saved their lives. Most vascular surgeons recommend generous resection of the infected aorta, wide debridement of the retroperitoneum, and vascular bypass grafting through clean tissue plane, and the most popular one is axillofemoral bypass grafting. 4-8'1° It is generally believed that placement of synthetic vascular graft in the septic bed will eventually lead to anastomotic failure as a result of unrelenting retroperitoneal infection. 3'6'1°-1s It is interesting to note that in a recent review of the experience of Chan et al.14 on in situ graft replacement for mycotic aneurysm of the aorta (21 thoracic and suprarenal and 1 infrarenal abdominal aortic aneurysm), 19 of 22 patients st~r~ vived (four patients had salmonella mycotic aneurysms). ~4 There have also been many reports of successful in situ vascular bypass grafting for abdominal aortic aneurysms infected with salmonella organisms.a,s,s, ~sa7 In our three patients who were treated with in situ bypass surgery, with or without wide excision of the infected aorta and periaortic tissue, no infection reoccurred. Patient 7 demonstrated even one step further, because much of the aneurysmal wall was left intact and was used to cover the graft. The success of treatment in this patient seems to bring out more the significance of proper and prolonged antibiotic therapy and the usefulness of monitoring serum bactericidal activity. On the other hand all our patients who were treated by resection of the aneurysm and extraanatomic bypass grafting did not do very well. One patient died of recurrent infection and another one o~ multiple organ failure. The only one who survive~~
Volume 12 Number 1 Jul; 990
developed several complications, including thrombosis of the graft requiring a thrombectomy. Although theoretically this operation seems sound, it .has many disadvantages. There is a blind end of the aorta, which in one of our patients developed into a fistula communicating with the duodenum producing a fatal hemorrhage. The graft is extraanatomic, longer and subject to outside pressure, and vulnerable to thrombosis. In our experience the in situ bypass group yielded better result. In an attempt to find the best alternative for res'toration of blood flow after the resection of the abdominal aortic aneurysm infected by salmonella organisms, we reviewed the English-language literature on abdominal aortic salmonellosis. We found a total o~ 21 reports in which resection of aneurysms were fbdowed either by in situ or extraanatomic bypass ~grafting. 1-s'13,ls'17.27 There seemed to be a turnaround of the result of in situ grafting after 1970. Since that year, there have been reports of 12 patients who had in situ grafting and survived (including our three patients). On the other hand two out of eight patients died after extraanatomic bypass grafting. However, 'a closer look revealed that among the 12 patients with the in situ graft who survived, four did develop graft infection requiring graft removal and extraanatomic bypass grafting. In our estimation effective antibiotics together with more adequate administration have contributed 'a great deal to the success of the in situ graft. By monitoring the serum bactericidal activity the titer was not allowed to fall below 1 : 8, particularly in the trough period in which the serum antibiotic concentr ;:ion was at its minimum during the course of the treatment. We feel that this method of administration, together with extensive removal of aneurysm and periaortic infective tissue is the key to successful treatment. The authors gratefiflly acknowledge Professor Sira Bunyaratavej for his assistance in the preparation o f this manuscript. REFERENCES 1. Brown SL, Busuttil RW, Baker JD, Machleder HI, Moore WS, Barker WF. Bacteriologic and surgical determinants of survival in patients with mycotic aneurysms. J Vase Suv,a 1984;1:541-7. 2. Sower ND, Whelan TJ. Suppurative arteritis due to Salmonella. Surgery 1962;52:851-9. 3. Meade RH III, Moran JM. Salmonella arteritis-preoperative diagnosis and cure of Salmonella typhimurium aortic aneurysm. N Engl J Med 1969;281:310-2. 4. Mundth ED, Darling C, Alvarado RH, Buckley MJ, Linton RR, Austen WG. Surgical management of mycotic aneurysms and the complications of infection in vascular reconstructive surgery. Am J Surg 1969;117:460-70.
Aortic aneurysms infected with salmonella
19
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