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In situ repair of mycotic aneurysm of the ascending aorta
In situ repair of mycotic aneurysm of the ascending aorta Between 1969 and 1990 six patients (aged 14 to 64 years, mean 43 years) underwent in situ reconstruction for mycotic aneurysm of the ascending aorta. The primary source of infection was endocarditis in three patients (subacute bacterial endocarditis In = one patient], sepsis with prosthetic endocarditis after aortic valve replacement with bioprosthetic valve In = one patient], sepsis with acute endocarditis In = one patient]), sepsis with sternal osteomyelitis in one, sepsis with purulent pericarditis in one, and generalized febrile illness in one. In five of six patients the treatment consisted of the excision of changed tissue combined with a composite graft (n = one patient), a xenopericardial patch repair (n = one patient), a Dacron graft repair and aortic valve replacement (n = one patient), a Dacron graft repair alone (n = one patient), and a lateral suture combined with double valve replacement (n = one patient). In one patient with perforation of the mycotic aneurysm into the pulmonary artery, the place of rupture was oversewn without excision of the aortic or pulmonary artery tissue. Two patients with local pericardial inflammation were reoperated on during the hospital stay; one of them because of recurrent mycotic aneurysm of the ascending aorta at the other location and the other because of infection of the suture line after the Dacron patch repair. Antibiotic therapy was intravenously administered for 2 to 12 weeks postoperatively and continued orally for 4 to 8 weeks. The mean observation time was 6 years (range 4 months to 16 years). There was no late graft infection, except the chronic infection of the suture line in one patient who died suddenly 4 months after the operation. There was no early death, and there were three late deaths (chronic myocardial failure, one patient, chronic renal failure, one patient, sudden death, one patient). We concluded that in situ reconstruction for mycotic aneurysm of the ascending aorta combined with prolonged antibiotic therapy is an appropriate procedure with satisfactory early and good long-term results. (J THORAC CARDIOVASC SURG 1993;105:321-6)
Miralem Pasic, MD, SeD, Thierry Carrel, MD, Ludwig von Segesser, MD, and Marko Turina, MD, Zurich, Switzerland
h e standard surgical principle for the treatment of mycotic aneurysm consists of arterial ligation, aneurysm excision, and extraanatomic bypass grafting through clean, noninfected tissue. l - s It avoids use of bypass procedures in a contaminated region because of the great risk of graft infection. In recent years there has been a tendency to report patients successfully treated by in situ From the Clinic for Cardiovascular Surgery, University Hospital Zurich, Zurich, Switzerland. Received for publication Oct. I, 1991. Accepted for publication May 25, 1992. Address for reprints: Miralem Pasic, MD, SeD, Clinic for Cardiovascular Surgery, University Hospital Zurich, Riimistrasse 100,8091 Zurich, Switzerland. Copyright
w
1993 by Mosby-Year Book, Inc.
0022-5223/93/$1.00/+0.10
12/1/41793
reconstruction of mycotic aneurysm of the aorta and its branches after excision of entire infected tissue,6-12 especially in the presence of an infected organism of low virulence l 3, 14 and negative blood or perigraft cultures. IS The treatment for mycotic aneurysm of the ascending aorta by extraanatomic bypass grafting is difficult or often impossible because of its location close to the heart.f II In this study we report our experience with in situ reconstruction for treatment of mycotic aneurysm of the ascending aorta.
Patients and methods The records of six patients who underwent operation for mycotic aneurysm of the ascending aorta at the Clinicfor Cardiovascular Surgery, University HospitalZurich,fromJanuary 1969 to December 1990, werereviewed. Patientswithan aneu-
321
The Journal of Thoracic and Cardiovascular Surgery February 1993
3 2 2 Pasic et al.
Table I. Characteristics of six patients with mycotic aneurysms of ascending aorta treated at University Hospital Zurich between 1969 and 1990 Age (yr)
Sex
Follow-up
47
M
4 yr
2 3
28 14
M M
16 yr 13 yr
4
44
M
4mo
5
64
M
2 yr
6
61
M
7mo
Patient No.
Predisposing factor
Prosthetic endocarditis,sepsis Subacuteendocarditis Sternal osteomyelitis, sepsis Acute endocarditis, pericarditis, sepsis Status febrilis, miliarytuberculosis Sepsis, pericarditis
Previous operation
False aneurysm
AVR Aortic commissurotomy
Formation
Rupture
+
Solitary
+
+ +
Double Solitary
+*
+
Solitary
+
Solitary
+
Solitary
+
A VR, Aortic valve replacement. -Ruptured into the pulmonary artery.
Table II. Causative agents, causes of deaths, and early and late deaths in six patients with mycotic aneurysm of ascending aorta operated on at University Hospital Zurich between 1969 and 1990 Patient No.
Causative agent Staphylococcus
coagulase negative 2
3
4 5 6
Staphylococcus aureus Staphylococcus aureus Streptococcus viridans
Early death
Late death
+
+
+
Cause of death
Chronicrenal failure
Chronic myocardial failure Suddendeath
Unknown Staphylococcus aureus
rysm of the aortic root or with aortic anulus abscesses or with both, but without mycotic aneurysm of the other part of the ascending aorta, were not included in this study. All patients were male, aged from 14 to 64 years (mean 43 years) (Table I) (Figs. 1 to 3). A previous cardiac operation had been performed in two patients; one of them had undergone aortic valve replacement with a bioprosthetic valve, and the other aortic commisurotomy because of congenital aortic stenosis. One patient was previously operated on because of mycotic aneurysm of a popliteal artery. In all patients the diagnosis of mycotic aneurysm of the ascending aorta was made or suspected preoperatively after plain roentgenograms, echocardiography, aortography, or computed tomographic scan, or all of these were performed. Although echocardiography revealed the diagnosis, total aortography or nuclear magnetic resonance imaging or both were performed in three patients to exclude the presence of other mycotic aneurysms ofthe aorta or its great branches. In patients aged more than 60 years, coronary angiography was performed to exclude coronary artery disease.
Table III. Types of immunoinsufficiency, operations, and reoperations in six patients with mycotic aneurysm of ascending aorta Patient No. I
2 3 4 5 6
Type ofoperation
Composite graft Suture + AVR + MVR Suture Dacronpatch + AVR Dacronpatch Xenopericardial patch
Reoperation lmmunoinsufficieru:y
+ +
Alcoholism Alcoholism Alcoholism
AVR, Aortic valve replacement; MVR, mitral valve replacement.
All diagnoses were confirmed intraoperatively by clinical, microscopic, or microbiologic methods, or by all three methods. Positive blood cultures and signs of sepsis were observed in four patients before operation. Intraoperative culture of the arterial wall was also positive for bacteria in four patients. In patient 5 no organism was isolated from the wall of the aneurysm, and in patient 3 operated on in 1969, aortic wall culture was not performed (Table II). All surgical interventions were performed through median sternotomy. In a patient operated on in 1969 (patient 3), the operation was performed without cardiopulmonary bypass, and the perforated region in the aortic and pulmonary artery walls was oversewn. All other operations were employed using cardiopulmonary bypass and moderate hypothermia, except for one patient who was operated on in deep hypothermia. Cannulation of the external iliac artery was utilized in two patients. Treatment consisted of a composite graft replacement in one patient, a xenopericardial patch repair in one, and a Dacron patch repair and mitral valve replacement in one. In one patient lateral suture of the ascending aorta was combined with double valve replacement (Table III). All macroscopically changed tissue was excised in five patients. Debridement was not performed in patient 3. All patients were treated with antibiotics within 24 hours to 30 days before operation. Appropriate antibiotics were administered intravenously for 2 to 12 weeks postoperatively and were continued orally for 4 to 8 weeks. All patients were continuously followed up until death or comple-
The Journal of Thoracic and Cardiovascular Surgery Volume 105, Number 2
Pasic et al. 3 2 3
Fig. 1. A saccular aneurysm is evidenton the proximalpart of the ascendingaorta immediatelydistal to the aortic root. tion of the study. The mean follow-up was 6 years (range 4 months to 16 years). Results There were no early deaths. In two patients (patients 4 and 6) local infection recurred during the hospital stay. Sepsis and a local pericardial infection were present during the first operation in both patients. In the patient with Dacron patch repair of the ascending aorta and aortic valve replacement (patient 4), mitral valve endocarditis and infection of the suture line developed during hospitalization. The postoperative course of the same patient was also complicated by gastrointestinal bleeding. At reoperation the aortic wall was closed with Dacron patch repair again. A disruption of the suture line without signs of acute pericardial infection was found. The incomplete resection of the changed aortic wall was probably the cause of the rupture. The patient died suddenly 4 months later. Autopsy and pathohistologic examination revealed chronic infection of the suture line. In the patient with previous xenopericardial patch repair (patient 6), infection recurred 1 month after the first operation. Emergency reoperation was done because of the pericardial tamponade and airway compression. Reoperation revealed a second rupture of the ascending aortic wall 1 em distal to the previous aneurysm. After local excision into intact aortic wall, a xenopericardial patch angioplasty was performed in deep hypothermia and circulatory arrest. The postoperative course was uneventful. After discharge
from the hospital, the patients were followed up from 4 months to 16 years. Late death occurred in three patients (see Table 11). Besides patient 4, the second patient (patient 3) died from chronic myocardial failure and the third (patient 1) from renal failure during follow-up. Postmortem examinations revealed no signs of local infection of the prosthetic graft or the suture line. The postoperative course of other patients was uneventful. Discussion Our study showed that in situ reconstruction of the ascending aorta is a satisfactory procedure for treatment of mycotic aneurysm in this position. Although surgical decision for treatment of mycotic aneurysm in other locations depends on a location of arterial infection, the patient's general condition and immunologic state, type of bacteria causing infection, and local findings, there are usually two operative options for choosing: either in situ or extraanatomic reconstruction. In contrast, the management of mycotic aneurysm of the ascending aorta is different from operative strategy for mycotic aneurysms in other locations. It is frequently impossible to perform extraanatomic reconstruction by ascending aorta to abdominal aorta bypass or by left ventricle to abdominal aorta bypass because of technical difficulties and close position of the mycotic aneurysm to the heart or great vessels. Also, in case of infection of the pericardial sac, it is impossible to perform reconstruction through a clean
324
Pasic et al.
The Journal of Thoracic and Cardiovascular Surgery February 1993
Fig. 2. Typical "mushroom shape" of the mycotic false aneurysm of the ascending aorta.
Fig. 3. Aortogram showing large false aneurysm of the distal ascending aorta at the level near the aortic arch.
field. In case of evident pericarditis, as in our two patients, in situ reconstruction through the infected plane, should be combined with pericardiectomy to reduce a risk oflocal infection. If a mycotic aneurysm of the ascending aorta is combined with annular abscess formation or with acute valve endocarditis, an aortic homograft should be used.l? In situ reconstruction for mycotic ascending aortic
aneurysm has been reported sporadically. In the successfully treated patient reported by Albes and colleagues, I 1 the mycotic aneurysm developed in a 19-year-old woman after the heart-lung transplantation at the site of insertion of the cardioplegic cannula in the donor aorta. Under circulatory arrest the infected area was excised and was covered with pericardial patch repair. To prevent rupture
The Journal of Thoracic and Cardiovascular Surgery Volume 105, Number 2
of the aortic anastomosis, they used an additional muscle flap to cover an anastomotic region. Chan, Crawford, and colleagues" reported their experience with mycotic aneurysms of the ascending aorta in 7 of 22 patients with mycotic aortic aneurysms. The aneurysms were located only in the ascending aorta in two patients, and in the ascending aorta and in the other part of the aorta in five. In all patients surgical therapy consisted of placement of in situ grafts after evacuation of clot and after local debridement. Recurrent rupture occurred in four of seven patients, and there were two early deaths without late infection." Perforation of mycotic aortic aneurysm in the pulmonary artery presents a special technical problem, as in our patient 3. Brahan and Kahler l 7 reported a similar case of a 70-year-old female diabetic with pericarditis, mycotic aneurysm ofthe aortic arch caused by Clostridium septicum, and a fistula between the aneurysm and the pulmonary artery that was repaired with a Dacron graft. Mycotic aneurysm resulted from arterial infection through septic embolization from endocarditis in three of our patients. Although endocarditis had been the frequent source of embolism earlier, lately the prevalence of arterial embolism from endocarditis has decreased since antibiotics have been developed and rheumatic fever has been largely prevented.l'' Bacteria responsible for subacute endocarditis are usually staphylococcus, streptococcus, and, more rarely, gram-negative bacilli. 19-22 Our findings correlated with those from the literature. In four patients we found staphylococcus and in one patient streptococcus that caused infection. Although the arterial wall is resistant to infection, it may be involved by surrounding septic foci, such as osteomyelitis and mediastinal, pericardial, or pulmonary abscess.'? In our two patients the aortic infection developed by direct spread of infection; in one from the pericardial sac to the aortic wall and in another from sternal osteomyelitis. It is known that in the course of endocarditis, mycotic aneurysms are frequently latent and are often diagnosed when they are complicated by aortic rupture.P Rupture of mycotic aneurysm of the ascending aorta was quite common in our patients. The rupture in two patients caused pericardial pretamponade, and in one the aneurysm perforated into the pulmonary artery. Danger of rupture should be expected also after operation during the postoperative course. Rupture of the suture line caused acute respiratory insufficiency because of tracheal compression by hematoma in one of our patients. Coverage of the infected area with the omentum or muscle flap was recommended to protect the suture line from reinfection by enhancing microbiologic resistance. I I,24 The use of local antibiotic therapy can also contribute to the prevention of local or mediastinal infection.j> 26 although we did
Pasic et al.
325
not have a patient with a new postoperative sternal infection after the operation for mycotic aneurysm. Mycotic aneurysms arise in two different ways. The first way concerns embolization from a distant site or direct spread of infection from a nearby inflammatory locus into normal or atherosclerotic changed but not dilated arterial wall; the second way can be considered as an infection of the arterial wall or intraluminal clot in preexisting atherosclerotic aneurysm. In all of our patients an aneurysmatic dilation of the ascending aorta was not presented, so that the term "infected false aneurysm" or "infected spurious aneurysm" or "acute bacterial aortitis" is better than the term "mycotic aneurysm." Most of the patients with mycotic aneurysms have a predisposing factor to immunoincompetency and to infection, so that three of our six patients had a previous history of endocarditis, three of alcoholism, and one of miliary tuberculosis as a predisposing factor to infection. Our present management of mycotic ascending aortic aneurysm is as follows: All operations should be done through median sternotomy with use of cardiopulmonary bypass in moderate hypothermia. Deep hypothermia is recommended if an aneurysm is opposite to the origin of the great vessel of the aortic arch or if it involves the vessels. If an aneurysm is ruptured or if periaortic inflammation with adhesions or a rupture is suspected, or if the aneurysm is huge, cardiopulmonary bypass with cannulation of the external iliac or common femoral artery should be performed. We do not recommend operation without cardiopulmonary bypass even if an aneurysm is small in size and an operation seems to be feasible only with lateral clamping of the aorta. All macroscopically infected tissue of the aortic wall should be excised; thereafter the microbiologic and microscopic examination of excised aortic tissue should be done. In the case of a small mycotic aneurysm with localized changing of the aortic wall, and if there is no evidence of purulent pericarditis, we suggest replacement of the aortic defect with a part of autologous pericardial patch. If the autologous pericardium is not available or if it is inflamed, and if there is no arterial homograft available, xenopericardium should be used. In the case of destruction or infected changes of a larger part of the aortic wall not involving aortic root or aortic valve, we recommend also using aortic homograft without valve as a conduit for the ascending aorta. If it is necessary to perform a composite graft because of accompanied aortic root-infected changes or aortic anulus abscess, or if the aneurysm is located in the proximal aorta, we recommend the use of aortic homograft as a composite graft. Also, if there is obvious infection of the aortic valve or if there are signs of acute aortic valve endocarditis, homograft should be used as a replacement
3 2 6 Pasic et al.
for natural aortic valve. At the same time, with treatment of mycotic aneurysm of the ascending aorta, aortic valve replacement should be performed with a bioprosthetic or mechanical valve in the case of aortic insufficiency without valve endocarditis. Prosthetic graft as a patch or vascular conduit is the last choice, and we try to use this method only when the other possibilities are not available or technically cannot be performed. Coronary artery bypass graft should always be performed if significant coronary artery disease is found. To eliminate performing aortic anastomosis, we recommend use of the internal mammary artery as a conduit. We thank Ms. Annette Bauer for help in preparing the manuscript. REFERENCES 1. Taylor LM Jr, Deitz DM, McConnell DB, Porter JM.
Treatment of infected abdominal aneurysm by extraanatomic bypass, aneurysm excision,and drainage. Am J Surg 1988;155:655-8. 2. Dean RH, Meacham PW, Weaver FA, Waterhouse G, O'Neil JA Jr. Mycotic embolism and embolomycotic aneurysm: neglected lesson of the past. Ann Surg 1986; 204:303-7. 3. Miller BM, Waterhouse G, Alford RH, Dean RH, Hawkins SS, Smith BM. Histoplasma infection of abdominal aortic aneurysm. Ann Surg 1983;197:57-62. 4. Parson R, Gregory J, Palmer DL. Salmonella infection of the abdominal aorta. Rev Infect Dis 1983;5:227-37. 5. Asplund MW, Molinaro A. Infected solitary iliac artery aneurysm. J Vasc Surg 1990;12:219-20. 6. Chan FY, Crawford ES, CoselliJS, Safi HJ, Williams TW. In situ prosthetic graft replacement for mycotic aneurysm of the aorta. Ann Thorac Surg 1989;47:193-203. 7. Pasic M, Schwitter J, Carrel T, Vogt M, von Segesser L, Turina M. Ruptured mycotic extracranial carotid aneurysm treated by excision,PTFE graft interpositionand local antibiotic application. Vase Surg 1992;26:421-5. 8. Atnip RG. Mycotic aneurysm of suprarenal abdominal aorta: prolonged survival after in situ aortic and visceral reconstruction. J Vase Surg 1989;10:635-41. 9. Bitseff EL, Edwards WH, Mulherin JL Jr, Kaiser AB. Infected abdominal aortic aneurysm. South Med J 1987; 80:309-12. 10. Bogers AJJC, van't Wout JW, Manger Cats V, Quaegebeur JM, Hysmans HA. Mediastinal rupture of a thoracoabdominal mycotic aneurysm caused by Salmonella typhimurium in an immunocompromised patient. Eur J Cardiothorac Surg 1987;1:116-8.
The Journal of Thoracic and Cardiovascular Surgery February 1993
II. Albes J, Haverich A, Freihorst J, von der Hardt H, Manthey-Stires F. Management of mycotic rupture of the ascending aorta after heart-lung transplantation. Ann Thorac Surg 1990;50:982-3. 12. Trairatvorakul P, Sriphojanart S, Sathapatayvongs B. Abdominal aortic aneurysm infected with salmonella: problems of treatment. J Vase Surg 1990;12:16-9. 13. Jarett F, Darling C, Mundth ED, Austen WG. Experience with infected aneurysm of the abdominal aorta. Arch Surg 1975;110:1281-6. 14. Davis OG, Thorburn JD, Powell P. Cryptic mycotic abdominal aortic aneurysm. Am J Surg 1978;136:96-101. 15. Jacobs MJHM, Reul GJ, Gregoric I, Cooley DA. In-situ replacement and extra-anatomic bypass for treatment of infected abdominal aortic grafts. Eur J Vase Surg 1991; 5:83-6. 16. Glazier JJ, Verwilghen J, Donaldson RM, Ross DN. Treatment of complicated prosthetic aortic valve endocarditis with annular abscess formation by homograft aortic root replacement. J Am Coll CardioI1991;17:1177-82. 17. Brahan RB, Kahler RC. Clostridium septicum as a cause of pericarditis and mycotic aneurysm. J Clin Microbiol 1990;28:2377-8. 18. Etienne J, Eykyn SJ. Increase in native valve endocarditis caused by coagulase negative staphylococcus: an AngloFrench clinical and microbiological study. Br Heart J 1990;64:381-4. 19. Wilson SE, Gordon HE, van Wagenen PB. Salmonella arteritis. A precursor of aortic rupture and pseudoaneurysm formation. Arch Surg 1978;113:1163-6. 20. Wilson SE, van Wagenen PB, Pasaro E. Arterial infection. Curr Probl Surg 1978;15:12-38. 21. Bayliss R, Clarke C, Oakley CM, Sommerville W, Whitfield AGW, Young SEJ. The microbiologyand pathogenesis of infective endocarditis. Br Heart J 1983;50:513-9. 22. Jaffe WM, Morgan DE, Pearlman AS, Otto CM. Infective endocarditis, 1983-1988: echocardiographic findings and factors influencing morbidity and mortality. J Am Coll Cardiol 1990;15:1227-33. 23. Berkmen YM. Medical aspects of infectious aortitis. In: Lande A, Berkmen YM, McAllister A, eds. Aortitis: clinical, pathological and radiographic aspects. New York: Raven Press, 1986;1:161-72. 24. Hay RJ. Recent advances in the management of fungal infections. Q J Med 1987;64:631-9. 25. Wahlig H, Dingeldein E, Bergmann R, Reuss K. The release of gentamicin from polymethylmethacrylate beads. J Bone Joint Surg 1978;60-B:270-5. 26. Klemm K. Gentamycin-PMMA-Kugeln in der Behandlung abszedierender Knochen- und Weichteilinfektionen. Zentralbl Chir 1979;104:934-42.
Miralem Pasic, MD, SeD, Thierry Carrel, MD, Ludwig von Segesser, MD, and Marko Turina, MD, Zurich, Switzerland
h e standard surgical principle for the treatment of mycotic aneurysm consists of arterial ligation, aneurysm excision, and extraanatomic bypass grafting through clean, noninfected tissue. l - s It avoids use of bypass procedures in a contaminated region because of the great risk of graft infection. In recent years there has been a tendency to report patients successfully treated by in situ From the Clinic for Cardiovascular Surgery, University Hospital Zurich, Zurich, Switzerland. Received for publication Oct. I, 1991. Accepted for publication May 25, 1992. Address for reprints: Miralem Pasic, MD, SeD, Clinic for Cardiovascular Surgery, University Hospital Zurich, Riimistrasse 100,8091 Zurich, Switzerland. Copyright
w
1993 by Mosby-Year Book, Inc.
0022-5223/93/$1.00/+0.10
12/1/41793
reconstruction of mycotic aneurysm of the aorta and its branches after excision of entire infected tissue,6-12 especially in the presence of an infected organism of low virulence l 3, 14 and negative blood or perigraft cultures. IS The treatment for mycotic aneurysm of the ascending aorta by extraanatomic bypass grafting is difficult or often impossible because of its location close to the heart.f II In this study we report our experience with in situ reconstruction for treatment of mycotic aneurysm of the ascending aorta.
Patients and methods The records of six patients who underwent operation for mycotic aneurysm of the ascending aorta at the Clinicfor Cardiovascular Surgery, University HospitalZurich,fromJanuary 1969 to December 1990, werereviewed. Patientswithan aneu-
321
The Journal of Thoracic and Cardiovascular Surgery February 1993
3 2 2 Pasic et al.
Table I. Characteristics of six patients with mycotic aneurysms of ascending aorta treated at University Hospital Zurich between 1969 and 1990 Age (yr)
Sex
Follow-up
47
M
4 yr
2 3
28 14
M M
16 yr 13 yr
4
44
M
4mo
5
64
M
2 yr
6
61
M
7mo
Patient No.
Predisposing factor
Prosthetic endocarditis,sepsis Subacuteendocarditis Sternal osteomyelitis, sepsis Acute endocarditis, pericarditis, sepsis Status febrilis, miliarytuberculosis Sepsis, pericarditis
Previous operation
False aneurysm
AVR Aortic commissurotomy
Formation
Rupture
+
Solitary
+
+ +
Double Solitary
+*
+
Solitary
+
Solitary
+
Solitary
+
A VR, Aortic valve replacement. -Ruptured into the pulmonary artery.
Table II. Causative agents, causes of deaths, and early and late deaths in six patients with mycotic aneurysm of ascending aorta operated on at University Hospital Zurich between 1969 and 1990 Patient No.
Causative agent Staphylococcus
coagulase negative 2
3
4 5 6
Staphylococcus aureus Staphylococcus aureus Streptococcus viridans
Early death
Late death
+
+
+
Cause of death
Chronicrenal failure
Chronic myocardial failure Suddendeath
Unknown Staphylococcus aureus
rysm of the aortic root or with aortic anulus abscesses or with both, but without mycotic aneurysm of the other part of the ascending aorta, were not included in this study. All patients were male, aged from 14 to 64 years (mean 43 years) (Table I) (Figs. 1 to 3). A previous cardiac operation had been performed in two patients; one of them had undergone aortic valve replacement with a bioprosthetic valve, and the other aortic commisurotomy because of congenital aortic stenosis. One patient was previously operated on because of mycotic aneurysm of a popliteal artery. In all patients the diagnosis of mycotic aneurysm of the ascending aorta was made or suspected preoperatively after plain roentgenograms, echocardiography, aortography, or computed tomographic scan, or all of these were performed. Although echocardiography revealed the diagnosis, total aortography or nuclear magnetic resonance imaging or both were performed in three patients to exclude the presence of other mycotic aneurysms ofthe aorta or its great branches. In patients aged more than 60 years, coronary angiography was performed to exclude coronary artery disease.
Table III. Types of immunoinsufficiency, operations, and reoperations in six patients with mycotic aneurysm of ascending aorta Patient No. I
2 3 4 5 6
Type ofoperation
Composite graft Suture + AVR + MVR Suture Dacronpatch + AVR Dacronpatch Xenopericardial patch
Reoperation lmmunoinsufficieru:y
+ +
Alcoholism Alcoholism Alcoholism
AVR, Aortic valve replacement; MVR, mitral valve replacement.
All diagnoses were confirmed intraoperatively by clinical, microscopic, or microbiologic methods, or by all three methods. Positive blood cultures and signs of sepsis were observed in four patients before operation. Intraoperative culture of the arterial wall was also positive for bacteria in four patients. In patient 5 no organism was isolated from the wall of the aneurysm, and in patient 3 operated on in 1969, aortic wall culture was not performed (Table II). All surgical interventions were performed through median sternotomy. In a patient operated on in 1969 (patient 3), the operation was performed without cardiopulmonary bypass, and the perforated region in the aortic and pulmonary artery walls was oversewn. All other operations were employed using cardiopulmonary bypass and moderate hypothermia, except for one patient who was operated on in deep hypothermia. Cannulation of the external iliac artery was utilized in two patients. Treatment consisted of a composite graft replacement in one patient, a xenopericardial patch repair in one, and a Dacron patch repair and mitral valve replacement in one. In one patient lateral suture of the ascending aorta was combined with double valve replacement (Table III). All macroscopically changed tissue was excised in five patients. Debridement was not performed in patient 3. All patients were treated with antibiotics within 24 hours to 30 days before operation. Appropriate antibiotics were administered intravenously for 2 to 12 weeks postoperatively and were continued orally for 4 to 8 weeks. All patients were continuously followed up until death or comple-
The Journal of Thoracic and Cardiovascular Surgery Volume 105, Number 2
Pasic et al. 3 2 3
Fig. 1. A saccular aneurysm is evidenton the proximalpart of the ascendingaorta immediatelydistal to the aortic root. tion of the study. The mean follow-up was 6 years (range 4 months to 16 years). Results There were no early deaths. In two patients (patients 4 and 6) local infection recurred during the hospital stay. Sepsis and a local pericardial infection were present during the first operation in both patients. In the patient with Dacron patch repair of the ascending aorta and aortic valve replacement (patient 4), mitral valve endocarditis and infection of the suture line developed during hospitalization. The postoperative course of the same patient was also complicated by gastrointestinal bleeding. At reoperation the aortic wall was closed with Dacron patch repair again. A disruption of the suture line without signs of acute pericardial infection was found. The incomplete resection of the changed aortic wall was probably the cause of the rupture. The patient died suddenly 4 months later. Autopsy and pathohistologic examination revealed chronic infection of the suture line. In the patient with previous xenopericardial patch repair (patient 6), infection recurred 1 month after the first operation. Emergency reoperation was done because of the pericardial tamponade and airway compression. Reoperation revealed a second rupture of the ascending aortic wall 1 em distal to the previous aneurysm. After local excision into intact aortic wall, a xenopericardial patch angioplasty was performed in deep hypothermia and circulatory arrest. The postoperative course was uneventful. After discharge
from the hospital, the patients were followed up from 4 months to 16 years. Late death occurred in three patients (see Table 11). Besides patient 4, the second patient (patient 3) died from chronic myocardial failure and the third (patient 1) from renal failure during follow-up. Postmortem examinations revealed no signs of local infection of the prosthetic graft or the suture line. The postoperative course of other patients was uneventful. Discussion Our study showed that in situ reconstruction of the ascending aorta is a satisfactory procedure for treatment of mycotic aneurysm in this position. Although surgical decision for treatment of mycotic aneurysm in other locations depends on a location of arterial infection, the patient's general condition and immunologic state, type of bacteria causing infection, and local findings, there are usually two operative options for choosing: either in situ or extraanatomic reconstruction. In contrast, the management of mycotic aneurysm of the ascending aorta is different from operative strategy for mycotic aneurysms in other locations. It is frequently impossible to perform extraanatomic reconstruction by ascending aorta to abdominal aorta bypass or by left ventricle to abdominal aorta bypass because of technical difficulties and close position of the mycotic aneurysm to the heart or great vessels. Also, in case of infection of the pericardial sac, it is impossible to perform reconstruction through a clean
324
Pasic et al.
The Journal of Thoracic and Cardiovascular Surgery February 1993
Fig. 2. Typical "mushroom shape" of the mycotic false aneurysm of the ascending aorta.
Fig. 3. Aortogram showing large false aneurysm of the distal ascending aorta at the level near the aortic arch.
field. In case of evident pericarditis, as in our two patients, in situ reconstruction through the infected plane, should be combined with pericardiectomy to reduce a risk oflocal infection. If a mycotic aneurysm of the ascending aorta is combined with annular abscess formation or with acute valve endocarditis, an aortic homograft should be used.l? In situ reconstruction for mycotic ascending aortic
aneurysm has been reported sporadically. In the successfully treated patient reported by Albes and colleagues, I 1 the mycotic aneurysm developed in a 19-year-old woman after the heart-lung transplantation at the site of insertion of the cardioplegic cannula in the donor aorta. Under circulatory arrest the infected area was excised and was covered with pericardial patch repair. To prevent rupture
The Journal of Thoracic and Cardiovascular Surgery Volume 105, Number 2
of the aortic anastomosis, they used an additional muscle flap to cover an anastomotic region. Chan, Crawford, and colleagues" reported their experience with mycotic aneurysms of the ascending aorta in 7 of 22 patients with mycotic aortic aneurysms. The aneurysms were located only in the ascending aorta in two patients, and in the ascending aorta and in the other part of the aorta in five. In all patients surgical therapy consisted of placement of in situ grafts after evacuation of clot and after local debridement. Recurrent rupture occurred in four of seven patients, and there were two early deaths without late infection." Perforation of mycotic aortic aneurysm in the pulmonary artery presents a special technical problem, as in our patient 3. Brahan and Kahler l 7 reported a similar case of a 70-year-old female diabetic with pericarditis, mycotic aneurysm ofthe aortic arch caused by Clostridium septicum, and a fistula between the aneurysm and the pulmonary artery that was repaired with a Dacron graft. Mycotic aneurysm resulted from arterial infection through septic embolization from endocarditis in three of our patients. Although endocarditis had been the frequent source of embolism earlier, lately the prevalence of arterial embolism from endocarditis has decreased since antibiotics have been developed and rheumatic fever has been largely prevented.l'' Bacteria responsible for subacute endocarditis are usually staphylococcus, streptococcus, and, more rarely, gram-negative bacilli. 19-22 Our findings correlated with those from the literature. In four patients we found staphylococcus and in one patient streptococcus that caused infection. Although the arterial wall is resistant to infection, it may be involved by surrounding septic foci, such as osteomyelitis and mediastinal, pericardial, or pulmonary abscess.'? In our two patients the aortic infection developed by direct spread of infection; in one from the pericardial sac to the aortic wall and in another from sternal osteomyelitis. It is known that in the course of endocarditis, mycotic aneurysms are frequently latent and are often diagnosed when they are complicated by aortic rupture.P Rupture of mycotic aneurysm of the ascending aorta was quite common in our patients. The rupture in two patients caused pericardial pretamponade, and in one the aneurysm perforated into the pulmonary artery. Danger of rupture should be expected also after operation during the postoperative course. Rupture of the suture line caused acute respiratory insufficiency because of tracheal compression by hematoma in one of our patients. Coverage of the infected area with the omentum or muscle flap was recommended to protect the suture line from reinfection by enhancing microbiologic resistance. I I,24 The use of local antibiotic therapy can also contribute to the prevention of local or mediastinal infection.j> 26 although we did
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not have a patient with a new postoperative sternal infection after the operation for mycotic aneurysm. Mycotic aneurysms arise in two different ways. The first way concerns embolization from a distant site or direct spread of infection from a nearby inflammatory locus into normal or atherosclerotic changed but not dilated arterial wall; the second way can be considered as an infection of the arterial wall or intraluminal clot in preexisting atherosclerotic aneurysm. In all of our patients an aneurysmatic dilation of the ascending aorta was not presented, so that the term "infected false aneurysm" or "infected spurious aneurysm" or "acute bacterial aortitis" is better than the term "mycotic aneurysm." Most of the patients with mycotic aneurysms have a predisposing factor to immunoincompetency and to infection, so that three of our six patients had a previous history of endocarditis, three of alcoholism, and one of miliary tuberculosis as a predisposing factor to infection. Our present management of mycotic ascending aortic aneurysm is as follows: All operations should be done through median sternotomy with use of cardiopulmonary bypass in moderate hypothermia. Deep hypothermia is recommended if an aneurysm is opposite to the origin of the great vessel of the aortic arch or if it involves the vessels. If an aneurysm is ruptured or if periaortic inflammation with adhesions or a rupture is suspected, or if the aneurysm is huge, cardiopulmonary bypass with cannulation of the external iliac or common femoral artery should be performed. We do not recommend operation without cardiopulmonary bypass even if an aneurysm is small in size and an operation seems to be feasible only with lateral clamping of the aorta. All macroscopically infected tissue of the aortic wall should be excised; thereafter the microbiologic and microscopic examination of excised aortic tissue should be done. In the case of a small mycotic aneurysm with localized changing of the aortic wall, and if there is no evidence of purulent pericarditis, we suggest replacement of the aortic defect with a part of autologous pericardial patch. If the autologous pericardium is not available or if it is inflamed, and if there is no arterial homograft available, xenopericardium should be used. In the case of destruction or infected changes of a larger part of the aortic wall not involving aortic root or aortic valve, we recommend also using aortic homograft without valve as a conduit for the ascending aorta. If it is necessary to perform a composite graft because of accompanied aortic root-infected changes or aortic anulus abscess, or if the aneurysm is located in the proximal aorta, we recommend the use of aortic homograft as a composite graft. Also, if there is obvious infection of the aortic valve or if there are signs of acute aortic valve endocarditis, homograft should be used as a replacement
3 2 6 Pasic et al.
for natural aortic valve. At the same time, with treatment of mycotic aneurysm of the ascending aorta, aortic valve replacement should be performed with a bioprosthetic or mechanical valve in the case of aortic insufficiency without valve endocarditis. Prosthetic graft as a patch or vascular conduit is the last choice, and we try to use this method only when the other possibilities are not available or technically cannot be performed. Coronary artery bypass graft should always be performed if significant coronary artery disease is found. To eliminate performing aortic anastomosis, we recommend use of the internal mammary artery as a conduit. We thank Ms. Annette Bauer for help in preparing the manuscript. REFERENCES 1. Taylor LM Jr, Deitz DM, McConnell DB, Porter JM.
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