Asian Cardiovasc Thorac Ann 2006;14:e38-e40
© 2006 Asia Publishing EXchange Ltd
Stent-graft for Recurrent Melioidosis Mycotic Aortic Aneurysm
Ser Y Lee, MBBS,
Yoong K Sin, FRCS,
Asok Kurup, MRCP,
Thirugnanam Agasthian, FRCS,
Michael G Caleb, FRCS
Department of Cardiothoracic and Vascular Surgery, National Heart Centre, 17 Third Hospital Avenue, Singapore
For reprint information contact: Ser Yee Lee D Tel: 65 6443 3654 Fax: 65 6443 3608 Email: lee.ser.yee{at}singhealth.com.sg, Singapore Health Services Pte Ltd., 11 Third Hospital Avenue, SNEC Building, Singapore 168751.
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ABSTRACT
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Melioidosis is a tropical disease caused by Burkholderia pseudomallei and is prevalent in South East Asia and Northern Australia. It can infect any organ system and is potentially deadly. Melioidosis causing a mycotic aneurysm of the aorta is rare. We present a patient with a melioidosis mycotic aneurysm of the descending aorta presenting with fever and right pleural effusion, managed successfully with initial Dacron graft repair with staged omental reinforcement, and subsequent endovascular stent grafting of a late anastomotic leak.
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CASE STUDY
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A 64-year-old man with no significant past history presented with fever of two days duration associated with right sided chest pain radiating to the back. Physical examination revealed decreased air entry in the base of the right lung with stony dullness. A chest X-Ray confirmed a right pleural effusion with right lower lobe consolidation. Thoracentesis produced an exudative blood-stained fluid. Laboratory investigations revealed leucocytosis (18.2 x 109·L–1) and raised C-reactive protein (411 mg·L–1). Computed tomography (CT) scan of the chest (Figure 1A
) revealed a large right pleural effusion with a large saccular aneurysm of the distal descending thoracic aorta, measuring 6 cm in diameter and 10 cm long extending from the diaphragm to the origin of the celiac plexus. The aneurysm was capped by a thick rim of thrombus. There was evidence of subacute blood at the apex of this thrombus. The overall appearance was suspicious of a leak especially in view of the loculated effusion within the right hemithorax. The patient was subsequently referred to the cardiothoracic service for urgent surgery. Pleural fluid and 2 pairs of blood cultures at this point were negative.
A left posterolateral thoracotomy with Dacron graft replacement of the distal descending thoracic aorta using left heart bypass for distal aortic perfusion was performed. Intraoperatively, a 3 cm defect in the medial wall of the thoracic aorta was found, with the rupture contained by the surrounding tissues. Tissue culture from part of the thrombus grew Burkholderia pseudomallei. Postoperative blood and pleural fluid sampling also grew Burkholderia pseudomallei. Postoperatively the patient had persistent leucocytosis with a spiking fever despite 2 weeks of intravenous ceftazidime and oral trimethoprim-sulfamethoxazole. Postoperative CT scans showed fluid surrounding the graft. In view of the persisting sepsis, certainty of a prosthetic infection and an appropriate homograft not being available, the decision was made to reinforce the graft with omentum. Intraoperatively, the graft was surrounded by pus which was evacuated and sufficient omentum was mobilized to reinforce the graft especially at both suture lines.
His fever settled and his leukocyte count gradually normalized 5 days after the omental reinforcement. Subsequently 2 pairs of blood cultures a week apart were negative. Computed tomography thorax prior to discharge revealed resolution of the periaortic fluid and intact anastomoses. The clinical course was complicated by severe erythroderma to trimethoprim-sulfamethoxazole and ceftazidime, thus he was discharged with lifelong oral doxycycline.
Six months later the patient presented with hemoptysis and upper back pain. He was otherwise relatively well with no fever. Blood cultures were negative, and leukocytes and CRP were within normal limits. A CT scan revealed an anastomotic leak contained within the omentum. Repeat surgery was contemplated but deemed too high risk with only temporary benefit in view of the high probability of recurrence. Hence, endovascular stent grafting was performed using the Medtronic TalentTM (Medtronic Inc., Minneapolis, MN, USA) device covering both the proximal and distal anastomoses (Figure 1B). Recovery was uneventful. He was discharged well after 4 weeks of intravenous imipenem with lifelong oral doxycycline as prophylaxis.
The patient subsequently suffered two bouts of sepsis including an episode of melioidosis meningitis which resolved without neurological sequelae after 4 weeks of intravenous imipenem. There were no significant findings on CT scan of the head. Surveillance CT thorax at three monthly intervals showed an intact anastomosis with no endoleak. He continues to do well sixteen months after initial presentation.
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DISCUSSION
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Melioidosis manifesting as a mycotic aortic aneurysm is rarely reported.1–4 The first case described by Steinmetz et al1 died on day 12 after the aneurysm ruptured. The second case described by Lee et al2 was treated with antibiotics prior to surgical resection of the aneurysm with graft interposition and remained well after six months. Stent-graft therapy for mycotic aortic aneurysm is rarely published.5–6 The case described by Berchtold5 was successful, however, the other case described by Ishida et al6 was not.
Melioidosis, a rare tropical disease caused by the bacterium, Burkholderia pseudomallei, was first reported in 1912 by Whitmore and Krishnaswami. The organism is found in stagnant tropical water and soil and is prevalent in South East Asia. It has been called the "great mimicker" due to its varied clinical manifestations.7 Transmission occurs through inhalation, ingestion and direct contact of cutaneous wounds with soil or stagnant water e.g. rice paddies, swamps. The infection can affect any organ system and disease may be disseminated, localized or subclinical.
The patient recalled that he made a few fishing trips to swampy areas in a rural part of the country more than 20 years ago. He had no other significant contact with soil and stagnant water. He may have been infected during the fishing trips as long periods of latency, as long as 29 years, have been described.8 The mortality rate of patients with bacteremia and sepsis of melioidosis is approximately 40% and may be as high as 90%.9 Burkholderia pseudomallei is resistant to many antibiotics. Ceftazidime has emerged as a drug of choice, with imipenem and meropenem as alternatives.10
This case presented several problems to us. Firstly, the organism is an intrinsically persistent bacterium that is known to be difficult to treat, requiring long-term antibiotics. Secondly, the organism was only isolated after a prosthetic graft was already in situ for the aneurysm repair. Thirdly, the patient developed an allergic reaction to the standard antibiotics used to treat melioidosis. Lastly, the distal anastomosis leaked after 6 months. Traditional therapy includes excision of the infected aneurysm, wide local debridement and graft replacement. However, graft replacement was not a favorable option in view of the high likelihood of recurrent infection.
In view of his bacteremic state and the above considerations, we opted to treat the patient with drainage of the periaortic abscess and omental reinforcement of the graft and it’s anastomosis in addition to antibiotic therapy. He responded well with resolution of symptoms, normalization of leukocyte counts and radiological improvement on serial CT scans. Subsequent late anastomotic disruption was successfully contained within the omentum and endovascular treatment offered a low-risk option to a potentially disastrous clinical situation.
Notwithstanding that the graft remains as a persistent focus of infection, complete resection carries a significant risk of recrudescence and operative mortality. The combination of omental reinforcement followed by successful endovascular therapy for delayed anastomotic leak has proved to be a useful modality of treatment for this patient, and has prolonged his survival with a reasonable quality of life. We believe this is the first reported use of omentoplasty combined with endovascular stent-grafting for subsequent anastomotic leak. This method can be considered in patients where there is recurrent mycotic aortic aneurysm with prosthetic graft in situ and where surgery is limited by a high likelihood of recurrence and a lack of suitable conduits.
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REFERENCES
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- Steinmetz I, Stosiek P, Hergenrother D, Bar W. Melioidosis causing a mycotic aneurysm. Lancet 1996;347:1564–5.[Medline]
- Lee SS, Liu YC, Wang JH, Wann SR. Mycotic aneurysm due to Burkholderia pseudomallei. Clin Infect Dis 1998;26:1013–4.[Medline]
- Tanyaowalak W, Sunthornyothin S, Luengtaviboon K, Suankratay C, Kulwichit W. Mycotic aneurysm caused by Burkholderia Pseudomallei with negative blood cultures. Scand J Infect Dis 2004;36:68–70.[Medline]
- Patel MA, Schmoker JD, Moses PL, Anees R, D’Agostino R. Mycotic arch aneurysm and aortoesophageal fistula in a patient with melioidosis. Ann Thorac Surg 2001;71:1363–5.[Abstract/Free Full Text]
- Berchtold C, Eibl C, Seelig MH, Jakob P, Schonleben K. Endovascular treatment and complete regression of an infected abdominal aortic aneurysm. J Endovasc Ther 2002;9:543–8.[Medline]
- Ishida M, Kato N, Hirano T, Shimono T, Yasuda F, Tanaka K, et al. Limitations of endovascular treatment with stent-grafts for active mycotic thoracic aortic aneurysm. Cardiovasc Intervent Radiol 2002;25:216–8.[Medline]
- Yee KC, Lee MK, Chua CT, Puthucheary SD. Melioidosis, the great mimicker: a report of ten cases from Malaysia. J Trop Med Hyg 1988;91:249–54.[Medline]
- Chodimella U, Hoppes WL, Whalen S, Ognibene AJ, Rutecki GW. Septicemia and suppuration in a Vietnam veteran. Hosp Pract (Off Ed) 1997;32:219–21.[Medline]
- Simpson AJ, White NJ. Combination antibiotic therapy for severe melioidosis. Clin Infect Dis 1999;28:410.[Medline]
- White NJ, Dance DA, Chaowagul W, Wattanagoon Y, Wuthiekanun V, Pitakwatchara N. Halving of mortality of severe melioidosis by ceftazidime. Lancet 1989;2:697–701.[Medline]
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ABSTRACT
CASE STUDY
