Vascular prosthesis infection in thoracic aorta surgery: review of the experience and a case report illustrating treatment with an unconventional technique

Abstracts

Relatamos o caso de uma paciente de 37 anos de idade, que há cinco anos havia sido submetida à operação de Bental-de Bono em nosso serviço e retornou com dor de forte intensidade no toráx, sendo diagnosticada dissecção aguda de aorta do tipo III e tratada clinicamente. Um ano após esse episódio houve expansão dessa dissecção e a paciente foi submetida à cirurgia com interposição de prótese de dacron em aorta descendente. No pós-operatório imediato houve broncopneumonia esquerda e a paciente recebeu alta em boas condições e afebril. Após um mês da alta, retornou com febre e toxemia. Com diagnóstico de empiema pleural, foi submetida à toracotomia exploradora que não confirmou esse diagnóstico, havendo apenas intenso espessamento pleural. Quatro meses após a toracotomia exploradora, foram isolados Klebsiella pneumoniae e Enterobacter sp na hemocultura. A ressonância magnética revelou imagens compatíveis com infecção peri-prótese. Com esse quadro clínico e laboratorial foi indicada a remoção do enxerto e derivação axilo-bifemoral. A operação foi realizada com sucesso, a paciente recebeu alta em boas condições e continua fazendo controle ambulatorial e, atualmente, encontra-se com 57 meses de evolução sem complicações. São discutidos os métodos empregados para o diagnóstico e tratamento da infecção de prótese na cirurgia da aorta torácica.

CASE REPORT RELATO DE CASO

Vascular prosthesis infection in thoracic aorta surgery. Review of the experience and a case report illustrating treatment with an unconventional technique

Ronaldo Ducceschi Fontes; Noedir Antônio Groppo Stolf; Júlio Cesar Marino; David Pamplona; Luis Francisco Ávila; Sérgio Almeida Oliveira

Instituto do Coração do Hospital das Clínicas - FMUSP

^{Correspondence}

ABSTRACT

We report the case of a 37-year-old-female patient who had undergone a Bentall procedure at our service and returned with intense chest pain and acute aortic dissection type III, which was diagnosed and clinically treated. One year after this episode, this dissection expanded, and the patient underwent surgery with interposition of a Dacron graft in the descending aorta. In the immediate postoperative period, the patient experienced left bronchopneumonia and was discharged afebrile and in good condition. One month after discharge, she returned with fever and toxemia. Pleural empyema was diagnosed, and she underwent an exploratory thoracotomy that did not confirm this diagnosis, but revealed intense effusion thickening. Four months after the exploratory thoracotomy, Klebsiella pneumoniae and Enterobacter sp were isolated in a blood culture. Magnetic resonance imaging revealed shapes compatible with perigraft infection. With this clinical and laboratory picture, graft removal was indicated as was axillo-bifemoral grafting. Surgery was successfully performed, the patient was discharged in good condition, and remains well after a 57-month follow-up without complications. The methods used for diagnosis and treatment of prosthesis infection in thoracic aorta surgery are discussed.

In recent years, significant progress has been achieved in the treatment of aneurysms and aortic dissections ^1,2. The advances are related to surgical techniques, vascular prostheses in the postoperative period, antibiotic therapy, as well as methods of diagnostic investigation using computed tomography and magnetic resonance ³.

Despite these advances, severe ⁴ postoperative complications sometimes still occur with surgical procedures in the aorta. Among them, graft infection is one of the most severe, resulting in great morbidity and mortality ³.

Some methods may be used to treat this complication with favorable results ^3,5. The authors report their service's experience with vascular prosthesis infection and point out the case of a patient who evolved with prosthesis infection in the postoperative period of distal dissection surgery, with treatment performed with an alternative surgical technique.

Case Report

A 37-year-old, white female patient with Marfan's syndrome underwent surgery in 1985 to treat annuloaortic ectasia with the Bentall procedure. The patient was discharged in good condition and was being followed-up when she returned in 1990 complaining of intense thoracic pain. A De Bakey type III aortic dissection was diagnosed.

Since no complications were present, clinical treatment was maintained until May 1991, when she returned with pain and underwent a chest X-ray, digital angiography, and CT scan demonstrating an 80-mm dilation of the descending thoracic aorta.

The patient was referred for a surgical procedure and underwent correction of the dissection through interposition of a Dacron graft, replacing the descending aorta (fig. 1A and ^B). The surgery was performed using simple aortic clamping between the left carotid and the left subclavian artery. Poor tissue was verified in the proximal stump, and because the distal stump was near the diaphragm, access was hindered. During this period, cerebrospinal pressure was monitored and maintained below 10 mmHg through drainage of 50 mL of liquid.

The patient evolved with bronchopneumonia, received cefoxitin for 15 days, and was discharged in excellent clinical condition.

She was evolving well when she returned to the hospital after 1 month with fever suggesting empyema effusion. She underwent exploratory thoracotomy that did not confirm the diagnosis but demonstrated only intense pleural thickening. During this procedure, puncture of the perigraft region was performed without loss of fluid.

She remained in the hospital to recover from the thoracotomy and experienced fever and bacteremia crises. Three months later, Klebsiella pneumoniae and Enterobacter sp were isolated in a serial blood culture, and treatment with antibiotics was initiated; however, the clinical picture did not improve. Investigation continued with the use of CT scanning that revealed a large number of thrombi in the perigraft region and the presence of a small amount of air (fig. 2). This picture led to the diagnosis of prosthesis infection, and its removal was indicated so that an axillo-bifemoral graft could be performed due to the difficulties expected. The surgery was successfully performed in 1991 (fig. 3A and ^B). The Dacron graft was withdrawn, the proximal and distal aortic stumps were closed, and the axillo-bifemoral graft was preformed. The patient remained in the hospital for 45 days with antibiotics, the fever ceased, and the patient progressively improved until she was discharged.

She is still being followed-up, and she has been asymptomatic for 7 years. A late angiographic study demonstrated that the graft was pervious and the thoracic artery was excluded (fig. 4). She is currently taking oral anticoagulant medication and beta-blockers.

Discussion

Postoperative infection of a graft in thoracic artery surgery is a rare complication. It has occurred in between 0.5 and 5% of the patients undergoing this type of surgery ^6,7.

Large surgeries used to treat thoraco-abdominal or even abdominal aneurysms, requiring anastomoses with femoral and thoracic arteries, are usually more susceptible to infections, especially when infected cutaneous lesions are present in the abdominal region, together with the inadequate use of central venous catheters ^1,3.

The infectious process may start in the suture site leading to dehiscence and false aneurysm formation. These false aneurysms may tear in cavities or adjacent organs, leading to hemoptysis, hematemesis, or melena according to their location ⁸.

Infection of aortic prostheses is evident by the presence of fever and thoracic pain. The infectious process must therefore be carefully investigated. This investigation must entail complementary examinations that will indicate the appropriate conduct. The first important measure is to try to isolate the responsible germ by using serial blood cultures. The most frequently found germs are Staficoco Aureus, S. Epidermidis, Streptococo, Enterobacter, E. Coli, Proteus, and Pseudomonas. Clinical treatment includes specific antibiotics for a minimum 30-day period ⁹.

Complementary examinations through images must be used, and the most indicated are CT scan, and magnetic resonance, where the presence of air and liquid in the perigraft region can be observed. Other methods may contribute to the diagnosis, such as radioisotope study, aortography in the cases where false aneurysm or aortic obstruction is suspected; digestive endoscopy when stomach, esophagus, or duodenum erosion is suspected ³.

In almost all cases, the treatment for this complication is surgical, performed with graft replacement as well as graft withdrawal followed by extraanatomical derivation, and, occasionally, the prosthesis is covered with vascular grafts followed by extraanatomical derivation ^3,4,10.

In our case, the clinical picture that suggested perigraft infection was hindered by the radiologic image, which suggested the presence of empyema in the hemi-thorax apex. The patient previously underwent exploratory thoracotomy.

Surgery was indicated after the germs had been isolated in the blood culture, in association with the clinical picture and the examination using images. However, the risk of a third thoracotomy; the clinical picture of malnutrition; difficulty reconstructing the vascular graft from the diseased descending aorta; the ascending aorta with graft, paraplegia, and also the intolerance to synthetic material ¹¹; before the positive result of blood cultures made us wait too long before withdrawing the graft.

We believe that the increased time of clamping and bleeding during the first intervention were the factors that contributed to the development of infection and that other investigation methods, such as radiology with labelled leukocytes, could help early treatment ¹².

We have concluded that the incidence of perigrafts in surgeries to correct thoracic aorta aneurysms is low and, in the present case, axillo-bifemoral was the adequate option with excellent late and immediate results.

References

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2. Pêgo-Fernandes PM, Stolf NAG, Fontes RD, Verginelli G, Jatene AD. Cirugia das dissecções crônicas da aorta ascendente com insuficiência valvar. Rev Bras Cir Cardiov 1990; 5: 149-13.

3. Constantino MJ. Recurrent aortic graft infection following descending thoracic aorta to femoral artery bypass a case report and review: J Cardiovasc Surg 1991; 32: 477-81.

4. Svensson LG, Crawford ES, Hess KR, Coseli JS, Safi HJ. Dissection of the aorta and dissecting aortic aneurysm. Circulation 1990; 82(suppl IV) 5: IV24-IV46.

5. Matley PJ, Beningfield SJ, Lourens S, Immelman EJ. Successful treatment of infected thoracoabdominal aortic graft by percutaneous catheter drainage. Jvasc Surg 1991; 13: 513-5.

6. Reilly LM, Altman H, Lusby RJ, Kers RA. Late results following surgical managemento of vascular graft infections; J Vasc Surg 1984; 1: 36-44.

7. Ilgenfritz FM, Jordan FT. Microbiological monitoring of aortic aneurysm wall and contents during aneurismectomy. Arch Surg 1988; 123: 3506-8.

8. Tollefson DF, Bank DF, Kaebnick HW, Seabrook GR, Towne JB. Surface biofilm disruption: enhanced recovery of miocroorganismos from vascular prostheses. Arch Surg1987; 122: 38-43.

9. Olah A, Vogt M, Laske A, Carrell T, Bauer E, Turina M. Axillo-femoral bypass and simultaneous removal of the aorto-femoral vascular infection site: is the procedure safe? Eur J Vasc Surg 1992: 252-4.

10. O'Hara PJ, Hertez NR, Beven EG, Krajewaski LP. Surgical management of infected abdominal aortic grafts: review of a 25-year of experience. J Vasc Surg 1986; 725-31.

11. Vollmar PE, Mohr W, Haman H, Brecht-Kraus D. Perigraft reation: incompatibility of synthetic grafts? New aspects on clinical manifestations, pathogenesis and therapy. World J Surg 1982; 12: 750-5.

12. Wilson DG, Seabold JE, Liberman LM. Detection of aorto-arterial graft infections by leucocyte scintigraphy. Clin Nucl Med 1983; 8: 421-3.

Received: 11/25/2002

Accepted: 3/10/2003

Publication Dates

• Publication in this collection
  05 Apr 2004
• Date of issue
  Mar 2004

History

• Received
  25 Nov 2002
• Accepted
  10 Mar 2003