Open Repair of Superior Mesenteric Artery Mycotic Aneurysm in an Adolescent Girl Jean Marie Ruddy, Thomas F. Dodson, and Yazan Duwayri, Atlanta, Georgia
Aneurysmal degeneration of the superior mesenteric artery (SMA) is rare, particularly in the pediatric population. We report the case of a 16-year-old female who presented with abdominal discomfort, back pain, fever, and vomiting. Extensive work-up revealed a 3-cm SMA aneurysm (SMAA) with surrounding inflammation. No bacterial growth was identified on current cultures, but a mycotic etiology was suspected due to recent episodes of suppurative hidradenitis. In addition to broad-spectrum antibiotics, she underwent transabdominal surgical intervention, including proximal and distal aneurysm ligation with aortomesenteric bypass, utilizing the reversed saphenous vein. Although endovascular intervention in the mesenteric arterial system has increased in utilization, patient-specific considerations, such as age and potential for infectious etiology, must drive therapeutic decision-making, with open surgical bypass being liberally employed.
Visceral artery aneurysms have been reported in approximately 0.2% of the population, with the majority located in the splenic artery, but up to 5.5% may be in the superior mesenteric artery (SMA).1 With the increased use of cross-sectional imaging, more SMA aneurysms (SMAA) have been identified in the small, asymptomatic state, but up to 25% of patients still present with rupture, intestinal ischemia, and hemodynamic instability, leading to significant morbidity and mortality.2 In fact, the natural history of SMAA is one of continued expansion, with or without abdominal pain, and eventual rupture, thereby warranting intervention when identified.3 It has been estimated that 60% of SMAA are mycotic, occurring as a result of septic
Division of Vascular Surgery and Endovascular Therapy, Emory University School of Medicine, Atlanta, GA. Correspondence to: Yazan Duwayri, MD, Division of Vascular Surgery and Endovascular Therapy, Emory University School of Medicine, 1365 Clifton Road NE, Clinic AeSuite 3200, Atlanta, GA 30322, USA; E-mail:
[email protected] Ann Vasc Surg 2014; 28: 1032.e21–1032.e24 http://dx.doi.org/10.1016/j.avsg.2013.08.009 Ó 2014 Elsevier Inc. All rights reserved. Manuscript received: March 24, 2013; manuscript accepted: August 28, 2013; published online: November 1, 2013.
emboli from an infectious source, such as bacterial endocarditis.4,5 Although traditionally treated by surgical bypass with interval ligation and/or excision of the aneurysm, successful endovascular therapy has been reported.2,6 Decisions regarding appropriate therapeutic modality must consider anatomy, patient comorbid conditions, and occasionally patients’ demographics, such as age. We report a case of open surgical therapy for SMAA in an adolescent girl.
CASE REPORT A previously healthy 16-year-old African-American female presented with 1 week of abdominal pain, fever, nausea, vomiting, and loose stools. She also reported intermittent lower back and flank pain over the previous month. Her past medical history was significant for several episodes of axillary and groin suppurative hidradenitis requiring local drainage. She had no history of intravenous drug abuse. Her laboratory findings demonstrated white blood cell count 17000 cells per microliter, erythrocyte sedimentation rate 65 mm/hr, and C-reactive protein 26 mg/L. Broad-spectrum intravenous antibiotics were initiated (vancomycin and pipercillinetazobactam) and a site of infection was investigated; however, no bacterial, fungal, or parasitic growth was identified on cultures of blood, urine, or stool. Esophagogastroduodenoscopy, colonoscopy, and echocardiogram were unremarkable. 1032.e21
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Magnetic resonance imaging (MRI) of the spine revealed nonspecific enhancement along the anterior endplates of thoracic and lumbar vertebral bodies and in the sacroiliac joints, consistent with infective spondylitis. Computed tomographic angiography (CTA) of the abdomen and pelvis revealed two fusiform aneurysms (maximum diameter 3.1 cm) of the SMA with inflammation of the surrounding mesenteric adipose tissue (Fig. 1). Transabdominal surgical repair was performed by constructing a retrograde aortomesenteric bypass from the infrarenal aorta utilizing reversed saphenous vein graft (RSVG) (Fig. 2). The aneurysmal segment was excluded by proximal and distal ligation, thereby allowing end-toend anastomosis of RSVG to downstream SMA. Significant friability of the large phlegmon surrounding the aneurysm prohibited further exploration and retrieval of samples for tissue culture. The patient’s antibiotic regimen was altered to accommodate transient mild renal insufficiency, and she remained on intravenous daptomycin, intravenous ceftriaxone, and oral doxycycline for 6 weeks. Her white blood cell count normalized and she was discharged home on postoperative day 10 with resolution of all symptoms. At 8-month follow-up, the patient continued to be free of symptoms. Mesenteric ultrasound with color-flow Doppler imaging confirmed a patent aortomesenteric bypass and no evidence of residual inflammatory phlegmon.
Annals of Vascular Surgery
Fig. 1. CTA reconstructed sagittal image demonstrating two fusiform aneurysms along the SMA with surrounding inflammatory changes and patency maintained distally.
DISCUSSION Aneurysmal dilation of the SMA is a rare anomaly, especially in the pediatric population. A significant proportion of SMAA are mycotic and attributed to septic emboli, but etiologies such as atherosclerosis, pancreaticobiliary disease, trauma, dissection, fibrodysplasia and vasculitides have been increasingly reported.7 The pathophysiologic progression to mycotic aneurysm formation includes lodgment of a septic embolus in the adventitial vasa vasorum, local arteritis extending into the media arterial layer, degradative remodeling that may include suppuration and necrosis in its most virulent forms, and consequent aneurysm formation.4 The association between mycotic aneurysms and coexisting infective spondylitis, as demonstrated in the present case, is not uncommon and reflects simultaneous bacterial seeding to the vertebra.8 Infective endocarditis has been identified in more than 33% of SMAA patients, and extensive vessel wall destruction has resulted from intense inflammatory reactions to aggressive pathogens such as Staphylococcus aureus, Escherichia coli, Streptococcus oralis and bovis, Enterococcus species, and Mycobacterium tuberculosis.5,9e11 Mycotic aneurysms may be attributable to a localized infection, but, in some instances, bacterial growth on blood cultures provides the only proof of an infective source. In our case, blood cultures
Fig. 2. CTA three-dimensional reconstruction demonstrating the aortomesenteric bypass constructed with reversed saphenous vein graft in an end-to-side fashion with proximal ligation of the aneurysm.
were negative, an unfortunate common finding with mycotic aneurysms, underscoring the importance of documenting a complete history of present illness, comprehensive laboratory evaluation, and maintaining clinical suspicion. Tissue samples of the aneurysm wall or surrounding inflammatory mass may also be cultured to identify the offending bacterium; however, due to the intensely friable perianeurysmal tissue encountered intraoperatively, we avoided entering the large phlegmon with its associated bleeding risk and continued broadspectrum antibiotics postoperatively with guidance from the Infectious Disease Department regarding
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Case reports 1032.e23
Table I. Literature review of SMA bypass materials and patency rates Investigators
Number of patients
Reason for SMA bypass
Conduit
38
Occlusive
Johnston et al.21
20
Occlusive
Inoue et al.22 McMillan et al.23
5 24
Occlusive Occlusive
Cho et al.24 Stone et al.7 Zhao et al.1 Lorelli et al.2
20 2 1 1
Occlusive Aneurysm Mycotic aneurysm Mycotic aneurysm
26 prosthetic, 8 SVG 9 prosthetic, 11 SVG 5 prosthetic 6 prosthetic, 18 SVG Not specified 2 prosthetic 1 SVG 1 SVG
Liem et al.
20
Follow-up (years)
5 10 6 3 5 4.7 2.5 Undocumented
Primary patency rate
96% prosthetic, 88% SVG 78% prosthetic, 91% SVG 100% 84% prosthetic, 95% SVG 80% 100% 100% Undocumented
SVG, saphenous vein graft.
antibiotic selection. This algorithm is consistent with literature characterizing treatment of infections throughout the arterial tree to include surgical debridement with bypass or patch angioplasty to maintain antegrade flow, followed by 4e6 weeks of antibiotic therapy.12e14 Mesenteric mycotic aneurysms usually present with fever and abdominal pain, although other SMAA may be incidentally discovered on abdominal imaging for remote pathology. Diagnosis of an SMAA may be achieved with abdominal ultrasound, a modality frequently utilized in the pediatric population, but intrarterial angiography or cross-sectional imaging with CTA or magnetic resonance angiography (MRA) is necessary for operative planning.14 Should a mycotic aneurysm be suspected, a thorough investigation of the infective source must be conducted and broad-spectrum antibiotics initiated immediately. As in the case described herein, measurements of the inflammatory markers erythrocyte sedimentation rate and C-reactive protein may be informative in addition to the standard white blood cell count. Once discovered, timely operative repair is indicated in patients with acceptable surgical risks, regardless of aneurysm size, to decrease the likelihood of rupture, gastrointestinal bleeding, or bowel infarction.1,7 Operative intervention with a plan to remove or exclude the aneurysm and reestablish SMA continuity is ideal, but it is difficult to achieve due to friability of surrounding mesenteric tissue or adherence of nearby vital structures. Therefore, ligation of SMA proximal and distal to the aneurysm with reliance on collateral flow through the celiac trunk and inferior mesenteric artery (IMA) may be accepted in such cases.1,15 Careful intraoperative assessment of intestinal viability is mandatory in this situation and may be accomplished by clinical evaluation, flourescein dye, or Doppler flow study.7
Aneurysmectomy and aneurysmorrhaphy have been performed successfully when anatomy permits, and some investigators have advocated for the use of synthetic interposition grafts when infection can be confidently excluded.2,15 Use of cryopreserved allografts may be considered but has not been widely validated in the literature. Aortomesenteric and aortorenal bypass procedures in the pediatric population have often utilized autogenous hypogastric artery, but saphenous vein graft is the conduit of choice for mycotic aneurysms and has proven to be an effective and durable repair.15,16 Table I summarizes reported mesenteric bypass patencies with various conduits. Endovascular repair has also been effective in visceral artery aneurysms.6,17 More specifically, non-mycotic branch aneurysms of the SMA and pseudoaneurysms have been embolized successfully without complications from downstream ischemia, and stent-graft repair of SMAA has also been reported.18,19 However, endovascular management of mycotic SMAA and the use of synthetic material in this infected field remains undefined. In conclusion, we have described an unusual case of a previously healthy teenage girl who developed abdominal and lower back pain due to mycotic SMAA and infective spondylitis. She patient was expeditiously and successfully managed with broadspectrum intravenous antibiotics, aneurysm exclusion, and aortomesenteric bypass utilizing RSVG. Mycotic SMAA are rare, particularly in the pediatric population, but may be considered in the differential diagnosis of a patient with fever, abdominal pain, and risks for bacteremia. Due to significant rupture risk, aggressive surgical management is necessary. REFERENCES 1. Zhao J. Massive upper gastrointestinal bleeding due to a ruptured superior mesenteric artery aneurysm duodenum fistula. J Vasc Surg 2008;48:735e7.
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2. Lorelli DR, Cambria RA, Seabrook GR, et al. Diagnosis and management of aneurysms involving the superior mesenteric artery and its branchesda report of four cases. Vasc Endovasc Surg 2003;37:59e66. 3. Shanley CJ, Shah NL, Messina LM. Uncommon splanchnic artery aneurysms: pancreaticoduodenal, gastroduodenal, superior mesenteric, inferior mesenteric, and colic. Ann Vasc Surg 1996;10:506e15. 4. Cassada DC, Stevens SL, Schuchmann GS, et al. Mesenteric pseudoaneurysm resulting from septic embolism. Ann Vasc Surg 1998;12:597e600. 5. Motomura T, Bruckner B, Leon-Becerril J, et al. Superior mesenteric artery mycotic aneurysm in patients with left ventricular assist device support and intravenous drug abuse. Artif Org 2011;35:E164e7. 6. Gabelmann A, Gorich J, Merkle EM. Endovascular treatment of visceral artery aneurysms. J Endovasc Ther 2002;9:38e47. 7. Stone WM, Abbas M, Cherry KJ, et al. Superior mesenteric artery aneurysms: is presence an indication for intervention? J Vasc Surg 2002;36:234e7. 8. Chen SH, Lin WC, Lee CH, et al. Spontaneous infective spondylitis and mycotic aneurysm: incidence, risk factors, outcome and management experience. Eur Spine J 2008;17:439e44. 9. Buchs NC, Skala K, Sierra J, et al. Mycotic aneurysm of the superior mesenteric artery. Surgery 2013;153:133e4. 10. Chai HT, Tan BL, Yen HT, et al. Infective endocarditis caused by Streptococcus bovis complicated by a superior mesenteric artery mycotic aneurysm and systemic septic emboli in a patient with colon diverticulitis. Int J Infect Dis 2010;14(Suppl. 3):e317e8. 11. Grotemeyer D, Duran M, Park EJ, et al. Visceral artery aneurysmsdfollow-up of 23 patients with 31 aneurysms after surgical or interventional therapy. Langenbeck’s Arch Surg 2009;394:1093e100. 12. Johanning JM, Franklin DP, Elmore JR, et al. Femoral artery infections associated with percutaneous arterial closure devices. J Vasc Surg 2001;34:983e5.
Annals of Vascular Surgery
13. Swanson E, Freiberg A, Salter DR. Radial artery infections and aneurysms after catheterization. J Hand Surg 1990;15: 166e71. 14. Dziuban EJ, Teitelbaum DH, Bakhtyar A, et al. Mesenteric pseudoaneurysm and cerebral stroke as sequelae of infective endocarditis in an adolescent. J Pediatr Surg 2008;43: 1923e7. 15. Messina LM, Shanley CJ. Visceral artery aneurysms. Surg Clin N Am 1997;77:425e42. 16. Milas ZL, Dodson TF, Ricketts RR. Pediatric blunt trauma resulting in major arterial injuries. Am Surg 2004;70: 443e7. 17. Kasirajan K, Greenberg RK, Clair D, et al. Endovascular management of visceral artery aneurysm. J Endovasc Ther 2001;8:150e5. 18. Sachdev U, Baril DT, Ellozy SH, et al. Management of aneurysms involving branches of the celiac and superior mesenteric arteries: a comparison of surgical and endovascular therapy. J Vasc Surg 2006;44:718e24. 19. Schweigert M, Adamus R, Stadlhuber RJ, et al. Endovascular stent-graft repair of a symptomatic superior mesenteric artery aneurysm. Ann Vasc Surg 2011;25:e845e8. 20. Liem TK, Segall JA, Wei W, et al. Duplex scan characteristics of bypass grafts to mesenteric arteries. J Vasc Surg 2007;45: 922e7. 21. Johnston KW, Lindsay TF, Walker PM, et al. Mesenteric arterial bypass grafts: early and late results and suggested surgical approach for chronic and acute mesenteric ischemia. Surgery 1995;118:1e7. 22. Inoue Y, Sugano N, Iwai T. Long-term results of aortasuperior mesenteric artery bypass using a new route. Surg Today 2004;34:658e61. 23. McMillan WD, McCarthy WJ, Bresticker MR, et al. Mesenteric artery bypass: objective patency determination. J Vasc Surg 1995;21:729e40. 24. Cho JS, Carr JA, Jacobsen G, et al. Long-term outcome after mesenteric artery reconstruction: a 37-year experience. J Vasc Surg 2002;35:453e60.