Treatment and Outcomes of Aortic Graft Infections Using a Decision Algorithm

Contemporary Experience of the Neo-Aortoiliac System (NAIS) Procedure: A Case Series with Review of the Literature

OBJECTIVES

Aortic graft infection (AGI) is a life-threatening complication that can result in death, amputation, sepsis, aorto-enteric fistula, and pseudoaneurysm formation. After explantation of the infected graft, options for reconstruction include extra-anatomic bypass or in-line reconstruction using antibiotic-coated prosthetic graft, cryopreserved allograft, or a neo-aortoiliac system (NAIS) using autogenous femoral veins. While the NAIS procedure has shown promising results, there is relatively limited clinical experience due the magnitude and morbidity of the surgery. In this study, we reviewed our single-center experience using the NAIS procedure and performed a systematic review of the contemporary literature more than the past decade.

METHODS

A retrospective review was performed on all patients undergoing NAIS reconstruction with autogenous femoral vein conduits at a single institution from 2010 to 2022. Pubmed, Embase, and Cochrane Library databases were queried for studies published from 2012 to 2022 to identify those reporting on outcomes of patients undergoing the NAIS procedure. Outcome variables included early and late mortality, major complications including amputation, graft or conduit related complications, re-infection, and re-intervention. Additional variables collected include patient demographics, operative technique, and follow up.

RESULTS

There were 14 patients included in our case series with 30-day mortality of 21%. At a mean follow up of 22 months, complication rate was 64.3%, re-intervention rate was 14.3%, re-infection rate was 7.1%, and amputation rate was 7.1%. On review of the literature, 12 studies ultimately met criteria to be included in analysis with a combined total of 368 patients. Pooled averages included 30-day mortality of 9.0%, re-intervention rate of 20.5%, re-infection rate of 5.6%, and amputation rate of 6.5%.

CONCLUSIONS

The NAIS procedure for management of AGI is a formidable procedure with significant early mortality and morbidity. This treatment should be considered in the context of other revascularization options for management of an AGI.

Clinical outcome of graft removal versus preservation in abdominal aortic graft infection: a systematic review and meta-analysis

Purpose

The purpose of this study was to compare the clinical outcomes of abdominal aortic graft infection (AGI) treated with removal of the graft vs. graft preservation.

Methods

The electronic databases PubMed, Embase, and Cochrane Library for studies that reported on AGI were searched. Observational studies and case series of at least 10 cases that reporting on the prevalence, microbiology, and outcomes of AGI were included.

Results

Our search identified 23 studies that met our inclusion criteria, reporting on a total of 873 patients who underwent open surgical repair (OSR) or endovascular aneurysm repair (EVAR). Of these patients, 833 received graft removal, and 40 received graft preservation. The prevalence of AGI was reported to be 1.0% (95% confidence interval [CI], 0.5%-1.8%) after OSR and 0.4% (95% CI, 0%-1.1%) after EVAR. The pooled estimates of 1-year, 2-year, and 5-year mortality were 28.7% (95% CI, 19.4%-38.8%), 36.6% (95% CI, 24.6%-49.5%), and 51.8% (95% CI, 38.4%-65.1%) in the graft removal group and 16.1% (95% CI, 4.1%-32.2%), 18.5% (95% CI, 5.7%-35.1%), and 50.0% (95% CI, 31.6%-68.4%) in the graft preservation group. The 30-day mortality rate's risk ratio (RR) for graft removal vs. preservation was 0.98 (95% CI, 0.40-2.38), while the 1-year mortality rate's RR was 3.44 (95% CI, 1.60-7.42).

Conclusion

The 30-day mortality rate of AGI treatment was found to be high, whether using graft removal or preservation. In selected patients, implementing antibiotics with graft preservation as an initial management may be helpful in reducing the mortality rate.

Clinical outcomes of in situ graft reconstruction in treating infected abdominal aortic stent grafts following endovascular aortic aneurysm repair: a single-center experience

Purpose

This study aimed to review our experience with the explantation of infected endovascular aneurysm repair (EVAR) grafts.

Methods

This single-center, retrospective, observational study analyzed the data of 12 consecutive patients who underwent infected aortic stent graft explantation following EVAR between January 1, 2010 and December 31, 2019, of which 11 underwent in situ graft reconstruction following graft removal. The presentation symptoms, infection route, original pathology of abdominal aortic aneurysms (AAA), graft materials, and clinical outcomes were analyzed.

Results

Six patients underwent total explantation, whereas 5 underwent removal of only the fabric portions. For in situ reconstructions, prosthetic grafts and banked allografts were used in 8 and 3 patients, respectively. Four mechanisms of graft infection were noted in 11 patients: 4 had bacteremia from systemic infections, 3 had persistent infections following EVAR of primary infected AAA, 3 had ascending infections from adjacent abscesses, and 1 had an aneurysm sac erosion resulting in an aortoenteric fistula. No infection-related postoperative complications or reinfections occurred during the mean 65.27-month (standard deviation, ±52.51) follow-up period. One patient died postoperatively because of the rupture of the proximal aortic wall pseudoaneurysm that had occurred during forceful bare stent removal.

Conclusion

Regardless of graft material, in situ graft reconstruction is safe for interposition in treating an infected aortic stent graft following EVAR. In our experience, the residual bare stent is no longer a risk factor for reinfection. Therefore, it is important not to injure the proximal aortic wall when removing the bare stent by force.

Psoas Muscle Area as a Prognostic Factor for Survival in Patients Undergoing EVAR Conversion

OBJECTIVE

EVAR conversion(EVAR-c) is increasingly reported and known to be technically complex and physiologically demanding. It has been proposed that pragmatic anthropomorphic measures such as psoas muscle area(PMA) may reliably quantify levels of preoperative frailty and be used to inform point of care clinical decision making and patient discussions for a variety of complex operations. To date, there is mixed data supporting use of PMA as a prognostic factor in fenestrated endovascular and open AAA repairs; however, no literature exists evaluating the impact of preoperative PMA on EVAR-c results. Therefore, the purpose of this study was to review our EVAR-c experience and evaluate the association of PMA with perioperative and long-term mortality outcomes.

METHODS

A retrospective single-center review of all AAA repairs was performed(2002-2019) and EVAR-c procedures were subsequently analyzed(n=153). Cross-sectional PMA at the mid-body of the L3 vertebrae was measured. The lowest PMA tertile was used as a threshold value to designate patients as having "low" PMA(n=51) and this cohort was subsequently compared to subjects with "normal" PMA(n=102). Cox proportional hazards modeling was used to estimate covariate association with all-cause mortality.

RESULTS

Patients with low PMA were older(77 vs. 72 years;p=.002), more likely to be female(27% vs. 5%;p<.001), and had reduced BMI(26 vs. 29kg/m²;p=.002). Time to conversion, total number of EVAR reinterventions prior to conversion and elective EVAR-c presentation incidence were similar; however, patients with low PMA had larger aneurysms(8.3 vs. 7.5cm;p=.01) and increased post-EVAR sac growth(2.3 vs. 1cm;p=.005). Unadjusted inpatient mortality was significantly greater for low PMA patients(16% vs. normal PMA, 5%, p=.02). Similarly, the total number of complications was higher among low PMA subjects(1.5±1.9 vs. normal PMA, 0.9±1.5;p=.02). Although frequency of major adverse cardiovascular events and new onset inpatient hemodialysis were similar, low PMA patients had a more than four-fold increased likelihood of having persistent requirement of hemodialysis at discharge(18% vs. 4%,p=.01). The low PMA group had decreased survival at 1 and 5 years, respectively(77±5%, 65±6% vs. normal PMA, 86±3%, 82%±5%;log-rank p=.03). Low PMA was an independent predictor of mortality with every 100mm² increase in PMA being associated with a 15% reduction in mortality(HR 0.85,95% CI, .74-.97;p=.02).

CONCLUSION

Among EVAR-c patients, subjects with low preoperative PMA had higher rates of postoperative complications and worse overall survival. PMA assessments may be a useful adjunct to supplement traditional risk-stratification strategies when patients are being considered for EVAR-c.

Invasive non-typhoidal Salmonella infection complicated by metastatic infections: report of three cases

Non-typhoidal Salmonella (NTS) disease is usually a self-limiting infection presenting with digestive symptoms. However, disseminated presentation with involvement of secondary infectious sites is observed. We report diagnostic specificities and challenges related to the management of three patients with invasive NTS (iNTS) and secondary infectious locations. Among the seven patients (age range 46 – 83 years), four (two with extra-digestive infectious sites) had at least one immune debilitating condition. Two patients were incidentally discovered with iNTS and deceased after developing a septic shock despite antimicrobial treatment. Two individuals recovered under medical treatment without complications. Three other patients presented with secondary infectious sites. Case 1 suffered from urinary tract infection and dorsolumbar spondylodiscitis that responded well to antimicrobials and surgery. Abdominal prosthetic aortic aneurysm was diagnosed in case 2 and medical treatment only was applied. After four years of follow-up, he remains under antimicrobial treatment. Case 3 presented with conjoint thoracic aortic aneurysm and cutaneous abscesses managed with antimicrobials and surgery. Atherosclerosis and previous vascular intervention were the predisposing events for vascular involvement. iNTS is a serious disease carrying a high risk of mortality or secondary locations. Secondary locations can be managed by long duration antimicrobial therapy combined with surgery. Spine and aortitis are the most frequent secondary locations. Multi-drug resistant NTS represent an additional risk of mortality. Public health measures should be implemented to limit the spread of NTS to humans and the emergence of drug resistance.

Leriche Syndrome with Digital Gangrene: Is Aortic Bypass Grafting Safe in Intravenous Drug Abusers? A Case Report and Literature Review

A 47-year-old male with Leriche syndrome presented with digital gangrene due to TASC II type-D occlusion of the distal aorta and common iliac arteries. Open revascularization was performed using a Dacron aorto-biiliac bypass graft; however, the postoperative course revealed a nondisclosed history of intravenous opioid abuse as he went into withdrawal psychosis. Our report highlights ways to mitigate infection risk associated with prosthetic aortic grafts in suspected or confirmed intravenous drug abusers. The literature review suggests alternative strategies like aortoiliac endarterectomy, total endovascular approach using non-covered stents, or a hybrid approach. The primary use of autologous venous grafts should be considered as a last resort so that the veins are retained for future use in case of graft infection. Patient factors like comorbidities, fitness to undergo surgery, anatomical extent of occlusion, and availability of facilities/expertise can further guide the management plan owing to a lack of evidence-based guidelines.