Neoaortoiliac System Procedure to Treat Infected Aortic Grafts

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.

Neoaortoiliac system and cryopreserved human allograft for the treatment of aortic graft infections

OBJECTIVE

To report and compare neoaortoiliac system reconstruction and cryopreserved human allograft in treating aortic graft infections.

METHODS

We retrospectively analysed the data of the patients treated for aorto graft infections between January 2015 and May 2021 in our hospital. The clinical data, diagnostic procedures, and surgical options were evaluated. The primary endpoint of this study was the 30-day and 1-year mortality; secondary endpoints were major postoperative complications.

RESULTS

We retrospectively reviewed a series of 31 consecutive patients (28 males; median age 72 years, range, 50-87 years) with aortic graft infection treated with NAIS (n = 20, 65%) or cryopreserved allograft (n = 11, 36%). The clinical presentation included fever attacks in 18 (58%) patients, abdominal pain in 15 (48%) patients, haemodynamic instability in 6 (19%) patients, and haematemesis in 2 (7%) patients. The median operative time of the NAIS was longer than CHA without a statistically significant difference (458 min vs. 359 min, p = .505). The postoperative morbidity for all patients was 81%, with no significant difference between NAIS and CHA groups (85% vs. 73%, p = .638). There was no limb thrombosis of the new reconstructions. Limb loss occurred in 4 (13%) patients, including 2 (10%) NAIS patients and 2 (18%) CHA patients. One NAIS patient developed complications in the form of a distal (femoral) disruption of the vein 15 days after surgery. There were no significant differences between NAIS and CHA groups in ICU stay (12 vs 8 days, .984) but in hospitalization (22 vs 33, p = .033). The most common bacteria isolated were staphylococci strains in 15 (48%). In 13 (36%) patients, candida was positive. The in-hospital 30-day and 1-year mortality for all patients was 16% (5/31) and 29% (9/31), with no significant differences between NAIS and CHA at 30 days (25% vs. 0, p = .133) or 1 year (35% vs. 18%, .429). Five NAIS patients died during the hospital stay; three of them had end-of-life decisions. After a median follow-up of 16 months (1-66 months), 12 (39%) patients died, including 9 patients with NAIS and 3 with CHA reconstructions. The causes of death included overwhelming sepsis in 5 (42%) patients, graft disruption in one (8%) NAIS patient, non-small cell lung cancer in one (8%) patient, COVID-19 in one (8%) patient and unknown causes (8%) in one.

CONCLUSIONS

Non-staged neoaortoiliac system reconstruction and cryopreserved human allografts show comparable short- and midterm results for treating aortic graft infections. However, both procedures remain challenging with high morbidity and mortality rates.

Neoaortoiliac system in treating aortic graft infections: a single center long-term experience and review of the literature

BACKGROUND

Aortic graft infection represents one of the most challenging and life-threatening complication of surgical and endovascular treatment of aortic pathologies. The aim of this study was to report the results of a single center with in-situ revascularization for the treatment of aortic graft infections using the neo-aorto-iliac system (NAIS) and to review the literature about this surgical technique.

METHODS

We retrospectively reviewed our aortic graft infection case series and in-situ revascularization using the neo-aorto-iliac system. The study was conducted from January 2009 to June 2020. The primary outcomes analyzed were early mortality (<30 days), late mortality (>30 days), reinfection rate. Secondary outcomes were the primary patency rate, the secondary patency rate, and the lower limb salvage rate. A literature review of the last twenty years was performed on international medical databases Pubmed (Medline), Scopus and Web of Science.

RESULTS

During study period, 12 patients, all male (median age of 69 years [range: 52-87 years]), underwent to infected graft explantation and revascularization by NAIS using femoral-popliteal veins. Six cases were complicated by aorto-enteric fistulas, five were duodenal and one was colon. Patients spent the immediate postoperative period in the Intensive Care Unit for a median time of 4 days (range: 0-9 days). The median length of hospital stay was 27.5 days (range: 1-66 days). The mean follow-up was 21.5 months (range: 0-120). The 30-day mortality rate was 25% (3 patients) due to postoperative complications. No patient dropped out of the follow-up protocol. The primary patency rate was 92% while the secondary patency rate was 100%. No patient underwent lower limb amputation. Persistence of infection occurred in 1 case (8.3%). Overall Kaplan-Meier survival estimates were 75% for 30 days, 50% for 1 year, 48% for 5 years. Literature analysis identified 19 case series.

CONCLUSIONS

The literature regarding NAIS has low statistical evidence due to retrospective design of the studies. Our results are in agreement with retrospective studies in the literature. When the surgical team is confident with NAIS, this technique should be considered the preferred method, considering an acceptable and comparable mortality rate with other techniques and a better rate of patency, resistance to graft degeneration, recurrent infections and amputation rate.

Very Late Aortic Endograft Infection With Listeria monocytogenes in an Elderly Man

Endograft infection with Listeria monocytogenes is a rare, potentially devastating complication of endovascular aortic aneurysm repair. To our knowledge, only 8 cases have been reported. We describe the case of a 72-year-old man who presented with L. monocytogenes endograft infection and a 19-cm degenerative aneurysm 9 years after having undergone endovascular repair of an abdominal aortic aneurysm. The infection was successfully treated with open surgical excision of the infected aortoiliac endograft and its replacement with a rifampin-soaked, bifurcated Dacron graft.

Deep Femoral Vein Reconstruction for Abdominal Aortic Graft Infections is Associated with Low Aneurysm Related Mortality and a High Rate of Permanent Discontinuation of Antimicrobial Treatment

OBJECTIVE

Aortic prosthesis infection is a devastating complication of aortic surgery. In situ reconstruction with the neo-aorto-iliac system (NAIS) bypass technique has become increasingly used and is recommended in recent treatment guidelines. The main aim was to evaluate NAIS procedural outcomes when undertaken after previous open or endovascular aortic repair in Sweden.

METHODS

In this retrospective study, The National Quality Registry for Vascular Surgery (Swedvasc) was used to identify Swedish centres that offered the NAIS bypass procedure for aortic prosthesis infection between 2008 and 2018. Variables of special interest were procedural details, short and long term survival, renal and other complications, and the durtion of antimicrobial treatment.

RESULTS

Forty patients (36 males, four females [mean age 69 years], 32 open repairs, seven endovascular aortic repairs [EVAR] and one fenestrated EVAR; 21 presented with aorto-enteric fistula) operated on with NAIS bypass were reviewed. The median time from the primary aortic intervention to the NAIS bypass procedure was 32 months (range 0 - 252 months). Mean ± standard deviation operating time was 645 ± 160 minutes, mean blood loss was 6 277 ± 6 525 mL, mean length of intensive care unit stay was 5.3 ± 3.7 days, and mean length of overall hospital stay was 21.2 ± 11.4 days. Thirty-five patients (88%) had a positive microbial culture; the most commonly isolated pathogen was Candida spp. The majority of patients survived for 30 days (n = 35 [88%]), and 33 (83%) and 32 (80%) patients survived for 90 days and one year, respectively. The number of surviving patients free from antimicrobial treatment at 90 days, six months, and one year was 19 (58%), 29 (88%), and 30 (94%). After a mean long term follow up of 69.9 ± 44.7 months, 20 patients were still alive.

CONCLUSION

The NAIS bypass procedure offered reasonable survival and functional outcomes, and was associated with a high cure rate, defined as freedom from any antimicrobial treatment.

Venous outcomes at 1 year after using the femoral vein as a conduit for passage of percutaneous femoropopliteal bypass

OBJECTIVE

The DETOUR 1 study was performed to assess the safety of the femoral vein as a "pass through" conduit for covered stent placement during fully percutaneous femoropopliteal bypass, also known as the DETOUR procedure.

METHODS

At eight participating centers in this prospective, single-arm, international trial, 78 patients (82 femoropopliteal lesions) were enrolled. All patients had patent femoral veins measuring ≥10 mm in diameter at baseline. The DETOUR procedure involved delivery of a series of TORUS stent grafts, deployed from contralateral common femoral artery access, to the ipsilateral proximal superficial femoral artery, with entry into the femoral vein and re-entry into the arterial vasculature at the above-the-knee popliteal artery. The TORUS stent grafts are deployed in an overlapping configuration as an arterial-arterial conduit. Due to this novel transvenous approach, we assessed specific considerations related to the venous system to analyze the risk of risk of venous thromboembolic complications. Symptomatic deep vein thrombosis, nonocclusive material associated with the graft such as benign endovenous graft-associated material, pulmonary embolism, Venous Clinical Severity Score (VCSS) and Villalta scores, and luminal occupancy by the stent graft were assessed as the ratio of cross-sectional areas of the stent graft to the native vein at baseline and 1 year after the procedure.

RESULTS

A duplicate femoral vein was present in 20.7% of cases. The majority of patients (86.8%) had a femoral vein luminal area preservation of ≥55%. Thirty-two patients experienced an increase in the vein diameter over time after the procedure, but this pattern of venous remodeling was not uniform. The patients who had a compensatory increase in the vein diameter had a smaller average baseline vein diameter compared with the patients who did not have a compensatory increase in vein diameter (P = .0414). Only two patients (2.4%) developed ipsilateral symptomatic deep vein thrombosis) through 1 year of follow-up. There were no pulmonary embolism in any patient in the series. The overall VCSS and Villata scores did not change during follow-up. Mean VCSS and Villata were 0.8 ± 1.4 and 0.5 ± 1.1 at 1 year, compared with 0.6 ± 1.0 and 0.4 ± 0.9 at baseline, respectively.

CONCLUSIONS

As a percutaneous alternative to open surgical bypass for complex femoropopliteal peripheral arterial disease, the transvenous bypass has a low rate of deep venous thrombotic and obstructive complications. Cross-sectional vein area is preserved, and in some patients, the compensatory vein diameter increases with time, supporting the feasibility and safety of using the lower extremity deep venous system as a pass-through conduit for the DETOUR percutaneous femoropopliteal bypass.

TRIAL REGISTRATION

NCT02471638.

Reasons for and Outcomes of Open Abdominal Aortic Repair in the Endovascular Era

BACKGROUND

Endovascular aortic aneurysm repair (EVAR) has become the treatment of choice for most patients with abdominal aortic aneurysm (AAA). Open aneurysm repair (OAR) is still being used in a number of patients for specific reasons. The aim of the present study was to investigate the reasons and perioperative outcomes of OAR in a high-volume endovascular center.

METHODS

All patients who underwent OAR in a single center institution during the period April 2010 to July 2019 were retrospectively analyzed.

RESULTS

During the study period, 222 patients underwent OAR. One hundred and forty-one (63.5%) patients underwent elective surgery, and eighty-one (36.5%) patients were treated acutely. The reasons for the decision to perform OAR instead of EVAR were as follows: anatomical in 89 (40.1%) cases, rupture in unstable patient in 57 (25.7%) cases, AAA with concomitant iliac arterial occlusive disease in 44 (19.8%) cases, previous EVAR with complications in 14 (6.3%) cases, large pararenal aneurysm considered risky to wait for a customized fenestrated stent graft in 7 (3.2%) cases, young patient age in 4 (1.8%) cases, the patient's preference in 3 (1.4%) cases, infected/mycotic AAA in 2 (0.9%) cases, and simultaneous OAR with colon cancer resection (n = 1, 0.5%) and renal transplantation (n = 1, n = 0.5). Thirty-day mortality in elective cases was 5% (7/141) and in acute cases 34.6% (28/81).

CONCLUSIONS

This study shows that OAR is still used for selected patients despite improvements in EVAR technology. The most common reason for OAR was an unsuitable anatomy for EVAR. Perioperative mortality of OAR both for acute and elective cases as observed in this study is in line with published outcomes of other centers.

Aortic reconstruction in infected aortic pathology by femoral vein "neo-aorta"

The use of autologous femoral veins for in situ reconstruction of the aortoiliac segment is an effective technique to treat native aorta or prosthetic graft infections. The indications, technical details, and outcomes of this procedure are detailed. Graft infection involving the aortic segment, while rare, remains one of the most challenging vascular surgery conditions to treat. The original technique of "neo-aortoiliac surgery" with in situ autologous vein grafts has evolved over the past 25 years and remains a worthwhile alternative for the treatment of aortic graft infections, with lower mortality rates compared with other extra-anatomic or in situ surgical options. Acceptance of this surgical option is due to low graft re-infection rates, rare graft disruption, and low long-term aneurysmal degeneration. Excision of the femoral veins is associated with acceptable rates of lower limb edema. The use of an autologous femoral vein graft can be considered the standard of care in selected patients for the management of aortic graft infections. Optimal management of patients with aortic graft infections requires consideration of all potential therapeutic options because no single modality can be used, and individualizing treatment according to the clinical condition will yield the best patient outcomes.

Abdominal aortic aneurysms

An abdominal aortic aneurysm (AAA) is a localized dilatation of the infrarenal aorta. AAA is a multifactorial disease, and genetic and environmental factors play a part; smoking, male sex and a positive family history are the most important risk factors, and AAA is most common in men >65 years of age. AAA results from changes in the aortic wall structure, including thinning of the media and adventitia due to the loss of vascular smooth muscle cells and degradation of the extracellular matrix. If the mechanical stress of the blood pressure acting on the wall exceeds the wall strength, the AAA ruptures, causing life-threatening intra-abdominal haemorrhage - the mortality for patients with ruptured AAA is 65-85%. Although AAAs of any size can rupture, the risk of rupture increases with diameter. Intact AAAs are typically asymptomatic, and in settings where screening programmes with ultrasonography are not implemented, most cases are diagnosed incidentally. Modern functional imaging techniques (PET, CT and MRI) may help to assess rupture risk. Elective repair of AAA with open surgery or endovascular aortic repair (EVAR) should be considered to prevent AAA rupture, although the morbidity and mortality associated with both techniques remain non-negligible.

Deep Femoral Vein Reconstruction of the Abdominal Aorta and Adaptation of the Neo-Aortoiliac System Bypass Technique in an Endovascular Era

BACKGROUND:

Primary infection of the abdominal aorta is a rare pathology that may threaten the integrity of the aortic wall, while secondary aortic prosthesis infection represents a devastating complication to open surgical and endovascular aortic surgery. Curative treatment is achievable by removal of all infected prosthetic material followed by a vascular reconstruction.

DESIGN AND METHODS:

Twelve consecutive patients treated with the neo-aortoiliac system bypass (NAIS) procedure were reviewed. Nine were treated for a secondary aortic prosthesis infection (tube graft n = 3, bifurcated graft n = 4, endovascular aortic repair (EVAR) stent graft n = 1, and fenestrated EVAR [FEVAR] stent graft n = 1), while 3 patients underwent NAIS repair due to an emergent primary mycotic aortoiliac aneurysm.

PRIMARY RESULTS:

Ten of 12 patients survived 30 days. Three patients were operated on acutely, and 9 patients had elective or subacute NAIS surgery. Two of 3 patients operated acutely died within 30 days, whereas no 30-day or 1-year mortality was observed in patients undergoing elective or subacute surgery. The median time from primary reconstruction to the NAIS procedure was 11 months (range: 0-201 months). Stent grafts (n = 5 of 12) were in 4 cases explanted using endovascular balloon clamping. Of the explanted endografts, 2 patients presented with a secondary graft infection after EVAR/FEVAR, while 3 patients had been emergently treated with endovascular cuffs as a "bridge-to-surgery" procedure due to aortoenteric fistula (AEF). Patients who received a "bridge-to-surgery" regimen were treated with the NAIS procedure within 8 weeks (median 27 days, range: 27-60) after receiving emergency stent grafting.

PRINCIPAL CONCLUSIONS:

Aortic balloon-clamping during explantation of infected aortic prosthetic endografts is feasible and facilitates complete endograft removal. Endovascular bridging procedures could be beneficiary in the treatment of AEF or anastomotic dehiscence due to graft infection, offering a possibility to convert the acute setting to an elective definitive reconstructive procedure with a higher overall success rate.