Cryopreserved arterial allografts vs rifampin-soaked Dacron for the treatment of infected aortic and iliac grafts.

OBJECTIVE: Aortic and iliac graft infections remain complex clinical problems with high mortality and morbidity. Cryopreserved arterial allografts (CAAs) and rifampin-soaked Dacron (RSD) are options for in situ reconstruction. This study aimed to compare the safety and effectiveness of CAA vs RSD in this setting. METHODS: Data from patients with aortic and iliac graft infections undergoing in situ reconstruction with either CAA or RSD from January 2002 through August 2022 were retrospectively analyzed. Our primary outcomes were freedom from graft-related reintervention and freedom from reinfection. Secondary outcomes included comparing trends in the use of CAA and RSD at our institution, overall survival, perioperative mortality, and major morbidity. RESULTS: A total of 149 patients (80 RSD, 69 CAA) with a mean age of 68.9 and 69.1 years, respectively, were included. Endovascular stent grafts were infected in 60 patients (41 CAA group and 19 RSD group; P ≤ .01). Graft-enteric fistulas were more common in the RSD group (48.8% RSD vs 29.0% CAA; P ≤ .01). Management included complete resection of the infected graft (85.5% CAA vs 57.5% RSD; P ≤ .01) and aortic reconstructions were covered in omentum in 57 (87.7%) and 63 (84.0%) patients in the CAA and RSD group, respectively (P = .55). Thirty-day/in-hospital mortality was similar between the groups (7.5% RSD vs 7.2% CAA; P = 1.00). One early graft-related death occurred on postoperative day 4 due to CAA rupture and hemorrhagic shock. Median follow-up was 20.5 and 21.5 months in the CAA and RSD groups, respectively. Overall post-discharge survival at 5 years was similar, at 59.2% in the RSD group and 59.0% in the CAA group (P = .80). Freedom from graft-related reintervention at 1 and 5 years was 81.3% and 66.2% (CAA) vs 95.6% and 92.5% (RSD; P = .02). Indications for reintervention in the CAA group included stenosis (n = 5), pseudoaneurysm (n = 2), reinfection (n = 2), occlusion (n = 2), rupture (n = 1), and graft-limb kinking (n = 1). In the RSD group, indications included reinfection (n = 3), occlusion (n = 1), endoleak (n = 1), omental coverage (n = 1), and rupture (n = 1). Freedom from reinfection at 1 and 5 years was 98.3% and 94.9% (CAA) vs 92.5% and 87.2% (RSD; P = .11). Two (2.9%) and three patients (3.8%) in the CAA and RSD group, respectively, required graft explantation due to reinfection. CONCLUSIONS: Aorto-iliac graft infections can be managed safely with either CAA or RSD in selected patients for in situ reconstruction. However, reintervention was more common with CAA use. Freedom from reinfection rates in the RSD group was lower, but this was not statistically significant. Conduit choice is associated with long-term surveillance needs and reinterventions.

Cryopreserved Arterial Allografts Versus Rifampin-Soaked Dacron for the Treatment of Infected Aortic and Iliac Aneurysms.

BACKGROUND: Infected aortic and iliac artery aneurysms are challenging to treat. Cryopreserved arterial allografts (CAAs) or rifampin-soaked Dacron (RSD) are standard options for in situ reconstruction. Our aim was to compare the safety and effectiveness of CAA versus RSD for these complex pathologies. METHODS: This is a retrospective review of infected iliac, abdominal, and thoracoabdominal aortic aneurysms treated with either CAAs or RSD between 2002 and 2022 at our institution. The diagnosis was confirmed by intraoperative, radiologic, or microbiological evidence of aortic infection. Perioperative events, 30-day and long-term mortality, reinfection, and reintervention were analyzed. RESULTS: Thirty patients (17 CAA, 13 RSD) with a mean age of 61 and 68 years, respectively, were identified. The infected aneurysm was most commonly suprarenal or infrarenal. Culture-negative infections were present in 47% of the CAA group and 54% in the RSD group. Early major morbidity was 57% and 54% for the CAA and RSD, respectively. Thirty-day mortality was similar between groups (18% vs. 23% CAA vs. RSD, P ≥ 0.99). Median follow-up was longer in the RSD group (14.5 months vs. 13 months). Overall survival at 1 and 5 years was 80.8% and 64.8% in the CAA group and 69.2% and 57.7% in the RSD group. Reinterventions only occurred with CAA repairs and indications included graft occlusion (2), multiple pseudoaneurysms and reinfection (1), and hemorrhagic shock caused by graft rupture (1). Freedom from reintervention at 1 and 3 years was 87.5% and 79.5% (CAA group) versus 100% and 100% (RSD, P = 0.06). Freedom from reinfection at 1 year was 100% in both groups, while at 3 years it was 90.9% for the CAA group and 100% for the RSD group (P = 0.39). CONCLUSIONS: Infected aortic and iliac aneurysms have high early morbidity and mortality. CAA and RSD had similar outcomes in our series; CAA trended toward higher reintervention rates. Both remain viable options for complex scenarios but require close surveillance.

Outcomes of Onyx® Embolization of Type II Endoleaks After Endovascular Repair of Abdominal Aortic Aneurysms.

BACKGROUND: Type II endoleaks (T2ELs) are common following endovascular repair of abdominal aortic aneurysms (EVAR). Embolization with ethylene vinyl alcohol copolymer (Onyx) may present an effective treatment alternative for T2ELs. Due to limited data supporting its use, we sought to analyze outcomes of Onyx embolization for T2ELs. METHODS: Retrospective review of consecutive patients treated for T2ELs utilizing Onyx embolization agent from 2009-2018. All pre- and post-Onyx intervention CT scans were analyzed for diameter and volume changes with 3D reconstruction software. The primary outcomes were change in maximum AAA diameter and volume. Secondary outcomes included additional interventions, rupture, and mortality. A subset analysis was performed with patients with isolated T2ELs (no other types of endoleaks present). RESULTS: We identified 85 patients (73 males, mean age 77.6 ± 7.6 years) who underwent 112 Onyx interventions. Average time to first Onyx intervention after index EVAR was 3.3 ± 2.6 years and average sac growth was 6.3 ± 6.7 mm. Patients underwent mean 1.3 Onyx interventions using a mean of 4.9 ± 4.7 ml for treatment. Three complications occurred (Onyx extravasation, colon ischemia, and access site hematoma). Mean follow-up was 2.5 ± 2.1 years after initial Onyx treatment. At the most recent follow-up, sac diameter stabilization was seen in 47% and reduction >5 mm was seen in 19%. Sac growth of >5 mm was seen in 34% of patients following the first Onyx intervention. In our subset of isolated T2EL, 72% had sac stabilization or reduction >5 mm. Four patients experienced a ruptured aneurysm (3 had active type 1 endoleaks). Rupture-free survival was 95% at 5 years, and overall survival was 54% at 5 years. Notably, increasing Onyx interventions were not associated with sac stabilization or reduction (OR 0.6, P = 0.1). On multivariable analysis, AAA sac diameter stabilization or reduction was independently associated with BMI >30 kg/m2 (OR 4.2, P = 0.01) and having only 1 Onyx intervention (OR 3.8, P = 0.02). CONCLUSIONS: Onyx for embolization of T2ELs resulted in AAA sac diameter stabilization or reduction in 66% of patients, and up to 72% in isolated T2ELs. Further, increasing Onyx interventions were not associated with either aneurysm sac stabilization or reduction. Given its similar outcomes to other embolization strategies in the literature, Onyx embolization for management of T2ELs needs to be judiciously considered, particularly for T2ELs persisting after an initial Onyx embolization intervention.

Operative interventions for extrahepatic portomesenteric venous aneurysms and long-term outcomes.

BACKGROUND: Extrahepatic portal venous aneurysms (PVAs) are rare, and the pathogenesis is not fully understood. The optimum management of these patients is unknown. METHODS: Consecutive patients with PVA were identified over an 18-year period (1992-2010). A retrospective review was conducted. Clinical presentation, modality of diagnosis, surgical treatment, 30-day morbidity and mortality, and follow-up are reported. RESULTS: Four patients were identified who underwent surgical management of an extrahepatic PVA. Operative technique using left renal vein, femoral vein panel graft, polytetrafluoroethylene (ePTFE) graft, and segmental aneurysm wall resected with aneurysmorrhaphy is described. Early complications occurred in 1 patient with an ePTFE graft. The patient returned to the operating room for bleeding. In addition, the same patient had a late graft thrombosis 6 years postoperatively when the anticoagulation was discontinued for pregnancy. The remainder of the patients recovered without complication, and their repairs are still patent with a mean follow-up of 78 months (17-144 months). There were no mortalities in the series. CONCLUSIONS: Operative intervention for portomesenteric venous aneurysm can be done safely in select patients and should be considered in those with symptoms, rapid growth, mural thrombus, or aneurysms ≥4 cm in diameter. Repair with an autogenous interposition graft affords good long-term patency. Aneurysmorrhaphy may be performed if the remaining venous wall is of good quality.

Treatment strategies and outcomes in patients with infected aortic endografts.

OBJECTIVE: Endovascular abdominal (EVAR) and thoracic (TEVAR) endografts allow aneurysm repair in high-risk patients, but infectious complications may be devastating. We reviewed treatment and outcomes in patients with infected aortic endografts. METHODS: Twenty-four patients were treated between January 1997 and July 2012. End points were mortality, morbidity, graft-related complications, or reinfection. RESULTS: Twenty males and four females with median age of 70 years (range, 35-80 years) had 21 infected EVARs and 3 TEVARs. Index repairs performed at our institution included eight EVARs and two TEVARs (10/1300; 0.77%). There were 19 primary endograft infections, 4 graft-enteric fistulae, and 1 aortobronchial fistula. Median time from repair to presentation was 11 months (range, 1-102 months); symptoms were fever in 17, abdominal pain in 11, and psoas abscess in 3. An organism was identified in 19 patients (8 mono- and 11 polymicrobial); most commonly Staphylococcus in 12 and Streptococcus in 6. All but one patient had successful endograft explantation. Abdominal aortic reconstruction was in situ repair in 21 (15 rifampin-soaked, 2 femoral vein, and 4 cryopreserved) and axillobifemoral bypass in three critically ill patients. Infected TEVARs were treated with rifampin-soaked grafts using hypothermic circulatory arrest. Early mortality (30 days or in-hospital) was 4% (n = 1). Morbidity occurred in 16 (67%) patients (10 renal, 5 wound-related, 3 pulmonary, and 1 had a cardiac event). Median hospital stay was 14 days (range, 6-78 days). One patient treated with in situ rifampin-soaked graft had a reinfection with fatal anastomotic blowout on day 44. At 14 months median follow-up (range, 1-82 months), patient survival, graft-related complications, and reinfection rates were 79%, 13%, and 4%, respectively. CONCLUSIONS: Endograft explantation and in situ reconstruction to treat infections can be performed safely. Extra-anatomic bypass may be used in high-risk patients. Resection of all infected aortic wall is recommended to prevent anastomotic breakdown. Despite high early morbidity, the risk of long-term graft-related complications and reinfections is low.

Novel extra-anatomic intra-abdominal reconstruction for treatment of paravisceral aortic infection.

Adequate treatment of native or prosthetic aortic infection requires extensive surgical debridement and establishing flow to the extremities using extra-anatomic or in situ reconstruction, each with its inherent limitations. Infection of the paravisceral aortic segment precludes an axillofemoral bypass as the sole treatment because of inability to provide visceral perfusion. In situ autograft or allograft reconstructions could be limited by conduit availability or significantly prolonged operative time, or both. Placement of an antibiotic-soaked prosthetic in a field with gross purulence carries a high risk of reinfection. We describe a technique for extra-anatomic, intra-abdominal reconstruction using an antibiotic-soaked prosthetic graft to avoid the infected paravisceral aortic bed and achieve antegrade lower extremity and visceral vessel perfusion.

Factors affecting outcome of open and hybrid reconstructions for nonmalignant obstruction of iliofemoral veins and inferior vena cava.

OBJECTIVES: To identify factors affecting long-term outcome after open surgical reconstructions (OSR) and hybrid reconstructions (HR) for chronic venous obstructions. METHODS: Retrospective review of clinical data of 60 patients with 64 OSR or HR for chronic obstruction of iliofemoral (IF) veins or inferior vena cava (IVC) between January 1985 and September 2009. Primary end points were patency and clinical outcome. RESULTS: Sixty patients (26 men, mean age 43 years, range 16-81) underwent 64 procedures. Ninety-four percent had leg swelling, 90% had venous claudication, and 31% had active or healed ulcers (CEAP classes: C3 = 30, C4 = 12, C5 = 8, C6 = 12). Fifty-two OSRs included 29 femorofemoral (Palma vein: 25, polytetrafluoroethylene [PTFE]: 4), 17 femoroiliac-inferior vena cava (IVC) (vein: 3, PTFE: 14) and six complex bypasses. Twelve patients had HR, which included endophlebectomy, patch angioplasty, and stenting. Early graft occlusion occurred after 17% of OSR and 33% HR. Discharge patency was 96% after OSR, 92% after HR. No mortality or pulmonary embolism occurred. Five-year primary and secondary patency was 42% (95% confidence interval [CI] 29%-55%) and 59% (CI 43%-72%), respectively. For Palma vein grafts it was 70% and 78%, for femoroiliac and ilio-infrahepatic IVC bypasses it was 63% and 86%, and for femoro-infrahepatic IVC bypasses it was 31% and 57%, respectively. Complex OSRs and hybrid procedures had 28% and 30% 2-year secondary patency, respectively. The only factor that significantly affected graft patency in multivariate analysis was May-Thurner syndrome with associated chronic venous thrombosis. For HR, stenting into the common femoral vein patch vs iliac stents only significantly increased patency. At last follow-up, 60% of the patients had no venous claudication and no or minimal swelling. All ulcers with patent grafts healed but 50% of these recurred. CONCLUSIONS: Both OSR and HR are viable options if endovascular procedures fail or are not feasible. Palma vein bypass and femoroiliac or iliocaval PTFE bypasses have excellent outcomes with good symptomatic relief.

Magnetic forces enable rapid endothelialization of synthetic vascular grafts.

BACKGROUND: Synthetic vascular grafts cannot be used in small vessels because of graft failure caused by thrombosis and neointima formation. Rapid endothelialization may overcome this limitation. We hypothesized that a magnetic graft would be able to capture and retain endothelial cells labeled with paramagnetic particles. METHODS AND RESULTS: Porcine blood derived endothelial cells were allowed to endocytose superparamagnetic iron oxide microspheres. Cell survival was assessed by trypan blue exclusion and demonstrated a dose-dependent cell survival of 75% to 95%. A flexible magnetic sheet was annealed to the external surface of a knitted Dacron graft. Labeled cells (10(6)/mL) were placed within the graft for 5 minutes. Confocal and electron microscopy confirmed uniform cell capture at the magnetized surface. The effect of shear forces on the adherent cells was evaluated in a flow chamber. The cells remained attached at rates up to 300 mL/min, with cell loss commencing at 400 mL/min. Prototype magnetic grafts were implanted in porcine carotid arteries. Labeled cells were placed within the graft for 10 minutes at the time of implantation. The grafts were evaluated after one day and uniform cell coverage was noted on the magnetized surface. In comparison, relatively few labeled cells were seen attached to a nonmagnetized surface. CONCLUSIONS: Magnetic forces can be used to rapidly cover a vascular graft with paramagnetically labeled cells. This biophysical interaction is sufficient to retain cells in the presence of blood flow. Applications of this technique may include rapid endothelialization of synthetic vascular grafts and dialysis fistulas.

Fabrication of Small Caliber Stent-grafts Using Electrospinning and Balloon Expandable Bare Metal Stents.

Stent-grafts are widely used for the treatment of various conditions such as aortic lesions, aneurysms, emboli due to coronary intervention procedures and perforations in vasculature. Such stent-grafts are manufactured by covering a stent with a polymer membrane. An ideal stent-graft should have a biocompatible stent covered by a porous, thromboresistant, and biocompatible polymer membrane which mimics the extracellular matrix thereby promoting injury site healing. The goal of this protocol is to manufacture a small caliber stent-graft by encapsulating a balloon expandable stent within two layers of electrospun polyurethane nanofibers. Electrospinning of polyurethane has been shown to assist in healing by mimicking native extracellular matrix, thereby promoting endothelialization. Electrospinning polyurethane nanofibers on a slowly rotating mandrel enabled us to precisely control the thickness of the nanofibrous membrane, which is essential to achieve a small caliber balloon expandable stent-graft. Mechanical validation by crimping and expansion of the stent-graft has shown that the nanofibrous polyurethane membrane is sufficiently flexible to crimp and expand while staying patent without showing any signs of tearing or delamination. Furthermore, stent-grafts fabricated using the methods described here are capable of being implanted using a coronary intervention procedure using standard size guide catheters.

Benign superior vena cava syndrome: stenting is now the first line of treatment.

BACKGROUND: Endovascular repair (EVR) is emerging as first-line treatment for patients with superior vena cava (SVC) syndrome of benign etiology, but data on its durability remain scarce. The aims of this study were to assess the efficacy and durability of EVR and compare results of EVR with open surgical reconstruction (OSR). METHODS: Data from 70 consecutive patients undergoing treatment for benign SVC syndrome between November 1983 and November 2006 were retrospectively reviewed. RESULTS: There were 30 males and 40 females (mean age, 41 years; range, 5-75 years). Etiology included indwelling catheters or pacemaker wires in 35 patients, mediastinal fibrosis in 31, idiopathic thrombosis in 2, hypercoagulable disorder in 1, and postsurgical thrombosis in 1. In 42 patients, OSR was done through a median sternotomy: repair was with spiral saphenous vein in 22, expanded polytetrafluoroethylene (ePTFE) in 13, femoral vein grafts in 6, and human allograft in 1. Fifteen OSRs followed failed EVR interventions. EVR was attempted in 32 patients and was successful in 28 (88%): 19 had stenting, 14 had percutaneous transluminal balloon angioplasty (PTA), 2 had thrombolytic therapy with PTA, and 3 had stenting. All four technical failures subsequently underwent OSR. There were no early deaths in either group. Periprocedural morbidity was 19% after OSR and 4% in the EVR group. Six early surgical graft failures were successfully treated with surgical revision; one restenosis after EVR was restented. During a mean follow-up of 4.1 years (range, 0.1-17.5 years) after OSR, 11 patients underwent 18 secondary interventions. Mean follow-up after EVR was 2.2 years (range, 0.2-6.4 years), and nine patients underwent 21 secondary EVR interventions. Primary, assisted primary, and secondary patency rates of surgical bypass grafts were, respectively, 45%, 68%, and 75% at 3 and 5 years. Primary, assisted primary and secondary patency rates after EVR were 44%, 96%, and 96% at 3 years. Assisted primary patency was significantly higher in vein grafts than in ePTFE grafts (P = .05). Assisted primary and secondary patency was significantly higher in patients undergoing stenting compared with PTA (P = .02). At last follow-up, 93% of patients in both OSR and EVR groups had significant relief from symptoms. CONCLUSIONS: OSR of benign SVC syndrome is effective, with durable long-term relief from symptoms. EVR is less invasive but equally effective in the mid-term, albeit at the cost of multiple secondary interventions, and is an appropriate primary treatment for benign SVC syndrome. OSR remains an excellent choice for patients who are not suitable for EVR or in whom the EVR fails.

Early complications and long-term outcome after open surgical treatment of popliteal artery aneurysms: is exclusion with saphenous vein bypass still the gold standard?

BACKGROUND: Popliteal artery aneurysms (PAAs) are rare, but thromboembolic complications may result in limb loss. To define complications and outcomes after open surgical repairs, we reviewed our experience. METHODS: Clinical data of patients with PAA seen between 1985 and 2004 at Mayo Clinic, Rochester, Minnesota, were reviewed and outcomes in 289 patients with open revascularization were analyzed. Kaplan-Meier method with log-rank tests, chi(2), and Wilcoxon rank sum tests were used for analysis. RESULTS: A total of 358 PAAs were treated in 289 patients, consisting of 281 (97%) men and eight (3%) women. There were 133 (46%) unilateral and 156 (54%) bilateral PAAs with a mean diameter of 2.9 cm (range, 1.5 to 9 cm). Abdominal aortic aneurysm (AAA) was more frequent with bilateral than unilateral PAAs (65% [101/156] vs 42% [56/133] P = .001). There were 144 (40%) asymptomatic limbs (group 1), 140 (39%) had chronic symptoms (group 2), and 74 (21%) had acute ischemia (group 3). Great saphenous vein (GSV) was used in 242 limbs (68%), polytetrafluoroethylene (PTFE) in 94 (26%), and other types of graft in 22 (6%). Early mortality was 1% (3/358), all in group 3 (4% [3/74]). Six of seven patients with perioperative myocardial infarctions belonged to group 3 (8%). The 30-day graft thrombosis rate was 4%, with 1% in group 1 (1/144), 4% in group 2 (5/140), and 9% in group 3 (7/74). All six early amputations (8%) were in group 3, five with failed bypass (4 PTFE, 1 GSV). Mean follow-up was 4.2 years (range, 1 month to 20.7 years). The 5-year primary and secondary patency rates were 76% and 87%, respectively, higher with GSVs (85% and 94%) than PTFE (50% and 63%, P < .05). Seven recurrent PAAs (2%) required reintervention. The 5-year freedom from reintervention was 100% after endoaneurysmorrhaphy vs 97% after ligations (P = .03). Five-year limb salvage rate was 97% (85% in group 3). There was no limb loss in group 1 and none in group 2 with GSV. In group 3, preoperative thrombolysis reduced the amputation rate in class II patients with marginally threatened limbs (96% vs 69%, P = .02). CONCLUSION: Acute presentation of PAA continues to carry high mortality and cardiac morbidity; although preoperative thrombolysis appears to improve results, the 8% early and 15% late amputation rates remain ominous. Early elective repair is recommended because these patients had no surgical mortality, a low rate of complications, and asymptomatic patients had no limb loss at 5 years. GSV and endoaneurysmorrhaphy continues to be the gold standard for open repair of PAA.

Comparison of precuffed and vein-cuffed expanded polytetrafluoroethylene grafts for infragenicular arterial reconstructions: a case-matched study.

Distal vein cuff interposition is often added to prosthetic infragenicular arterial reconstruction in an attempt to improve hemodynamics and patency rates. The purpose of this study was to compare the outcome of a precuffed expanded polytetrafluroethylene (ePTFE) graft with a vein-cuffed ePTFE graft for infragenicular bypass. We reviewed the clinical outcome of 77 patients with critical limb ischemia without available autologous vein conduits who underwent arterial reconstruction of 80 limbs to below-knee popliteal or tibioperoneal vessels using either ePTFE precuffed graft (precuffed group, 38 patients 40 limbs) or ePTFE vein-cuffed graft (vein-cuffed group, 39 patient, 40 limbs). Precuffed group patients were enrolled in a prospective cohort study. Vein-cuffed group patients consisted of consecutive case-matched patients operated on during the same study period. End points were primary graft patency and limb salvage rates. There were 42 males and 35 females with a mean age of 73.4 years (range, 44-92 years). Both groups were matched to demographics, risk factors for atherosclerosis, previous ipsilateral reconstruction, and location of the distal anastomosis. Proximal anastomosis was to the common (n = 68) or superficial (n = 12) femoral arteries. Distal anastomosis was to the below-knee popliteal (n = 28), anterior tibial (n = 12), posterior tibial (n = 15) and peroneal (n = 25) arteries. Operative mortality was 1.3%. Graft patency at dismissal was 90% and 95% in the precuffed and vein-cuffed groups, respectively. The mean follow-up was 25.7 months (range, 2.4-61 months). Primary patency rates at 1 and 3 years were 70% and 57% in the precuffed group, and 78% and 54% in the vein-cuffed group (p = 0.32). Limb salvage rates at 1 and 3 years were 97% and 70% in the precuffed group, and 95% and 81% in the vein-cuffed group (p = 0.49). Overall patient survival at 1 and 3 years was 81 % and 57%, respectively. In this case-control study, results of precuffed ePTFE graft were similar to those obtained with vein-cuffed ePTFE grafts. The precuffed ePTFE graft is an adequate alternative conduit for infragenicular arterial reconstruction in patients with critical limb ischemia and no available autologous veins.