Rifampin-soaked Graft Research Articles

S1410 Mycotic Abdominal Aneurysm Associated With Chronic Pancreatitis

INTRODUCTION: Vascular complications are a rare but serious manifestation of pancreatitis. The mechanism is thought to be due to inflammation and necrosis from local spread of proteolytic enzymes, compressive forces, or local infection. Splanchnic and gastroduodenal vessels are the most common given their proximity, but in rare cases, the aorta is affected. CASE DESCRIPTION/METHODS: A 53-year-old white male with long-standing chronic alcohol induced pancreatitis complicated by pancreatic ascites and pseudocysts presented with one day history of epigastric pain, nausea and emesis. Other history included gastroesophageal reflux, peptic ulcer disease complicated by a gastric bleed 4 months prior, and hypertension. He reported 37 pack years of tobacco use and marijuana use. He had a history of alcohol abuse but had been abstinent for the past 10 months. He denied intravenous drug use. His exam was notable for moderate distress due to pain, thin appearing (BMI 18), poor dentition, and epigastric tenderness to palpation without rebound or guarding. Labs were notable for a mild leukocytosis (WBC 16.7 g/L) and anemia (HGB 12.3 g/dL). His lipase was within normal limits (17 U/L). A CT scan revealed a bilobed aortic aneurysm (4.4 × 4.5 cm) with wall thickening and surrounding fluid and tissue suggestive of a mycotic aneurysm (Figures 1 and 2). Infectious workup including blood, fungal, and urine cultures, and bartonella and Q fever serologies was unrevealing. Comparison to a CT scan done 4 months prior showed periaortic inflammation and caliber of 2.4 cm (Figure 3). The patient was started on empiric antibiotics and surgery was consulted. Given the rapid expansion and complexity, he was deemed high-risk and completed outpatient antibiotics prior to surgery. He returned two months later for a planned open repair of the aneurysm with a rifampin-soaked graft. Intraoperative cultures and pathology were unrevealing for infections etiology. On outpatient follow up, his symptoms improved and had no signs of ongoing infection. He was placed on suppressive doxycycline and continues to do well 17 months later. DISCUSSION: Aortic pseudoaneurysms are a rare complication of pancreatitis with both infected and non-infected cases being reported in literature. Surgery is the definitive management, often done promptly upon diagnosis. Here we present a case of mycotic aortic aneurysm associated with chronic pancreatitis in which the surgical management was successfully postponed for infection control and stabilization of the patient.Figure 1.: CT angiography performed on admission showing bilobed aortic aneurysm above and below the renal arteries.Figure 2.: Abdominal CT on admission showing aortic aneurysm just superior to the renal arteries.Figure 3.: CT abdomen performed 4 months prior to admission aortic caliber just superior to the renal arteries.

Ruptured Mycotic Aortic Aneurysm Secondary to Escherichia Coli Bacteremia in an HIV-Positive Patient

Mycotic aortic aneurysms are an aggressive form of degenerative remodeling reported more commonly in immunosuppressed patients. These aneurysms carry a high risk of progression to rupture, fulminant sepsis, and death, and therefore require prompt operative intervention. The human immunodeficiency virus (HIV) has also been associated with a broad spectrum of vascular disease, including development of aneurysms, however these have typically been identified in the peripheral vasculature. We report the case of a 71-year-old, HIV-positive male who presented with Escherichia coli bacteremia and aortitis which rapidly progressed to a ruptured infrarenal mycotic aortic aneurysm. He was managed successfully with open debridement and in situ implantation of a rifampin-soaked prosthetic graft as well as long-term antibiotic therapy. Here, we review the epidemiology, pathophysiology, and optimal surgical treatment of mycotic aortic aneurysms.

Treatment strategies and outcomes in patients with infected aortic endografts

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. Twenty-four patients were treated between January 1997 and July 2012. End points were mortality, morbidity, graft-related complications, or reinfection. 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. 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.

Contained Ruptured Paravisceral Aortic Aneurysm Related to Immunoglobulin G4 Aortitis

To describe a case of autoimmune inflammatory abdominal aortic aneurysm (AAA) associated with rupture. A 63-year-old woman presented with 5 days of abdominal pain, malaise, fever, and chills after 6 months of debilitating back pain with a 3-kg weight loss. On examination, she was shown to have a tender palpable pulsatile abdominal mass. Computed tomographic angiography revealed a multilobulated paravisceral AAA (5.5 cm in maximal diameter) and bilateral popliteal aneurysms. The appearance of the aneurysms was indicative of primary aortic infection. Laboratory examinations demonstrated a white blood cell (WBC) count of 12.3×10(9)/L, erythrocyte sedimentation rate of 131 mm/hr, normal antinuclear antibody level, and C-reactive protein level of 211 mg/L. Nuclear WBC scan showed no uptake of tracer around the aorta. Blood and urine cultures were negative. Because of the AAA size and symptoms, open repair was expedited. The operation was performed through a transabdominal midline incision with a mediovisceral rotation. Extensive retroperitoneal inflammation extending into the paravisceral aorta was encountered. Supraceliac clamping was possible. The aorta was replaced from the level of the superior mesenteric artery to the aortic bifurcation with a 16-mm rifampin-soaked graft with reimplantation of the left renal artery. Cultures and biopsies were done. Histology demonstrated vessel wall rupture, adventitial fibrosis and inflammatory cell infiltration, obliterative phlebitis, lymphoid follicles, perineural inflammation, and immunoglobulin G4 (IgG4) plasma cell infiltration, consistent with a contained ruptured aneurysm associated with IgG4 periaortitis. The patient had a long postoperative course with prolonged intubation and renal failure requiring hemodialysis, which resolved 8 weeks postoperatively. Immunosuppression was paramount for her improvement. IgG4-related inflammatory AAAs are rare; this is the first report of one with a contained rupture. The patient's symptoms, the unusual appearance on computed tomography, the presence of popliteal aneurysms in a woman, and the normal WBC scan were indicative of an inflammatory etiology. Tissue biopsy was critical to obtain histological diagnosis and direct treatment.

Daptomycin and Rifampin Alone and in Combination Prevent Vascular Graft Biofilm Formation and Emergence of Antibiotic Resistance in a Subcutaneous Rat Pouch Model of Staphylococcal Infection

Objective To investigate the efficacy of daptomycin and rifampin either alone or in combination in preventing prosthesis biofilm in a rat model of staphylococcal vascular graft infection. Design Prospective, randomised, controlled animal study. Materials Graft infections were established in the back subcutaneous tissue of adult male Wistar rats by implantation of Dacron prostheses followed by topical inoculation with 2 × 10 7 colony forming units of Staphylococcus aureus, strain Smith diffuse. Methods The study included a control group, a contaminated group that did not receive any antibiotic prophylaxis and three contaminated groups that received intra-peritoneal daptomycin, rifampin-soaked graft and daptomycin plus rifampin-soaked graft, respectively. Each group included 15 animals. The infection burden was evaluated by using sonication and quantitative agar culture. Moreover, an in vitro antibiotic susceptibility assay for S. aureus biofilms was performed to elucidate the same activity. Results When tested alone, daptomycin and rifampin showed good efficacies. Their combination showed efficacies significantly higher than that of each single compound. The in vitro studies showed that Minimum Inhibitory Concentration and Minimum Bactericidal Concentration values for daptomycin were lower in presence of rifampin. Daptomycin prevented the emergence of rifampin resistance. Conclusion Daptomycin is an important candidate for prevention of staphylococcal biofilm-related infection and rifampin could serve as an interesting anti-staphylococcal antibiotic enhancer.

Prophylaxis against Staphylococcus aureus Vascular Graft Infection with Mupirocin-Soaked, Collagen-Sealed Dacron

A rat model was used to investigate the efficacy of mupirocin in the prevention of vascular prosthetic graft infections. The effect of mupirocin-soaked Dacron was compared with the effect of rifampin-soaked, collagen-sealed Dacron in the rat model of graft infection caused by methicillin-susceptible Staphylococcus aureus and methicillin-resistant S. aureus. Graft infections were established in the back subcutaneous tissue of 195 adult male Wistar rats by implantation of 1-cm2 Dacron prostheses followed by topical inoculation with 5 × 107 colony-forming units of S. aureus. The study included a control group (no graft contamination), two contaminated groups that did not receive any antibiotic prophylaxis, two contaminated groups in which perioperative intraperitoneal amoxicillin clavulanate prophylaxis (50 mg/kg) was administered, four contaminated groups that received mupirocin- or rifampin-soaked graft, and four contaminated groups that received mupirocin- or rifampin-soaked graft and perioperative intraperitoneal amoxicillin clavulanate prophylaxis (50 mg/kg). The grafts were sterilely removed 7 days after implantation and the infection was evaluated by using sonication and quantitative agar culture. Data analysis showed that the efficacy of mupirocin against both strains was significantly different from that of the untreated control. In addition, mupirocin was more effective than rifampin against the methicillin-resistant strain. Finally, only the combination of mupirocin and amoxicillin clavulanate produced complete suppression of growth of all strains.

Polycationic peptides as prophylactic agents against methicillin-susceptible or methicillin-resistant Staphylococcus epidermidis vascular graft infection.

Several polycationic peptides isolated from animals, plants, and bacterial species possess a broad spectrum of antimicrobial activity. A rat model was used to investigate the efficacies of two peptides, ranalexin and buforin II, in the prevention of vascular prosthetic graft infections. The effect of peptide-soaked collagen-sealed Dacron was compared to that of rifampin-soaked collagen-sealed Dacron in the rat model of graft infection caused by methicillin-susceptible rifampin-susceptible Staphylococcus epidermidis and methicillin-resistant rifampin-susceptible S. epidermidis. Graft infections were established in the back subcutaneous tissue of 240 adult male Wistar rats by implantation of 1-cm(2) Dacron prostheses, followed by topical inoculation with 2 x 10(7) CFU of S. epidermidis. The study included a control group (no graft contamination), two contaminated groups that did not receive any antibiotic prophylaxis, two contaminated groups to which perioperative intraperitoneal cefazolin prophylaxis (30 mg/kg of body weight) was administered, six contaminated groups that received a peptide- or rifampin-soaked graft, and six contaminated groups that received a peptide- or rifampin-soaked graft and perioperative intraperitoneal cefazolin prophylaxis (30 mg/kg). The grafts were sterilely removed 7 days after implantation, and the infection was evaluated by using sonication and quantitative agar culture. Overall, the efficacies of the polycationic peptides against the methicillin-susceptible and methicillin-resistant strains were not significantly different from that of rifampin. Nevertheless, the combinations of ranalexin- and buforin II-coated grafts with cefazolin treatment demonstrated efficacies significantly higher than that of the combination of rifampin-coated grafts and cefazolin treatment against the methicillin-resistant strain.

The results of in situ prosthetic replacement for infected aortic grafts

Background: Treatment of aortic graft infection with graft excision and axillofemoral bypass may carry an increased risk of limb loss, aortic stump blowout, and pelvic ischemia. A review of patients with aortic graft infection treated with in situ prosthetic graft replacement was undertaken to determine if mortality, limb loss, and reinfection rates were improved with this technique. Methods: The clinical data of 25 patients, 19 males and 6 females, with a mean age of 68 years (range 35 to 83), with aortic graft infection, treated between January 1, 1989, and December 31, 1998, by in situ prosthetic graft replacement were reviewed. Follow-up was complete in the 23 surviving patients and averaged 36 months (range 4 to 103). Results: Twenty aortofemoral, 3 aortoiliac, and 2 straight aortic graft infections were treated with excision and in situ replacement with standard polyester grafts in 16 patients (64%), or with rifampin-soaked collagen or gelatin-impregnated polyester grafts in 9 patients (36%). Fifteen patients (60%) had aortic graft enteric fistulas, 8 patients (32%) had abscesses or draining sinuses, and 2 patients (8%) had bacterial biofilm infections. Thirty-day mortality was 8% (2 of 25). There were no early graft occlusions or amputations. There was one late graft occlusion. There were no late amputations. The reinfection rate was 22% (5 grafts). All reinfections occurred in patients operated upon for occlusive disease. Only one reinfection occurred in the rifampin-soaked graft group (11% versus 29%, P = NS). Reinfection tended to be lower in patients with aortoenteric fistulas and without abscess. Autogenous tissue coverage provided statistically significant protection against reinfection. There were no late deaths related to in situ graft infection. Conclusions: Patients treated with in situ graft replacement had an 8% mortality and 100% limb salvage rate. Reinfection rates were similar to those of extra-anatomic bypass, but a trend of lower reinfection rates with rifampin-impregnated grafts was apparent. Patients with aortoenteric fistula and without abscess appear to be well treated by the technique of in situ prosthetic grafting and autogenous tissue coverage.

In situ replacement of infected vascular prostheses with rifampin-soaked vascular grafts: Early results

Based on the excellent results of experimental studies with antibiotic-bonded vascular prostheses for prevention of graft infection, gelatin-sealed grafts soaked with rifampin were implanted in situ in five patients with vascular infection. All patients were at risk for limb loss or death and could not be treated by standard techniques such as graft excision and extra-anatomic bypass. In one patient an infected aortic stump aneurysm with involvement of both renal and visceral arteries was found. He was treated by implantation of a bifurcation rifampin-soaked graft between the subdiaphragmal aorta and both renal arteries and reimplantation of celiac and superior mesenteric artery into the graft. In four patients with in-flow or runoff problems on angiography, an antibiotic-soaked graft was used for replacement of a partially or totally infected graft. Cultures were positive for Staphylococcus aureus in three and coagulase-negative staphylococci in two patients. Wound healing was uncomplicated; there was no need for amputation. After a follow-up of at least 6 months, all grafts were patent without any evidence of reinfection on computed tomographic scan. We conclude that infected vascular prostheses can be replaced in situ by rifampin-soaked grafts in patients at high risk for death or major amputation.

In situ replacement of infected vascular prostheses with rifampin-soaked vascular grafts: Early results

Based on the excellent results of experimental studies with antibiotic-bonded vascular prostheses for prevention of graft infection, gelatin-sealed grafts soaked with rifampin were implanted in situ in five patients with vascular infection. All patients were at risk for limb loss or death and could not be treated by standard techniques such as graft excision and extraanatomic bypass. In one patient an infected aortic stump aneurysm with involvement of both renal and visceral arteries was found. He was treated by implantation of a bifurcation rifampin-soaked graft between the subdiaphragmal aorta and both renal arteries and reimplantation of celiac and superior mesenteric artery into the graft. In four patients with in-flow or runoff problems on angiography, an antibiotic-soaked graft was used for replacement of a partially or totally infected graft. Cultures were positive for Staphylococcus aureus in three and coagulase-negative staphylococci in two patients. Wound healing was uncomplicated; there was no need for amputation. After a follow-up of at least 6 months, all grafts were patent without any evidence of reinfection on computed tomographic scan. We conclude that infected vascular prostheses can be replaced in situ by rifampin-soaked grafts in patients at high risk for death or major amputation.