Two-year results of a randomized controlled trial of rifampicin-bonded extra-anatomic dacron grafts

Successful surgical treatment of Stanford type A aortic dissection due to Salmonella aortitis

BACKGROUND

Salmonella spp. cause infectious aortitis through the hematogenous spread of an intestinal Salmonella infection. Salmonella aortitis can result in extensive tissue damage in the aorta leading to complications including dissection, abscess formation, pseudoaneurysms, and rupture, which require early diagnosis and treatment with both surgery and antibiotic therapy.

CASE PRESENTATION

We report a case of Salmonella aortitis complicated by Stanford type A aortic dissection. A 62-year-old man with a history of heroin use presented with chest pain, epigastric pain and vomiting. The computed tomography scan showed Stanford type A aortic dissection without malperfusion. At the time of surgery, an aortic dissection with purulent fluid and contained rupture was noted in the ascending aorta. Fluid culture was consistent with Salmonella. A composite valve-graft conduit aortic root replacement with ascending aorta and hemiarch replacement was performed. The patient recovered well and was discharged on long-term antibiotics.

CONCLUSIONS

This rare case of a Stanford type A aortic dissection with contained rupture due to Salmonella aortitis was successfully treated with emergent surgery and antibiotic therapy.

How to Prevent Surgical Site Infection in Vascular Surgery: A Review of the Evidence

BACKGROUND

This review aims to identify and review the current evidence for preventing postoperative surgical site infections in abdominal aortic aneurysm surgery or infrainguinal arterial surgery.

METHODS

Extended literature review of clinical trials that examined the prevention of postoperative surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. Searches were conducted on Ovid MEDLINE (1950 - 13 March 2020) using key terms for vascular surgery, surgical site infections and specific preventative techniques. Articles were included if they discussed a relationship between a preventative technique and surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. The GRADE guidelines were used to assess the quality of evidence.

RESULTS

21 techniques and 81 studies were included. Prophylactic antibiotics and negative pressure wound therapy have a high quality of evidence for the prevention of surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. A moderate quality evidence base was identified for gentamicin containing collagen implant (confined to high surgical site infection risk centers). Currently, there is a low or very low quality of evidence to suggest a reduction in the surgical site infection rate for combination therapy, glycaemic control, Methicillin-resistant Staphylococcus aureus screening and absorbable suture. Evidence suggests no beneficial effect for nutritional supplementation, chlorhexidine bath, hair removal therapy, Staphylococcus aureus nasal eradication, cyanoacrylate microsealant, silver grafts, rifampicin bonded grafts, triclosan coated suture and postoperative wound drains. Endoscopic saphenous vein harvest may reduce surgical site infection rate (very low quality of evidence) but may lower long-term patency. Autologous vein grafts may increase surgical site infections (very low quality of evidence) but may provide better long-term patency rates in above-knee infrainguinal bypass surgery. There was no identified evidence for perioperative normothermia, electrosurgical bipolar vessel sealer or Dermabond and Tegaderm for surgical site infection prevention in vascular surgery.

CONCLUSIONS

Prophylactic antibiotics and postoperative negative pressure wound therapy are effective in the prevention of postoperative surgical site infection in abdominal aortic aneurysm or infrainguinal arterial surgery. There exists a significant risk of bias in the literature for many preventative techniques and further studies are required to investigate the efficacy of gentamicin containing collagen implant, and specific combination therapies.

Pre-clinical in vivo Models of Vascular Graft Coating in the Prevention of Vascular Graft Infection: A Systematic Review

OBJECTIVE

Vascular graft infection (VGI) remains an important complication with a high mortality and morbidity rate. Currently, studies focusing on the role of vascular graft coatings in the prevention of VGI are scarce. Therefore, the aims of this study were to survey and summarise key features of pre-clinical in vivo models that have been used to investigate coating strategies to prevent VGI and to set up an ideal model that can be used in future preclinical research.

DATA SOURCES

A systematic review was conducted in accordance with the Preferred reporting items for Systematic Reviews and Meta-Analysis guidelines. A comprehensive search was performed in MEDLINE (PubMed), Embase, and Web of Science.

REVIEW METHODS

For each database, a specific search strategy was developed. Quality was assessed with the Toxicological data Reliability Assessment Tool (ToxRTool). The type of animal model, graft, coating, and pathogen were summarised. The outcome assessment in each study was evaluated.

RESULTS

In total, 4 667 studies were identified, of which 94 papers focusing on in vivo testing were included. Staphylococcus aureus was the organism most used (n = 65; 67.7%). Most of the graft types were polyester grafts. Rifampicin was the most frequently used antibiotic coating (n = 43, 48.3%). In the outcome assessment, most studies mentioned colony forming unit count (n = 88; 91.7%) and clinical outcome (n = 72; 75%). According to the ToxRTool, 21 (22.3%, n = 21/94) studies were considered to be not reliable.

CONCLUSION

Currently published in vivo models are very miscellaneous. More attention should be paid to the methodology of these pre-clinical reports when transferring novel graft coatings into clinical practice. Variables used in pre-clinical reports (bacterial strain, duration of activity coating) do not correspond well to current clinical studies. Based on the results of this review, a proposal for a complete and comprehensive set up for pre-clinical invivo testing of anti-infectious properties of vascular graft coatings was defined.

Vascular Graft Impregnation with Antibiotics: The Influence of High Concentrations of Rifampin, Vancomycin, Daptomycin, and Bacteriophage Endolysin HY-133 on Viability of Vascular Cells

Background

Rifampin-soaked synthetic prosthetic grafts have been widely used for prevention or treatment of vascular graft infections (VGIs).

This in vitro study investigated the effect of the antibiotics daptomycin and vancomycin and the new recombinant bacteriophage endolysin HY-133 on vascular cells, as potential alternatives compared to rifampin.

Material/Methods

Primary human ECs, vascular smooth muscle cells (vSMC), and fibroblasts were cultivated in 96-well plates and incubated with rifampin, daptomycin, vancomycin, and endolysin HY-133 for 24 h. Subsequently, after washing, cell viability was determined by measuring mitochondrial ATP concentration. Antibiotics were used in their corresponding minimum and maximum serum concentrations, in decimal multiples and in maximum soaking concentration. The experiments were performed in triplicate.

Results

The 10-fold max serum concentrations of rifampin, daptomycin, and vancomycin did not influence viability of EC and vSMC (100 μg/ml, p>0.170). Higher concentrations of rifampin (>1 mg/ml) significantly (p<0.001) reduced cell viability of all cell types. For the other antibiotics, high concentrations (close to maximum soaking concentration) were most cytotoxic for EC and vSMC and fibroblasts (p<0.001). Endolysin did not display any cytotoxicity towards vascular cells.

Conclusions

Results of this in vitro study show the high cytotoxicity of rifampin against vascular cells, and may re-initiate the discussion about the benefit of prophylactic pre-soaking in high concentrations of rifampin. Further studies are necessary to determine the influence of rifampin on the restoration of vessel functionality versus its prophylactic effect against VGIs. Future use of recombinant phage endolysins for alternative prophylactic strategies needs further investigations.

Xenopericardial self-made tube grafts in infectious vascular reconstructions: Preliminary results of an easy and ready to use surgical approach

PURPOSE

Infections are a major setback of vascular reconstruction and associated with considerable morbidity and mortality. We evaluated retrospectively our results with self-made bovine pericardial grafts in infected vessel revascularization versus standard graft material.

BASIC METHODS

Retrospective analysis of 9 patients with bovine reconstruction and 10 patients with miscellaneous grafts (vein, homograft) for vascular infections.

PRINCIPAL FINDINGS

Infection-free rate of the pericardial group was 100% in 17 months. For patients after reconstructions with miscellaneous grafts, the infection-free rate was 82% in 45 months. Overall in-hospital mortality was 10.5%. There were no in-hospital deaths in the pericardial group. Graft patency of the whole cohort was 100%. The median follow up was 11.74 months.

CONCLUSION

Self-made bovine pericardial tube grafts can be crafted to almost any size and adjusted to complex anatomic requirements. The use was feasible in various situations and was associated with good preliminary results concerning patency and reinfection.

New bacteriological patterns in primary infected aorto-iliac aneurysms: a single-centre experience

OBJECTIVES

To assess causative pathogens and surgical outcomes in patients with primary infected aorto-iliac aneurysms at our institution.

DESIGN

Retrospective study of patients treated at a university hospital between 1992 and 2009.

RESULTS

We identified 26 patients (median age, 63 years) with primary infected aneurysms on the aorta (descending thoracic, n = 2; thoraco-abdominal, n = 3; suprarenal, n = 2; infrarenal, n = 15) or iliac arteries (n = 4). Among them, 22 were symptomatic, including 13 with ruptured aneurysms. The causative organisms, identified in 25/26 patients, were Campylobacter fetus, n = 6; Streptococcus pneumoniae, n = 4; Listeria, n = 3; Salmonella, n = 2; Mycobacterium tuberculosis, n = 2; Staphylococcus aureus, n = 1; and other, n = 7. Immune suppression was a feature in 10 (38.4%) patients. Revascularisation was performed in situ in 23 patients (10 allografts, eight grafts, three superficial femoral veins, and 2 stentgrafts) and by extra-anatomic bypass in three patients. Hospital mortality was 23% (in situ group, 17.4%; extra-anatomic group, 66.7%; χ(2)(Yates), P = 0.24). During follow-up in the 20 survivors (median, 48.5 months), there were two non-infection-related deaths (five and 24 months) and six (30%) vascular complications.

CONCLUSIONS

The bacteriological spectrum of primary infected aorto-iliac aneurysms was wider than previously reported. The availability of new diagnostic tests and increased prevalence of immunosuppression may explain this finding.

Efficacy of collagen silver-coated polyester and rifampin-soaked vascular grafts to resist infection from MRSA and Escherichia coli in a dog model

The primary objective of this study was to compare the efficacy of a collagen silver-coated polyester graft, InterGard, with a gelatin-sealed graft, Gelsoft, both soaked in rifampin, for resistance to direct bacterial contamination in an animal model. The second objective was to confirm the lack of inflammation from silver acetate. Vascular grafts, 6 mm in diameter, were implanted in the infrarenal aorta of 28 dogs. Intravenous cefamandole (20 mg/kg) was injected intraoperatively in all dogs. The dogs were divided into three groups. Group I included 12 dogs. Six dogs received silver grafts and six dogs received gelatin-sealed grafts, all soaked with rifampin. Grafts implanted in group I were directly infected with methicillin-resistant Staphylococcus aureus (MRSA). Group II included also six silver grafts and six gelatin-sealed grafts, all soaked with rifampin. Dogs of group II were directly infected with Escherichia coli. Group III comprised four dogs, which received gelatin unsealed grafts, directly infected with MRSA, the control group. All dogs were followed by regular clinical examination, including blood cultures. Grafts in groups I and III and in group II were harvested at 30 days and 10 days, respectively. Bacterial analyses were performed on the explanted grafts. Histology was performed on both the tissue samples and the anastomotic sites of the harvested grafts. In group I, no grafts were infected with MRSA, irrespective of graft type. In group II, no silver grafts were infected with E. coli, whereas one (16.6%) of six gelatin-sealed grafts was infected (p = 0.317). In group III, three (75%) of the four grafts were infected with MRSA. The infection rate in the silver grafts and the gelatin-sealed grafts soaked in rifampin in group I compared with the unsealed gelatin grafts in group III was statistically significantly different (p < 0.05). There was no statistically significant difference in the inflammation score, obtained by histological analysis, between rifampin-soaked silver and Gelsoft grafts in either group I or group II. There were signs of necrosis at the anastomoses in three (25%) gelsoft grafts of 12 in groups I and II. There were no clinical or biological signs of inflammation from use of silver-coated grafts. These results indicate that collagen silver-coated grafts and gelatin-sealed grafts, both soaked in rifampin, provide resistance against MRSA and E. coli. There was a trend toward better resistance but without statistical significance against E. coli from the rifampin silver graft compared with the rifampin-soaked Gelsoft graft, without signs of inflammation from InterGard silver grafts.

Prosthetic Vascular Conduit in Contaminated Fields: A New Technology to Decrease ePTFE Infections

Vascular reconstruction using prosthetic materials in contaminated fields can lead to infection, graft loss, and subsequent amputation. We hypothesized that minocycline and rifampin bound to an ePTFE graft using a unique methacrylate technology would provide for resistance from infection and controlled antibiotic elution. Kirby Bauer susceptibility testing was performed on plates overlaid with Staph aureus (SA) and Staph epidermidis (SE) using 6 mm diameter discs of uncoated graft or antibiotic coated graft (ABX). Zones of inhibition (ZIH) were determined after 24 hours. ABX grafts were then placed in a continuous water bath and a recirculating, pulsatile flow device. Susceptibility testing and high performance liquid chromatography with mass spectroscopy was performed to determine graft performance and antibiotic elution rate. ABX grafts had an average ZIH of 35 mm for SA and 44 mm for SE (each P < 0.0001). After the 1 week water bath, the ZIH of the ABX grafts was 23 mm on both the SA and SE plates. The high performance liquid chromatography with mass spectroscopy revealed that after 24 hours, 50 per cent of the antibiotics remained on the graft, and there was a sustained elution for 7 days. Minocycline and rifampin can be bound to ePTFE vascular grafts using a unique methacrylate method. In vitro, the grafts provide a slow elution of antibiotics that provide resistance from infection by SA and SE for up to 2 weeks after graft insertion.

Endovascular Repair of an Actively Hemorrhaging Aortoduodenal Fistula

Aortoenteric fistulae require urgent definitive intervention and traditionally carry a high mortality. We describe a patient who suffered a traumatic aortic dissection following an auto versus pedestrian collision. He underwent open fenestration of his infrarenal aorta and visceral resection, complicated by abdominal sepsis and enterocutaneous fistulae. One month later he developed massive hematemesis, and endoscopic examination revealed an aortoduodenal fistula. Due to an impassable abdominal wall, a stent-graft repair was performed. This report describes the successful use of endovascular techniques to achieve immediate hemostasis in an actively hemorrhaging aortoduodenal fistula. An endovascular approach provides a valuable option in settings where a hostile abdomen precludes the traditional open technique and may serve as a bridge to later definitive repair.

Prevention of infection in peripheral arterial reconstruction: A systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review and meta-analysis was to determine the effectiveness of perioperative strategies to prevent infection in patients undergoing peripheral arterial reconstruction.

METHODS

All randomized controlled trials (RCTs) evaluating measures intended to reduce or prevent infection in arterial surgery were identified through searches of the Cochrane Peripheral Vascular Diseases Group specialized trials register, the Cochrane Central Register of Controlled Trials (CENTRAL), and reference lists of relevant articles. Two authors independently selected and assessed the quality of included trials. Relative risk (RR) was used as a measure of effect for each dichotomous outcome.

RESULTS

The study included 34 RCTs. Of these, 22 were trials of prophylactic systemic antibiotics, 3 of rifampicin-bonded grafts, 3 of preoperative skin antisepsis, 2 of suction wound drainage, 2 of minimally invasive in situ bypass techniques, and individual trials of intraoperative glove change and wound closure techniques. Wound infection or early graft infection outcomes were recorded in all trials. Only two trials, both of rifampicin bonding, followed up graft infection outcomes to 2 years. Prophylactic systemic antibiotics reduced the risk of wound infection (RR, 0.25; 95% confidence interval [CI], 0.17 to 0.38) and early graft infection in a fixed-effect model (RR, 0.31; 95% CI, 0.11 to 0.85, P = .02). Antibiotic prophylaxis for >24 hours appeared to be of no added benefit (RR, 1.28; 95% CI, 0.82 to 1.98). There was no evidence that prophylactic rifampicin bonding to Dacron grafts reduced graft infection at 1 month (RR, 0.63; 95% CI, 0.27 to 1.49), or 2 years (RR, 1.05; 95% CI, 0.46 to 2.40). There was no evidence of a beneficial or detrimental effect on rates of wound infection with suction groin wound drainage (RR, 0.96; 95% CI, 0.50 to 1.86) or from preoperative bathing with antiseptic agents compared with unmedicated bathing (RR, 0.97; 95% CI, 0.70 to 1.36).

CONCLUSIONS

There is clear evidence of the benefit of prophylactic broad-spectrum antibiotics for vascular reconstruction. Many other interventions intended to reduce the risk of infection in arterial reconstruction lack evidence of effectiveness.

InterGard silver bifurcated graft: Features and results of a multicenter clinical study

OBJECTIVES

Recent research in vascular surgery has focused on development of infection-resistant prosthetic grafts. This article describes the results of a multicenter study to evaluate safety, patency, and infection rates after implantation of the InterGard Silver bifurcated polyester graft coated with collagen and silver.

METHODS

Between October 2000 and February 2002, 289 consecutive patients were implanted with a collagen and silver acetate-coated polyester bifurcated graft at 16 French vascular surgery centers. Mean patient age was 65.3 +/- 10.9 years. The indication for prosthetic bypass was aortic aneurysm in 160 patients (55.4%) and symptomatic aortoiliac occlusive disease in 129 (44.6%). All but four patients received prophylactic antibiotic therapy. Patency was assessed at 30 days, 1 year, 2 years, and 3 years, primarily by duplex scan.

RESULTS

Two patients (0.7%) died during the first 30 days. Median duration of hospitalization was 11 days. The Kaplan-Meier survival rate at 3 years was 85.7% +/- 4.1%. Primary and secondary patency rates at 3 years were 94.9% +/- 2.6% and 97.5% +/- 1.8%. Thrombectomy was performed successfully in seven patients, and a major amputation was required in two patients with patent grafts. Postoperative complications, including 39 nosocomial infections, were observed in 107 patients (37.0%). Eleven patients presented with 12 wound infections that were classified Szilagyi grade I in eight cases, grade II in two cases, and grade III with graft infection in two cases (0.7%). Among the 149 patients undergoing aortofemoral bypass, eight (5.4%) presented with wound infection, including two graft infections (1.3%). Among the 140 patients undergoing aortoiliac bypass, only three patients (2.1%) presented wound infection and none with graft infection (P = .15). Three (16.7%) of 18 patients who had undergone previous femoral revascularization and eight (3%) of 271 patients without previous femoral revascularization presented with wound infection. This difference was statistically significant (P = .03), with a relative risk of 5.6 (95% confidence interval [CI], 1.6 to 19.5). Five (11.9%) of 42 diabetic patients and six (2.4%) of 247 nondiabetic patients presented with wound infection. This difference was also statistically significant (P = .01), with a relative risk of 3.4 (95% CI, 1.7 to 6.9). Lymphorrhea or lymphocele developed in the groin of 25 patients (8.6%) with negative culture.

CONCLUSION

This multicenter prospective study shows that the InterGard Silver graft is safe with no side effects. The primary patency rate was excellent, and the graft infection rate was low, despite a high incidence of nosocomial infections.

Prevention of infection in arterial reconstruction

BACKGROUND

Arterial reconstructions with prosthetic graft materials or vein are susceptible to infection with a resultant high patient mortality and risk of limb loss. To reduce the risk of infection effective perioperative measures are essential.

OBJECTIVES

To determine the effectiveness of perioperative strategies to prevent infection in patients undergoing peripheral arterial reconstruction.

SEARCH STRATEGY

We searched the Cochrane Peripheral Vascular Diseases Group trials register (last searched May 2006) and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched Issue 2, 2006), and reference lists of relevant articles.

SELECTION CRITERIA

All randomised controlled trials (RCTs) evaluating measures intended to reduce or prevent infection in arterial surgery.

DATA COLLECTION AND ANALYSIS

AS and PSE independently selected and assessed the quality of included trials. Relative risk was used as a measure of effect for each dichotomous outcome.

MAIN RESULTS

Thirty-five RCTs were included. Of these, 23 were trials of prophylactic systemic antibiotics, three of rifampicin-bonded grafts, three of preoperative skin antisepsis, two of suction wound drainage, two of minimally invasive in situ bypass techniques, and individual trials of intraoperative glove change and wound closure techniques. Wound infection or early graft infection outcomes were recorded in all trials. Only two trials, both of rifampicin bonding, followed up graft infection outcomes to two years. Trials of antibiotics versus placebo were of highest quality with six double-blind studies of the ten included. Prophylactic systemic antibiotics reduced the risk of wound infection (Relative Risk (RR) 0.25, 95% Confidence Interval (CI) 0.17 to 0.38) and early graft infection in a fixed-effect model (RR 0.31, 95% CI 0.11 to 0.85, P = 0.02). Antibiotic prophylaxis for greater than 24 hours appears to be of no added benefit (RR 1.28, 95% CI 0.82 to 1.98). There was no evidence that prophylactic rifampicin bonding to dacron grafts reduced graft infection at either one month (RR 0.63, 95% CI 0.27 to 1.49) or two years (RR 1.05, 95% CI 0.46 to 2.40). There was no evidence of a beneficial or detrimental effect on rates of wound infection with suction groin-wound drainage (RR 0.96 95% CI 0.50 to 1.86) or of any benefit from a preoperative bathing or shower regimen with antiseptic agents over unmedicated bathing (RR 0.97, 95% CI 0.70 to 1.36).

AUTHORS' CONCLUSIONS

There is clear evidence of the benefits of prophylactic broad spectrum antibiotics. Many other interventions intended to reduce the risk of infection in arterial reconstruction lack evidence of effectiveness.