Tiziano Curti

Prophylaxis of graft infection with rifampicinbonded Gelseal graft: 2-year follow-up of a prospective clinical trial

Between March 1991 and June 1992, 600 patients were treated with mono-, bifemoral or iliofemoral arterial graft revascularization for occlusions and/or aneurysms. The patients were divided into two groups: group A (n = 296) received a Gelseal Vascutek graft immersed for 15 min before implant in a solution containing 1 mg/ml rifampicin; group B (n = 304) received an untreated Gelseal Vascutek graft. Both groups received perioperative antibiotic treatment with cephalosporins. Clinical follow-up was performed at 1, 6, 12 and 24 months after surgery to exclude signs of graft infection. Statistical analysis (X(2)) of pre-, intra- and postoperative risk factors showed both groups to be well matched. Among 600 patients treated, the 2-year follow-up showed 12 cases of graft infection (2.0%): five in group A (1.7%) and seven in group B (2.3%) (P = n.s.). All cases of graft infection originated in the groin and Staphylococcus aureus was isolated in 50% of cases. Statistical analysis (Mann-Whitney U test) showed a significant prevalence of lymphatic complications and immediate redo surgery in patients with graft infection. Of the 12 cases with infection, one was lost to follow-up, three were treated with total graft removal, six with partial graft removal and two with conservative therapy: there were no deaths. In spite of the relatively limited series and follow-up, no statistically significant difference emerged from the clinical use of vascular grafts pretreated with antibiotics.

Platelet and coagulation factor variations induced in vitro by polyethylene terephthalate (Dacron®) coated with pyrolytic carbon

The haemocompatibility of polyethylene terephthalate (Dacron) coated with pyrolytic carbon was examined in vitro, evaluating its capability of inducing adhesion and platelet activation, and of modifying the intrinsic coagulation pathway. Platelet adhesion was evaluated by counting platelets before and after in vitro contact of human plasma with the material under examination. Platelet activation was evaluated by determining platelet factor 4 (PF4) and thromboxane B2. Intrinsic coagulation pathway alterations were studied by determining activated partial thromboplastin time (APTT) and the activity of single factors. The results obtained show that pyrolytic carbon-coated Dacron induces platelet adhesion, reduction in platelet volume and lower increase in thromboxane production than that obtained after contact with uncoated Dacron. Pyrolytic carbon-coated Dacron does not induce PF4 release, contrary to uncoated Dacron induces a significant release. Moreover, pyrolytic carbon-coated Dacron, induces a significant extension of APTT by reducing the activity of intrinsic pathway factors, particularly factor XI.

Endovascular Repair as First-Choice Treatment for Anastomotic and True Iliac Aneurysms

Purpose: To report our experience with the endovascular repair of iliac aneurysms secondary to aortoiliac bypass grafting. Methods: Thirteen patients (12 men; age range 62–86 years) with histories of aortoiliac reconstructions were treated with endovascular stent-grafts for 11 false and 2 true iliac aneurysms that averaged 5.2 cm in diameter (range 3.0–7.0). Via a percutaneous access and 9-F or 12-F sheaths, Passager or Wallgraft stent-grafts were delivered to exclude the aneurysms. Results: Twelve (92%) of 13 interventions were completed satisfactorily; 1 procedure for a true iliac aneurysm was converted to traditional bypass grafting. Two patients underwent additional surgical procedures. The average hospital stay for the patients with endovascular repairs only was 3 days (range 2–5). After a mean follow-up of 28 months (range 17–40), no complication or endoleak has been detected in any patient, and all endografts are patent. Conclusions: Endovascular repair is an effective treatment for secondary aneurysms arising after aortoiliac surgery. It is less invasive and involves a shorter hospital stay. Endovascular repair should be the first choice treatment for iliac aneurysms.

CASE REPORT: Endovascular Treatment of an Ilio-enteric Fistula: a “Bridge” to Aortic Homograft

Introduction adhering to the anterior surface of a right iliac anastomotic aneurysm. Having detached the ileal loop, Secondary aorto-enteric fistula is associated with sigan opening was detected in the aneurysmal wall revealing the iliac endograft without periprosthetic nificant morbidity and mortality. A fresh aortic homograft may not be immediately bleeding (Fig. 2A, B on page 206). The hypogastric artery was occluded by a thrombus. Ten centimetres available. Endovascular techniques have been used to treat of the ileal loop were resected. Macroscopic examination of the loop showed an ulceration with iliac pseudo-aneurysms and trauma with good immediate results. These procedures can also be applied granulation tissue. Dacron which was not incorporated was isolated and resected. A freshly prepared hoin an emergency to treat iliac-ureteral fistulae. mograft removed 48 h beforehand from an ABO compatible donor was implanted (Fig. 2C). Postoperative recovery was uneventful. Case Report Cultures from the prosthesis and endograft were positive for Candida albicans. A 59-year-old male presented with rectal bleeding, Contrast CT demonstrated satisfactory graft placehaving fainted at home. Three years previously he ment (Fig. 2D). had undergone repair of a ruptured abdominal aortic At 6 months the patient remains well, with no aneurysm with an aortobiiliac dacron graft. Contrast evidence of recurrent infection or homograft-related CT scan revealed a right iliac anastomotic aneurysm complications. with an intestinal loop adhering to its anterior wall (Fig. 1A). This was confirmed as arteriography. An endograft (Passager – 12 mm×10 cm) was positioned between Discussion the right limb of the graft and the external iliac artery, excluding the hypogastric artery and aneurysmal sac The endovascular technique arrested the bleeding but (Fig. 1B, C, D). Gastroduodenoscopy and colonoscopy did not, of course, eradicate the prosthetic infection. showed no bleeding part and a labelled white cell scan This only resolved once the prosthesis had been comwas negative. Three weeks later contrast CT showed pletely removed and replaced with a fresh ABO comcomplete exclusion of the aneurysmal sac but the patible aortic homograft. presence of gas. Blood culture was positive for StaphyThe successful treatment of the iliac-enteric fistula lococcus epidermis. was important because it allowed adequate preAt laparotomy a week later, an ileal loop was found paration for surgery and a subsequent wait for a compatible donor. ∗ Please address all correspondence to: T. Curti, Chirurgia Vascolare, Policlinico S. Orsola, Via Massarenti, 9, 40138 Bologna, Italy. However, in these circumstances, endovascular

An Ultrastructural and Immunocytochemical Analysis of Human Endothelial Cell Adhesion on Coated Vascular Grafts

Human adult endothelial cells were enzymatically harvested from adipose tissue. Cell viability was established by Trypan blue exclusion and transmission and scanning electron microscopy. Endothelial cells were identified by immunocytochemical investigation at light microscopy, transmission electron microscopy, and scanning electron microscopy. Isolated cells were positive for actin and vimentin, negative for desmin. Factor VIII RA was mainly expressed at cell surface and occasionally disclosed in the cytoplasm. Reactivity for UEA I and J15 was weak or undetectable. Human endothelial cells were seeded and left to adhere for one hour onto different nonvascular substrates (glass, poly-l-lysine, formvar-carbon, fibronectin, Teflon). Scanning electron microscopy defined surface features, suggesting tenacious cell adhesion on the substrate. Different vascular substrates were tested (preclotted Dacron, albumin Dacron, Hemashield Dacron, Gelseal Dacron, ePTFE, fibronectin-ePTFE). Commercially available coated grafts showed qualitative and quantitative differences in cell adhesion. In particular, Gelseal Dacron provided the best quantitative results, even though a wide variability was observed. In contrast, fibronectin-coated ePTFE gave more reliable results and high spreading efficiency. In the short term, coated grafts do not seem to offer greater advantages than fibronectin-coated ePTFE. However, specific incubation times for each coated graft should be selected and the long-term approach (graft culture) should also be attempted.

Electron Microscopic and Immunocyto- chemical Profiles of Human Subcutaneous Fat Tissue Microvascular Endothelial Cells

The ultrastructural and immunocytochemical characteristics of microvascular cells from human subcutaneous fat tissue were studied after the addition of collagenase and Percoll density gradient, respectively. Monoclonal and polyclonal antibodies directed against antigens specific for endothelial cells (factor VIII,Ulex europeaus, CD31, and CD34), pericytes (muscle-specific actin and desmin), adipocytes (S-100 protein), and monocytes-macrophages (MAC 387 and 150.95 protein) were demonstrated by alkaline phosphatase monoclonal antialkaline phosphatase and protein A-gold techniques. In addition, to determine whether the harvesting method interfered with microvascular cell function, DOT immunoassays of factor VIII and CD34 were conducted on solutions recovered at collagenase incubation as well as after nylon filtration and Percoll administration, respectively. After the collagenase step, the vast majority of microvascular cells had the typical ultrastructural and immunophenotypical features of endothelial cells. In sharp contrast, following the Percoll step, only 1% to 18% of microvascular cells stained with factor VIII,Ulex europeaus, and CD31, whereas 90% of them expressed the CD34 antigen. Surprisingly, DOT immunoassay revealed the presence of factor VIII in the washing buffer recovered after the Percoll step only. Consequently the decreased expression of common endothelial cell markers (factor VIII,Ulex europaeus, and CD31) observed at the end of the cell isolation procedure was related to the adverse effects of Percoll on endothelial cell function. The CD34 surface molecule, being highly resistant, is particularly well suited for unequivocal characterization of microvascular cells as true endothelium.

Case ReportCASE REPORT: Endovascular Treatment of an Ilio-enteric Fistula: a “Bridge” to Aortic Homograft

Introduction adhering to the anterior surface of a right iliac anastomotic aneurysm. Having detached the ileal loop, Secondary aorto-enteric fistula is associated with sigan opening was detected in the aneurysmal wall revealing the iliac endograft without periprosthetic nificant morbidity and mortality. A fresh aortic homograft may not be immediately bleeding (Fig. 2A, B on page 206). The hypogastric artery was occluded by a thrombus. Ten centimetres available. Endovascular techniques have been used to treat of the ileal loop were resected. Macroscopic examination of the loop showed an ulceration with iliac pseudo-aneurysms and trauma with good immediate results. These procedures can also be applied granulation tissue. Dacron which was not incorporated was isolated and resected. A freshly prepared hoin an emergency to treat iliac-ureteral fistulae. mograft removed 48 h beforehand from an ABO compatible donor was implanted (Fig. 2C). Postoperative recovery was uneventful. Case Report Cultures from the prosthesis and endograft were positive for Candida albicans. A 59-year-old male presented with rectal bleeding, Contrast CT demonstrated satisfactory graft placehaving fainted at home. Three years previously he ment (Fig. 2D). had undergone repair of a ruptured abdominal aortic At 6 months the patient remains well, with no aneurysm with an aortobiiliac dacron graft. Contrast evidence of recurrent infection or homograft-related CT scan revealed a right iliac anastomotic aneurysm complications. with an intestinal loop adhering to its anterior wall (Fig. 1A). This was confirmed as arteriography. An endograft (Passager – 12 mm×10 cm) was positioned between Discussion the right limb of the graft and the external iliac artery, excluding the hypogastric artery and aneurysmal sac The endovascular technique arrested the bleeding but (Fig. 1B, C, D). Gastroduodenoscopy and colonoscopy did not, of course, eradicate the prosthetic infection. showed no bleeding part and a labelled white cell scan This only resolved once the prosthesis had been comwas negative. Three weeks later contrast CT showed pletely removed and replaced with a fresh ABO comcomplete exclusion of the aneurysmal sac but the patible aortic homograft. presence of gas. Blood culture was positive for StaphyThe successful treatment of the iliac-enteric fistula lococcus epidermis. was important because it allowed adequate preAt laparotomy a week later, an ileal loop was found paration for surgery and a subsequent wait for a compatible donor. ∗ Please address all correspondence to: T. Curti, Chirurgia Vascolare, Policlinico S. Orsola, Via Massarenti, 9, 40138 Bologna, Italy. However, in these circumstances, endovascular

Traumatic Dissection in an Inflammatory Aneurysm

Primary dissections of the abdominal aorta are rare (0.4–4% of aortic dissections) and in most cases are traumatic (accidental or iatrogenic) in origin. The authors describe a case of iatrogenic dissection of the abdominal aorta following arteriography. The macroscopic and histological appearance of the aortic wall was compatible with an inflammatory aneurysm. In this type of aneurysm and in the presence of aortoiliac atherosclerosis, aortic catheterization carries a risk of aortic wall dissection.