Unusual inflammatory responses around a collagen-impregnated vascular prosthesis

Endotoxin, not DNA, determines the host response and tissue regeneration behavior of acellular biologic scaffolds

Established quantitative standards for assessing decellularization of biologic scaffolds based on residual DNA levels have been well-documented and widely acknowledged. However, post-implantation complications, such as fever and seroma, are commonly observed which negatively impact clinical outcomes. The presence of cellular debris following decellularization or using source tissues that are naturally high in endotoxin may contribute to the host response to a biologic scaffold. In the study, several multi-step decellularization methods were used to decellularize small intestinal submucosa (SIS) to obtain materials with three distinct levels of residual DNA, lipid residues, and endogenous endotoxin. The potential influence of these residual components on macrophage and lymphocyte polarization in vitro, as well as on the host inflammatory response in vivo post intra-abdominal implantation or abdominal wall defect repair in rats, was assessed. Urinary bladder matrix (UBM) meeting established decellularization criteria and naturally devoid of endotoxin was utilized as a control. The presence of endogenous endotoxin in SIS-ECM resulted in notable changes in macrophage phenotype. SIS-ECM samples with endotoxin levels below FDA limits still upregulated pro-inflammatory factors in vitro. Conversely, SIS with minimal endotoxin content and UBM controls prompted a shift towards a pro-remodeling M2 phenotype, fostering constructive tissue remodeling in a rodent model of abdominal wall defects, irrespective of DNA content. These findings suggest that endotoxin may be a crucial factor influencing biologic scaffolds that are not fully accounted by current decellularization standards. STATEMENT OF SIGNIFICANCE: Clinically utilized decellularized biologic scaffolds that meet the established quantitative standards still suffer problems in high incidence of inflammatory complications, including fever and seroma. In this study, we confirmed that endotoxin, rather than residual DNA, is the crucial factor influencing host responses and regenerative outcomes. Tissue sources and decellularization processes are critical for reducing endotoxin levels and attenuating immuno-inflammatory complications. These findings enhance the evaluation of ECM scaffold performance for clinical application, thereby facilitating improved preparation and utilization for tissue defect repairs.

Expanding perigraft seroma after ascending aorta replacement

Background

Perigraft seroma is a persistent and sterile fluid confined within a fibrous pseudomembrane surrounding a graft that develops after graft replacement. Development of perigraft seroma is an uncommon complication that occurs after the surgical repair of the thoracic aorta using woven polyester grafts. mechanism underlying perigraft seroma formation remains unclear.

Case presentation

Herein, we describe the case of 77-year-old man who underwent repeat sternotomy for the treatment of large perigraft seroma 1 year after ascending aorta replacement for acute type A dissection. After removing a cloudy yellow fluid, we covered the prosthetic graft with fibrin glue and wrapped it with a new graft. Bacterial culture and laboratory examination of the fluid confirmed the final diagnosis of perigraft seroma, and there was no evidence of recurrence. The area in which fluid accumulated around the graft shrunk 1 year after surgery.

Conclusions

The cause of a expanding perigraft after repair of the thoracic aorta remains unknown. Physicians should be aware that chronic expanding mediastinal seroma with Dacron grafts is one of the rare postoperative complications of thoracic aortic surgery. Applying fibrin glue to the graft surface might effectively prevent the recurrence of perigraft seroma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-022-02018-y.

Eight-year experience with cryopreserved arterial homografts for the in situ reconstruction of abdominal aortic infections

OBJECTIVE

This study investigated short-term and long-term outcomes in patients with abdominal aortic infection (mycotic aneurysm, prosthetic graft infection, aortoenteric fistula) managed by total excision of the aneurysm or the infected vascular graft and in situ aortic reconstruction with a cryopreserved arterial homograft (CAH).

METHODS

From January 2000 to December 2008, 110 consecutive patients underwent CAH implantation for treatment of vascular infections. In 57 (52%), in situ revascularization of the abdominal aorta with Y-prosthesis constructed from CAHs was performed. Early outcome included 30-day mortality and the levels of daily blood markers (leucocytes, C-reactive protein, and platelets) during the postsurgical 10-day period. We reported long-term survival and freedom from reoperation rates, including all indications for reoperation.

RESULTS

Indications for operation were infected vascular graft in 31 patients (55%), aortodigestive fistulae in 11 (19%), nonruptured mycotic aneurysms in 4 (7%), and ruptured mycotic aneurysms of abdominal aorta in 11 (19%). In 39 of 57 patients (68%), the intraoperative specimens were positive for at least one microorganism, and Staphylococcus aureus was present in 14 (25%). In 32 patients (82%) with intraoperative specimens positive for microorganisms, there was no evidence of the intraoperatively detected microorganisms in the postoperative specimens (wound, blood culture, and drainage fluid). The peak value of leucocytes (13.7 +/- 4.4 x 10(3)/L) and C-reactive protein (200 +/- 75 mg/L) occurred on postoperative day 3. Platelets reached the lowest value on postoperative day 2 (178 +/- 67 x 10(9)/L). Median peak body temperature was 37.7 degrees +/- 0.6 degrees C. Thirty-day mortality was 9% (5 of 57 patients). Median follow-up was 36 months (range, 4-118 months); 3-year survival was 81%, and freedom from reoperation was 89%. Five patients (9%) required reoperation, in one patient each for postoperative bleeding, acute cholecystitis, homograft occlusion, homograft-duodenum fistula, and aneurysmal degeneration. No recurrence of infection was reported.

CONCLUSION

These results demonstrate an encouraging outcome after cryopreserved allograft implantation for the treatment of vascular infections in the abdominal aorta. The data represent a basis for future comparisons with other treatment modalities for vascular infections, including silver-coated prostheses and autogenous femoral veins.

Diagnostics of "non-acute" vascular prosthesis infection using 18F-FDG PET/CT: our experience with 96 prostheses

INTRODUCTION

Vascular prosthesis infection (VPI) is a life-threatening complication that occurs in 0.5-5% of prostheses. Low-grade infections in non-acute patients are a diagnostic challenge requiring a new method with good diagnostic accuracy. The aim of this work was to define the accuracy of (18)F-FDG PET/CT in these settings and to identify essential parameters of the evaluation.

MATERIAL AND METHODS

PET/CT was performed prospectively in 76 consecutive patients with a total of 96 vascular prosthetic grafts in which infection was suspected. PET/CT scans were analysed in terms of the presence and intensity of focal and diffuse FDG uptake, the presence of an anastomotic pseudoaneurysm, the presence of an irregular boundary of infiltration, a combination of these, and the uptake ratio between the graft and blood background. The gold standard was based on operative/histopathological finding or a clinical follow up of >6 months.

RESULTS

Among the various assessed parameters only focal FDG uptake and an irregular graft boundary were significant predictors of VPI. Focal intense FDG uptake together with an irregular boundary of the lesion on CT scan predicted VPI with 97% probability, while smooth lesion boundaries and no focal FDG uptake predicted a probability of VPI of less than 5%. Even in lesions with nondiagnostic inhomogeneous focal FDG uptake (18/96) an irregular boundary effectively helped in decision-making with a probability of 28% (smooth) or 77% (irregular) for VPI.

CONCLUSION

PET/CT gave reliable results with an accuracy >95% in 75% of prostheses. PET/CT can identify those prostheses (25% of prosthesis) for which its diagnostic accuracy is diminished to 70-75%. In our series PET/CT was an excellent diagnostic modality for suspected VPI.

Evaluation of the biocompatibility of a new vascular prosthesis coating by detection of prosthesis-specific antibodies

In recent experimental studies, we could demonstrate the occurrence of antibodies against the prosthesis matrix and coating following implantation of polyester-based vascular grafts. Therefore, this study aimed at evaluating the biocompatibility of a new absorbable polymer coating by detection of antibodies against the coating and the polyester matrix. Two polyester vascular prostheses coated either with the polymer (PP-prosthesis) or with gelatine (PG-prosthesis) were functionally implanted into sheep (n = 22 per group). Blood was drawn on days 1 (pre-OP) and 7, 14, 28, 56, 84, 140 (post-OP). Homogenates from both prostheses (PP-target or PG-target) or from an uncoated prosthesis (P-target) were used as assay targets in a particle-based immunoassay. The antibody binding against the P-target was significantly higher in the PP-group than in the PG-group on days 7-56, but not on days 84 and 140. Within both groups, no significant differences but a significant correlation between the binding against the P-target and the coated target was found. Therefore, the absorbable polymer did not induce a specific humoral immune response. In conclusion, the overall immunogenicity of the polymer-coated graft was comparable to the gelatine-coated graft. The detection of prosthesis-specific antibodies seems to be useful for in vivo biocompatibility testing.

CT Appearance of Thoracic Aortic Graft Complications

OBJECTIVE

The purpose of this study was to document the spectrum of CT findings and the clinical outcome of thoracic aortic graft complications.

CONCLUSION

Aortic graft complications detected with CT may or may not be clinically apparent and/or relevant. CT characterization in combination with clinical findings helps to determine patient treatment.

In vitro pyrogen test—A new test method for solid medical devices

Medical devices manufactured for implantation into humans must be free of any contamination with viable bacteria. However, remnants of dead bacteria and bacterial components alone may induce an inflammatory immune response. Pyrogen tests for such inflammatory contaminations are generally performed either by determining the content of lipopolysaccharide in rinsing solutions of batch samples by limulus amoebocyte lysate assay, by injecting the rinsing solutions into rabbits or by implanting batch samples into rabbits and measuring change of body temperature. In this study, we show that the in vitro pyrogen test (IPT), which measures the release of the inflammatory cytokine IL-1beta in fresh or cryopreserved human whole blood, can be used to assess the pyrogenic contamination of implantable medical devices. This test was used to check neurosurgical implants, namely aneurysm clips, as a proof of principle. Owing to the direct contact of the test material with the blood cells, this test does not require rinsing procedures, which have variable efficacy. The use of human blood ensures the detection of all substances that are pyrogenic for humans and reflects their relative potency. The safety of the products as delivered could be confirmed. The effects of sterilization and depyrogenization procedures on intentional pyrogenic contaminations of samples could be followed. This new application of the already internationally validated method promises to replace further rabbit pyrogen tests. It generates extremely sensitive results with an extended range of detectable pyrogenic contaminants.

Endotoxin contamination in wound dressings made of natural biomaterials

Contamination by endotoxin of nine kinds of wound dressings made of natural biomaterials (calcium alginate, collagen, chitin, and poly-L-leucine) was examined with the use of water extracts. By applying the Limulus amoebocyte lysate (LAL) test, high concentrations of endotoxin were detected in extracts from three kinds of products made of calcium alginate. These extracts evoked fever in rabbits and induced the release of a proinflammatory (pyrogenic) cytokine, interleukin-6 (IL-6), from human monocytic cells (MM6-CA8). The effects disappeared when the extracts were treated with endotoxin-removing gel column chromatography or with an endotoxin antagonist, B464, confirming that the contaminating pyrogen was endotoxin. A noteworthy finding was that one of the endotoxin-containing extracts showed very weak IL-6-inducibility in human monocytic cells in contrast to its high pyrogenicity to rabbits. The discrepancy could be explained based on differences between humans and rabbits in sensitivity to the endotoxin, because the extract showed higher proinflammatory-cytokine (TNF-alpha)-inducibility in rabbit whole-blood cells (WBCs) than human WBCs. The results suggest that the LAL test is a useful method of detecting endotoxin contamination in wound dressings and the MM6-CA8 assay is a good supplement to the LAL test for evaluating pyrogenicity in humans accurately.

Immunogenicity of polymeric implants: long-term antibody response against polyester (Dacron) following the implantation of vascular prostheses into LEW.1A rats

Implanted biomaterials trigger acute and chronic inflammatory responses directly correlated to the central role of phagocytic cells at the host-implant interface. This study was designed to evaluate specific humoral immune responses following repeated intraperitoneal implantations of collagen-impregnated polyester (Dacron) prosthetic segments into LEWIS rats. Serum antibody detection was performed by enzyme immunoassay with the prosthetic segments as a target. Cutoff values for antibody positivity were greater than or equal to the 99th percentile for control rats. Polymer immunoglobiulin G (IgG) antibodies were significantly increased (p < 0.05) by repeated implantation and were subsequently followed until experimental day 293. Antibody formation was significantly enhanced through the application of complete Freund's adjuvant in combination with the first implantation. All rats within this group were antibody-positive on day 53, but only 6 of 10 animals that received the prosthesis without the adjuvant were. After preincubation of sera with bovine collagen type I (solid phase adsorbed or in solution), polymer antibody binding was discovered not to be diminished, indicating that the IgG antibodies detected were not directed against the prosthesis impregnation. Furthermore, a significant correlation was obtained between polymer antibody binding to collagen-impregnated and nonimpregnated prostheses (r(s) = 0.797, p < 0.001). There was no substantiated correlation between antibody binding to polyester and to an irrelevant polymer (Tecoflex EG 80). We conclude that specific polymer antibodies may indeed provide an additional parameter for biocompatibility testing as well as a possible serological marker of an inflammatory response to implants.

Cytotoxicity of glutaraldehyde crosslinked collagen/poly(vinyl alcohol) films is by the mechanism of apoptosis

Collagen has been investigated as a potential natural biomaterial, because of its occurrence in the extracellular matrix. Collagen requires crosslinking in this context, by reagents that are often cytotoxic. Glutaraldehyde is one such agent that is potentially cytotoxic. The aim of this study was to determine the cause of poor cell attachment and growth on collagen/poly(vinyl alcohol) bioartificial composite films, when crosslinked with glutaraldehyde. Dehydrothermal crosslinking was used as a comparison. Human osteoblasts were observed to undergo apoptosis on glutaraldehyde crosslinked films dependent on concentration of collagen present. Higher collagen content resulted in higher levels of apoptosis with poor cell attachment and spreading of remaining cells. Post-treatment of films with 8% L-glutamic acid prevented the apoptotic response of osteoblasts and allowed attachment and spreading. The addition of 100 nM insulin-like growth factor-1 to the culture medium also prevented apoptosis. Glutaraldehyde toxicity of crosslinked collagen has been demonstrated in this study, the mechanism of which is apoptosis. This study indicates that poor biocompatibility and induction of apoptosis on collagen/poly(vinyl alcohol) films crosslinked by glutaraldehyde are attributed to glutaraldehyde components on the surface of the films (not residual glutaraldehyde), whose effects can be quenched by glutamic acid, and prevented by insulin-like growth factor-1.

Antigenicity of Polyester (Dacron) Vascular Prostheses in an Animal Model

Objectives to investigate the specific humoral immune response to three different polyester (Dacron) prostheses in pigs. Design, materials and methods twenty-four growing pigs were randomly divided into three groups. The infrarenal aorta was replaced by a segment of collagen-impregnated woven polyester prosthesis (low, medium and high porosity). Serum antibodies were detected by modified enzyme immunoassay using non-impregnated prosthesis as the target for the blood samples taken on experimental days 1, 10, 17, 24, 62 and 116 of the 22 pigs followed over the whole observation period. Results significantly enhanced (p <0.05) mean IgG antibody binding against polyester was detected on experimental days 10, 17, 24 and 62 with antibody prevalences of 41%, 41%, 32% and 37%, respectively. Antibody positive pigs were divided into early responders (n =9) and late responders ( n =5) with antibody detection on day 10 and/or 17 vs day 62 and/or 116. No significant differences between the three different prostheses were found. The formation of specific IgG antibodies against polyester in the animals investigated demonstrates a broad individual variability. Conclusions polyester is an antigenic polymer. Specific antibodies, reflecting the inflammatory response, might be not only a parameter for testing biomaterials but also for determining individual bio(in)compatibility for long-term biomaterial function.

Hemashield implantation in young patients with congenital cardiovascular lesions

BACKGROUND

There is substantial controversy regarding the use of Hemashield in young patients.

METHODS

Twenty-one consecutive patients younger than 20 years of age with a variety of congenital cardiovascular lesions underwent surgical procedures using a Hemashield woven graft. Hemashield was used for reconstruction of the aortic wall (n = 16), ventricular septum (n = 10), and right ventricular free wall or pulmonary artery (n = 6).

RESULTS

A sterile inflammatory reaction was observed including high fever, increased white cell count, and elevated plasma C-reactive protein concentration for up to 4 weeks after implantation. Multivariable analysis identified the use of Hemashield in the right ventricular free wall or pulmonary artery as an incremental risk factor for elevation of plasma C-reactive protein concentration during the first 3 weeks after implantation (p = 0.002). There were no midterm complications including restenosis of the grafts in the right ventricular outflow tract.

CONCLUSIONS

Hemashield can be used in a variety of situations for reconstruction of congenital cardiovascular lesions in young patients. Impregnated collagen can cause a significant systemic inflammatory reaction for several weeks after implantation, especially when used in the low-pressure right heart.

Bovine type I collagen as an endovascular stent-graft material: biocompatibility study in rabbits

PURPOSE

To study the biocompatibility of a bovine type I collagen preparation as a material for small-vessel stent-grafts in rabbits.

MATERIALS AND METHODS

A composite nitinol-collagen endovascular stent-graft with a 4-mm inner diameter was deployed in the abdominal aorta in nine rabbits. Angiography was performed, and the rabbits were sacrificed at 1, 2, and 7 days and at 1 and 3 months. The portion of the aorta containing the stent-graft was excised and was histologically evaluated.

RESULTS

All stent-grafts were patent at all time points. On days 1, 2, and 7 after implantation, scattered red and white blood cells adhered to the stent-graft. At 1 month, the stent-graft was endothelialized and was infiltrated with fibroblasts that deposited collagen within the interstices of the implanted collagen material. At 3 months, there was additional collagen deposition within the interstices of the stent-graft that did not narrow the lumen of the stent-grafts.

CONCLUSION

Type I collagen as a intravascular stent-graft material is biocompatible for at least 3 months in rabbits. It is rapidly endothelialized and does not cause reactive stenosis. As a versatile and biocompatible polymer, collagen is potentially useful in the construction of endovascular stent-grafts for use in human arteries.

Measurement and removal of adherent endotoxin from titanium particles and implant surfaces

Aseptic loosening is thought to be due primarily to osteolysis induced by cytokines and prostaglandins that are produced in response to implant-derived wear particles. Because endotoxin has many of the same effects as have been reported for wear particles, we hypothesized that adherent endotoxin may be responsible for the biological responses induced by wear particles. We demonstrated the presence of significant levels of adherent endotoxin on commonly used preparations of titanium particles as well as on titanium and titanium-alloy implant surfaces. In contrast, supernatants obtained by centrifugation of particle suspensions contained approximately 1% as much endotoxin as did the particles. Therefore, it is erroneous to assume that particles do not contain endotoxin on the basis of data that it cannot be detected in their supernatants or filtrates. These results emphasize the importance of considering the potential role of adherent endotoxin when examining the in vitro effects of wear particles and the in vivo performance of orthopaedic implants. We also developed a protocol that removed more than 99.94% of the adherent endotoxin from the titanium particles without detectably affecting their size or shape. The removal of adherent endotoxin will allow comparison of the biological responses induced by particles with or without adherent endotoxin.

Impregnated polyester arterial prostheses: performance and prospects

Impregnated polyester arterial prostheses have gained wide acceptance by most vascular surgery teams, probably because these prostheses are easy to use, without any preclotting. We offer here a synthesis of the main studies that have appraised the experimental and clinical performance of these prostheses, and we delineate their major prospects.

Succinylated collagen crosslinked by thermal treatment for coating vascular prostheses

Vascular prostheses coated with collagen carefully prepared to avoid contamination were tested to see if it could induce endothelial cell lining throughout the graft surface in a natural way. The collagen fibers were succinylated. Hydrogel produced with the succinylated collagen was used for the sealant to reduce the amount of solid substance. To avoid contamination and the side effects of chemical reagents, the collagen thermally crosslinked under sterile conditions. A suspension of the collagen fibers was enmeshed in the interstices of Dacron fibers of fabric prostheses, which were then thermally crosslinked at 130 degrees C for 20 h. The prostheses were porous when the collagen fiber network was dry. Under wet conditions, however, the water permeability of the grafts was reduced to 0.1 ml/min from the 1,250 ml/min of the original prostheses. Three weeks after implantation in the abdominal aortas of dogs, 81.2 +/- 11% of the luminal surface was macroscopically thrombus free, and 56 +/- 14% was endothelialized. More than 95% of the coated collagen had been absorbed. Numerous fibroblasts had migrated into the graft walls, and capillary blood vessels had infiltrated the inside of the graft walls without foreign body reaction. In the controls, thrombus free areas averaged 9.0 +/- 5%, and endothelialized areas averaged 5.2 +/- 4%. Many giant cells, plasma cells, and lymphocytes had migrated into the graft walls, but no fibroblasts. These results suggest that rapid endothelialization is possible when clean collagen is used.

Myristoyl gelatin as a sealant for Dacron vascular prostheses

Myristoyl gelatin (MG) retains its gel structure at temperatures above body temperature without any crosslinking. As a coating material, MG adheres well to polyester fibers, and the outermost layers of the sealant that are in contact with blood or surrounding tissue become hydrophilic. We produced MG-impregnated knitted Dacron vascular prostheses (MG graft [MGG]) and investigated the usefulness of MG as a sealant by replacing the thoracic aorta of dogs. MGGs (5 cm long with an inner diameter of 10 mm) were implanted in 5 mongrel dogs (10-20 kg), and the grafts were retrieved at intervals of 4 h and 2, 4, 8, and 15 weeks after grafting. There was no thrombus formation on the flow surface of the MGGs, indicating adequate antithrombogenic properties. No resorption of MG occurred until after 2 weeks, and neither immune reaction nor excessive foreign body reaction was noted. Fragmentation of the sealant induced by cell infiltration began to occur at 4 weeks, yet the sealing effect persisted. The organization of MGG was almost complete at 8 weeks. Because of its pliability and effective adhesion to polyester fibers, its antithrombogenicity, and the persistent sealing effect due to delayed biodegradation and resorption, we conclude that MG is an extremely useful sealant for polyester vascular prostheses.

Eradication of aortic infections with the use of cryopreserved arterial homografts

BACKGROUND

The surgical treatment of vascular infection is associated with a substantial early and late mortality. Cryopreserved homografts were evaluated for in situ reconstruction in aortic infections.

METHODS

Between January 1991 and July 1995, homografts were used in 19 patients (mean age, 61 +/- 13 years; range, 40-85 years) with mycotic aneurysms (9/19; 47%) or infected grafts (10/19; 53%) in the thoracic (7/19; 37%) or abdominal (12/19; 63%) aorta. Sepsis was present preoperatively in 14 of 19 (74%) patients, and 18 of 19 (95%) had received antibiotic treatment for 6.4 +/- 6 months (range, 1-36 months). Up to ten previous vascular procedures had been done in 11 of 19 patients (58%).

RESULTS

There was one (5.2%) early and two (11%) late deaths, with one (5.5%) of the late deaths being homograft related. The mean hospital stay was 27 +/- 26 days (range, 7-84 days). Antibiotics were given postoperatively for 30 +/- 12 days (range, 4-84 days). During the follow-up period of 18.6 +/- 13 months (range, 7-60 months), there were no instances of reinfection, suture line rupture, homograft stenosis, or anastomotic aneurysms.

CONCLUSIONS

Cryopreserved arterial homografts allow safe in situ reconstruction, decrease early and midterm mortality, and reduce antibiotic requirements. Early and midterm reoperations are unnecessary.

Sealing of a fabric vascular prosthesis with autologous adipose tissue: a preliminary report of its clinical application

A new method of sealing fabric vascular prostheses with autologous adipose tissue was clinically applied as an alternative to preclotting with fresh blood. Thirty-six patients with peripheral arterial occlusive disease were implanted with highly porous fabric prostheses. The prostheses were prepared by sealing the fabric pores with autologous adipose tissue that had been chopped up into small pieces and enmeshed in the fabric by forceful injection of the tissue suspension through a syringe. There was no complication related to the sealed graft such as graft bleeding after implantation. In-hospital mortality occurred in 4 patients: 1 case each of pneumonia, pulmonary infarction, sepsis, and acute myocardial infarction. During the period of 274 +/- 190 days, 3 prostheses were found to be occluded. All the other grafts were patent. The overall patency rate was 91.4%. Postoperative angiography revealed neither intimal thickening at the anastomotic sites nor irregularity of the prosthetic surface. The method proved safe and useful for implantation of smaller caliber artificial grafts.

Clinical use of low porosity woven ultrafine polyester fiber grafts

A woven fabric graft made of ultrafine polyester fibers (UFPF) (Toray Graft, water porosity: 100 ml/min/cm2:120 mm Hg H2O) was clinically applied in 81 cases (28 thoracic aortic aneurysms, 6 thoracoabdominal aortic aneurysms, 42 abdominal aortic aneurysms, and 5 atherosclerotic obstructions of the peripheral arteries). Eight patients died after surgery due to causes unrelated to the graft. The other 73 patients were in good condition after surgery. For operations requiring extracorporeal circulation, the graft was presealed with human albumin. For the abdominal aortic aneurysms, the graft was preclotted in situ with nonheparinized autoblood after the completion of the proximal anastomosis. It took about 2 min to complete the preclotting. A nonsealed graft was used for the reconstruction of peripheral arteries for the intraaortic balloon pumping procedure. The graft was easy to handle. There was no cut edge fraying problem with the graft in any direction of cutting. Even after presealing, the graft was soft and pliable enough to enable easy adaptation and anastomosis. Just after implantation, bleeding was minimal from the graft wall, anastomotic sites, and suture pores, and it stopped spontaneously. These clinical data showed that the woven UFPF graft exhibited both easy handling despite in spite of low porosity and safe application in the reconstruction of arterial systems even under totally heparinized conditions during extracorporeal circulation.