Influence of hemodialysis membrane permeability on serum levels of advanced glycation end products (AGEs) and homocysteine metabolites.

BACKGROUND: [corrected] Advanced glycation end products (AGEs), total homocysteine (tHcy) and the homocysteine metabolites cystathionine (Cysta) and dimethylglycine (DMG) are increased in serum of patients with end-stage renal disease. The aim of this prospective randomized study was to compare the efficacy of polysulfone high-flux vs. polysulfone low-flux hemodialysis (HD) treatment regarding removal of AGEs, tHcy, Cysta and DMG. PATIENTS AND METHODS: Twenty-nine patients on chronic HD treatment were randomly assigned to 2 groups in a 3-period 2-treatment design with low flux (A)--high flux (B)--low flux (A) for group I and B-A-B for group II, 6 weeks each period. The following parameters were measured in pre- and postdialytic serum samples at baseline and the end of each period: total serum fluorescence, Nepsilon-carboxymethyllysine (CML), free and protein-bound pentosidine, tHcy, Cysta and DMG. RESULTS: There was increased removal of free pentosidine during high-flux HD treatment compared to low-flux HD treatment, attaining significance between the second and third treatment periods (group 1: 86.0 +/- 4.7% vs. 79.2 +/- 8.8%, p = 0.007; group II: 84.0 +/- 6.3% vs. 79.8 +/- 9.8%, p = 0.049 for high vs. low flux). The intradialytic reduction rates for total serum fluorescence, tHcy, Cysta, DMG did not differ between high- and low-flux HD treatment. Protein-bound pentosidine and CML did not decrease during the dialysis sessions, neither with high-flux nor with low-flux HD membrane. Despite a strong decrease during single HD session, the predialytic levels of free pentosidine, tHcy, Cysta and DMG remained unchanged during the study period both for high- and low-flux HD treatment. CONCLUSION: The more pronounced effect of high-flux dialysis on the removal rate of free pentosidine, found in this randomized crossover study, could not translate into a significant difference in predialysis levels after a 6-week treatment period. We could not find any differences between polysulfone high- and low-flux membranes for lowering predialytic serum concentrations of the measured AGEs, which are mainly bound on albumin.

[Embolization of aneurysma spurium of the superior gluteal artery]. / Embolisationsbehandlung eines Aneurysma spurium der A. glutea superior.

While for the surgical treatment there are the transgluteal and the retroperitoneal approach, the alternative radiological modality is less invasive. It is performed by a from contralateral placed guidant-catheter in combination with a tracker catheter with the possibility of transcatheter embolization with liquid, particles or coils. The rate of success is high, complications are seldom and the hospital stay is short. Both modalities can and should be used complementary. In the case of an intractable acute hemorrhage transcatheter embolization should be used firstly.

Species-dependent premature degradation of absorbable suture materials caused by infection--impact on the choice of thread in vascular surgery.

BACKGROUND: In case of infection after vascular reconstruction, preference is often given to absorbable suture material with the aim of preventing persistence of infection. We have investigated the functional deficit of absorbable sutures on incubation with various different bacteria. MATERIAL AND METHODS: Four suture materials Dexon bicolor, Vicryl, Maxon and PDS II--were placed in contact with reference bacterial cultures (Staphylococcus aureus, Pseudomonas aeroginosa, E. coli, coagulase-negative staphylococci and Proteus mirabilis). The bacteria were incubated for 7 days at 37 degrees C, together with the suture material. A logarithmic phase (Group A) and a static phase (Group B) were simulated. The linear tensile strength (LTS) of the suture material was measured (Instron Tensiometer). RESULTS: In the case of Staphylococcus aureus, a significant decrease in LTS was established for Dexon bicolor (group A: 31%, group B: 22%), and Vicryl (53% and 43%), but not for the monofilament threads. With regard to the other bacteria, a considerably more dramatic effect was observed: in both groups the braided sutures had completely disintegrated after 7 days. The monofilament sutures also revealed a significant loss of function (Maxon: 88%, PDS II 66%). CONCLUSIONS: The absorbable sutures revealed a premature, species-dependent loss of function due to the presence of the bacteria. On the basis of our results, the use of absorbable threads for vessel sutures in case of infection cannot be recommended, with the exception of monofilament material in a monocultural Staphylococcus aureus infection.

[The superficial femoral vein in aorto-iliac position--suitable as autogenous vascular replacement in deep prosthesis infection?]. / Vena femoralis superficialis in aorto-iliacaler Position--als autogener Gefässersatz beim tiefen Protheseninfekt geeignet?

The current standard therapy of aortic graft infection is connected with a high incidence of operative and late complications. The usefulness of autogenous tissue revascularization techniques as promising therapeutic alternatives is limited by the complexity of these procedures and by the lack of suitable donor vessels. Since several authors have shown that serious venous stasis of the donor leg does not occur after superficial femoral vein (SFV) resection, we have started to use this deep leg vein for arterial in situ reconstructions in the treatment of aortic graft infection. During the past 3 years seven patients have received autogenous SFV grafts in this way. There were no intraoperative deaths. Two critically ill patients with severe Pseudomonas sepsis and extensive retroperitoneal abscess each died on the 4th postoperative day, due to acute massive bleeding in the operating area. In all of the five survivors infection could be eradicated; only one limb had to be amputated. Mild to moderate transient swelling of the lower extremity without stasis was regularly seen after SFV resection. During follow-up one patient died of cardiac arrest 5 months postoperatively. The remaining four patients are still alive with patent SFV grafts at 6, 22, 30 and 36 months after the operation.

The superficial femoral vein as arterial substitute in infections of the aortoiliac region.

In situ autogenous reconstruction is an alternative therapy for abdominal aortic prosthetic graft infection. We have used the superficial femoral vein (SFV) as an arterial substitute for proximal aortic anastomosis in seven patients. Six patients presented with aortic perigraft infections and one had a mycotic aneurysm of the infrarenal aorta with a primary aortoenteric fistula. There were no intraoperative but two postoperative deaths. During follow-up (mean: 19.8 months), one patient died at 5 months unrelated to his preceding vascular procedures; the others were doing well with patient SFV grafts 6-36 months after autogenous aortoiliac reconstruction. The SFV is a valuable donor vessel for autogenous reconstruction in the management of aortoiliac prosthetic graft infection. We explain both perioperative deaths in our treatment group with respect to the extent of the underlying infection and the virulence of the causative organism.

[Arterial reconstruction in arteriopathic diabetic perforating ulcer--is it effective? Revascularization in diabetes mellitus and peripheral arterial occlusive disease]. / Die arterielle Rekonstruktion beim arteriopathischen diabetischen Malum perforans--lohnt sich der Aufwand? Revaskularisation bei Diabetes mellitus und pAVK.

OBJECTIVE: In the present study long-term patency and limb-salvage rates of femoro-distal bypasses were compared for patients suffering from PAOD stage III and IV with and without DM. METHODS: Between 1990 and 1994, some 192 femoro-crural bypass procedures were performed; 132 reconstructions were carried out on patients with PAOD, 60 bypasses on patients with PAOD and DM. The two groups did not differ significantly regarding age, gender and risk pattern. RESULTS: The comparison of the two groups showed a significant advantage for the diabetic patients regarding the limb-salvage rate. In both groups there was also a significant difference regarding patency in favour of the diabetics. CONCLUSION: Patients suffering from DM and PAOD profit from femoro-distal bypasses. An aggressive vasosurgical reconstructive therapy is indicated for these patients.

Influence of dialysis modalities on serum AGE levels in end-stage renal disease patients.

BACKGROUND: The accumulation of advanced glycation end-products (AGEs) in end-stage renal disease (ESRD) influenced by dialysis modalities is of current interest. Highly permeable membranes in haemodialysis or haemofiltration should be able to eliminate circulating AGEs as well as their AGE precursors more efficiently. METHODS: In our study, 10 non-diabetic and 10 diabetic ESRD patients were on haemodialysis with low-flux membranes (LF) followed by a cross-over haemodialysis with high-flux or super-flux polysulfone membranes (HF, SF) for 6 months each. We measured the protein-bound pentosidine and free pentosidine serum levels by high-performance liquid chromatography (HPLC) as well as the serum AGE peptide, AGE-beta(2)-microglobulin and beta(2)-microglobulin concentrations, using ELISA assays. RESULTS: All parameters investigated were significantly higher in dialysis patients than in healthy subjects. The reduction rates during a single dialysis session were found to be higher using the SF than those obtained with the HF (free pentosidine 82.4+/-7.3 vs 76.6+/- 8.7%; AGE peptides 79.7+/-7.7 vs 62.3+/-14.7%; AGE-beta(2)-microglobulin 64.0+/-16.5 vs 45.4+/-17.7%; beta(2)-microglobulin 70.5+/-5.6 vs 58.2+/-6.0%). The protein-bound pentosidine levels remained constant over the respective dialysis sessions. In the 6-month treatment period with the SF, decreased pre-dialysis serum levels of protein-bound pentosidine, free pentosidine and AGE peptides were observed in non-diabetics and diabetics as compared with values obtained with the LF. The respective pre-dialysis AGE-beta(2)-microglobulin concentrations decreased insignificantly, whereas those of beta(2)-microglobulin were significantly lower. Using the HF dialyser, only moderate changes of the parameters measured were noted. CONCLUSION: Treatment with the biocompatible polysulfone SF dialyser seems to be better suited to lower serum AGE levels and to eliminate their precursors.