Vascular replacement using a layered elastin-collagen vascular graft in a porcine model: one week patency versus one month occlusion.

A persistent clinical demand exists for a suitable arterial prosthesis. In this study, a vascular conduit mimicking the native 3-layered artery, and constructed from the extracellular matrix proteins type I collagen and elastin, was evaluated for its performance as a blood vessel equivalent. A tubular 3-layered graft (elastin-collagen-collagen) was prepared using highly purified type I collagen fibrils and elastin fibers, resembling the 3-layered native blood vessel architecture. The vascular graft was crosslinked and heparinised (37 ± 4 µg heparin/mg graft), and evaluated as a vascular graft using a porcine bilateral iliac artery model. An intra-animal comparison with clinically-used heparinised ePTFE (Propaten®) was made. Analyses included biochemical characterization, duplex scanning, (immuno)histochemistry and scanning electron microscopy. The tubular graft was easy to handle with adequate suturability. Implantation resulted in pulsating grafts without leakage. One week after implantation, both ePTFE and the natural acellular graft had 100% patencies on duplex scanning. Grafts were partially endothelialised (Von Willebrand-positive endothelium with a laminin-positive basal membrane layer). After one month, layered thrombi were found in the natural (4/4) and ePTFE graft (1/4), resulting in occlusion which in case of the natural graft is likely due to the porosity of the inner elastin layer. In vivo application of a molecularly-defined tubular graft, based on nature's matrix proteins, for vascular surgery is feasible.

Remote Ischemic Preconditioning To Reduce Contrast-Induced Nephropathy: A Randomized Controlled Trial.

BACKGROUND: Despite the increasing use of pre- and post-hydration protocols and low osmolar instead of high osmolar iodine containing contrast media, the incidence of contrast induced nephropathy (CIN) is still significant. There is evidence that contrast media cause ischemia reperfusion injury of the renal medulla. Remote ischemic preconditioning (RIPC) is a non-invasive, safe, and low cost method to reduce ischemia reperfusion injury. The aim of this study is to investigate whether RIPC, as an adjunct to standard preventive measures, reduces contrast induced acute kidney injury in patients at risk of CIN. METHODS: The RIPCIN study is a multicenter, single blinded, randomized controlled trial in which 76 patients at risk of CIN received standard hydration combined with RIPC or hydration with sham preconditioning. RIPC was applied by four cycles of 5 min ischemia and 5 min reperfusion of the forearm. The primary outcome measure was the change in serum creatinine from baseline to 48 to 72 hours after contrast administration. RESULTS: With regard to the primary endpoint, no significant effect of RIPC was found. CIN occurred in four patients (2 sham and 2 RIPC). A pre-defined subgroup analysis of patients with a Mehran risk score ≥11, showed a significantly reduced change in serum creatinine from baseline to 48 to 72 hours in patients allocated to the RIPC group (Δ creatinine -3.3 ± 9.8 µmol/L) compared with the sham group (Δ creatinine +17.8 ± 20.1 µmol/L). CONCLUSION: RIPC, as an adjunct to standard preventive measures, does not improve serum creatinine levels after contrast administration in patients at risk of CIN according to the Dutch guideline. However, the present data indicate that RIPC might have beneficial effects in patients at a high or very high risk of CIN (Mehran score ≥ 11). The RIPCIN study is registered at: http://www.controlled-trials.com/ISRCTN76496973.

Components of pain assessment after laparoscopic donor nephrectomy.

BACKGROUND: Pain after laparoscopic surgery can be divided into three components: incisional or superficial wound pain, deep intra-abdominal pain and referred shoulder pain. Better understanding and adequate assessment of post-operative pain may be an important clue to the optimisation of recovery after laparoscopic surgery. Therefore, we performed a components of pain assessment after laparoscopic donor nephrectomy. METHODS: Twenty patients who underwent a laparoscopic donor nephrectomy were included in this prospective study. Pain was subdivided into three components: superficial wound pain, deep intra-abdominal pain and referred shoulder pain, and for each component a numeric rating scale (from 0 to 10) was obtained at 1, 24 and 48 h after surgery. RESULTS: Repeated measurements analysis of variance showed that during the first 48 h after surgery, the superficial wound and deep intra-abdominal pain components were significantly higher as compared with the referred shoulder pain component. Although the deep intra-abdominal pain component was slightly higher as compared with superficial wound pain, this difference was not significant (P = 0.097). Further assessment of superficial wound pain showed that the Pfannenstiel incision was the most significant determinant of this component of pain (P = 0.004), whereas deep intra-abdominal pain was significantly higher at the ipsilateral side of the abdomen (P = 0.015). DISCUSSION: The components of pain assessment revealed that pain related to the Pfannenstiel incision and the deep intra-abdominal pain component are the most important determinants of pain after laparoscopic donor nephrectomy. Further improvement of the management of post-operative pain should focus on these components of pain.

Low-pressure pneumoperitoneum during laparoscopic donor nephrectomy to optimize live donors' comfort.

Nowadays, laparoscopic donor nephrectomy (LDN) has become the gold standard to procure live donor kidneys. As the relationship between donor and recipient loosens, it becomes of even greater importance to optimize safety and comfort of the surgical procedure. Low-pressure pneumoperitoneum has been shown to reduce pain scores after laparoscopic cholecystectomy. Live kidney donors may also benefit from the use of low pressure during LDN. To evaluate feasibility and efficacy to reduce post-operative pain, we performed a randomized blinded study. Twenty donors were randomly assigned to standard (14 mmHg) or low (7 mmHg) pressure during LDN. One conversion from low to standard pressure was indicated by protocol due to lack of progression. Intention-to-treat analysis showed that low pressure resulted in a significantly longer skin-to-skin time (149 ± 86 vs. 111 ± 19 min), higher urine output during pneumoperitoneum (23 ± 35 vs. 11 ± 20 mL/h), lower cumulative overall pain score after 72 h (9.4 ± 3.2 vs. 13.5 ± 4.5), lower deep intra-abdominal pain score (11 ± 3.3 vs. 7.5 ± 3.1), and a lower cumulative overall referred pain score (1.8 ± 1.9 vs. 4.2 ± 3). Donor serum creatinine levels, complications, and quality of life dimensions were not significantly different. Our data show that low-pressure pneumoperitoneum during LDN is feasible and may contribute to increase live donors' comfort during the early post-operative phase.

Poor early graft function impairs long-term outcome in living donor kidney transplantation.

BACKGROUND: Poor early graft function (EGF) after living donor kidney transplantation (LDKT) has been found to decrease rejection-free graft survival rates. However, its influence on long-term graft survival remains inconclusive. METHODS: Data were collected on 472 adult LDKTs performed between July 1996 and February 2010. Poor EGF was defined as the occurrence of delayed or slow graft function. Slow function was defined as serum creatinine above 3.0 mg/dL at postoperative day 5 without dialysis. RESULTS: The incidence of slow and delayed graft function was 9.3 and 4.4%, respectively. Recipient overweight, pretransplant dialysis and warm ischemia were identified as risk factors for the occurrence of poor EGF. The rejection-free survival was worse for poor EGF as compared to immediate graft function with an adjusted hazard ratio (HR) of 6.189 (95% CI 4.075-9.399; p < 0.001). Long-term graft survival was impaired in the poor EGF group with an adjusted HR of 4.206 (95% CI 1.839-9.621; p = 0.001). CONCLUSIONS: Poor EGF occurs in 13.7% of living donor kidney allograft recipients. Both, rejection-free and long-term graft survivals are significantly lower in patients with poor EGF as compared to patients with immediate graft function. These results underline the clinical relevance of poor EGF as phenomenon after LDKT.

Deleterious influence of prolonged warm ischemia in living donor kidney transplantation.

BACKGROUND: Recent studies investigating early graft function (EGF) after living donor kidney transplantation (LDKT) identified prolonged warm ischemia time (WIT) as a risk factor for the occurrence of poor EGF. The latter is associated with long-term graft loss; therefore the question arises whether prolonged WIT affects long-term outcomes in LDKT. METHODS: Data were collected on 472 consecutive adult LDKTs. Patients were divided according to the total WIT into 3 groups with short (<30 minutes), intermediate (30-45 minutes), or prolonged (>45 minutes) WIT. RESULTS: Of all patients, 193 (40.9%) experienced short, 249 (52.8%) intermediate, and 30 (6.4%) prolonged WIT. Prolonged WIT was a significant risk factor for the occurrence of poor EGF with an adjusted odds ratio of 4.252 (95% confidence interval [CI), 1.914 -9.447). Long-term graft survival was impaired in patients with prolonged WIT, with an adjusted hazard ratio of 3.163 (95% CI, 1.202-8.321). Multivariate analysis revealed determinants of prolonged WIT, including laparoscopic procurement, recipient overweight, right donor kidney, and multiple renal arteries. CONCLUSION: Prolonged WIT impairs long-term graft survival in LDKT. This finding underlines the need to develop strategies to avoid the occurrence of prolonged WIT in LDKT.

Biological mechanisms influencing prosthetic bypass graft patency: possible targets for modern graft design.

In recent years, ample attention has been directed towards the mechanisms that play a major role in the process of vascular graft failure, especially graft thrombosis and intimal narrowing have been highlighted. In this article, a survey is conducted into the key mechanisms of the biological processes of intimal hyperplasia and ultimate graft failure. The sequence of biochemical events that lead to thrombosis of grafts is used as a guideline to describe possible counteracting prosthetic surface interventions in each separate phase of the process.

The inflammasome and caspase-1 activation: a new mechanism underlying increased inflammatory activity in human visceral adipose tissue.

The immune competent abdominal adipose tissue, either stored viscerally [visceral adipose tissue (VAT)] or sc [sc adipose tissue (SAT)], has been identified as a source of IL-1ß and IL-18. To become active, the proforms of these cytokines require processing by caspase-1, which itself is mediated by the inflammasome. In this descriptive study, we investigate the expression of inflammasome components and caspase-1 in human fat and determine whether caspase-1 activity contributes to the enhanced inflammatory status of VAT. Paired SAT and VAT biopsies from 10 overweight subjects (body mass index, 25-28 kg/m(2)) were used to study the cellular composition and the intrinsic inflammatory capacity of both adipose tissue depots. The percentage of CD8(+) T cells within the lymphocyte fraction was significantly higher in VAT compared with SAT (41.6 vs. 30.4%; P < 0.05). Adipose tissue cultures showed a higher release of IL-1ß (10-fold; P < 0.05), IL-18 (3-fold; P < 0.05), and IL-6 and IL-8 (3-fold, P < 0.05; and 4-fold, P < 0.05, respectively) from VAT compared with SAT that was significantly reduced by inhibiting caspase-1 activity. In addition, caspase-1 activity was 3-fold (P < 0.05) higher in VAT compared with SAT, together with an increase in the protein levels of the inflammasome members apoptosis-associated speck-like protein containing a C-terminal caspase-recruitment domain (2-fold; P < 0.05) and nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (2-fold; nonsignificant). Finally, caspase-1 activity levels were positively correlated with the percentage of CD8(+) T cells present in adipose tissue. Our results show that caspase-1 and nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 inflammasome members are abundantly present in human VAT. The increased intrinsic caspase-1 activity in VAT represents a novel and specific inflammatory pathway that may determine the proinflammatory character of this specific depot.

Preservation of kidneys from controlled donors after cardiac death.

BACKGROUND: Donation after cardiac death (DCD) expands the pool of donor kidneys, but is associated with warm ischaemic injury. Two methods are used to preserve kidneys from controlled DCD donors and reduce warm ischaemic injury: in situ preservation using a double-balloon triple-lumen catheter (DBTL) inserted via the femoral artery and direct cannulation of the aorta after rapid laparotomy. The aim of this study was to compare these two techniques. METHODS: This was a retrospective cohort study of 165 controlled DCD procedures in two regions in the Netherlands between 2000 and 2006. RESULTS: There were 102 donors in the DBTL group and 63 in the aortic group. In the aortic group the kidney discard rate was lower (4·8 versus 28·2 per cent; P < 0·001), and the warm (22 versus 27 min; P < 0·001) and the cold (19 versus 24 h; P < 0·001) ischaemia times were shorter than in the DBTL group. Risk factors for discard included preservation with the DBTL catheter (odds ratio (OR) 5·19, 95 per cent confidence interval 1·88 to 14·36; P = 0·001) and increasing donor age (1·05, 1·02 to 1·07; P < 0·001). Warm ischaemia time had a significant effect on graft failure (hazard ratio 1·04, 1·01 to 1·07; P = 0·009), and consequently graft survival was higher in the aortic cannulation group (86·2 per cent versus 76·8 per cent in the DBTL group at 1 year; P = 0·027). CONCLUSION: In this retrospective study, direct aortic cannulation appeared to be a better method to preserve controlled DCD kidneys.

Does a plain X-ray of the pelvis predict arterial complications in renal transplantation? A prospective study.

BACKGROUND: It is unknown whether if a plain X-ray of the iliac arteries (pelvic X-ray) is a reliable tool to detect calcifications and predict vascular complications. METHODS: In a prospective study, a pelvic X-ray was performed before transplantation in patients without evidence of peripheral vascular disease (n = 109) and vascular calcifications were scored. Vascular calcifications in the iliac arteries and complications were scored by the transplant surgeon during the operation (gold standard). RESULTS: Vascular calcifications were found on the pelvic X-ray in 33 patients (30.2%). The transplant surgeon identified vascular calcifications in 35%. Sensitivity and specificity of the pelvic X-ray for vascular calcifications in the iliac arteries were 48 and 82%, respectively. Technical problems with the arterial anastomosis due to vascular calcifications were observed in five patients. The negative predictive value and positive predictive value of a pelvic X-ray for complications with the arterial anastomosis were 99 and 14%, respectively. CONCLUSIONS: A pelvic X-ray is not a reliable tool to detect vascular calcifications. Technical problems with the arterial anastomosis due to calcifications are infrequent in the absence of vascular calcifications on the pelvic X-ray.

Controlled fabrication of triple layered and molecularly defined collagen/elastin vascular grafts resembling the native blood vessel.

There is a consistent need for a suitable natural biomaterial to function as an arterial prosthesis in achieving arterial regeneration. Natural grafts are generally obtained by decellularization of native blood vessels, but batch to batch variations may occur and the nature/content of remaining contaminants is generally unknown. In this study we fabricated a molecularly defined natural arterial graft from scratch resembling the native three layered architecture from the fibrillar extracellular matrix components collagen and elastin. Using casting, moulding, freezing and lyophilization techniques, a triple layered construct was prepared consisting of an inner layer of elastin fibres, a middle (porous) film layer of collagen fibrils and an outer scaffold layer of collagen fibrils. The construct was carbodiimide cross-linked and heparinized. Characterization included biochemical/biophysical analyses, scanning electron microscopy, micro-computed tomography, (immuno)histology and haemocompatibility. Burst pressures were up to 400mm Hg and largely conferred by the intermediate porous collagen film layer. The highly purified type I collagen fibrils and elastin fibres used did not evoke platelet aggregation in vitro. Suturability of the graft in end to side anastomosis was successful and considered adequate for in vivo application.

Conventional surgery and endovenous laser ablation of recurrent varicose veins of the small saphenous vein: a retrospective clinical comparison and assessment of patient satisfaction.

OBJECTIVES: Recurrences of varicosities of the small saphenous vein (SSV) are common. Surgical reintervention is associated with increased complication rates. The aim of the study was to assess the feasibility of endovenous laser ablation (EVLA) in recurrent varicose veins of the SSV and to compare this technique with surgical reintervention. METHODS: All case files of patients treated for SSV varicosities between May 2006 and October 2008 were evaluated and recurrences were selected. Demographics, duplex findings, clinical, aetiological, anatomical and pathological classification, perioperative and follow-up data were all registered. Additionally, a questionnaire focusing on patient satisfaction was taken. RESULTS: Two hundred and eighty-one patients were treated for varicosities of the SSV, of which 42 were for recurrences. Twenty-six of these were treated with EVLA, all under local anaesthesia, and 16 were surgically treated. Most surgically treated patients were treated under regional anaesthesia (88%). Technical success was achieved in 94% of surgically treated patients and in all EVLA-treated patients. Complications in both groups were mostly minor and self-limiting. Sural nerve neuralgia appeared to be more frequent in the surgically treated group (20% versus 9%). After correction for length of follow-up, the incidence of rerecurrences was not statistically significant between groups. CONCLUSION: EVLA is feasible in patients with recurrent varicose veins of the SSV with possibly a lower incidence of sural nerve injury. Patient satisfaction is high for both treatment modalities. Studies with larger samples are indicated to confirm these observations.

Validation of the Simulator for Testing and Rating Endovascular SkillS (STRESS)-machine in a setting of competence testing.

AIM: Endovascular skills are an integral part of modern-day vascular surgery. The STRESS machine has been developed to test these skills in vascular surgeons. This study aims to define an optimal pass/fail cutoff value for the STRESS test score. METHODS: The STRESS machine consists of a dry glass model of the abdominal aorta and its tributaries with various stenotic lesions, elongations, and tortuosities. A camera and computer software are used to simulate plain fluoroscopy-mode. The test subjects are given two assignments after which two reviewers use a combination of the ICEPS and MRS to produce the final total score; 43 subjects were tested. According to previous endovascular experience, subjects were classified into four groups: novice-low (no experience, less than 11 performed procedures, less than 50 assisted procedures), novice-high (11-25 performed procedures, more than 50 assisted procedures), intermediate (1-10 performed and >11-25 assisted procedures, 11-25 performed and >1-10 assisted procedures or 25-50 performed procedures) and advanced (more than 50 performed procedures). RESULTS: Test-score and noted experience showed a correlation of 0.794. All intermediate and advanced test subjects scored more than 50 points compared to 4 out of 15 novices. CONCLUSION: We demonstrated that it is possible to determine an optimal cut-off value for competence testing with the STRESS machine.

[Cold ischaemia time and outcome of renal transplantation]. / Koude-ischemietijd en resultaat niertransplantatie. Nederland, 1990-2007.

OBJECTIVE: To determine the effect of cold ischaemia time (CIT) on the outcome of cadaveric renal transplantation in the Netherlands. DESIGN: Retrospective, comparative. METHODS: We studied data from the Netherlands organ transplant registry of cadaveric renal transplants from 1990-2007. RESULTS: 6322 cadaveric renal transplant recipients were studied, of whom 5306 were from heart-beating donors (HBD) and 1016 from non-heart-beating donors (NHBD). The mean CIT was 24.0 h in the HBD group and 21.6 h in the NHBD group. The rate of delayed graft function (DGF) was 12.3% in the HBD group and 50.4% in the NHBD group. Multivariate analysis showed that prolonged CIT was an independent risk factor for graft failure. Prolonged CIT was also associated with the more frequent occurrence of DGF and primary non-function (PNF). Recipients of renal allografts from HBD with CIT

Acute arterial occlusion after deployment of the Angio-Seal closure device: is it as uncommon as we think?

Angio-Seal is a frequently used vascular closure device after arterial catheterisation. Major complications are infrequently reported. We present four cases occurring within a 2-month period in our hospital with dislodgement of an Angio-Seal causing acute arterial occlusion, resulting in loss of limb in one case. Surgical intervention was necessary in all cases. Acute arterial occlusion after deployment of the Angio-Seal in patients with peripheral arterial disease might be less uncommon than the literature suggests.

Preservation for future use of the autologous saphenous vein during femoro-popliteal bypass surgery is inexpedient.

PURPOSE: To investigate the usefulness of greater saphenous vein preservation for future vascular reconstructions during femoro-popliteal bypass surgery. DESIGN: Post-hoc analysis of data acquired in a randomized multi-centre clinical trial comparing two different vascular prostheses (ClinicalTrials.gov ID: NCT 00523263). PATIENTS AND METHODS: The true frequency of ipsilateral saphenous vein use in subsequent femoro-popliteal and coronary bypass surgery was investigated through case-record analysis with a median follow-up of 60 months in 100 consecutive patients, that received a prosthetic femoro-popliteal bypass between 1996 and 2001. RESULTS: An ipsilateral secondary femoro-popliteal bypass was performed in 11 patients (11%) at a mean interval of 34 months (range 1-96). The ipsilateral saphenous vein was applied for these procedures in 8 cases (8%). The cumulative probability of receiving a subsequent bypass was 8% at 3 years and 10% at 5 years follow-up respectively. One patient (1%) underwent CABG at 8 years follow-up with the use of ipsilateral lower leg saphenous vein segments only. CONCLUSION: Preservation of the greater saphenous vein in supragenicular femoro-popliteal bypass surgery is not a valid argument for application of prosthetic material.