Biomedical subjects

J D Blankensteijn

Publications and source records attributed to J D Blankensteijn.

At least 19 recordsLinked to original sources

PubMed2006

Wall stress analysis in small asymptomatic, symptomatic and ruptured abdominal aortic aneurysms.

OBJECTIVES: To evaluate the potential of wall stress analysis for the identification of abdominal aortic aneurysm (AAA) at elevated risk of rupture in spite of small diameter. MATERIALS AND METHODS: Thirty patients with small AAA, 10 asymptomatic, 10 symptomatic and 10 ruptured, were included. Demographic data and results from physical examinations were recorded in a retrospective fashion. After CT-evaluation and the creation of a patient specific 3D model, wall stress was calculated using the finite element method. RESULTS: No differences were observed in diameter between asymptomatic, symptomatic or ruptured aneurysms (5.1+/-0.2 cm vs. 5.1+/-0.2 cm vs. 5.3+/-0.2 cm respectively; p=0.57). Peak aortic wall stress at maximal systolic blood pressure is significantly higher in ruptured than asymptomatic aneurysms (51.7+/-2.4 N/cm(2) vs. 39.7+/-3.3 N/cm(2) respectively; p=0.04). Wall stress analysis at uniform blood pressure, performed to correct for higher blood pressure in the symptomatic and rupture group did not result in significant differences in peak wall stress (asymptomatic 31.7+/-2.3 N/cm(2); symptomatic 30.5+/-1.3 N/cm(2); rupture 36.7+/-4.0 N/cm(2); p=0.26). CONCLUSIONS: Wall stress analysis at maximal systolic blood pressure is a promising technique to detect aneurysms at elevated aneurysm rupture risk. Since no significant differences were found at uniform blood pressure, the need for adequate blood pressure control in aneurysm patients is reiterated.

Aged↗

PubMed2006

Impact of study design on outcome after endovascular abdominal aortic aneurysm repair. A comparison between the randomized controlled DREAM-trial and the observational EUROSTAR-registry.

BACKGROUND: Patients with abdominal aortic aneurysm (AAA) can be treated by transfemoral endovascular intervention and by conventional open surgery. Level-one evidence of the safety and efficacy of one treatment mode over the other is only provided by a randomised controlled trial (RCT). Results reported by voluntary registries are considered less valid than data from RCTs. On the other hand the outcome of a RCT may not be generalisable to the common practice because of vigorous selection of patients and institutions. PURPOSE: The outcomes reported by the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial were compared with the results of the EURopean collaborators on Stent-graft techniques for AAA Repair (EUROSTAR) registry. METHODS: To obtain comparable study groups with regard to risk factors equal proportions of ASA I, II and III patients as observed in the endovascular arm of the DREAMtrial were selected at random from the EUROSTAR-registry. All patients had an aneurysm of at least 50mm. Only patients, who had been enrolled into the registry from 1999, were selected to avoid the influence of first generation endografts which are not longer in use. Patient characteristics and outcomes of endovascular AAA repair (EVAR) of EUROSTAR and DREAM-trial participants were compared. Differences in early findings between study groups were assessed by Chi-Square tests for discrete variables and by Wilcoxon rank sum tests for continuous variables. Follow-up variables were analysed by Kaplan-Meier and Cox proportional hazard models. RESULTS: Data of 177 patients of the DREAM trial with randomization to EVAR and 856 patients selected in the EUROSTAR-registry were compared. Baseline characteristics were comparable between the EUROSTAR-cohort and EVAR-arm of the DREAM-trial. The 36-month survival-rate was 87.6% for EVAR-arm in the DREAM-trial similar to the 86.8% found in this EUROSTAR-study population. The freedom of secondary procedures reached after 3 years 85.7%, and 86.9% in the DREAM and EUROSTAR-cohort, respectively. CONCLUSION: We found comparable characteristics and outcomes between patients of comparable risk class of the EUROSTAR-registry and the EVAR-cohort of the DREAM-trial. This demonstrates the following: first, the EUROSTAR-data provide reliable information, and further comparisons of registry data with patients treated by conventional AAA surgery may be justified. Secondly, the various outcomes of the randomised DREAM trial appear generalisable, as it agrees with observations in a broad common practice derived database.

Aged↗

PubMed2006

Subintimal angioplasty of supra- and infrageniculate arteries.

We retrospectively reviewed our experience with subintimal angioplasty for chronic limb ischemia. Hospital records and films of all subintimal angioplasty procedures performed between October 2002 and December 2004 were reviewed and analyzed for demographic data, clinical data, and comorbid condition status. Thirty-nine subintimal angioplasties were performed in 37 patients (65% male, 35% female), with a median age of 73 years. Median follow-up was 9 months. The 30-day mortality rate was 8%. All-cause mortality was 33% after 24 months. In 23 cases (59%), a subintimal angioplasty of the superficial femoral artery (SFA) alone was performed. Both the SFA and popliteal/crural vessels were used in nine limbs (23%), the popliteal artery alone in three limbs (8%), and the crural arteries alone in four limbs (10%). Initial technical and clinical success rates were 67% and 49%, respectively. The complication rate was 28%. Twenty-four additional surgical interventions were performed after the initial angioplasty procedure, of which 12 were major amputations. Amputation-free survival (limb-salvage rate) was 69% at 12 months [95% confidence interval (CI) 52-85%], and overall survival was 69% (95% CI 52-85%) at 12 months. In patients with critical limb ischemia, subintimal angioplasty is feasible and in most cases technically successful. In these high-risk patients, often with combined cardiac, pulmonary, and diabetic risk and considered unfit for bypass surgery, subintimal angioplasty offers a safe and effective alternative.

Aged↗

PubMed2006

Computed tomography versus magnetic resonance imaging of endoleaks after EVAR.

AIM: The aim of study was to compare the sensitivity of MRI and CTA for endoleak detection and classification after EVAR. PATIENTS & METHODS: Twenty-eight patients, between 2 days and 65 months after EVAR, were evaluated with both CT and MRI. Twenty-five patients had an Ancure graft and the other three had an Excluder. The MRI protocol for endoleak evaluation included: a T1-weighted spin echo, a high-resolution 3D CE-MRA, and a post-contrast T1-weighted spin echo. In total 40 ml Gadolinium was administered. The CT protocol consisted of a blank survey followed by a spiral CT angiography (CTA) using 140 ml of Ultravist. An experienced, blinded observer evaluated all CTs and MRIs. RESULTS: Using MRI and MRA techniques significantly more endoleaks (23/35) were detected than with CTA (11/35) (p=0.01, Chi-Square). CT could not determine the type of endoleak in 3 of the 11 endoleaks detected and was uncertain in one. MRI was uncertain about the type in 14 of the 23 endoleaks detected. All endoleaks visible on CT were visible by MRI as well. CONCLUSIONS: MRI techniques are more sensitive for the detection of endoleak after endovascular AAA repair than CT.

Aged↗

PubMed2005

Dynamic CE-MRA for endoleak classification after endovascular aneurysm repair.

AIM: To evaluate the value of dynamic contrast enhanced magnetic resonance angiography (CE-MRA) for classification of endoleaks after endovascular aneurysm repair (EVAR). MATERIALS AND METHODS: Twenty-eight patients, between 2 days and 54 months after EVAR, were evaluated with CTA, MRI and dynamic CE-MRA. The additional diagnostic value of the dynamic 3D CE-MRA was evaluated by determining the ability of the dynamic series in pinpointing the site of inflow of an endoleak. RESULTS: An endoleak was detected in 23 patients. Seventeen of the 23 dynamic series were technically successful (no disturbing artifacts limiting the diagnostic value). Using MRI our findings were: 2 type I, 6 type II, 1 type III, no type IV endoleaks and in 14 cases classification could not be made. The classification results for MRI plus the dynamic CE-MRA were: 2 type I, 12 type II, 1 type III, no type IV endoleaks and in eight cases classification could not be made. In six cases the dynamic MRA allowed classification of the endoleak, which was not possible with the non-dynamic images alone (p=0.091, Fisher exact). CONCLUSION: This pilot study shows that dynamic CE-MRA can have additional value in the classification of endoleaks. Dynamic CE-MRA might obviate the need for diagnostic digital subtraction angiography and aid planning for intervention.

Aged↗

PubMed2005

Endovascular aneurysm repair versus open aneurysm repair: comparison of treatment outcome and procedure-related reintervention rate.

We conducted a retrospective study to compare treatment outcome and procedure-related reintervention rates of endovascular aneurysm repair (EVAR) with those of open repair. Clinical and radiological data of patients treated at the Rijnstate Hospital (Arnhem, The Netherlands) for nonsymptomatic aortic abdominal aneurysm during October 1998-January 2004 were reviewed and analyzed for demographic data, aneurysm specifics, comorbid condition status, and perioperative outcome. There were 99 patients treated with EVAR and 116 patients treated with open repair. Significant differences in age were seen between treatment groups, patients under the age of 80 being more likely to have open repair (p < 0.004). The EVAR group consisted of significantly fewer women (p < 0.029). Of seven comorbid conditions, four reached significant differences between treatment groups; patients with ischemic heart disease (p < 0.044), heart failure (p < 0.006), renal failure (p < 0.033), or peripheral arterial disease (p < 0.006) were more likely to have EVAR. Comparison of aneurysm anatomy showed no difference in size between EVAR (mean 57.7 mm, 95% CI 55.9-59.5 mm) and open repair (mean 60.1 mm, 95% CI 57.9-62.3 mm). Significant differences were seen in aneurysm neck length and diameter. Operative outcome showed differences in length of hospital stay (median, EVAR 7 vs. open repair 11 days), 30-day mortality (p < 0.048), postoperative hematoma (p < 0.001), and postoperative pulmonary infections (p < 0.001), all in favor of EVAR. Follow-up of the EVAR group showed a decrease (mean 10 mm, 95% CI 7-14 mm) of aneurysm diameter in 15% of cases during follow-up (mean 18 months, range 1-66). Despite higher age and more comorbidity of patients undergoing EVAR, 30-day mortality, postoperative pulmonary infection rate, and length of hospital stay were lower than for those undergoing open repair. Both EVAR and open repair can be performed on a subset of patients with low mortality, complication, and reintervention rates.

Aged↗

PubMed2005

In-hospital operative mortality of ruptured abdominal aortic aneurysm: a population-based analysis of 5593 patients in The Netherlands over a 10-year period.

OBJECTIVE: To determine the operative mortality of ruptured abdominal aortic aneurysm (RAAA) in The Netherlands. DESIGN: Retrospective population-based study of nation-wide in-hospital mortality of RAAA repair. METHODS: Data were obtained from a national registry for medical diagnosis and procedures. In-hospital mortality of RAAA repair, defined as death during hospital admission irrespective of the cause of death, was determined in the period 1991-2000. Variables of potential influence on in-hospital mortality, including age, gender, date of surgery and hospital type (0-399 beds, > or =400 beds or university hospitals) were studied in a multivariate analysis. RESULTS: The overall in-hospital mortality of RAAA repair in 5593 patients in the 10-year period was 41% (95% confidence interval: 40-42%). In the multivariate analysis, age and hospital type were the most important independent predictors for in-hospital mortality. Gender, year and season of surgery could not be identified as significant risk factors. CONCLUSIONS: Over a recent decade, in-hospital mortality of RAAA repair remained unchanged at 41%. Age and hospital class were the most important independent risk factors.

Age Factors↗

PubMed2004

Quality of life endovascular and open AAA repair. Results of a randomised trial.

AIM: To compare the quality of life (QoL) in the first postoperative year after elective endovascular abdominal aortic aneurysm repair (EVAR) and open repair (OR) in a randomised study. METHODS: In the Dutch Randomised Endovascular Aneurysm Management (DREAM) trial, patients are randomly allocated to EVAR or OR. QoL questionnaires (SF-36 and EuroQoL-5D) were sent to all patients preoperatively (PREOP) and at five time points in the first postoperative year (3W, 6W, 3M, 6M and 12M). Between November 1999 and August 2002, 153 patients (141 male; 12 female) were randomised (78 EVAR and 75 OR; one crossover from OR to EVAR). The EuroQoL-5D scores and the eight domains of the SF-36 for the two groups were compared using the Mann-Whitney test. Changes over time were analysed using the Wilcoxon sign test. RESULTS: There were no statistically significant differences in baseline characteristics (age, gender and SVS risk factors). The preoperative QoL scores of the study group were similar to the QoL scores of the general population of the same age. After 3W the OR group showed a significant decrease on the EuroQol-5D (p=0.022) and in six of the eight SF-36 domains. The EVAR group also showed a significant decrease on the EuroQol-5D (p=0.004) and in 5 of the 8 domains of the SF-36. At 6W the EuroQol-5D had recovered to baseline in the OR group and the decreased domains of the SF-36 had partially recovered. In the EVAR group the EuroQol-5D and three of the five decreased SF-36 domains, had returned to baseline. From 6M on, the OR group reported a significantly higher score on the EuroQoL-5D than the EVAR group (p=0.045 (6M) and p=0.001 (12M)). CONCLUSION: In the early postoperative period there is a small, yet significant QoL advantage for EVAR compared to OR. At 6 months and beyond, patients reported better QoL after OR than after EVAR.

Aged↗

PubMed2004

The impact of endovascular treatment on in-hospital mortality following non-ruptured AAA repair over a decade: a population based study of 16,446 patients.

OBJECTIVES: We hypothesised that over the past decade, the nation-wide outcome of infrarenal abdominal aortic aneurysm (AAA) repair has improved with the introduction of endovascular treatment. The aim of the study was to identify endovascularly-treated patients in a national registry and to assess the impact on in-hospital mortality of non-ruptured AAA repair, if any, after the introduction of endovascular repair. MATERIALS AND METHODS: We retrospectively studied the nation-wide outcome of non-ruptured AAA repair over the past decade. Variables studied were age and gender of the patients, hospital size and type and the year in which treatment was performed and the outcome on in-hospital mortality. The in-hospital mortality of non-ruptured AAA repair in 16,446 patients in the 10-year period from 1991 to 2000 was 7.3% (6.2-8.2%). In the 15,589 (95%) patients that underwent conventional treatment, in-hospital mortality was 7.6% (7.0-8.1%), whereas in the endovascular group it was 1.9% (0.6-3.5%). In the multivariate analysis, age and endovascular repair were the most important independent predictors of in-hospital mortality. CONCLUSION: With the limitations of a national registry aside, the introduction of endovascular aneurysm repair seems to have had a small but significant impact on in-hospital mortality following infrarenal AAA repair.

Age Factors↗

PubMed2004

Application of a clinical grade CD34-mediated method for the enrichment of microvascular endothelial cells from fat tissue.

BACKGROUND: Microvascular endothelial cells (MVEC) derived from s.c. fat are seeded on vascular grafts to prevent early occlusion. We have demonstrated the presence of contaminating cells contributing to MVEC seeding-related intimal hyperplasia in MVEC isolates from fat tissue. We found that cell isolates additionally purified after the isolation process, were associated with a reduced thrombogenicity and development of intimal hyperplasia in vitro. A combination of 11Fibrau (F11)- and CD14-coated Dynabeads was used to deplete the contaminating cells, fibroblasts, and monocytes/macrophages. Unfortunately, clinical-grade F11 is not available, and thus cannot be used for clinical practice. CD34 selection with clinical-grade products is widely used for the isolation of hematopoietic progenitors, and endothelial cells (EC) express CD34 on their surfaces. The aims of this study were to test the effectiveness of two different CD34-selection techniques for purification of MVEC, and to compare the results with those of the F11/CD14-method. METHODS: Liposuction fat was enzymatically digested and centrifuged twice to remove adipocytes and collagenase. CD34 selection was performed using the commercially available methods from Nexell or Miltenyi. Both techniques were modified for our use. The purity after isolation and culture, and recovery were determined by flow-cytometry (CD31-expression) and compared with that of cells purified with the F11/CD14-method. RESULTS: Besides MVEC, the contaminating fibroblasts and macrophages/monocytes weakly expressed the CD34 Ag. Enrichment of MVEC was not successful with the Miltenyi method. Variations in neither the dose of Ab nor the use of direct selection and different separation programs improved the results. With the Nexell method, MVEC were enriched to 86%, a comparable purity to that obtained with the F11/CD14-method. However, a lower recovery was achieved with the Nexell method. CONCLUSION: Enrichment of MVEC could be achieved with a modified protocol of the clinical grade CD34(+) selection method from Nexell, but not with the CD34 method from Miltenyi.

Adipose Tissue↗

PubMed2004

In vivo transluminal microvascular endothelial cell seeding on balloon injured rabbit arteries.

AIM: Seeding venous endothelial cells (EC) onto damaged vascular surfaces attenuates the development of intimal hyperplasia. Unlike venous EC, fat derived microvascular endothelial cells (MVEC) do not require a culture step to increase the yield. The authors investigated whether fat derived MVEC are suitable to reduce intimal hyperplasia after PTA. METHODS: Five rabbits were subjected to percutaneous transluminal angioplasty (PTA) of both iliac arteries. One side was seeded transluminally with autologous perirenal fat derived MVEC, using a double balloon catheter. The contralateral side was sham seeded, and served as a control. Follow-up was 4 weeks. Another rabbit was used for a feasibility experiment. This rabbit was subjected to a 1-sided seeding procedure and was sacrificed after 1 week. In a 7th rabbit, a 1-sided PTA was transformed, and autologous labelled cells were injected in the distal aorta instead of seeded, follow-up was 1 week. Histological investigation was per-formed. RESULTS: The MVEC seeded artery of the pilot experiment was patent. All sham seeded arteries (5) except for 1 were patent. The patent ones showed moderate intimal hyperplasia. MVEC seeding (5) resulted in occlusion twice. In the patent MVEC seeded arteries intimal hyperplasia was present in more extended form than in the sham seeded arteries. Both the patent MVEC- and sham-seeded arteries were covered with an EC layer. Injected labelled MVEC were not found again on the de-endothelialized artery. CONCLUSION: In this study seeding of fat derived MVEC on damaged native arteries results in an increased development of intimal hyperplasia and a decreased patency. One of the reasons may be the presence of non-EC in the seeded cell population.

Angioplasty, Balloon, Coronary↗

PubMed2003

[Endovascular treatment of 4 patients with a traumatic rupture of the thoracic aorta].

OBJECTIVE: To present our initial results with the endovascular treatment of traumatic rupture of the thoracic aorta. DESIGN: Retrospective. METHOD: Between April and October, 2002, 4 men between the ages of 22 and 46 were treated endovascularly for a traumatic rupture of the thoracic aorta. The diagnosis 'rupture of the thoracic aorta' was made on the basis of CT-angiography in all cases. In the first case, a thoracic Gore TAG-endoprosthesis (Gore & Associates; Den Bosch) was used, and in 3 cases a Talent-endoprosthesis (Medtronic AVG; Heerlen). RESULTS: There was an average of 2.5 days (limits: 0-5 days) between admission and the placement of the endoprosthesis. There was one intra-operative complication in the form of a dissection of the right femoral artery when the endoprosthesis was inserted. In 3 cases, the left subclavian artery was occluded by the prosthesis. This had no negative consequences for the patients during the follow-up period (limits: 4-12 months). The CT-angiogram taken 3 months after the operation consistently showed a good position of the endoprosthesis with no signs of leakage. CONCLUSION: For a limited follow-up period, the endovascular treatment of a traumatic rupture of the thoracic aorta has been shown to be safe and effective. The long term results must be awaited.

Adult↗

PubMed2003

[Treatment of abdominal aortic aneurysms].

Three treatment options are available for an asymptomatic abdominal aortic aneurysm (AAA): an expectant approach with ultrasonographic check-ups, reconstruction of the abdominal aorta via the conventional ('open') approach and endovascular repair. For aneurysms less than 5.5 cm in diameter the annual rupture risk is less than 1%. For these patients a better alternative to the expectant approach does not seem to exist. The risk of rupture needs to be weighed up against the risks of a conventional operation. The operation mortality of patients with a non-ruptured AAA is about 7% while other serious complications occur in about 10%. The short to medium-term results of endovascular aneurysm repair are characterized by high reintervention rates, material fatigue and device failure. The three treatment options described are currently being investigated in several large-scale randomised studies for AAAs greater than 5.5 cm in diameter.

Aorta, Abdominal↗

PubMed2003

Rapid, arteriovenous graft failure due to intimal hyperplasia: a porcine, bilateral, carotid arteriovenous graft model.

BACKGROUND: The loss of patency constitutes the major complication of arteriovenous (AV) polytetrafluoroethylene hemodialysis grafts. In most cases, this graft failure is due to intimal hyperplasia at the venous outflow tract, including proliferation of vascular, smooth muscle cells and fibroblasts with deposition of extracellular matrix proteins. Thus far, procedures developed for improving patency have proven unsuccessful, which can be partly explained by the lack of relevant animal models. For this purpose, we developed a porcine model for AV graft failure that will allow the assessment of promising therapeutic strategies in the near future. MATERIALS AND METHODS: In 14 pigs, AV grafts were created bilaterally between the carotid artery and the jugular vein using expanded polytetrafluoroethylene. Two, 4 or 8 weeks after AV shunting, the grafts and adjacent vessels were excised and underwent histologic analysis. RESULTS: From 2 weeks onwards, a thick neo-intima developed at the venous anastomosis, predominantly consisting of alpha-actin-positive vascular smooth muscle cells (VSMC). Intimal area increased over time, coinciding with a decreased graft flow. Grafts remained patent for at least 4 weeks. At 8 weeks, patency rates declined to less than 50% due to thrombus formation superimposed on progressive neo-intima formation. CONCLUSIONS: Implantation of an AV graft between the carotid artery and jugular vein in pigs causes a rapid neo-intimal response, accompanied by a loss of patency of 50% at 8 weeks after surgery. This model offers a suitable tool to study local interventions aimed at the improvement of AV graft patency rates.

Animals↗

PubMed2003

Screening for asymptomatic internal carotid artery stenosis and aneurysm of the abdominal aorta: comparing the yield between patients with manifest atherosclerosis and patients with risk factors for atherosclerosis only.

OBJECTIVE: The purpose of this study was to investigate whether screening for internal carotid artery stenosis (ICAS) and aneurysm of the abdominal aorta (AAA) is indicated in patients with either manifest atherosclerotic disease or with only risk factors for atherosclerosis. STUDY DESIGN: Data were obtained for 2274 patients enrolled in the SMART study, an ongoing single-center, prospective cohort study of patients referred to our vascular center with manifest atherosclerotic disease (peripheral atherosclerotic disease [PAD]; transient ischemic attack [TIA], stroke, or ICAS; AAA; angina pectoris; or myocardial infarction [MI]) or with only risk factors for atherosclerosis (diabetes mellitus, hypertension, hyperlipidemia). The presence of ICAS or AAA was determined with duplex scanning and ultrasonography. RESULTS: The prevalence of ICAS 70% or greater is low in patients with risk factors for atherosclerosis only (1.8%-2.3%), intermediate in patients with angina pectoris or MI (3.1%), and highest in patients with PAD (12.5%) or AAA (8.8%). The prevalence of AAA 3 cm or larger is low in patients with risk factors for atherosclerosis only (0.4-1.6%), intermediate in patients with angina pectoris or MI (2.6%), and highest in patients with PAD (6.5%) or TIA, stroke, or ICAS (6.5%). The prevalence of AAA larger than 5 cm is low in all of the considered patient groups. The yield of screening can be optimized through selection on the basis of simple patient characteristics. In patients with PAD, selecting those with advanced age (>54 years) increased the prevalence of ICAS to 21.8%. Selecting patients with lower diastolic blood pressure (<83 mm Hg) increased the prevalence of ICAS to 17.9%. In patients with both advanced age and lower diastolic blood pressure, the prevalence of ICAS increased to 34.7%. Selecting patients with advanced age increased the prevalence of AAA 3 cm or larger to 9.6%. In patients with TIA, stroke, or ICAS, selecting those with advanced age increased the prevalence of AAA 3 cm or larger to 8.2%. Selecting patients with taller stature (>169 cm) increased the prevalence of AAA 3 cm or larger to 9.3%. In patients with advanced age and taller stature, the prevalence of AAA 3 cm or larger increased to 13.1%. CONCLUSIONS: Screening for ICAS should be limited to patients referred with PAD or AAA, especially those with advanced age or with low diastolic blood pressure. Screening for AAA should be limited to patients referred with PAD or with TIA, stroke, or ICAS, particularly those with advanced age or tall stature. In patients referred with angina pectoris or MI and those referred with only risk factors for atherosclerosis, screening cannot be endorsed.

Adult↗

PubMed2003

Decision-making in follow-up after endovascular aneurysm repair based on diameter and volume measurements: a blinded comparison.

OBJECTIVE: to assess whether volume, in addition to diameter, measurements facilitate decision-making after endovascular aneurysm repair (EVAR). MATERIAL/METHODS: patients (n = 82) with an immediately post-EVAR, and at least one follow-up (3-60 months), computed tomographic angiogram (CTA) were studied. The actual and all preceding proportional sac size changes were recorded. The resulting 347 diameter and 347 volume data were placed in random order and reviewed by three blinded observers who then recommended one of three treatment policies: "good/wait", "uncertain/intensify follow-up" or "not good/further diagnostics (Dx) or intervention (Rx)". The observers were instructed to consider changes of 10% relevant. One observer reviewed the graphs twice. RESULTS: the interobserver agreements (kappa) for the diameter were 0.92, 0.81 and 0.76 and for volumes 0.91, 0.88 and 0.86. The intra-observer agreement was 0.93 for both diameter and volume. Volume data resulted in significantly more "good/wait" decisions out to 36 months. Diameter data resulted in more "not good/Dx or Rx"-decisions out to 36 months (all p < 50.005). CONCLUSION: post-EVAR aneurysm sac volume data appears to provide earlier reassurance, reduce unnecessary interventions and to be more sensitive to secondary problems than diameter data alone.

Aneurysm↗

PubMed2002

Contaminants from the transplant contribute to intimal hyperplasia associated with microvascular endothelial cell seeding.

OBJECTIVES: seeding prosthetic grafts with fat-derived microvascular endothelial cells (MVEC) results not only in a non-thrombogenic EC layer, but also in intimal hyperplasia. Here we investigated incidence, composition, progression, and cause of this intimal hyperplasia. DESIGN: EPTFE grafts with MVEC were implanted as carotid interpositions in six dogs with 1 month, and in three dogs with 4, 8 and 12 months follow-up. Grafts seeded without cells, implanted in the contralateral carotid, served as a control. In another three dogs labelled cells were seeded to investigate the contribution of the seeded cells (2-3 weeks). MATERIALS AND METHODS: MVEC were isolated from the falciform ligament. Cells were pressure seeded on ePTFE grafts. Labelling was performed using retroviral gene transduction. The grafts were analysed with immunohistochemical techniques. RESULTS: after 1 month, all patent non-seeded grafts (5/6) showed fibrin and platelet deposition, and all patent seeded grafts (5/6) were covered with a confluent endothelial monolayer on top of a multilayer of myofibroblasts, elastin and collagen. After long term follow-up, all non-seeded grafts were occluded, all patent seeded grafts (4 and 12 months) were covered with an EC-layer with intimal hyperplasia underneath. The thickness of the intima did not progress after 1 month. Transduced cells were found in the endothelial monolayer, hyperplastic intima and luminal part of the prosthesis. CONCLUSIONS: MVEC seeding in dogs results in intimal hyperplasia in all patent grafts, which contains myofibroblasts. Contaminants from the transplant contribute to this intimal hyperplasia.

Animals↗

PubMed2002

Reduction of non-endothelial cell contamination of microvascular endothelial cell seeded grafts decreases thrombogenicity and intimal hyperplasia.

INTRODUCTION: fat derived microvascular endothelial cells (MVEC) seeded on prosthetic vascular grafts, improve patency in animals. Results in humans were disappointing, due to thrombogenicity and progressive intimal hyperplasia. Also in animals intimal hyperplasia was found. We postulate that contaminating cells present in the transplant are involved in the intimal hyperplasia. We developed a method to further purify human MVEC from 40-90%. Here we tested the effects of enrichment upon thrombogenicity and seeding-related intimal hyperplasia. METHODS: liposuction fat was enzymatically digested and centrifuged. To enrich MVEC, contaminating macrophages and fibroblasts were removed with dynabeads coated with macrophage- and fibroblast-specific antibodies. Thrombogenicity was assessed by measuring tissue factor and thrombomodulin activity, presence of endothelial nitric oxide synthase and via perfusion of the cells with whole blood. To investigate seeding-related intimal hyperplasia, PTFE grafts were seeded with the cells and cultured for 3 weeks. RESULTS: tissue factor activity of purified cells was reduced compared to nonpurified cells. Purified cells showed thrombomodulin activity and eNOS expression. Fragment 1+2 and Fibrinopeptide A generation after perfusion of purified cells were significantly lower than after perfusion of nonpurified cells, and only nonpurified cells were covered with platelets and fibrin. Prostheses seeded with nonpurified cells showed an EC monolayer above a multilayer of myofibroblasts, prostheses seeded with purified cells only showed a single EC monolayer. Mixing experiments with human umbilical cord EC (HUVEC) and fibroblasts showed that when more than 25% HUVEC were present a confluent EC layer was formed. When the amount of fibroblasts was 25% or less, no development of a subendothelial multilayer of myofibroblasts was found within 3 weeks. CONCLUSION: reduction of non-endothelial cell contamination of microvascular endothelial cell seeded grafts decreases thrombogenicity and might prevent seeding-related intimal hyperplasia.

Cell Separation↗