B C Eikelboom

University Medical Center Utrecht, Utrecht, Utrecht, Netherlands

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Publications (243)651.47 Total impact

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    Journal of Vascular Surgery 10/2010; 52(4):825-33. · 2.98 Impact Factor
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    ABSTRACT: Dual antiplatelet therapy with clopidogrel plus acetylsalicylic acid (ASA) is superior to ASA alone in patients with acute coronary syndromes and in those undergoing percutaneous coronary intervention. We sought to determine whether clopidogrel plus ASA conferred benefit on limb outcomes over ASA alone in patients undergoing below-knee bypass grafting. Patients undergoing unilateral, below-knee bypass graft for atherosclerotic peripheral arterial disease (PAD) were enrolled 2 to 4 days after surgery and were randomly assigned to clopidogrel 75 mg/day plus ASA 75 to 100 mg/day or placebo plus ASA 75 to 100 mg/day for 6 to 24 months. The primary efficacy endpoint was a composite of index-graft occlusion or revascularization, above-ankle amputation of the affected limb, or death. The primary safety endpoint was severe bleeding (Global Utilization of Streptokinase and Tissue plasminogen activator for Occluded coronary arteries [GUSTO] classification). In the overall population, the primary endpoint occurred in 149 of 425 patients in the clopidogrel group vs 151 of 426 patients in the placebo (plus ASA) group (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.78-1.23). In a prespecified subgroup analysis, the primary endpoint was significantly reduced by clopidogrel in prosthetic graft patients (HR, 0.65; 95% CI, 0.45-0.95; P = .025) but not in venous graft patients (HR, 1.25; 95% CI, 0.94-1.67, not significant [NS]). A significant statistical interaction between treatment effect and graft type was observed (P(interaction) = .008). Although total bleeds were more frequent with clopidogrel, there was no significant difference between the rates of severe bleeding in the clopidogrel and placebo (plus ASA) groups (2.1% vs 1.2%). The combination of clopidogrel plus ASA did not improve limb or systemic outcomes in the overall population of PAD patients requiring below-knee bypass grafting. Subgroup analysis suggests that clopidogrel plus ASA confers benefit in patients receiving prosthetic grafts without significantly increasing major bleeding risk.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 10/2010; 52(4):825-33, 833.e1-2. DOI:10.1016/j.jvs.2010.04.027 · 2.98 Impact Factor
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    ABSTRACT: Background: The purpose of this study was to determine the cerebrovascular risk stratification potential of baseline degree of stenosis, clinical features, and ultrasonic plaque characteristics in patients with asymptomatic internal carotid artery (ICA) stenosis. Methods: This was a prospective, multicenter, cohort study of patients undergoing medical intervention for vascular disease. Hazard ratios for ICA stenosis, clinical features, and plaque texture features associated with ipsilateral cerebrovascular or retinal ischemic (CORI) events were calculated using proportional hazards models. Results: A total of 1121 patients with 50% to 99% asymptomatic ICA stenosis in relation to the bulb (European Carotid Surgery Trial [ECST] method) were followed-up for 6 to 96 months (mean, 48). A total of 130 ipsilateral CORI events occurred. Severity of stenosis, age, systolic blood pressure, increased serum creatinine, smoking history of more than 10 pack-years, history of contralateral transient ischemic attacks (TIAs) or stroke, low grayscale median (GSM), increased plaque area, plaque types 1, 2, and 3, and the presence of discrete white areas (DWAs) without acoustic shadowing were associated with increased risk. Receiver operating characteristic (ROC) curves were constructed for predicted risk versus observed CORI events as a measure of model validity. The areas under the ROC curves for a model of stenosis alone, a model of stenosis combined with clinical features and a model of stenosis combined with clinical, and plaque features were 0.59 (95% confidence interval [CI] 0.54-0.64), 0.66 (0.62-0.72), and 0.82 (0.78-0.86), respectively. In the last model, stenosis, history of contralateral TIAs or stroke, GSM, plaque area, and DWAs were independent predictors of ipsilateral CORI events. Combinations of these could stratify patients into different levels of risk for ipsilateral CORI and stroke, with predicted risk close to observed risk. Of the 923 patients with <70% stenosis, the predicted cumulative 5-year stroke rate was <5% in 495, 5% to 9.9% in 202, 10% to 19.9% in 142, and <20% in 84 patients. Conclusion: Cerebrovascular risk stratification is possible using a combination of clinical and ultrasonic plaque features. These findings need to be validated in additional prospective studies of patients receiving optimal medical intervention alone.
    Journal of Vascular Surgery 01/2010; 52(6):1486-1496. · 2.98 Impact Factor
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    ABSTRACT: Patients with peripheral arterial disease are at high risk of ischemic events and therefore are treated with antithrombotics. In patients with coronary artery disease or cerebrovascular disease, bleeding is related to the subsequent occurrence of ischemic events. Our objective was to assess whether this is also the case in patients with peripheral arterial disease. All patients from the Dutch Bypass and Oral Anticoagulants or Aspirin (BOA) Study, a multicenter randomized trial comparing oral anticoagulants with aspirin after infrainguinal bypass surgery, were included. The primary outcome event was the composite of nonfatal myocardial infarction, nonfatal ischemic stroke, major amputation, and cardiovascular death. To identify major bleeding as an independent predictor for ischemic events, crude and adjusted hazard ratios with 95% confidence intervals were calculated with multivariable Cox regression models. From 1995 until 1998, 2650 patients were included with 101 nonfatal major bleedings. During a mean follow-up of 14 months, the primary outcome event occurred in 218 patients; 22 events were preceded by a major bleeding. The mean time between major bleeding and the primary outcome event was 4 months. Major bleeding was associated with a 3-fold increased risk of subsequent ischemic events (crude hazard ratio, 3.0; 95% confidence interval, 1.9 to 4.6; adjusted hazard ratio, 3.0; 95% confidence interval, 1.9 to 4.7). In patients with peripheral arterial disease, as in patients with coronary artery disease or cerebrovascular disease, major bleeding was independently associated with major ischemic complications. Without compromising the benefits of antithrombotics, these findings call for caution relative to the risks of major bleeding.
    Circulation 10/2009; 120(16):1569-76. DOI:10.1161/CIRCULATIONAHA.109.858365 · 14.95 Impact Factor
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    ABSTRACT: Objectives: This study tested the hypothesis that silerit embolic infarcts on computed tomography (CT) brain scans can predict ipsilateral neurologic hemispheric events and stroke in patients with asymptomatic internal carotid artery stenosis. Methods: In a prospective multicenter natural history study, 821 patients with asymptomatic carotid stenosis graded with duplex scanning who had CT brain scans were monitored every 6 months for a maximum of 8 years. Duplex scans were reported centrally, and stenosis was expressed as a percentage in relation to the normal distal internal carotid criteria used by the North American Symptomatic Carotid Endarterectomy Trialists. CT brain scans were reported centrally by a neuroradiologist. In 146 patients (17.8%), 8 large cortical, 15 small cortical, 72 discrete subcortical, and 51 basal ganglia ipsilateral infarcts were present; these were considered likely to be embolic and were classified as such. Other infarct types, lacunes (n = 15), watershed (n = 9), and the presence of diffuse white matter changes (n = 95) were not considered to be embolic. Results: During a mean follow-up of 44.6 months (range, 6 months-8 years), 102 ipsilateral hemispheric neurologic events (amaurosis fugax in 16, 38 transient ischemic attacks [TIAs], and 47 strokes) occurred, 138 patients died, and 24 were lost to follow-up. In 462 patients with 60% to 99% stenosis, the cumulative event-free rate at 8 years was 0.81 (2.4% annual event rate) when embolic infarcts were absent and 0.63 (4.6% annual event rate) when present (log-rank P = .032). In 359 patients with <60% stenosis, embolic infarcts were not associated with increased risk (log-rank P = .65). In patients with 60% to 99% stenosis, the cumulative stroke-free rate was 0.92 (1.0% annual stroke rate) when embolic infarcts were absent and 0.71 (3.6% annual stroke rate) when present (log-rank P = .002). In the subgroup of 216 with moderate 60% to 79% stenosis, the cumulative TIA or stroke-free rate in the absence and presence of embolic infarcts was 0.90 (1.3% annual rate) and 0.65 (4.4% annual rate), respectively (log-rank P = .005). Conclusion: The presence of silent embolic infarcts can identify a high-risk group for ipsilateral hemispheric neurologic events and stroke and may prove useful in the management of patients with moderate asymptomatic carotid stenosis.
    Journal of Vascular Surgery 01/2009; 49(4):902-909. · 2.98 Impact Factor
  • Seminars in Interventional Radiology 03/2008; 15(01):81-88. DOI:10.1055/s-2008-1057061
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    ABSTRACT: We investigated whether total cerebral blood flow (CBF) was associated with brain atrophy, and whether this relation was modified by white matter lesions (WML). Within the Second Manifestations of ARTerial disease-magnetic resonance (SMART-MR) study, a prospective cohort study among patients with arterial disease, cross-sectional analyses were performed in 828 patients (mean age 58±10 years, 81% male) with quantitative flow, atrophy, and WML measurements on magnetic resonance imaging (MRI). Total CBF was measured with MR angiography and was expressed per 100 mL brain volume. Total brain volume and ventricular volume were divided by intracranial volume to obtain brain parenchymal fraction (BPF) and ventricular fraction (VF). Lower BPF indicates more global brain atrophy, whereas higher VF indicates more subcortical brain atrophy. Mean CBF was 52.0±10.2 mL/min per 100 mL, mean BPF was 79.2±2.9%, and mean VF was 2.03±0.96%. Linear regression analyses showed that lower CBF was associated with more subcortical brain atrophy, after adjusting for age, sex, vascular risk factors, intima-media thickness, and lacunar infarcts, but only in patients with moderate to severe WML (upper quartile of WML): Change in VF per s.d. decrease in CBF 0.18%, 95% CI: 0.02 to 0.34%. Our findings suggest that cerebral hypoperfusion in the presence of WML may be associated with subcortical brain atrophy.
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    ABSTRACT: To compare the consequences of occlusion of infrainguinal venous and prosthetic grafts. In total, 2690 patients were included in the Dutch BOA study, a multicenter randomised trial that compared the effectiveness of oral anticoagulants with aspirin in the prevention of infrainguinal bypass graft occlusion. Two thousand four hundred and four patients received a femoropopliteal or femorodistal bypass with a venous (64%) or prosthetic (36%) graft. The incidence of occlusion and amputation was calculated according to graft material and the incidence of amputation after occlusion was compared with Cox regression to adjust for differences in prognostic factors. The indication for operation was claudication in 51%, rest pain in 20% and tissue loss in 28% of patients. The mean follow up was 21 months. After venous bypass grafting 171 (15%) femoropopliteal and 96 (24%) femorodistal grafts occluded. After prosthetic bypass grafting 234 (30%) femoropopliteal and 25 (38%) femorodistal grafts occluded. Patients with occlusions in the venous group had more severe ischemia, less runoff vessels and were older than the patients with prosthetic grafts. In the venous occlusion group 54 (20%) amputations were performed compared to 42 (16%) in the prosthetic occlusion group; crude hazard ratio 1.17 (95% CI 0.78-1.75). After adjustment for above mentioned differences in patient characteristics the hazard ratio was 0.86 (95% CI 0.56-1.32). The need for amputation after occlusion is not influenced by graft material in infrainguinal bypass surgery.
    European Journal of Vascular and Endovascular Surgery 01/2006; 30(6):604-9. DOI:10.1016/j.ejvs.2005.06.023 · 3.07 Impact Factor
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    ABSTRACT: Patch closure after carotid endarterectomy (CEA) improves clinical outcome compared with primary closure. Whether there are differences in outcome between various patch materials is still not clear. The objective of this retrospective study was to investigate whether a relationship exists between the patch type and the number of microemboli as registered during CEA by transcranial Doppler imaging, the clinical outcome (transient ischemic attack and cerebrovascular accident), and the occurrence of restenosis. We included 319 patients who underwent CEA. Intraoperative microembolus registration was performed in 205 procedures. Microembolization was recorded during four different periods: dissection, shunting, clamp release, and wound closure. The decision to perform primary closure or to use a patch for the closure of the arteriotomy was made by the surgeon, and Dacron patches were used when venous material was insufficient. Cerebral events were recorded within the first month after CEA, and duplex scanning was performed at 3 months (n = 319) and 1 year (n = 166) after CEA. A diameter reduction of more than 70% was defined as restenosis. Primary, venous, and Dacron patch closures were performed in 83 (26.0%), 171 (53.6%), and 65 (20.4%) patients, respectively. Primary closure was significantly related to sex (Dacron patch, 35 men and 30 women; venous patch, 108 men and 63 women; primary closure, 72 men and 11 women; P < .001). The occurrence of microemboli during wound closure was also related to sex (women, 2.5 +/- 0.6; men, 1.0 +/- 0.2; P = .01). Additionally, during clamp release, Dacron patches were associated with significantly more microemboli than venous patches (11.1 +/- 3.4 vs 4.0 +/- 0.9; P < .01), and this difference was also noted during wound closure (3.1 +/- 0.9 vs 1.4 +/- 0.4; P < .05). Transient ischemic attacks and minor strokes after CEA occurred in 5 (2.4%) of 205 and 6 (2.9%) of 205 procedures, respectively, and the degree of microembolization during dissection was related to adverse cerebral events (P = .003). In contrast, the type of closure was not related to immediate clinical adverse events. However, primary closure and Dacron patches were associated with an increase in the restenosis rate compared with venous patches: after 400 days, the restenosis rate for Primary closure was 11%, Dacron patch 16%, and venous patch 7% (P = .05; Kaplan-Meier estimates). Microemboli are more prevalent during clamp releases and wound closure when Dacron patches are used. Additionally, the observed differences in embolization noted by patch type were mainly evident in women. However, the use of Dacron patches was not related to immediate ischemic cerebral events but was associated with a higher restenosis rate compared with venous patch closure. This suggests that venous patch closure may be preferred for CEA.
    Journal of Vascular Surgery 01/2006; 42(6):1082-8. DOI:10.1016/j.jvs.2005.08.011 · 2.98 Impact Factor
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    ABSTRACT: This study investigated whether recommendations given to the treating vascular specialist and the GP by a multidisciplinary team of vascular specialists concerning the medical treatment of risk factors, based on international guidelines, led to an increased medication use in a high-risk population. Data were obtained from 618 patients enrolled in the SMART study, an ongoing single-center prospective cohort study of patients referred to the University Medical Center Utrecht for atherosclerotic vascular diseases. All patients underwent a vascular screening and their physicians received recommendations concerning the medical treatment of newly detected or not yet sufficiently treated vascular risk factors. After a median follow-up of 29 months, questionnaires about medication use were sent to 618 patients; 534 (86%) questionnaires were returned. Actual use of medication was compared with medical treatment recommendation given at baseline. The proportion of patients on antihypertensive medication with hypertension (> or =140/90 mmHg) and not diagnosed with coronary heart disease increased from 56% to 68% (95% confidence interval (95% CI) 2 - 23). The frequency of lipid-lowering medication use increased substantially from 47% to 69% (95% CI 17 - 28). The frequency of glucose-lowering medication use increased slightly from 11% to 14% (95% CI 1 - 7). The use of folic acid increased from 2% to 14% (95% CI 9 - 15) in patients with hyperhomocysteinaemia. Medical treatment recommendations, formulated by a multidisciplinary team, led to a significant increase in medication use. The increase is marginal compared with trends in medication use without this intervention in usual care.
    Cardiovascular Drugs and Therapy 12/2005; 19(6):429-35. DOI:10.1007/s10557-005-6127-8 · 2.95 Impact Factor
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    ABSTRACT: The beneficial effect of oral anticoagulants after infrainguinal venous bypass surgery is compromised by bleeding complications. We developed a model to identify patients, treated with anticoagulation, at risk of major haemorrhage and estimated whether this complication could have been prevented if patients had received aspirin. Randomised clinical trial. Data of patients who participated in the Dutch Bypass Oral Anticoagulation or Aspirin Study were reanalysed using Cox regression. After infrainguinal bypass surgery these patients were randomised to oral anticoagulants (n = 1326) or aspirin (n = 1324). Predictors of major haemorrhage for patients on oral anticoagulants were increased systolic blood pressure (> or = 140 mmHg, hazard ratio [HR] 1.62), age > or = 75 years (HR 2.77) and diabetes mellitus (HR 1.60). If the 345 patients in the highest risk quartile had received aspirin, major haemorrhages would have been reduced from 46 to 22, with no major changes in ischemic events and graft occlusions. In the subgroup with venous bypasses major haemorrhages would have been reduced from 27 to 13, at the cost of seven more ischemic events (mostly fatal) and 17 more graft occlusions. Treating patients at highest risk of major haemorrhage with aspirin instead of oral anticoagulants would have resulted in a reduction of non-fatal haemorrhages, but for venous bypasses this reduction was outweighed by an increase in ischemic events and graft occlusions. We still recommend treatment with oral anticoagulants after peripheral venous bypass surgery.
    European Journal of Vascular and Endovascular Surgery 08/2005; 30(2):154-9. DOI:10.1016/j.ejvs.2005.03.005 · 3.07 Impact Factor
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    ABSTRACT: To assess the cost-effectiveness of noninvasive imaging strategies in patients who have had a transient ischemic attack (TIA) or minor stroke and are suspected of having significant carotid artery stenosis. From 1997 through 2000, 350 patients were included in a multicenter blinded consecutive cohort study. The sensitivities and specificities of duplex ultrasonography (US), magnetic resonance (MR) angiography, and these two examinations combined were estimated by using digital subtraction angiography (DSA) as the reference standard. The actual costs (from a societal perspective) of performing imaging and endarterectomy were estimated. The survival, quality of life, and costs associated with stroke were based on data reported in the literature. Markov modeling was used to predict long-term outcomes. Subsequently, a decision model was used to calculate costs, quality-adjusted life-years (QALYs), and incremental costs per QALY gained for 62 examination-treatment strategies. Extensive sensitivity analyses were performed. Duplex US had 88% sensitivity and 76% specificity with use of conventional cutoff criteria. MR angiography had comparable values: 92% sensitivity and 76% specificity. Combined concordant duplex US and MR angiography had superior diagnostic performance: 96% sensitivity and 80% specificity. Duplex US alone was the most efficient strategy. Adding MR angiography led to a marginal increase in QALYs gained but at prohibitive costs (cost-effectiveness ratio > 1 500 000 per QALY gained). Performing DSA owing to discordant duplex US and MR angiographic findings and to confirm duplex US and MR angiographic findings led to extra costs and QALY loss owing to complications. Sensitivity analyses revealed that duplex US as a stand-alone examination remained the preferred strategy while estimates and assumptions were varied across plausible ranges. Duplex US performed without additional imaging is cost-effective in the selection of symptomatic patients suitable for endarterectomy. Adding MR angiography increases effectiveness slightly at disproportionately high costs, whereas DSA is inferior because of associated complications.
    Radiology 11/2004; 233(1):101-12. DOI:10.1148/radiol.2331030863 · 6.21 Impact Factor
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    ABSTRACT: 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. 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. 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. 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.
    The Journal of cardiovascular surgery 05/2004; 45(2):129-37. · 1.37 Impact Factor
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    ABSTRACT: 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. 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. 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. 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.
    Cytotherapy 02/2004; 6(1):30-42. DOI:10.1080/14653240310004476 · 3.10 Impact Factor
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    ABSTRACT: Tracing and treating cardiovascular risk factors in patients with arterial vascular disease and in patients with high risk of developing vascular diseases. Descriptive. In September 1996 at the University Medical Center Utrecht, the Netherlands, a vascular screening and prevention programme was started for newly referred patients aged between 18 and 79 years presenting with one or more of the following: coronary artery disease, cerebrovascular disease, peripheral arterial disease, hypertension, diabetes mellitus or lipid disorders. In all patients, risk factors for developing (new) vascular diseases were assessed and non-invasive vascular diagnostics aimed at finding asymptomatic vascular disease were done. Between 1 September 1996 and 31 October 2002, 3075 patients took part in the screening programme. Within the various patient groups and often despite treatment, there was a high prevalence of hypertension, smoking, dyslipidaemia, hyperhomocystemia and overweight. In patients with peripheral artery disease, carotid artery stenosis > or = 50% was detected in 17% and an aneurysm of the abdominal aorta in 5%. In patients presenting with diabetes mellitus, hypertension or lipid disorders the prevalence of asymptomatic arterial disease was 1-5%. Asymptomatic vaso-dilatory disease in particular was uncommon. A hospital-wide vascular screening and prevention programme for a wide range of high-risk vascular patients was shown to be feasible and resulted in the detection of risk factors and asymptomatic arterial disease. It is a reliable starting point for actual risk intervention. More attention should be paid to treating existing risk factors.
    Nederlands tijdschrift voor geneeskunde 11/2003; 147(48):2376-82.
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    Journal of Vascular Surgery 10/2003; 38(3):629. DOI:10.1016/S0741-5214(03)00469-5 · 2.98 Impact Factor
  • F L J Visseren, B C Eikelboom
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    ABSTRACT: Patients with peripheral artery disease suffer from a high incidence of ischemic vascular complications in coronary, cerebral, and peripheral vascular beds. Reduction of atherothrombotic complications with aspirin or clopidogrel has proven to be successful. The role of oral anticoagulants in patients with symptomatic peripheral artery is limited. Randomized controlled trials comparing the effects of aspirin with oral anticoagulants are scarce. Oral anticoagulants (International Normalized Ratio = 2.5 to 4.5) are more effective than aspirin in preventing infrainguinal bypass occlusion only when venous graft material is used and the bypass is considered to be at high risk for occlusion. Whether the use of oral anticoagulants reduces all-cause morbidity and mortality is not unequivocally clear. The risk of ischemic events is reduced at the expense of an increased number of bleeding complications, which is one of the main reasons that therapy has not been widely adopted.
    Seminars in Vascular Medicine 09/2003; 3(3):339-44. DOI:10.1055/s-2003-44470
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    ABSTRACT: To assess accuracy of contrast material-enhanced magnetic resonance (MR) angiography as compared with three-dimensional (3D) time-of-flight (TOF) MR angiography and reference digital subtraction angiography (DSA) in diagnosis of carotid artery stenosis. Enhanced and 3D TOF MR angiography and DSA were performed in 51 consecutive patients suspected of having carotid artery stenosis at duplex ultrasonography. Stenoses were measured by two independent observers blinded to clinical information and other test results. Pearson correlation coefficients were used, and kappa for interobserver variabilities was estimated. Sensitivity and specificity of enhanced and 3D TOF MR angiography were calculated and compared with those of DSA. Pearson correlation coefficients were 0.94 (P <.01) for enhanced angiography versus DSA, 0.92 (P <.01) for 3D TOF angiography versus DSA, and 0.93 (P <.01) for enhanced versus 3D TOF angiography for observer 1 and 0.94 (P <.01), 0.95 (P <.01), and 0.94 (P <.01), respectively, for observer 2. kappa statistics were 0.81 for enhanced angiography, 0.79 for 3D TOF angiography, and 0.78 for DSA. Stenosis measurements of observer 1 at enhanced MR angiography, with inclusion of carotid arteries on the symptomatic side only, compared with those of DSA yielded a sensitivity of 90% (95% CI: 68%, 99%) and a specificity of 77% (95% CI: 55%, 92%). 3D TOF angiography yielded a sensitivity of 86% (95% CI: 67%, 97%) and a specificity of 73% (95% CI: 50%, 89%) compared with those of DSA. For observer 2, sensitivity and specificity for enhanced angiography were 91% (95% CI: 70%, 99%) and 76% (95% CI: 52%, 91%), respectively, and 90% (95% CI: 68%, 99%) and 77% (95% CI: 51%, 92%), respectively, for 3D TOF angiography. Accuracy of enhanced MR angiography in diagnosis of severe stenosis is similar to that of 3D TOF MR angiography.
    Radiology 09/2003; 228(3):677-82. DOI:10.1148/radiol.2283020824 · 6.21 Impact Factor

Publication Stats

4k Citations
651.47 Total Impact Points

Institutions

  • 1989–2009
    • University Medical Center Utrecht
      • • Laboratory of Experimental Cardiology
      • • Julius Center for Health Sciences and Primary Care
      • • Department of Hematology
      • • Department of Surgery
      • • Department of Nephrology
      • • Department of Radiology
      Utrecht, Utrecht, Netherlands
  • 2002
    • Medisch Centrum Haaglanden
      's-Gravenhage, South Holland, Netherlands
  • 1994–2002
    • Utrecht University
      • Department of Epidemiology
      Utrecht, Utrecht, Netherlands
  • 1998
    • Philips
      Eindhoven, North Brabant, Netherlands
  • 1995
    • University of Amsterdam
      Amsterdamo, North Holland, Netherlands
  • 1982–1994
    • St. Antonius Ziekenhuis
      • • Department of Vascular Surgery
      • • Department of Surgery
      • • Department of Radiology
      Nieuwegen, Utrecht, Netherlands