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Biomedical subjects

J A van der Vliet

Publications and source records attributed to J A van der Vliet.

At least 19 recordsLinked to original sources

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↗

Time course of proteinuria after living-donor kidney transplantation.

BACKGROUND: After cadaveric kidney transplantation, preservation-reperfusion damage results in glomerular and tubular proteinuria. There are no data on the time course of proteinuria after living-donor (LD) transplantation. METHODS: In 10 patients receiving a kidney graft from an LD, the excretion of high molecular weight proteins (albumin, transferrin, and immunoglobulin G) and low molecular weight proteins (beta2-microglobulin and alpha1-microglobulin) was measured at various time points during the first 5 days after transplantation. RESULTS: Immediately after restoration of the circulation, we observed a massive nonselective high molecular weight proteinuria, indicative of glomerular damage. This proteinuria rapidly decreased to slightly elevated values beyond 24 hr after transplantation. Low molecular weight proteinuria, reflecting tubular damage, was also prominent and remained grossly abnormal even at day 5. CONCLUSION: After LD transplantation, preservation-reperfusion injury causes massive proteinuria during the first 24 hr. Thereafter proteinuria rarely exceeds 1 g per day.

Adult↗

Mass screening on abdominal aortic aneurysm in men aged 60 to 65 years in The Netherlands. Impact on life expectancy and cost-effectiveness using a Markov model.

OBJECTIVES: To predict the costs and effects on life expectancy of an AAA screening programme. METHODS: A Markov model was designed to compare the effects of a single screening for a cohort of men 60-65 years with the current no screening strategy. The following health states were distinguished: no AAA, unknown small AAA, follow-up small AAA, unknown large AAA, repaired AAA, rejected large AAA and death. Transition rates between the health states were simulated using cycle times of one year. Transition probabilities were derived from literature and a previous feasibility study. Incremental costs per life year saved were calculated. Sensitivity analyses and discounting for future effects were performed. RESULTS: The expected individual AAA costs for non-screening and AAA screening were euro; 196 and euro; 530 respectively. A difference of 3.5 months life expectancy was found in favour of screening leading to euro; 1176/life-year gained. Costs increased as compliance fell. With a discount rate of 4% the costs are euro; 2021/life-year gained. CONCLUSIONS: One-time ultrasonographic screening for AAA in men aged 60-65 years appears to be cost-effective.

Aged↗

Primary aortoenteric fistula: report of six new cases.

Primary aortoenteric fistula (PAEF) is defined as a communication between the native aorta and the gastrointestinal tract, in contrast to secondary fistulas, which arise between a suture line of a vascular graft and the intestine. Arteriosclerosis is the predominant cause of PAEF and accounts for more than two-thirds of the cases reported. The pathogenesis is usually based on direct adhesion of a segment of the gastrointestinal tract to an aortic aneurysm, followed by progressive erosion through the bowel wall. The clinical presentation is usually one of intermittent gastrointestinal haemorrhage resulting in lethal exsanguination. Pain in the abdomen, a pulsatile abdominal mass or fever may be present. The choice of various diagnostic procedures is often decided by the clinical presentation. Esophagogastroduodenoscopy, ultrasound and CT scan may be useful in the evaluation of these patients. Current recommendations for repair include debridement of the aneurysmal aorta, repair with an in situ graft and primary repair of the gastrointestinal tract, followed by aggressive antimicrobial therapy. We present six cases of PAEF surgically treated at the St. Radboud Hospital, the Canisius Wilhelmina Hospital in Nijmegen and the Lukas Hospital in Apeldoorn over a period of 15 years.

Aged↗

The influence of hyperhomocysteinemia on graft patency after infrainguinal bypass surgery in the Dutch BOA Study.

OBJECTIVE: Hyperhomocysteinemia has been identified as a risk factor for (cardio)vascular disease. Whether hyperhomocysteinemia contributes to graft failure after peripheral bypass surgery remains unclear. The present study evaluated the influence of hyperhomocysteinemia on graft patency after infrainguinal bypass surgery. DESIGN: The present study was designed as a nested case-control study. METHOD: In this study (nested in the Dutch Bypass Oral anticoagulants or Aspirin Study), 150 patients with graft occlusion were each matched with two randomly selected controls with patent grafts (N = 299) from the same trial. Venous blood samples were drawn from cases and controls, and total plasma homocysteine (tHcy) was determined. Mean serum homocysteine levels and the presence of hyperhomocysteinemia (>95th percentile in healthy individuals) were compared between cases and controls. RESULTS: No significant differences were found between serum levels of homocysteine in patients with and without graft occlusion. The mean plasma homocysteine levels were 14.4 micromol/L and 14.9 micromol/L in the case and control groups, respectively. The resulting mean difference was -0.4 (95% confidence interval [CI], -1.8-0.9). The odds ratio of hyperhomocysteinemia was 0.81 (95% CI, 0.49-1.33). Adjustment for risk factors of graft occlusion did not change these results. CONCLUSIONS: Postoperative raised serum levels of homocysteine proved not to be a risk factor for graft occlusion after infrainguinal bypass grafting.

Aged↗

Occupational health in European member states: a road to organizational health.

After an introduction, giving a short historical perspective on European Health and Safety legislation, the first experiences and opportunities for occupational physicians regarding international co-operation are described, with the first result in a form of a Position Paper on Occupational Health, adopted by the Standing Committee of European Doctors and presented to the European Commission. Since the ultimate shared goal for occupational physicians should be to contribute to the promotion of healthy workforce in safe and sound working conditions, the characteristics of a healthy organization are described with the possible activities to reach these characteristics, with particular attention drawn to the role of different disciplines. The growing importance of the management responsibility for health and safety in their enterprises is stressed and the possible benefits elucidated. The implications and consequences of such an extensive and ambitious program are pointed out with special regard to the challenge to contribute pro-actively to ensuring a healthy workforce in safe and sound working conditions for the benefit of employees, hereby clarifying the role and improving the general perception and position of occupational physicians. The importance of speaking with one voice and sharing ideas with colleagues, employers, employees and governments is essential, if the mission "to contribute to the realization of a healthy workforce in safe and sound working conditions" is to be reached.

European Union↗

Hyperhomocysteinemia as a cause of superior vena cava syndrome.

A case is presented in which superior vena cava (SVC) syndrome was caused by a stenosis of the SVC due to thrombosis. Hyperhomocysteinemia was diagnosed as a possible underlying mechanism. The role of hyperhomocysteinemia as a risk factor for the development of recurrent venous thrombosis, its diagnosis, and treatment are discussed.

Adult↗

Early assessment of skeletal muscle damage after ischaemia-reperfusion injury using Tc-99m-glucarate.

PURPOSE: After acute arterial obstruction of the lower extremity, muscle damage is the critical determinant for clinical outcome. The extent of muscle damage and limb viability are currently assessed by clinical examination, which is inaccurate. Tc-99m-pyrophosphate (PYP) has been applied for imaging ischaemia-reperfusion damage. More recently, a new imaging agent, Tc-99m-glucarate (GLUC), was introduced for delineating early myocardial infarction after ischaemia-reperfusion. The aim of this study was to determine if GLUC could delineate early skeletal muscle damage after ischaemia-reperfusion. Both tracers were used in a novel murine model of hindlimb ischaemia-reperfusion. METHODS: In anaesthetised mice, ischaemia of one hindlimb was maintained for 2, 3 and 4h using a tourniquet, followed by a reperfusion period of 1h. Additionally, reperfusion periods of 3, 24 and 96h were studied after 3h of ischaemia. PYP or GLUC was injected 45min before end of reperfusion. Concentrations of both agents were determined in blood, reperfused and contralateral muscle. Reperfused-to-contralateral muscle ratios were calculated. In separate experiments, muscle biopsies were obtained for histologic examination. RESULTS: Ischaemia and reperfusion damage was demonstrated histologically. Using scintigraphy GLUC depicted reperfusion significantly better than PYP. After 2, 3 and 4h of ischaemia, the reperfused-to-contralateral ratios for GLUC were 10.7+/-0.9, 8.9+/-0.9 and 8.6+/-1.1, as compared to 4.5+/-0.7, 4.9+/-0.4 and 4.5+/-0.4 for PYP (P<0.05 at all points). For longer periods of reperfusion, the ratios for GLUC decreased to similar levels as observed for PYP. CONCLUSION: The present study indicates that GLUC is a specific early marker of myocyte necrosis after ischaemia-reperfusion. GLUC may become an useful agent for clinical, early, non-invasive monitoring of skeletal muscle damage after ischaemia-reperfusion.

Animals↗

[Delayed (tension) pneumothorax after placement of a central venous catheter].

Laborious attempts at introducing a central venous catheter for parenteral nutrition in two women, aged 36 and 62 years, were followed by shortness of breath after 32 and 10 hours, respectively. This symptom was due to a (tension) pneumothorax not visible on earlier roentgenograms. Thoracic drainage led to recovery. In all patients with a central venous catheter an undetected delayed pneumothorax can be present. Urgent chest X-ray examination should be performed in all patients with acute respiratory symptoms. Patients undergoing elective intubation with positive pressure breathing should be examined carefully, since they are at risk of developing a late (tension) pneumothorax.

Adult↗

Depression of plasma levels of cytokines and ex-vivo cytokine production in relation to the activity of the pituitary-adrenal axis, in patients undergoing major vascular surgery.

The relation between the immune and neuroendocrine response during surgery was studied. In 18 patients undergoing major vascular surgery, circulating interleukin (IL)-1beta and ex-vivo production of IL-1beta and tumour necrosis factor (TNF)-alpha were lower on day 1 after surgery compared to pre-operation values (-14+/-5%, P<0.05; -62+/-9%, P<0.05; and -31+/-54%, P<0.005, respectively). Circulating IL-1 receptor antagonist (IL-1ra) was higher on the 5th day post-operatively compared to pre-operation values (mean +640%+/-400, P<0.05). In a more detailed study in six patients, the ex-vivo production of IL-1beta and TNF-alpha started to decrease at induction of general anaesthesia and dropped to under 10% of initial values at the end of surgery. Circulating IL-1ra and ex-vivo production of IL-1ra started to increase at the end of surgery and remained elevated up to 6 days post-operatively. Plasma antidiuretic hormone (ADH) and adrenocorticotropic hormone (ACTH) increased during surgery, but cortisol remained unchanged. We demonstrate a depression of circulating pro-inflammatory IL-1beta and an increase of circulating anti-inflammatory IL-1ra during surgical stress. The ex-vivo production of IL-1beta and TNF-alpha was suppressed, indicating a downregulation of the production of these cytokines. This parallelled the hormonal reaction with high ADH and ACTH, but not of cortisol, suggesting that glucocorticoid is not the key-factor in downregulation of production and release of pro-inflammatory cytokines.

Adrenocorticotropic Hormone↗

Lumbar sympathectomy in critical limb ischaemia: surgical, chemical or not at all?

The value of surgical and chemical lumbar sympathectomy was studied in patients with critical lower-limb ischaemia without the option of vascular reconstruction. Clinical success rates, defined as improvement of ischaemia stage, and limb salvage rates were recorded for 76 limbs of 70 consecutive patients. Chemical lumbar sympathectomy patients were older and had more concomitant diseases than surgical lumbar sympathectomy patients. The short-term (6-week) success rate in 36 cases treated with surgical lumbar sympathectomy (44%) was better than in 40 cases treated with chemical lumbar sympathectomy (18%) (P = 0.01). The long-term (1-year) success rate was 47% for surgical lumbar sympathectomy and 45% for chemical lumbar sympathectomy (P = NS). The 1-year limb salvage rates were 61% for surgical lumbar sympathectomy and 58% for chemical lumbar sympathectomy (P = NS). Complications were minor in both groups. Lumbar sympathectomy still has a limited role in the treatment of critical limb ischaemia in patients without the option of vascular reconstruction. Both surgical and chemical lumbar sympathectomy can be performed with very little morbidity and may provide a benefit over the natural course of the arterial insufficiency.

Arterial Occlusive Diseases↗

[The Organ Donation Law: changes in the procurement of organs and tissues for transplantation].

The Organ Donation Act fills an old gap in the legislation, leading to improvement of the legal position of those involved. Much attention is given to the protection of the potential donor. A new consent procedure is introduced, including the registration of the consent or refusal of all persons aged 18 years or older. Because of the persistent shortage of donor organs the noncommittal nature of organ procurement is changed. Hospitals and nursing homes are obliged to have a protocol for organizing tissue donation. Also, conditions have been created for a just division of the available organs and tissues for transplantation.

Adolescent↗

[The regional explantation team: an important contribution to organ procurement for transplantation in the Netherlands].

If organ donations concern not only the kidneys, but also the liver, pancreas and, sometimes, the heart and (or) lungs, several surgical removal teams, often from different (foreign) transplantation centres, may be involved. This has created organizatory problems resulting in loss of organs for transplantation. In the Nijmegen area since October 1994 a removal team has been active that in the regional donor hospital removes all abdominal organs from the donor on behalf of the various transplantation centres. This regional removal team performed 105 multi-organ explanations in the period from October 1994 to December 1997. The reports that came back from the transplantation centres that had received the organs showed that none of these organs had been lost for transplantation through organizatory problems or anatomical damage. Experiences of operating room staff involved were positive: it was especially the standard surgical techniques and the quiet in the operating room that were appreciated. Special removal teams may greatly improve the evolution of organ donation in the Netherlands.

Female↗

[Kidney donation by a 'non-heart-beating' donor from an ethical perspective].

In asystolic patients, kidney donation is possible by using a non-heart-beating (NHB) donation procedure. This involves in situ perfusion of the kidneys by inserting a catheter into the femoral artery and flushing cold fluid through the kidneys. The introduction of an NHB donation programme leads to ethical questions concerning the guarantees for prudent procedure: How should death of a patient be defined in case of NHB donation? Is there a strict separation of responsibilities of the medical teams in the different phases of the procedure (patient treatment and actual donation procedure)? Are sufficient attention and care given to the relatives? Does the NHB donation procedure not interfere with the care of a patient who is expected to die soon? Extensive discussion with the Medical Ethics Committee of the University Hospital Nijmegen, the Netherlands, has led to a protocol for NHB kidney donation that meets the required guarantees.

Cadaver↗

Changes in venous hemodynamics after renal transplantation.

To explain an occasionally observed transient swelling of the ipsilateral leg in renal transplant recipients in the absence of deep vein thrombosis, we took serial measurements of venous outflow resistance and duplex examinations of both legs. Fourteen recipients of a living related donor kidney graft were submitted to strain gauge plethysmography and duplex examination before transplantation and 1 and 6 weeks thereafter. Venous outflow resistance and venous flow were measured and the veins were assessed for thrombosis. Strain gauge plethysmography showed a significant increase in venous outflow resistance in the leg on the side of the renal transplant 1 week after transplantation [0.28 +/- 0.13 vs 0.40 +/- 0.15 mmHg.s (ml/100 ml)-1; P < 0.05]. Six weeks later, the venous outflow resistance had returned to preoperative values [0.30 +/- 0.11 mmHg.s (ml/100 ml)-1; P = NS]. On the contralateral side, no significant differences were found. Duplex examinations showed no signs of thrombosis. Venous flow measurements in the common femoral vein showed no significant differences. We conclude that the additional blood supply to the iliac veins results in an increase in venous outflow resistance in the ipsilateral leg, which can explain the observed swelling of this leg and may have implications for the preferred method of diagnosis of venous thrombosis after renal transplantation.

Adult↗

Detection of microorganisms in vessel wall specimens of the abdominal aorta: development of a PCR assay in the absence of a gold standard.

A procedure in which the "Invitrogen Easy-DNA" kit was followed by a silica-based method for the isolation of DNA was developed for extraction of PCR-inhibitor-free DNA from up to 300 mg of human vessel wall tissue. Optimally designed PCR assays were developed for the detection of at least one infected cell in this amount of tissue. Details of the procedure are given for the detection of DNA of Chlamydia pneumoniae, cytomegalovirus and herpes simplex virus type 1 and type 2 in human vessel walls. The procedure can serve as a reference method or as a gold standard when a high-performance method is needed.

Aorta, Abdominal↗