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J H van Bockel

Publications and source records attributed to J H van Bockel.

At least 19 recordsLinked to original sources
PubMed1997

Risk factors for delayed graft function in cadaveric kidney transplantation: a prospective study of renal function and graft survival after preservation with University of Wisconsin solution in multi-organ donors. European Multicenter Study Group.

BACKGROUND: Delayed graft function (DGF) remains an important complication in renal transplantation. In this multicenter study, we investigated the influence of donor and recipient factors on the occurrence of DGF and DGF's effect on long-term graft survival. METHODS: A total of 547 transplanted kidney allografts, retrieved from multi-organ donors, were analyzed, and results were compared with literature on kidney-only donors. RESULTS: Median follow-up of patients without graft failure was 3.4 years. Twenty-four percent of the recipients developed DGF. In univariate analysis, the following factors significantly increased the incidence of DGF: (a) among the donor factors, mean creatinine level >120 micromol/L and prolonged cold ischemia time (CIT); and (b) among the recipient factors, previous transplant(s), no intraoperative use of mannitol, poor quality of reperfusion, absence of intraoperative diuresis, and pretransplant anuria or oliguria. After stepwise logistic regression, donor age, CIT, recipient's number of previous transplants, and intraoperative diuresis proved to be of independent prognostic value for the occurrence of DGF. Overall graft survival was 91%, 87%, and 72% at 3 months, 1 year, and 4 years after transplantation, respectively. In case of DGF, graft survival was approximately 10% lower when compared with cases with immediate graft function (P<0.001). No difference in incidence of DGF was found between grafts of multi-organ donors and kidney-only donors. CONCLUSIONS: DGF results in an approximately 10% higher rate of graft failure. DGF incidence can be reduced by the administration of mannitol during transplantation, which minimizes CIT and optimizes donor management. Grafts from multi-organ donors and kidney-only donors appear to be of equal quality.

Cadaver↗
PubMed1997

Vessel wall and flow characteristics after carotid endarterectomy: eversion endarterectomy compared with Dacron patch plasty.

OBJECTIVES: Experimental studies have demonstrated that decreases in vessel wall compliance and increases in turbulence may contribute to (re)stenosis. We studied vessel wall and flow characteristics after endarterectomy with Dacron patch plasty and after eversion endarterectomy, and compared those findings with the characteristics of non-stenotic, unoperated carotid arteries (controls). METHODS: Seventy-four patients who underwent 84 carotid endarterectomies were studied postoperatively by ultrasonography (2-24 months) Recorded variables included the diameter of the bulb, strain, elastic modulus (stiffness), and presence of turbulent flow. RESULTS: The vessel wall and flow characteristics of the two groups differed significantly. The diameter was higher and the strain lower in Dacron patch plasty than in controls; eversion endarterectomy did not differ from controls. The elastic modulus was higher (stiffer) in Dacron patch plasty than in eversion endarterectomy; neither Dacron patch plasty nor eversion endarterectomy differed significantly from controls. The stiffness index was not significantly different between the groups. Turbulence was present in Dacron patch plasty and eversion endarterectomy when compared with controls. CONCLUSION: In diameter, strain and stiffness, the operated carotid artery resembles the non-stenotic, unoperated artery more closely after eversion endarterectomy than after Dacron patch plasty.

Aged↗
PubMed1997

Ruptured popliteal artery aneurysm. An insidious complication.

OBJECTIVES: To evaluate the incidence and clinical presentation of ruptured popliteal aneurysms. METHODS: The records of 89 consecutive patients, all males, seen between 1958 and 1995 with 124 arteriosclerotic popliteal aneurysms were reviewed retrospectively. Most aneurysms were symptomatic (69/124; 55.6%). In six cases (6/124; 4.8%) a rupture was present. RESULTS: There was a wide range in primary diagnosis varying from deep venous thrombosis to peroneal nerve palsy. In all cases primary reconstructive surgery was performed. No primary or secondary amputations were necessary. Surgical outcome was good in four cases. In the remaining cases one patient suffered from a permanent peroneal nerve palsy and one from non-disabling claudication. Review of the literature showed a rupture incidence of 2.5% (range 0-16%) and amputation rates as high as 100%. CONCLUSION: An acute rupture of a popliteal aneurysm is rare. Although the clinical presentation can be non-specific, this possibility must be especially taken into account when dealing with older male patients presenting with signs and symptoms of generalised atherosclerosis and non-specific pain in the popliteal region.

Acute Disease↗
PubMed1997

Hemodynamic significance of renal artery stenosis: digital subtraction angiography versus systolically gated three-dimensional phase-contrast MR angiography.

PURPOSE: To compare digital subtraction angiography with three-dimensional phase-contrast magnetic resonance (MR) angiography in detection of significant renal artery stenosis. MATERIALS AND METHODS: Sixteen patients underwent digital subtraction angiography and systolically gated three-dimensional phase-contrast MR angiography within 1 week. Scoring of stenosis on MR angiograms was based on presence and length of a flow void and quality of flow signal intensity in the distal part of the artery. Intraarterial pressure measurement was the reference standard for hemodynamically significant renal artery stenosis. RESULTS: MR angiography depicted two of five patent accessory arteries. Comparison of digital subtraction angiography and MR angiography with intraarterial pressure measurements was possible in 25 main renal arteries. In 13 arteries, a pressure gradient of more than 15 mm Hg was found. Digital subtraction angiography depicted 10 of these stenoses (sensitivity, 77%; specificity, 92%). A flow void was present at MR angiography in eight stenoses (sensitivity, 62%; specificity, 83%). In 12 of the stenosed vessels, distal flow signal intensity was impaired at MR angiography (sensitivity, 92%; specificity, 75%). There was no difference between the two modalities (P > .05) in grading hemodynamic significance of renal artery stenosis. CONCLUSION: Systolically gated MR angiography and digital subtraction angiography are equally effective in depicting hemodynamically significant stenoses in the main renal arteries. MR angiography, however, is not adequate in depiction of accessory renal arteries.

Adult↗
PubMed1997

Chronic splanchnic ischaemia: is tonometry a useful test?

OBJECTIVE: To find out if gastric tonometry is of sufficient accuracy to diagnose chronic splanchnic syndrome. DESIGN: Prospective open study. SETTING: University hospital, The Netherlands. SUBJECTS: 10 patients in whom chronic splanchnic syndrome had been suspected, and in 5 of whom it was subsequently confirmed. INTERVENTION: Standardised measurement of intramucosal gastric pH (tonometry) and multiplane angiography of the abdominal aorta and splanchnic arteries. MAIN OUTCOME MEASURE: Correlation between intramucosal gastric pH and angiographic and clinical findings. RESULTS: The mean basal pH preoperatively was 7.48 among 5 patients subsequently found to have splanchnic syndrome (group 1) and 7.41 among the 5 who did not (group 2). Those in group 1 all had extensive three vessel disease with stenoses of 70% or more in at least two of the three splanchnic arteries. The 5 patients in group 2 had no clinically important stenoses in either the coeliac or the superior mesenteric artery; 4 had occlusions of the inferior mesenteric artery. CONCLUSION: Gastric tonometry is of no use in the diagnosis of chronic splanchnic syndrome.

Adult↗
PubMed1997

Atherosclerotic popliteal aneurysm.

BACKGROUND: A popliteal artery aneurysm (PAA) has been described as a 'sinister harbinger of sudden catastrophe'. This review seeks to provide data regarding the epidemiological aspects, natural history, clinical presentation and results of treatment to help clinicians make appropriate decisions. METHODS: A systematic review of data in the English language literature published since 1980. RESULTS: The authors include 29 studies containing 1673 patients with 2445 PAAs. No controlled trials exist regarding the management of PAAs. CONCLUSION: (1) At most, only four or five patients are seen each year by a major vascular centre; (2) aortic aneurysms are found in 37 per cent and bilateral PAAs in 50 per cent of patients; (3) more than 95 per cent of patients are men with a mean age of 65 years and 45 per cent have hypertension; (4) approximately one-third of patients are asymptomatic at the time of initial diagnosis; (5) the risk of ischaemic complications after conservative follow-up varies from 8 to 100 per cent (mean 36 per cent), depending on the selection of patients and duration of follow-up; (6) elective surgical reconstruction is recommended for all asymptomatic aneurysms; (7) 5-year graft patency rates after surgical repair range from 29 to 100 per cent, with 5-year limb salvage ranging from 75 to 98 per cent; (8) patient survival rates at 5 and 10 years are 70 and 44 per cent respectively; (9) lifelong, careful patient surveillance is essential to detect and treat new aneurysms at other sites.

Aged↗
PubMed1997

The splanchnic syndrome. Diagnosis and indications for treatment.

The typical chronic splanchnic syndrome is characterized by upper abdominal pain usually provoked by a meal, the finding of an epigastric bruit and weight loss in conjunction with haemodynamically significant stenosis of two or more of the splanchnic arteries. Diagnosis of chronic splanchnic syndrome depends mainly on a strong clinical suspicion. Usually the classical triad is incomplete or absent. Therefore chronic splanchnic syndrome should be considered, in every patient with chronic abdominal discomfort, after exclusion of other more common causes of upper abdominal discomfort. Findings from nonvasive and invasive diagnostic tests support the presence of chronic splanchnic syndrome. However, until now, the diagnosis of chronic splanchnic syndrome has usually only been made retrospectively if all the symptoms disappeared after technically successful reconstructive surgery. A variety of surgical techniques has been advocated to repair the splanchnic arteries. The choice of the technique is usually based on the preference and experience of the surgeon.

Adult↗
PubMed1996

[Results of kidney transplantation in Leiden, 1966-1994, and prognostic factors].

OBJECTIVE: Evaluating prognostic determinants and results of renal transplantation. DESIGN: Descriptive study. SETTING: Leiden University Hospital, The Netherlands. METHODS: Follow-up of all 1289 patients who had a kidney transplantation in Leiden University Hospital between March 1966 and December 1994. The following determinants were investigated: age and sex of donors and recipients. HLA matching, type of immunosuppression, presensitization, presence of diabetes mellitus, and living or post-mortem donor. RESULTS: Renal transplantation was very successful during the first few years, one-year graft survival dropped to 50% during the second decade and gradually increased to almost 90% during the last years. 5-year and 10-year graft survival were 65% and 50% respectively. The mean age of recipients increased from 32.8 years to 45.7 years, that of donors from 24.9 to 37.9 years. Duration of dialysis before transplantation increased from 19.7 months to 35.7 months. The introduction of cyclosporine and matching on the HLA-DR locus were responsible for better transplantation results. Other favourable prognostic factors were absence of diabetes mellitus, absence of panel reactive antibodies, kidney from a living donor, male donor and donor age between 20 and 50 years. CONCLUSION: Both short term and long term results of renal transplantation improved in spite of a strong increase of mean donor age and mean recipient age and an increase of co-morbidity of the recipients. Introduction of HLA-DR matching and cyclosporine immunosuppression contributed to better graft survival.

Adult↗
PubMed1996

Evaluation of various methods to quantify endothelial cells attached to vascular prostheses: comparison with a new "gold standard" FACS method.

For in vitro evaluation of functional properties of endothelial cells seeded on synthetic vascular prostheses accurate and reproducible quantification of cells is mandatory. Comparison of these properties with those resulting from other studies requires correlation of the functional parameters to reliably counted cell numbers. The accuracy of methods of quantification currently being used is unknown due to the lack of a "gold standard" method to which these methods can be compared. To determine the accuracy and reproducibility of four widely used methods, we have developed a "gold standard" model, using a flow cytometer (FACS). Endothelial cells, attached to collagen-coated Dacron vascular prostheses, were counted by four conventional methods and a new method of quantification after the attached number of cells had been determined with 99% accuracy by FACS. Subsequently, ratios were computed by dividing the cell numbers determined by the methods under investigation by those determined by FACS (x100%). The four conventional methods investigated were (1) removal and subsequent counting of cells from substrata by trypsin (T), (2) digestion of cells by citric acid and counting of crystal violet-stained cell nuclei (CV), (3) light microscopy after hematoxylin staining (LM), and (4) scanning electron microscopy (SEM). The new method consists of the measurement of cell fluorescence after labeling with fluorescein-diacetate (FDA). T and CV had average accuracy ratios of 127 +/- 58% and 96 +/- 48%, respectively (+/- standard deviation). The ratios for LM and SEM were 116 +/- 101% and 44 +/- 10% (respectively). FDA had a ratio of 99 +/- 7%. Reproducibility of cell quantification by T and CV was significantly less than that of quantification by LM, SEM, and FDA, as expressed by data on inter- and intraobserver agreement. Our results indicate that the investigated conventional methods of quantification failed to meet criteria of both high accuracy and reproducibility. Light microscopy and scanning microscopy methods were inaccurate but yielded reproducible countings. We conclude that the FACS method can serve as a "gold standard" to compare the accuracy and reproducibility of cell quantification methods. Moreover, the FDA method results in both accurate and reproducible quantification of endothelial cells attached to vascular prosthetic material.

Blood Vessel Prosthesis↗
PubMed1996

Diagnosis and therapy of aortic prosthetic fistulas: trends over a 30-year experience.

A retrospective study was carried out of patients from a single institution over a 30-year period. Thirty-one patients presented with 33 fistulas, four non-enteric and 27 enteric. In 25 of 27 patients with a prosthesis-related enteric fistula gastrointestinal bleeding was present. Angiography revealed the fistula in five patients endoscopy in three, and barium studies, echography and computed tomography each revealed one fistula. Six patients died before and five died during operation. In 20 patients various techniques were used for treatment. In-hospital mortality decreased from six of eight patients before 1970, to seven of ten between 1971 and 1980, and to four of 13 after 1981. In the long term, patients treated with an extra-anatomic reconstruction had a poorer prognosis than those treated by in situ reconstruction. This experience shows that diagnostic tests often fail to reveal a prosthesis-related fistula and that mortality can be substantially reduced by early exploration in patients with negative diagnostic studies.

Adolescent↗
PubMed1996

Nature and origin of the neointima in whole vessel wall organ culture of the human saphenous vein.

Intimal proliferation is a characteristic feature of arteriosclerosis. Whole vessel wall organ culture systems have been developed to study the early stages of neointima formation. We have cultured a large number of explants of human saphenous vein specimens for several weeks, and have identified the nature of the cells in the newly formed intima by a panel of monoclonal antibodies recognizing endothelial cells (von Willebrand factor, platelet endothelial cell adhesion molecule-1 and EN-4 antigen), smooth muscle cells (monoclonal antibodies HHF35 and CGA-7) and fibroblasts (5B5 antibody). In addition we determined the uptake of fluorescently labelled acetylated low density lipoprotein by the surface cells of the explants. We found that an apparent neointima was formed in the vein organ system, the cells of which were predominantly smooth muscle cells and originated from the cut edges and from the adventitia of the vein segment. The endothelial cells originally lining the luminal surface of the vessel segments became overgrown by these cells. They remained at the base of the newly formed neointima and a number of them reorganized into capillary-like structures. Our data suggest that explant culture of saphenous vein does not reflect the classical concept of neointima formation, in which intimal smooth muscle cells migrate through the internal elastic lamina and accumulate in the intima. Although it has this limitation, the model may serve well to study specific aspects of cell migration, smooth muscle cell differentiation and angiogenesis, and may reflect aspects of intimal thickening at surgical suture sites.

Adult↗
PubMed1996

Pitfalls in the diagnosis of origin stenosis of the coeliac and superior mesenteric arteries with transabdominal color duplex examination.

The purpose of this study is to evaluate the effects of respiration, localization of the Doppler sample, and the presence of origin stenosis on the Doppler parameters of coeliac and superior mesenteric arteries in 22 patients undergoing elective abdominal vascular reconstructive surgery under standardized stable anesthesia. Deep inspiration decreased peak systolic and end diastolic velocities of the coeliac artery origin. Proximal to distal Doppler velocities of normal coeliac and superior mesenteric artery origins were comparable. However, in the presence of an origin stenosis, the increase of Doppler velocities at the origin of the coeliac and superior mesenteric arteries is likely to be missed by transabdominal scanning.

Adult↗
PubMed1996

Isolated liver perfusion with mitomycin C in the treatment of colorectal cancer metastases confined to the liver.

We evaluated the technical feasibility of isolated liver perfusion (ILP) in the treatment of patients with colorectal cancer metastases confined to the liver, and investigated whether ILP allows exposure of the tumor to high concentrations of mitomycin C (MMC). Furthermore, survival time and tumor response were studied. Nine patients were treated with 30 mg/m2 MMC recirculated for one hour in the isolated circuit. The MMC concentration in the perfusate and plasma was measured using a high-performance liquid chromatography assay. All complications directly related to the surgical procedure were treated effectively (no mortality). The peak concentration of MMC in the perfusate was 5 to 11 times higher than that measured in the plasma of patients treated with 20 to 60 mg/m2 MMC i.v., and the concentration remained significantly higher during the whole perfusion period. In contrast, the peak concentration of MMC in plasma was approximately two thirds of the lowest peak plasma level measured after i.v. administration of 10 mg/m2 MMC. No systemic toxicity was observed in any of our patients. However, four patients developed veno-occlusive disease of the liver which was mild in three but lethal in one. One of the eight evaluable patients had an objective complete response (25 months), one an objective partial response and five others a clear reduction in tumor size (25-50%). The median survival time was 17 months. This study demonstrates that ILP is technically feasible in patients, and in comparison with systemic therapy allows exposure of hepatic metastases to much higher concentrations of MMC, while systemic toxicity is absent. Remarkably, this single exposure to a high concentration of MMC resulted in a complete response and a median survival time comparable to that in recently published hepatic artery infusion studies with floxuridine and leucovorin. However, due to the hepatotoxicity we are continuing our studies with melphalan to further exploit the possible therapeutic benefit of ILP.

Adult↗
PubMed1996

Comparison of sufentanil/propofol versus isoflurane/nitrous oxide anaesthesia on mesenteric artery blood flow.

Duplex sonography was used to determine the changes in mesenteric arterial blood flow occurring in patients undergoing aortic surgery, anaesthetised either by total intravenous anaesthesia with propofol and sufentanil (group A) or inhalational anaesthesia with isoflurane and nitrous oxide (group B). Sixteen patients were studied. Measurements were performed immediately before and 15 min after induction of anaesthesia, before surgery. There was a 38% decrease (p = 0.015) in the superior mesenteric artery end diastolic velocity in group A and a 23% decrease (p = 0.033) in the superior mesenteric artery peak systolic velocity in group B. There were no changes in any of the other sonography parameters in either group. We conclude that neither total intravenous anaesthesia with propofol and sufentanil nor inhalational anaesthesia with isoflurane and nitrous oxide have any clinically significant influence on mesenteric blood flow in the absence of surgical stimulation.

Aged↗
PubMed1996

Renal artery stenosis: endovascular flow wire study for validation of Doppler US.

PURPOSE: To compare the accuracy of proximal and peripheral Doppler parameters for detection of renal artery stenosis (RAS). MATERIALS AND METHODS: The authors obtained absolute velocities and peripheral Doppler waveforms in 16 stenotic and 14 normal renal arteries by using a 0.45-mm endovascular flow wire. Hemodynamically significant stenosis was established by measuring transstenotic invasive pressure gradients, with a 10 mm Hg or greater pressure drop indicating RAS. Accuracy of the Doppler parameters and of digital subtraction angiographic (DSA) results were compared by using receiver operating characteristic analysis. RESULTS: Measurements of absolute velocities at the site of the stenosis (maximal peak systolic velocity [PSVmax], PSV ratio, renal artery-to-aortic PVS ratio) showed high accuracy for diagnosis of RAS similar to that of DSA (areas under the ROC curve were 0.96, 0.97, 0.93, respectively). The distal intrarenal Doppler indexes (notably loss of early systolic peak, acceleration, acceleration time, pulsatility index, and resistive index) did not show statistically significant correlation with RAS. CONCLUSION: Doppler measurements in the main renal artery correlate well with RAS. The intrarenal Doppler spectrum, however, has no diagnostic value. The authors conclude that duplex Doppler US is not a suitable screening test for RAS.

Angiography, Digital Subtraction↗
PubMed1996

Fate of renal allografts connected to vascular prostheses.

OBJECTIVE: The outcome of renal transplantation with an arterial anastomosis to a vascular prosthesis in the aortofemoral tract is evaluated. PATIENTS AND METHODS: All 7 Dutch transplant centers were invited to review their experience. Among a total of 5791 cadaveric renal transplantations performed between 1978 and 1994, 13 cases (0.2%) in 3 different centres were identified. In 6 cases the vascular reconstruction and transplant operation were performed simultaneously, and in 7 cases separately, with a mean interval of 3.5 yr. The indications for vascular reconstruction were aneurysmal disease in 4 and obstructive disease in 9 cases. RESULTS: The early vascular complications of these procedures were hemorrhage in 4 and renal vein thrombosis in 1 and led to graft loss in 3 cases. The perioperative mortality was 2/13 (15%). The graft and patient survival were 68 and 83% respectively after 1 yr and 17 and 37% after 5 yr. Late mortality was mainly due to cardiovascular disease. CONCLUSIONS: Renal transplantation with an arterial anastomosis to a vascular prosthesis in the aortofemoral tract is a hazardous procedure with relatively poor short- and long-term results. These observations should be considered in the choice of renal replacement therapy in this special patient population.

Adult↗
PubMed1995

Perioperative mortality of elective abdominal aortic aneurysm surgery. A clinical prediction rule based on literature and individual patient data.

BACKGROUND: Abdominal aortic aneurysm surgery is a major vascular procedure with a considerable risk of (mainly cardiac) mortality. OBJECTIVE: To estimate elective perioperative mortality, we developed a clinical prediction rule based on several well-established risk factors: age, gender, a history of myocardial infarction, congestive heart failure, ischemia on the electrocardiogram, pulmonary impairment, and renal impairment. METHODS: Two sources of data were used: (1) individual patient data from 246 patients operated on at the University Hospital Leiden (the Netherlands) and (2) studies published in the literature between 1980 and 1994. The Leiden data were analyzed with univariate and multivariate logistic regression. Literature data were pooled with meta-analysis techniques. The clinical prediction rule was based on the pooled odds ratios from the literature, which were adapted by the regression results of the Leiden data. RESULTS: The strongest adverse risk factors in the literature were congestive heart failure and cardiac ischemia on the electrocardiogram, followed by renal impairment, history of myocardial infarction, pulmonary impairment, and female gender. The literature data further showed that a 10-year increase in age more than doubled surgical risk. In the Leiden data, most multivariate effects were smaller than the univariate effects, which is explained by the positive correlation between the risk factors. In the clinical prediction rule, cardiac, renal, and pulmonary comorbidity are the most important risk factors, while age per se has a moderate effect on mortality. CONCLUSIONS: A readily applicable clinical prediction rule can be based on the combination of literature data and individual patient data. The risk estimates may be useful for clinical decision making in individual patients.

Adult↗