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Biomedical subjects

J H van Bockel

Publications and source records attributed to J H van Bockel.

At least 19 recordsLinked to original sources
PubMed1998

Morbidity and mortality of reconstructive surgery of noninfected false aneurysms detected long after aortic prosthetic reconstruction.

OBJECTIVE: To determine the morbidity and mortality of surgical treatment of false (anastomotic) aneurysms, we analyzed the results of 158 consecutive surgical procedures for repair of false aneurysms that were detected as a result of a surveillance program after aortic reconstruction with a prosthesis. DESIGN: Retrospective analysis of patient data from a vascular registry that included information on the long-term follow-up of our patients. SETTING: A university hospital (tertiary referral center) in the Netherlands that has been performing vascular reconstructive surgery since 1958. PATIENTS: We performed 158 surgical procedures on 135 patients with 220 noninfected false aneurysms. Using a yearly surveillance program, the false aneurysms were detected at a mean interval of 8 years after the initial reconstruction. Most patients (60%) were asymptomatic. The operation was performed as an emergency in 25 instances (16%). RESULTS: The mortality rate of patients receiving nonsurgical treatment was very high (61%) owing to documented rupture (11 of 18 patients). The intraoperative death rate was 7.6% per procedure. This was higher for emergency (24%) than for elective procedures (4.5%). CONCLUSIONS: Conservative follow-up carries a very high mortality rate, as does emergency surgery for a false aneurysm. However, the intraoperative mortality rate of elective reconstruction of a false aneurysm can be in the same range as that of elective primary aortic reconstruction. Therefore, we advocate a surveillance program, including yearly ultrasound studies, after prosthetic aortic reconstruction for the timely detection and elective repair of all false aneurysms.

Adult↗
PubMed1998

Long-term graft survival after liver transplantation in the UW era: late effects of cold ischemia and primary dysfunction. European Multicentre Study Group.

The use of University of Wisconsin (UW) solution in liver transplantation (LTX) has significantly prolonged preservation times and facilitated semielective transplant procedures. Despite this advantage potential risk factors related to the donor, recipient, or cold storage method will persist in the UW era and detrimental effects will be reflected by primary dysfunction (PDF) after LTX. Concern has been voiced about the maximum period of UW preservation in LTX and various cold ischemia times (CIT) are mentioned. To evaluate the effect of UW solution in LTX, a prospective European multicenter study was initiated in 1988 and short-term results have been reported previously. This report focuses on the long-term effects and survival of prolonged preservation with UW solution and primary function after LTX. Three hundred and fifteen LTXs were performed in 288 patients in participating European centers. Complete follow up of at least 6 years was available for 296 grafts in 277 patients. Effects of donor, preservation, and recipient risk factors on PDF including primary non-function (PNF) and initial poor function (IPF) were evaluated. Next, the effect of risk factors on graft survival (GS) was analyzed including the long-term impact of PNF and IPF using multivariate analyses and the Kaplan-Meyer method. PDF occurred in 15.2% (45/296) with PNF in 7.8% and IPF in 7.4%. Patients with IPF had a 34% lower GS at 3 months those with immediate function (IF; 58% vs 91%; P < 0.001). This difference persisted up to 6 years for patients with IPF with a 39% GS vs 72% after IF (P < 0.001). Median CIT was significantly longer in grafts with PNF compared to IPF or IF (P = 0.03). Long-term GS, however, was significantly influenced at a lower CIT threshold with a 6-year GS for CIT < or = 16 h of 67%, compared to a CIT > 16 h of 51% (P = 0.02). Other independent risk factors for the 6-year survival rate were re-LTX, ABO incompatibility, and recipient diagnosis of acute hepatic failure. In conclusion, liver patients with PNF, but not with IPF, have a significantly lower CIT. IPF is associated with a significantly lower 3 month GS compared to IF, but this difference of 34% does not further increase during a 6-year follow up. Although a short term follow up (3 months) shows that with UW solution CIT up to 18 h has no adverse effect on GS, the 6-year data clearyl suggest that CIT should be kept to less than < 16 h to avoid tetrimental effects on lang-term GS after LTX.

Adenosine↗
PubMed1998

Streptococcus pneumoniae, an emerging pathogen in mycotic aneurysms?

Two patients are described with a mycotic aneurysm caused by streptococcus pneumoniae infection. The patients presented with back pain and fever, and had an antecedent history of lower respiratory tract infection; neither of them were suffering from endocarditis. Mycotic aneurysms are a rare disorder with, over the years, a changing spectrum of presentation, localisation and bacterial aetiology. S. pneumoniae infection has only very rarely been reported as a cause of mycotic aneurysms. Since 1986, 14 patients with a mycotic aneurysm were treated at the Leiden University Hospital. Of these patients, 5 had mycotic aneurysms caused by S. pneumoniae infection. The mortality in these patients was high. In this communication, we would like to draw attention to S. pneumoniae infections as an emerging cause of mycotic aneurysms.

Aged↗
PubMed1998

Endoleakage after stent-graft treatment of abdominal aneurysm: implications on pressure and imaging--an in vitro study.

BACKGROUND: Endoleakage is a fairly common problem after endovascular repair of abdominal aortic aneurysm and may prevent successful exclusion of the aneurysm. The consequences of endoleakage in terms of pressure in the aneurysmal sac are not exactly known. Moreover, the diagnosis of endoleakage is a problem because visualization of endoleaks can be difficult. METHOD: With an ex vivo model of circulation with an artificial aneurysm managed by means of a tube graft, studies were performed to evaluate precisely known diameters of endoleaks with both imaging techniques (computed tomography and digital subtraction angiography) and pressure measurements of the aneurysmal sac. The experiments were performed without endoleak (controls) and with 1.231-French (0.410 mm), 3-French (1 mm), and 7-French (2.33 mm) endoleaks. Pressure and imaging were evaluated in the absence and presence of a simulated open lumbar artery. The pressure in the prosthesis and in the aneurysmal sac were recorded simultaneously. Digital subtraction angiography with and without a Lucite acrylic plate, computed tomographic angiography, and delayed computed tomographic angiography were performed. For the first experiments, the aneurysmal sac was filled with starch solution. All tests were repeated with fresh thrombus in the aneurysmal sac. RESULTS: Each endoleak was associated with a diastolic pressure in the aneurysmal sac that was identical to diastolic systemic pressure, although the pressure curve was damped. At digital subtraction angiography without a Lucite acrylic plate, the 1.231-French (0.410 mm) endoleak was visualized without an open lumbar artery. When a Lucite acrylic plate was added, the endoleak was not visible until a lumbar artery was opened. In the presence of thrombus within the aneurysmal sac, all endoleaks were not visualized at digital subtraction angiography. At computed tomographic angiography, all endoleaks were not visualized in the absence of a thrombus mass in the aneurysmal sac. In the presence of thrombus within the aneurysmal sac, the 1.231-French (0.410 mm) endoleak became visible after opening of a simulated lumbar artery. At delayed computed tomographic angiography, all endoleaks were visualized without and with thrombus. CONCLUSION: Every endoleak, even a very small one, caused pressure greater than systemic diastolic pressure within the aneurysmal sac. However, small endoleaks were not visualized with digital subtraction angiography and computed tomographic angiography, whereas all endoleaks were visualized with a delayed computed tomographic angiography protocol. We believe that follow-up examinations after stent graft placement for aortic aneurysms should focus on pressure measurements, but until this is clinically feasible, delayed computed tomographic angiography should be performed.

Angiography, Digital Subtraction↗
PubMed1998

Vascular morbidity and mortality during long-term follow-up in claudicants selected for peripheral bypass surgery.

OBJECTIVES: To identify claudicants at high risk (and low risk) of late vascular morbidity and mortality after peripheral bypass surgery. DESIGN: Prospective cohort study with mean follow-up of 8.6 years. PATIENTS: One-hundred and fifty-five claudicants selected for peripheral bypass surgery. Only three patients were lost to follow-up. End points were major vascular events, additional interventions, all-cause mortality, and functional outcome. RESULTS: Major vascular events occurred in 59 patients. Life-table analysis revealed an annual risk increase of 3.5%. Strong predictors were hypertension (hazard ratio (HR) 2.7; 95% confidence interval (CI) 1.5-4.8), diabetes (HR 2.4; 95% CI 1.0-5.4) and cardiac disease (HR 2.2; 95% CI 1.2-4.0). Sixty patients needed additional interventions with a highest incidence (17%) in the first year, and thereafter 2.8% each year. None of the known risk factors were associated with an altered incidence of interventions. Approximately 3.5% of patients died per year compared with 2% per year in the control group. Prominent high-risk factors for mortality were cardiac disease (HR 3.3; 95% CI 1.8-6.0) and diabetes (HR 3.0; 95% CI 1.5-7.1). CONCLUSION: Major vascular events and additional interventions are common and serious in claudicants. However, it is possible to select low-risk patients in which peripheral bypass surgery is justified.

Arteriovenous Shunt, Surgical↗
PubMed1998

Complications of standard elective abdominal aortic aneurysm repair.

OBJECTIVE: To evaluate complications of standard elective repair of infrarenal abdominal aortic aneurysms. DESIGN: Prospective multicentre study. MATERIALS: Two-hundred and ninety-one consecutive patients undergoing standard elective surgery for an infrarenal aortic aneurysm. METHODS: Recording adverse events according to the recommendations of the Ad Hoc Committee on Reporting Standards. RESULTS: Seventy-five patients (26%) experienced some complication following elective aortic aneurysm surgery. Twenty-two patients had a mild complication (7.6%, 95% C.I. 4.8-11.2%), 27 a moderate (9.3%, 95% C.I. 6.2-13.2%) and 26 patients had a severe and/or fatal complication (8.9%, 95% C.I. 5.9-12.8%). The in-hospital mortality was 4.1% (12 patients, 95% C.I. 2.2-7.1%). Cardiac failure was the commonest primary cause for death (58%). Twenty-two per cent of the patients had a non-fatal complication: the most frequent being pulmonary (10%) and cardiac (10%). Patients with a history of cardiac events had a five times higher risk of a fatal outcome (95% C.I. 1.1-24.0) and a two and a half times higher risk of any severe fatal or non-fatal complication (95% C.I. 1.0-6.5). Other risk factors were advancing age and the presence of pulmonary disease. CONCLUSIONS: In addition to mortality, morbidity figures of standard aneurysm operations are important, as well as associated risk factors. This is especially true when evaluating early repair of small aneurysms and new endovascular techniques.

Age Factors↗
PubMed1998

Ruptured abdominal aortic aneurysm: initial misdiagnosis and the effect on treatment.

OBJECTIVE: To evaluate the incidence of misdiagnosis in ruptured abdominal aortic aneurysm and its effect on treatment and outcome. DESIGN: Retrospective study. SETTING: Teaching hospital, The Netherlands. SUBJECTS: 97 consecutive patients admitted with ruptured abdominal aortic aneurysm during the 5-year period, 1 January 1989--31 December 1993. MAIN OUTCOME MEASURES: Initial diagnosis, interval between onset of symptoms and admission, and mortality. RESULTS: 38 Patients (43%) presented with symptoms of their aneurysm exceeding nine hours prior to admission (range 10 hours to 14 days, median 2 days). Fifty patients (60%) were initially misdiagnosed by the referring practitioner. Ultrasonography was consistent with rupture in only 36/70 (51%). 52 Patients died (54%), (operative mortality 45 (46%)), and was not affected by delay in diagnosis or treatment. CONCLUSIONS: Although delay in diagnosis or treatment did not seem to affect mortality, improved awareness of non-specific presentations of (imminent) rupture will result in fewer misdiagnoses and earlier treatment. A group of patients will undoubtedly benefit from this as they can be operated on at a stage when expected mortality is lower.

Aged↗
PubMed1998

Carotid recurrent stenosis and risk of ipsilateral stroke: a systematic review of the literature.

BACKGROUND: The main goal of follow-up after carotid endarterectomy is to prevent new strokes caused by recurrent stenosis. To determine the most cost-effective follow-up schedule, it is necessary to know the incidence of recurrent stenosis and the risk of stroke it carries. METHODS: A systematic review of the literature was performed using standard meta-analytical techniques. RESULTS: Incidence of recurrent stenosis: The data were very heterogeneous. The risk of recurrent stenosis was 10% in the first year, 3% in the second, and 2% in the third. Long-term risk of recurrent stenosis is about 1% per year. Risk of stroke: The reported relative risks of stroke in patients with recurrent stenosis compared with patients without recurrent stenosis showed extreme heterogeneity and ranged from 10 to 0.10. The random effects summary estimator of relative risk was 1.88. CONCLUSIONS: The data were very heterogeneous, and much better data are needed to arrive at truly reliable estimates of these important parameters of follow-up. It is clear, though, that the risk of recurrent stenosis is highest in the first few years after carotid endarterectomy and very low in later years. By use of general decision-analytic arguments, it can be argued that, given the test characteristics of carotid ultrasound, a small number of tests can be done in the first few years and that testing for restenosis should not be done after 4 years.

Aged↗
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

Bifurcated stent-graft for abdominal aortic aneurysm.

The purpose of this study was to examine bifurcated stent-graft implantation for abdominal aortic aneurysm. Fifty-seven patients were treated and followed with serial computed tomography scans for up to 3 years. Patients were allocated to three groups (first 20, second 20, last 17) according to when the repair was performed. Successful treatment is defined as exclusion of the aneurysm from the circulation, based on contrast computed tomography. Success rates in the three groups were 55%, 70% and 100%. Perigraft leak (endoleak) was present on initial assessment in 4/20, 2/20 and 1/17. Two of these aneurysms ruptured early in the postoperative period. Thereafter, leaks were sought and treated aggressively. Kinking and thrombosis occurred in six of the first 20 patients, but did not occur in any of the last 37 patients, in whom the graft limbs were routinely stent-supported throughout. Infrarenal implantation in very a short neck (< 10 mm), or a thrombus-lined neck was associated with proximal stent migration. In conclusion, changes in patient selection and technique have led to a steady rise in the short-term success rate of the stent-grafted implantation.

Aneurysm, Ruptured↗
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↗