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Biomedical subjects

R van Schilfgaarde

Publications and source records attributed to R van Schilfgaarde.

At least 73 records · Page 4Linked to original sources
PubMed1989

Renovascular hypertension.

Renovascular hypertension is caused by renovascular disease and it can be potentially cured by ablative or reconstructive operation or PTA. The incidence of renovascular hypertension is 1 to 2 per cent among nonselected hypertensive patients. Renovascular disease in hypertensive patients is progressive in 20 to 40 per cent. The diagnosis of renovascular hypertension can only be made retrospectively after successful intervention. The accuracy of all tests for the determination of the functional significance of a stenosis before intervention remains limited. It has been demonstrated that medical therapy, reconstructive surgical treatment and PTA each can effectively lower high blood pressure. Although medical therapy has been considerably improved because of the development of new drugs, it should be recognized that medical management does not prevent the natural progression of renovascular disease. Therefore, renovascular hypertension is best treated by correction of the underlying renal arterial stenosis. Improvements in surgical management include improved selection of patients for surgical treatment, increased beneficial blood pressure response rates in 70 to 95 per cent of the patients and decreased surgical mortality rates of less than 5 per cent. The anatomic failure rates have been reduced because of the increase in surgical expertise, the use of autologous materials for bypass, the avoidance of combined procedures in the event of concomitant aortoiliac disease, the use of extra-anatomic reconstructions when appropriate and the introduction of extra-corporeal reconstruction and autotransplantation. PTA has evolved as a relatively safe and effective method in the treatment of renovascular hypertension. However, complications do occur and orificial arteriosclerotic lesions and renal arterial branch lesions should not be considered for angioplasty. At present, the question of whether renovascular surgical treatment or PTA should be the treatment of choice cannot be answered completely. Treatment of renovascular hypertension should be accommodated to each patient.

Humans↗
PubMed1988

[Cystic dilatation of the choledochus. 9 cases].

A retrospective study of 9 cases of extra-hepatic biliary cyst is presented. Prior to admission to our hospital, 5 patients had been operated upon elsewhere. This initial operation proved to be of great importance. In 4 patients initial excision of the cyst was performed resulting in complete regression of symptoms, and no further surgery was required. In 5 patients the cyst was not excised initially and cysto-enterostomy was performed. Recurrence of symptoms and complaints, with major morbidity, occurred in all but one of these patients. After several operations, only final excision of the cyst definitively suppressed the symptoms, but in one patient the cyst could no longer be excised. Cysto-enterostomy results in recurrent symptoms and cholangitis and should be avoided. Early excision of extra-hepatic biliary cysts should be performed whenever technically feasible, not only to prevent these complications but also because of the risk of malignant degeneration related to the cyst.

Adolescent↗
PubMed1988

Influence of preoperative risk factors and the surgical procedure on surgical mortality in renovascular hypertension.

The present study was undertaken to assess surgical risk in 112 severely hypertensive patients with renovascular disease secondary to atherosclerosis. The influence of preoperative risk factors and the surgical procedure on surgical mortality was also investigated. Extrarenal atherosclerosis was present in 51 percent of the patients, and hypertensive target organ damage was present in 66 percent. Renal artery reconstruction was performed unilaterally in 92 patients and bilaterally in 20 patients. Simultaneous aortoiliac operations were performed in 25 patients. There were nine operative deaths (8 percent). The presence of extrarenal atherosclerosis was particularly associated with mortality (14 percent compared with 1.8 percent when it was absent; p = 0.02). The surgical procedure also represented a significant risk; the mortality rate was 1.4 percent if surgery was restricted to unilateral reconstruction, but otherwise it increased to 20 percent (p = 0.001). This increase in mortality rate was clearly associated with aortoiliac surgery (20 percent compared with 4.6 percent when aortoiliac surgery was not performed; p = 0.025) and could be explained by the increased blood loss during operation. We conclude that the surgical treatment of renovascular disease secondary to atherosclerosis can be safely performed, provided that extrarenal atherosclerosis is absent and that simultaneous aortoiliac surgery can be avoided.

Adult↗
PubMed1988

Quantitative assessment of long-term changes in insulin secretion after canine duct-obliterated pancreas transplantation.

In this study, we have quantitatively assessed the changes in insulin-secreting capacity after duct-obliterated segmental pancreatic autotransplantation in dogs. To this end, we have used a technique for the sampling of the complete and undiluted pancreatic venous blood with simultaneous flow measurement, by which means the actual insulin-secreting capacity was determined in a direct fashion. Histologic changes were analyzed in addition in order to address the underlying mechanisms of the changes in insulin-secreting capacity. Intraoperative glucose-stimulated insulin secretion of the left pancreatic lobe was measured before (group I, n = 8), at 6 weeks (group II, n = 5), and at 18-24 months (group III, n = 7) after duct-obliterated segmental pancreatic autotransplantation. At all 3 intervals, histologic analysis was performed. Since the experiments in groups I-III were performed under general anesthesia, a 4th group of dogs (group IV, n = 6) was studied in addition in order to determine the effect of general anesthesia on glucose metabolism. K-values appeared to be reduced to 1/5 and peripheral insulin response (AUC) to about 1/3 of the values obtained from fasting conscious dogs. Although all animals in groups I-III had normal fasting glucose levels and normal K-values at each test interval, a 75% reduction of insulin secretion after duct-obliterated transplantation was observed. Insulin secretion not only showed marked quantitative changes but significant qualitative alterations in glucose-stimulated insulin response were found. Disturbance of functional islet architecture appears to be the main causative factor in the decrease in insulin secretion. If applicable to man, our results indicate that especially the duct-obliterated graft, with its borderline endocrine capacity, is prone to loss of sufficient graft function by the damage induced by eventual rejection crises.

Animals↗
PubMed1988

Reconstructive surgery for renovascular hypertension. II. Influence of patient selection and anatomical result on the blood pressure response after operation.

The results of renovascular surgery for renovascular hypertension are influenced markedly by patient selection. Our method of patient selection was based primarily on clinical characteristics rather than functional tests. To determine its effect on the results obtained by surgery, we studied all 115 patients in whom angiography showed that surgery had eliminated the renal artery stenosis. Six to 12 months after the operation, hypertension was cured or improved in 83 per cent of the patients and 17 per cent were classified as treatment failures. The results obtained for patients with stenosis caused by arteriosclerosis were similar to those found for patients with fibrodysplasia. Clinical characteristics (sex, blood pressure, duration of hypertension, creatinine level and extrarenal arteriosclerosis or target organ damage before surgery) were analysed separately. The characteristics of patients with a beneficial blood pressure response were not significantly different from those of patients who failed to respond, except for the blood pressure level itself. On the basis of our findings and the results of functional tests reported in the literature, we conclude that the decision to operate should be based on all of the clinical data available. Functional tests can be used to support the diagnosis of renovascular hypertension in selected patients. The presence of extrarenal arteriosclerosis before surgery is not associated with a poorer chance of a beneficial blood pressure response.

Adult↗
PubMed1988

The influence of the surgical technique upon the short term and long term anatomic results in reconstructive operation for renovascular hypertension.

The anatomic results of reconstructive operation for renovascular disease was analyzed in 161 patients with hypertension who were treated between 1959 and 1983. Arteriosclerotic lesions in 103 patients were repaired by endarterectomy (58 per cent), autologous bypasses (27 per cent) and miscellaneous procedures (15 per cent). Fibrodysplastic lesions in 58 patients were treated by in situ procedures (54 per cent) and by extracorporeal repair and autotransplantation (46 per cent). The results were evaluated by means of angiography at both a short term and long term interval after the operation. Angiograms were taken of 79 per cent of the reconstructions at the short term interval and 65 per cent at the long term interval. For the short term interval, the failure rate of angiographically verified reconstructions was 5.7 per cent for arteriosclerotic and 5.8 per cent for fibrodysplastic lesions. The secondary nephrectomy rate was 3.4 and 4.5 per cent, respectively. Surgical expertise appeared to be an important factor, since all failures but one occurred during the first period of the study. Furthermore, the introduction of extracorporeal reconstruction reduced the failure rate for reconstructive operation for fibrodysplasia; residual lesions in the main renal artery did not occur and those of reconstructed hilar branches were only occasionally observed (6.9 per cent). For the long term interval, failure rates were 17 per cent for arteriosclerotic and 14 per cent for fibrodysplastic lesions. In this respect, the results obtained with endarterectomy and arterial bypasses were superior to those obtained with venous bypasses. We conclude that surgical technique is the most important factor for successful reconstruction and that the use of autologous materials, except autologous veins, is preferred.

Arteries↗
PubMed1987

Interference by cyclosporine with the endocrine function of the canine pancreas.

This study addresses itself to the eventual interference of cyclosporine (CsA) with the function of pancreatic beta cells in vivo. We have used dogs that had at least six weeks previously been subjected to segmental pancreatic autotransplantation. This model has been well established to be associated with stable normoglycemia but with incomplete endocrine reserve capacity, which renders it suitable for detecting eventual toxic drug effects. CsA was administered for 6 weeks in an oral dose of either 30 mg/kg/day (first series of 4 dogs) or 40 mg/kg/day (second series of 7 dogs). CsA trough levels in blood were determined at least weekly, and the mean of the levels in each dog ranged from 218 to 1274 ng/ml, with one exception (2191 ng/ml). The endocrine function was tested not only before and after 6 weeks of CsA administration, but also at 4 weeks after cessation of CsA administration. The postprandial insulin output was reversibly reduced in the first series (P less than 0.05) and the i.v. glucose-stimulated insulin output was reversibly reduced in the second series (P less than 0.001). Other parameters, like postprandial peak and mean blood glucose levels and K-values, showed reversible changes that, although not always statistically significant, were compatible with a reversible suppressive effect by CsA in all instances. Finally, we found that the severity of suppression as expressed in individual reduction of i.v. glucose-stimulated insulin output correlated with the individual mean CsA trough level (r = 0.71, P less than 0.015). It is concluded that CsA exerts a detrimental effect on the function of canine beta cells in vivo, which effect is reversible and dependent upon the CsA blood level.

Animals↗
PubMed1987

Pancreatic duct obliteration: clinical application, morphological and functional effects.

Pancreatic duct obliteration is a procedure to abolish exocrine secretion in order to prevent complications such as leakage, abscess and fistula occurring formation after diversion techniques like pancreatico-enterostomy. Pancreatic duct obliteration is applicable after all sorts of partial pancreatic resections, pancreas transplantation included. Although the method is safe, experiments have shown that not only complete exocrine atrophy is induced, but that also the endocrine architecture is destroyed. In dogs, the destruction of islet architecture leads to about 70% reduction of the insulin secreting capacity. It is not known whether such a severe reduction of endocrine function also occurs after pancreatic duct obliteration in man. This would discard duct obliteration as a procedure suitable for pancreas transplantation, since optimal endocrine pancreas function is the aim of pancreas transplantation in patients suffering from type-I diabetes mellitus.

Animals↗
PubMed1987

A model for direct and quantitative assessment of pancreatic hormone secretion.

The usual parameters for the assessment of pancreatic endocrine function are oral or intravenous tolerance tests with various kinds of stimuli, generally glucose. Such tests provide information as to the pancreatic endocrine capacity in an indirect fashion, and the actual hormone output cannot be readily determined. The results are presented of a model in dogs with which the hormone producing capacity of the left lobe of the pancreas can be quantitatively assessed directly. The complete and undiluted venous blood from the left pancreatic lobe is sampled by cannulation of the splenic and the portal vein, under general anaesthesia. Removal of the right lobe is obligatory. With this model pancreatic blood flow, hormone secretion, and oxygen consumption can be studied after different sorts of stimuli. Moreover there is opportunity to determine the effect of various manipulations of the pancreas on its hormone secreting capacity directly.

Animals↗
PubMed1987

Pancreas transplantation in The Netherlands: report of the first case.

This case report describes the first clinical pancreas transplant performed in The Netherlands. A duct-obliterated segmental graft from a cadaver donor was transplanted to a male recipient who was insulin-dependent after total pancreatectomy eight years earlier. The recipient was off insulin for four postoperative months; during this period a rejection crisis was successfully treated. The graft was removed eight months after transplantation. Histologic examination indicated both fibrosis and rejection to have presumably contributed to graft failure. The patient is well but again insulin-dependent.

Chronic Disease↗