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Biomedical subjects

R J Welten

Publications and source records attributed to R J Welten.

12 recordsLinked to original sources
PubMed2000

Effects of a venous cuff at the venous anastomosis of polytetrafluoroethylene grafts for hemodialysis vascular access.

INTRODUCTION AND METHODS: The most frequent complication of polytetrafluoroethylene (PTFE) arteriovenous grafts for hemodialysis is thrombotic occlusion due to stenosis caused by intimal hyperplasia. This complication is also known for peripheral bypass grafts. Because the use of a venous cuff at the distal anastomosis improves the patency of peripheral bypass grafts, we considered that it might also improve the patency of PTFE arteriovenous grafts. Therefore, a randomized multicenter trial was carried out to study the effect of a venous cuff at the venous anastomosis of PTFE arteriovenous grafts on the development of stenoses and the patency rates. RESULTS: Of the 120 included patients, 59 were randomized for a venous cuff. The incidence of thrombotic occlusion was lower in the cuff group (0.68 per patient-year) than in the no-cuff group (0. 88 per patient-year; P =.0007). However, the primary and secondary patency rates were comparable. The cuff group tended to have fewer stenoses at the venous and arterial anastomoses when examined with duplex scan. Graft failure was higher in patients with an initial anastomosing vein diameter smaller than 4 mm (7 of 18 [39%]) than in those with a vein diameter of 4 mm or larger (16 of 88 [18%]; P =. 052). Local edema, skin atrophy, and obesity yielded a higher risk on graft failure (23% vs 11%). CONCLUSION: A venous cuff at the venous anastomosis of PTFE arteriovenous grafts for hemodialysis reduced the incidence of thrombotic occlusions; stenosis at the venous anastomosis was reduced. However, this did not result in a better patency rate. Therefore, the venous cuff should not be used routinely. Initial vein diameter and local problems (edema, obesity, or skin atrophy) appear to be the most important risk factors for graft failure.

Arteriovenous Shunt, Surgical↗
PubMed2000

Splenic abscess after appendicitis.

We report an appendicitis complicated by a splenic abscess in a patient with polycystic kidneys and multiple cystic lesions in the liver. Clinical decision making for operative intervention was made difficult by the extensive intra-abdominal abnormalities seen on computer tomography. Finally curation was achieved by splenectomy and appendectomy.

Abdominal Abscess↗
PubMed1994

Benefits of carotid patching: a prospective randomized study with long-term follow-up.

A prospective study with random selection between primary closure and saphenous vein patching after carotid endarterectomy was conducted. Patients were evaluated with intravenous digital subtraction angiography during the initial postoperative period, followed by duplex scanning at 3 and 6 months, and then yearly examinations. The series consisted of 129 carotid endarterectomies, of which 62 were primary closures and 67 were patch procedures. Both groups were identical with regard to risk factors, symptoms, and postoperative control digital subtraction angiography. Restenosis was defined as a stenosis with > or = 50% diameter reduction, as assessed by duplex scanning. Of special interest was the development of restenosis along with the occurrence of cerebrovascular symptoms at long-term follow-up. The follow-up data from the 129 carotid endarterectomies are presented in a life-table analysis. The mean length of follow-up was 5 years (range 1 to 96 months). During the follow-up period 38 patients who had undergone 39 operations died (mortality rate 30%); three deaths were attributed to cerebral causes (two in-hospital deaths due to intracerebral hemorrhage and one cerebral hemorrhage after 6 months). Restenosis occurred in 25 cases (19%). This restenosis was detected in 5 of 45 men with primary closure (11%), 12 of 17 women with primary closure (70%), 7 of 49 men with patch closure (14%), and 1 of 18 women with patch closure (5.5%). The difference between patch and primary closures was found to be statistically significant (hazard ratio 0.39; 95% confidence interval 0.17 to 0.91; p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid Stenosis↗
PubMed1992

Outcome of progression from carotid stenosis to occlusion.

The incidence of symptoms at the moment the internal carotid artery (ICA) occludes was assessed in 33 patients. Duplex scanning was performed to determine the progression from stenosis to ICA occlusion. There were 24 patients with a primary stenosis and nine with a restenosis after a carotid endarterectomy. In 18% (6/33) the occlusion was accompanied by a stroke. A transient ischaemic attack (TIA) was seen in 12% (4/33) of patients and 70% (23/33) remained asymptomatic. There was no difference in stroke rate between patients with primary stenosis (4/24:17%) and those with restenosis (2/9:22%). The mean follow-up was 3.2 years and the mean elapse time to occlusion in patients with a stroke was 20 months, with a TIA, 32 months, and in asymptomatic patients, 44 months. It was also shown that a stenosis of greater than 80% diameter reduction had a faster progression (mean 1 year) than a less than 80% stenosis (mean 3.5 years) (p = 0.04). Patients with a stenosis greater than 80% tended to have a higher incidence (40%:2/5) of stroke at the time of occlusion than patients with a stenosis less than 80% (14%:2/28). The results show that an occlusion of the ICA is accompanied by a stroke in 18% of the cases and that patients with a rapid progression and/or greater than 80% stenosis are at high risk. From this point of view a carotid endarterectomy should be considered in order to prevent an occlusion of the ICA and a high risk of stroke.

Aged↗
PubMed1991

A future role for loop ileostomy in colorectal surgery?

Thirty patients underwent a defunctioning loop ileostomy. Elective ileostomy was performed in 23 patients to protect a potentially vulnerable colorectal anastomosis and in one patient as a permanent faecal diversion for colonic atony. Six emergency loop ileostomies were performed; in four patients after colonic perforations and in two patients as a primary treatment secondary to colonic anastomotic leakage. Peri-operatively, none of the patients with an elective operation died. Four patients with an emergency operation, however, all died of irreversible peritoneal sepsis. Complications were a diversion colitis and an abdominal sepsis after anastomotic leakage in a second patient who required a re-operation. During follow-up (up to four years) one patient suffered from an episode of severe dehydration six months after operation. The ileal continuity was, without mortality, restored in 23 patients. Two patients had a wound infection with, in one of them, a late cicatricial hernia. In our experience, a defunctioning loop ileostomy is a relatively safe procedure and is, in our opinion, preferable to loop colostomy for temporary faecal diversion. The high mortality following emergency loop ileostomy reflects the bad prognosis of these patients and indicates the need for resection of the primary disease.

Emergencies↗
PubMed1988

Benefits of carotid patching: a randomized study.

Advocates of carotid artery patching claim a reduced incidence of recurrent stenosis after endarterectomy. A prospective study was undertaken to determine its value with random selection between primary closure and saphenous vein patching. A consecutive series of 129 carotid endarterectomies was evaluated by duplex scanning at 3, 6, and 12 months after operation. Intravenous digital subtraction angiography (DSA) was performed in the first postoperative days for control of the surgical technique and after 1 year to serve as a reference for the duplex scanning. Sixty-two patients were selected to have primary closure and 67 were chosen for the patching technique. Both groups were identical with regard to risk factors (mean age 63 years, 74% were men, 57% had hypertension, 41% had coronary disease, 37% had peripheral arterial disease, and 9% had diabetes mellitus), side of operation (55% left), symptoms (18% were asymptomatic), and postoperative DSA (81% were normal, 17% had residual lesions, and 2% had occlusions). A complete 1-year follow-up was obtained in 105 cases (81%); duplex scanning showed recurrent stenosis of more than 50% in 12 cases (11%). This was significantly higher after primary closure (10 of 48 patients = 21%) compared with patch closure (2 of 57 = 3.5%; p = 0.006) and also in women (6 of 25 = 24%) compared with men (6 of 80 = 7.5%; p = 0.03). Recurrent stenosis was present in 6 of 11 women with primary closure (55%), 4 of 37 men with primary closure (11%), 2 of 43 men with patching (5%), and none of 14 women with patch closure (0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1987

Recognising stroke prone patients with a poor collateral circulation.

The prognosis in carotid disease is extremely variable and is influenced by the availability of collateral circulation. This study investigates the possibility of recognising patients with a poor collateral potential by using non-invasive tests. Preoperative OPG and EEG were compared with intraoperative EEG during test clamping in 208 carotid endarterectomies. Clamping ischaemia occurred in 29 patients (14%). Preoperative EEG had a sensitivity of 62% and a specificity of 82%. OPG showed a sensitivity of 96% and a specificity of 54%. Combined OPG and EEG resulted in a sensitivity of 93% and a specificity of 73%. Both tests are safe and easy to perform and interpret. These techniques can be used to identify those patients with carotid stenosis who have an increased risk of stroke due to a poor collateral circulation and may help to refine the indications for carotid endarterectomy.

Brain Ischemia↗