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Biomedical subjects

T Schroeder

Publications and source records attributed to T Schroeder.

At least 127 records · Page 7Linked to original sources
PubMed1988

Urothelial atypia and survival rate of 500 unselected patients with primary transitional-cell tumour of the urinary bladder.

In a consecutive series of 500 unselected patients with primary urinary bladder tumours the influence of urothelial atypia on the 5 years survival-rate was examined. All tumours were transitional-cell tumours categorized according to the T-classification. Mucosal biopsies from 7 pre-selected sites were taken at the initial cystoscopy in 391 patients (78%) to identify urothelial atypia. The over-all cumulative 5 years survival-rate was 48%. Submucosal and muscle invasion had major influence on survival, whereas tumour grade was less important. Patients with urothelial atypia fared significantly worse than those with normal bladder mucosa (5 years survival 42% versus 62%). This difference in survival-rate became apparent first after two years of observation. Grade II atypia in the bladder mucosa and grade III (carcinoma in situ) had equal significance assessed by the survival-rates.

Adult↗
PubMed1987

Asymptomatic carotid lesions after endarterectomy of contralateral carotid artery. Five-year follow-up study and prognosis.

Of 185 patients who consecutively underwent carotid endarterectomy five years ago, 135 had a patent asymptomatic contralateral internal carotid artery (ICA). During follow-up (median, 59 months), 36 patients developed new neurologic symptoms (18 strokes and 18 transient ischemic attacks). Thirteen patients developed symptoms referable to the territory of the previously asymptomatic ICA (five strokes and eight transient ischemic attacks). Using life-table analysis, the annual stroke rate was estimated to be 1% and 2.2% considering the previously asymptomatic and symptomatic ICA, respectively. Separating patients according to the degree of stenosis on the preoperative angiogram and according to the presence of ulceration revealed a significantly higher incidence of neurologic events and strokes in patients with stenoses exceeding 50% and/or patients with obvious ulcerations. Although the risk of stroke without warning was increased in these subgroups, we did not consider the risk high enough to warrant prophylactic endarterectomy. An exception enough to warrant prophylactic endarterectomy. An exception may be the patient with a more than 90% stenosis.

Actuarial Analysis↗
PubMed1987

Doppler examination of the periorbital arteries adds valuable hemodynamic information in carotid artery disease.

The periorbital flow direction and internal carotid artery (ICA) angiogram were compared to the ICA pressure gradient across the stenosis and the distal ICA pressure in 51 patients subjected to carotid endarterectomy. All 17 patients with inverted periorbital flow had stenoses exceeding 50%. The remaining 16 patients with the same degree of stenosis had antegrade flow, which was also observed in all patients with less than 50% stenosis. In 16 of 17 patients with inverted periorbital flow, the mean pressure gradient exceeded 10 mmHg, whereas 33 of 34 patients with antegrade flow had gradients of 12 mmHg or less. For diagnostic purpose, the periorbital Doppler test is inferior to direct Doppler examination or angiography. However, as an adjunct to direct techniques, patients can be classified into 3 groups: Patients with less than 50% stenosis, Patients with 50% stenosis or more and good collaterals and, Patients with 50% stenosis or more and insufficient collaterals.

Arteries↗
PubMed1987

The clinical use of objective quantification of flow disturbance in carotid artery disease: correlation between spectral broadening index and arteriography.

In order to assess the accuracy of objective quantification of carotid flow disturbance, 147 carotid arteries were examined with continuous wave (CW) Doppler technique. The systolic spectral broadening index (SBI), determined as (maximum-mean)/maximum frequency, was calculated from the power spectrum and together with the peak frequency related to the angiographic degree of stenosis. Receiver operating characteristics curves were calculated and the SBI predicted disease with a specificity of 94%. On the other hand, the ability of the SBI to discriminate minor disease was not satisfactory. Both the SBI and the peak frequency were accurate in discriminating between greater or less than 50% stenosis. The study concludes that using CW Doppler the SBI can reliably predict carotid artery stenoses. For exclusion of minor lesions an additional test should be performed, e.g., pulsed Doppler spectral analysis.

Angiography↗
PubMed1987

Carotid endarterectomy in patients with occlusion of the contralateral carotid artery. Perioperative risk and late results.

Recent reports on the outcome of carotid endarterectomy in patients with contralateral occlusion have been conflicting. Therefore, we reviewed 51 cases identified, among 675 consecutive carotid endarterectomies. A perioperative mortality of 2% and a permanent morbidity rate of 16% was observed. Compared with a complication rate of about 5% previously reported from this institution, this clearly indicates contralateral carotid occlusion as a major risk factor in carotid surgery. Though not statistically significant, patients with severely reduced cerebral perfusion pressure (CPP) had suffered more severe strokes when compared to patients with only minor reduction in CPP. In addition, the internal carotid artery blood flow following endarterectomy was significantly higher in the low pressure group (P less than 0.02). No patients were lost during follow-up, for a mean of 34 months. The cumulative five-year survival rate was 74%, not significantly different from the expected survival of an age and sex matched population. During the period of follow-up 16 patients experienced new neurologic symptoms, in six (2 strokes and 4 TIA's) referable to the hemisphere ipsilateral to operation and in 10 (2 strokes and 8 TIA's) referable to the contralateral hemisphere. The five-year stroke rate was 16%. This together with the observed survival rate indicated a better-than-expected course in this group of patients with severe cerebrovascular atherosclerosis.

Carotid Artery Diseases↗
PubMed1987

Intracerebral haemorrhage after carotid endarterectomy.

Among 662 consecutive carotid endarterectomies eight cases of postoperative ipsilateral intracerebral haemorrhage were identified, occurring into brain areas which, preoperatively were without infarction. As blood pressures across the stenosis were routinely measured during surgery, the internal carotid artery (ICA) perfusion pressure could be related to the occurrence of haemorrhage. In addition, cerebral blood flow (CBF) was studied with the intravenous xenon-133 technique in four patients and histopathologic examination of the brain was available in four patients who died subsequent to their haemorrhage. All eight patients had a high grade of ICA stenosis and a marked reduction of ICA perfusion pressure (average of 40%) which was significantly greater than that observed (average of 6%) in the other patients undergoing carotid surgery (P less than 0.0001). Relative hyperperfusion of the ipsilateral hemisphere was seen in the four patients studied postoperatively. In at least two cases the haematoma was preceded by an asymptomatic postoperative ischaemic infarct. Histologic examination did not confirm previous findings of changes resembling those seen in malignant hypertensive encephalopathy. These results substantiate the view, that patients at risk of haemorrhage after endarterectomy are those with a low preoperative cerebral perfusion pressure and postoperative hyperperfusion. Postoperative silent brain infarction is an additional risk factor.

Adult↗
PubMed1987

Youth cancer education through a combined American Cancer Society-Boy Scouts of America pilot program.

A pilot cancer education program for Boy Scouts in grades six through nine was developed. Motivation to complete requirements was provided by awarding a "Cancer Awareness Patch." Content of the program included health issues related to smoking and tobacco use, diet, and sun exposure, plus education about the practice of testicular self-examination, and sunscreen usage. Retention of factual material was good up to 18 months post-program. Participants developed positive attitudes toward lifestyle development and volunteerism. The program is recommended for supplementation of school health promotion curricula.

Adolescent↗
PubMed1987

Dihydralazine induces marked cerebral vasodilation in man.

Dihydralazine is widely used for acute control of hypertension. In experimental studies it seems to dilate cerebral resistance vessels and increase intracranial pressure. However, the effect on cerebral blood flow (CBF) in man has been little studied. Measurements of CBF were performed with the i.v. xenon-133 technique in seven young, normotensive volunteers before and 15, 60 and 180 min after 6.25 mg i.v. dihydralazine, corresponding approximately to 0.1 mg kg-1 body weight. For comparison the CBF reactivity to inhalation of 5% CO2 in air was investigated. Dihydralazine increased CBF throughout the period of study, in median 16, 27 and 23% at the three periods of measurements, respectively. The arterial blood pressure remained unchanged, whereas heart rate increased significantly. During CO2 inhalation, CBF increased on average 29%. Thus, the cerebral vasodilation exerted by a small i.v. dose of dihydralazine was of the same order of magnitude as the effect of 5% CO2 inhalation. These results in normal subjects should be extrapolated to diseased persons only with extreme caution. Still, the very marked and long lasting vasodilation observed suggests that dihydralazine, from a theoretical point of view, in certain clinical situations may be harmful.

Adult↗
PubMed1987

Cerebral hyperperfusion following carotid endarterectomy.

Serial measurements of cerebral blood flow (CBF) were performed in 56 patients before and one to four times after uncomplicated carotid endarterectomy. The findings were related to the ratio between internal carotid artery (ICA) and common carotid artery (CCA) mean pressures. Within the 1st postoperative day CBF increased by a median of 37% in the ipsilateral and 33% in the contralateral hemisphere. Later recordings showed a gradual return of CBF toward the preoperative level. Sixteen patients with an ICA/CCA pressure ratio below 0.7 showed a significantly more pronounced and longer-lasting flow increase than did 40 patients with a ratio above this level. On Day 1, the median CBF increase in the ipsilateral hemisphere was 61% and 24% in the two groups, respectively (p less than 0.01). A significant improvement in side-to-side asymmetry, resulting from a higher gain in the ipsilateral hemisphere, occurred in the low pressure ratio group, while the hemispheric asymmetry on average was unchanged in the high pressure ratio group. This relative hyperemia was most pronounced 2 to 4 days following reconstruction. The marked hyperemia, absolute as well as relative, in patients with a low ICA/CCA pressure ratio suggests a temporary impairment of autoregulation. Special care should be taken to avoid postoperative hypertension in such patients, who typically have preoperative hypoperfusion, to avoid the occurrence of cerebral edema or hemorrhage.

Adult↗
PubMed1986

Fate in intermittent claudication: outcome and risk factors.

The fate of 257 consecutive patients (100 women) aged 36-85 years (mean 65) first seen with intermittent claudication in 1977 was analysed after a mean of 6.5 (SD 0.5) years. When first seen none of the patients complained of rest pain or had ulcers or gangrenous lesions on the feet. At follow up 113 of the patients (44%) had died. Causes of death were no different from those in the general population. Mortality was twice that of the general population matched for age and sex. Mortality among the men was twice that among the women. In men under 60 mortality was four times that expected. The rate of clinical progression of the arteriosclerotic disease (that is, rest pain or gangrene) of the worst affected leg was 7.5% in the first year after referral. Thereafter the rate was 2.2% a year. An ankle systolic blood pressure below 70 mm Hg, a toe systolic blood pressure below 40 mm Hg, or an ankle/arm pressure index below 50% were individually significantly associated with progression of the arteriosclerotic disease. These findings show the importance of peripheral blood pressure measurements in the management of patients with intermittent claudication due to arteriosclerotic disease.

Adult↗
PubMed1986

Noninvasive xenon-133 measurements of cerebral blood flow using stationary detectors compared with dynamic emission tomography.

Repeated bedside measurements of CBF have been made possible by the recent development of a mobile unit with 10 stationary detectors using the intravenous xenon-133 method. To evaluate this technique, comparative CBF studies at rest and following the application of a cerebral vasodilatory stimulus (acetazolamide, 1 g i.v.) were performed with the mobile equipment and with xenon-133 single-photon emission inhalation tomography in patients with cerebrovascular disease. The CBF level and the flow response to acetazolamide as determined with the two methods were well correlated, although at low flow levels the stationary detectors yielded somewhat lower CBF values than did emission tomography. Considering the side-to-side asymmetry, an excellent correlation was obtained. Using the initial slope index, the stationary detectors revealed quantitatively 83% of the interhemispheric asymmetry and 63% of the asymmetry in the middle cerebral artery territory shown with the tomograph. As illustrated by a case history, the nontomographic CBF unit used in this study may provide reliable and useful information in patients with occlusive cerebrovascular disease by performing repeated CBF studies and challenging the cerebral circulation with acetazolamide.

Adult↗
PubMed1986

Cerebrovascular reactivity to acetazolamide in carotid artery disease. Enhancement of side-to-side CBF asymmetry indicates critically reduced perfusion pressure.

Cerebral blood flow (CBF), measured with a mobile 10 detector unit and non-invasive Xenon-133 technique, was investigated before and after cerebral vasodilation with acetazolamide (Diamox) in 78 patients prior to carotid endarterectomy. The change in side-to-side CBF asymmetry from baseline to Diamox study, the Diamox asymmetry enhancement, was compared with the intraoperatively measured cerebral perfusion pressures. Asymmetry enhancement exceeded the methodological variation in 14 patients, 13 of whom had a perfusion pressure below 65 mmHg. Insignificant asymmetry enhancement was found in 64 patients: 52 with unilateral and 12 with bilateral disease. Of these two and four patients, respectively, had perfusion pressures below 65 mmHg. Enhancement of CBF asymmetry following a potent cerebral vasodilator stimulus is a reliable predictor, in unilateral carotid artery disease, of critically reduced cerebral perfusion pressure.

Acetazolamide↗
PubMed1986

Measurement of cerebral blood flow by intravenous xenon-133 technique and a mobile system. Reproducibility using the Obrist model compared to total curve analysis.

The recent development of a mobile 10 detector unit, using i.v. Xenon-133 technique, has made it possible to perform repeated bedside measurements of cerebral blood flow (CBF). Test-retest studies were carried out in 38 atherosclerotic subjects, in order to evaluate the reproducibility of CBF level and side-to-side asymmetry. Data were analysed according to the Obrist model and the results compared with those obtained using a model correcting for the air passage artifact. Reproducibility was of the same order of magnitude as reported using stationary equipment. The side-to-side CBF asymmetry was considerably more reproducible than CBF level. Using a single detector instead of five regional values averaged as the hemispheric flow increased standard deviation of CBF level by 10-20%, while the variation in asymmetry was doubled. In optimal measuring conditions the two models revealed no significant differences, but in low flow situations the artifact model yielded significantly more stable results. The present apparatus, equipped with 3-5 detectors covering each hemisphere, offers the opportunity of performing serial CBF measurements in situations not otherwise feasible.

Adult↗
PubMed1986

Staged bilateral carotid endarterectomy.

In a series of 56 staged bilateral carotid endarterectomies, new neurologic symptoms developed in 5% and 20% following the first and second procedure, respectively. All complications were transient or minor. The incidence of postendarterectomy hypertension was significantly higher following the second procedure, when operations were staged less than 3 weeks apart. A correlation between these hypertensive episodes and the occurrence of new neurologic symptoms could not be shown. However, as this correlation has been proved in several other reports, bilateral carotid endarterectomy is advised to be staged at least 3 weeks apart. In addition, a conservative attitude towards contralateral asymptomatic lesions is proposed.

Adult↗
PubMed1985

Ischemic colitis complicating reconstruction of the abdominal aorta.

A review of 23 patients with ischemic colitis after surgical treatment of the abdominal aorta disclosed a pathogenetic heterogeneous finding. Ligation of the inferior mesenteric artery, abolished collateral blood supply or nonocclusive low flow state, or both, was a common feature. An incidence of 0.5 per cent was revealed for full-thickness necrosis. The mortality was 70 per cent since diagnosis was made first since perforation and peritonitis had occurred. On the basis of these findings vital prophylactic measures and diagnostic possibilities are discussed herein.

Aged↗