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Biomedical subjects

A J Hilson

Publications and source records attributed to A J Hilson.

At least 73 records · Page 4Linked to original sources
PubMed1992

Screening for renovascular disease with captopril-enhanced renography.

Changes in renal function caused by angiotensin-converting-enzyme (ACE) inhibitors can be detected on 99mTc-DTPA renography so that DTPA scanning before and after a single dose of captopril can be used to screen for renovascular disease. We have performed captopril-DTPA scans with renal arteriography on 104 patients, of whom 27 had renal artery stenosis, all due to atheroma. Using a 5% fall in divided function or a delay of greater than 15 min in time to peak activity on one side after captopril, or the finding of greater than 90% divided function on one side before captopril as criteria for a positive scan, a sensitivity of 93% and specificity of 70% was achieved. The negative predictive value of the test in our population was 93%. Bilateral improvement in renographic function after captopril was seen in patients with accelerated phase hypertension. The presence of bilateral renal artery disease did not reduce the sensitivity of the test, but sensitivity was reduced (75%) in patients with renal impairment. Clinical characteristics in our patients most strongly associated with renal artery stenosis were abdominal bruit, recurrent left ventricular failure, and peripheral vascular disease. In view of the well-publicized risks of ACE inhibitor therapy, care should be exercised in the use of these agents in such patients.

Adult↗
PubMed1991

Radionuclide studies in impotence.

Impotence may be of physiological origin with causes including vascular or neurological pathology. Alternatively, it may be of psychogenic origin. Clinicians can distinguish between psychological and organic impotence by observing nocturnal penile tumescence. Non-radionuclide investigations for organic impotence include penile plethysmography or pulse Doppler analysis for arterial supply, cavernosometry for venous drainage, and biothesiometry or evoked potentials for neurological pathology. Radionuclide studies are primarily based on the use of technetium 99m-pertechnetate, 99mTc-red blood cells, or xenon 133 to study the blood flow, with or without pharmacological intervention, commonly papaverine.

Alprostadil↗
PubMed1991

European Captopril Radionuclide Test Multicenter Study. Preliminary results. Inspective renographic analysis. The European Captopril Radionuclide Test Multicenter Study Group.

Captopril radionuclide test (CRT) has been introduced in clinical practice as a screening test for renovascular hypertension, since it allows the detection of the decrease of glomerular filtration rate that may be induced by angiotensin converting enzyme inhibition (25 mg oral captopril) in kidneys ipsilateral to a renal artery stenosis. However, due to the low prevalence of the disease, experiences in single centers may hardly satisfy the need for representative series of patients to validate the test. Nineteen centers participated in a collaborative study (CRT European Multicenter Study) that collected data from 424 patients. Here we report on the first results obtained by inspective renographic analysis. The captopril radionuclide test greatly potentiated the diagnostic performance of conventional renography and the accuracy was maximal when relying simply on postcaptopril findings alone. Specificity was 84.1% in the overall population and 91.8% in uncomplicated patients without nephropathy and renal insufficiency. Taking into account the sole arteriographic diagnosis, sensitivity was 73.2% or 90.7% for the subjects with unilateral or bilateral stenosis and an angiographic degree of stenosis greater than or equal to 70%. On the other hand, when a successful outcome of blood pressure after revascularization or nephrectomy was considered as the gold standard for the diagnosis of renovascular hypertension, a high sensitivity was obtained (92.7%). Moreover, the test became negative after intervention in the great majority (88%) of patients who had a positive preintervention CRT and a normalization of blood pressure after revascularization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The use of captopril-DTPA scanning in the diagnosis of atherosclerotic renal artery stenosis in patients with impaired renal function.

We have analyzed our use of captopril-diethylene-triaminepentaacetic acid (DTPA) scanning in patients presenting to the Royal Free Hospital predominantly with renal impairment. The sensitivity was found to be as good in patients with bilateral disease or disease of a single kidney as in patients with unilateral disease. On a number of occasions, though, the scan suggested unilateral disease when bilateral disease existed. There were, however, a large number of patients for whom captopril-DTPA scanning was not performed because of severe renal impairment or the possibility of renal artery stenosis in a single functioning kidney.

Aged↗
PubMed1991

Report of the Working Party Group on Determining the Radionuclide of Choice.

There are a variety of radiopharmaceuticals that can be used to perform captopril renography effectively. We examined a number of technetium and iodine compounds and the circumstances under which each radiopharmaceutical compound is the compound of choice. Considerations of cost, ease of use, reliability, dosage, and the effects of different protocols were all examined.

Captopril↗
PubMed1990

High incidence of cardiomyopathy in beta-thalassaemia patients receiving regular transfusion and iron chelation: reversal by intensified chelation.

Cardiac scintigraphy has been performed in 60 beta-thalassaemia major patients aged 8-35 years who received regular blood transfusions and subcutaneous desferrioxamine (DFX) chelation. Fifty-seven showed no clinical, radiological or electrocardiographic evidence of heart disease and 3 had clinically apparent cardiac failure. Twenty-two patients (37%) showed severe cardiac functional impairment defined by a resting left ventricular ejection fraction (LVEF) less than 45% and/or a drop of greater than 12% on stress, while 19 were normal and 19 had a mild abnormality. There was no significant correlation between abnormality of LVEF and age, serum ferritin, number of units transfused, dose and duration of subcutaneous DFX therapy, liver disease or sexual maturation. Non-compliant patients (defined as the use of subcutaneous DFX less than 4 times weekly) generally showed worse cardiac function. Repeat study on 17 patients after 6-28 months of better compliance with subcutaneous or intravenous DFX (using an indwelling catheter) showed a significant overall improvement in LVEF associated with a significant drop in serum ferritin. We conclude that cardiac scintigraphy uncovers a high incidence of cardiac functional abnormality in asymptomatic, well-transfused thalassaemia patients, particularly those poorly compliant with chelation. Those with poor LVEF results should be offered intensive chelation therapy to improve cardiac function.

Adolescent↗
PubMed1989

Radionuclide imaging of ureteric peristalsis.

Dynamic renal scintigraphy is a successful and minimally invasive technique for evaluating renal function. An extension to the basic technique involving fast-frame acquisition and a modified analysis is described which enables ureteric function to be examined. Ureteric peristalsis was assessed in 32 patients using this technique. The results from 5 representative studies are described in detail. Normally functioning ureters exhibit peristaltic contractions at a frequency of up to 3/min. Hyperperistalsis that exceeds 4 contractions/min is associated with obstruction. Peristaltic behaviour in 9 patients examined before and after ESWL was not altered.

Adult↗
PubMed1988

Haemodynamic effects of DPI 201-106, following single intravenous dose administration to patients with moderate cardiac failure.

DPI 201-106 is a novel compound unrelated to other cardioactive agents and has been shown to have an inotropic effect in animal preparations. The drug was given by intravenous infusion (20 mg over 10 min) to 10 patients with moderate cardiac failure and the haemodynamic effects measured at intervals up to 1 h following infusion. Maximal effects were seen immediately following the infusion of DPI 201-106. Cardiac index showed an increase from baseline 2.72 (0.16) 1 min-1 m-2 to 3.18 (0.21) 1 min-1 m-2 at the end of infusion (P less than 0.001). Subsequent values were not significantly raised. Pulmonary capillary wedge pressure and pulmonary artery pressure fell from 27.6 (3.2) and 36.9 (4.4) to 15.3 (3.6) and 24.2 (4.9) mmHg, respectively (P less than 0.001 in both cases). A statistically significant effect on cardiac index was not seen at 1 h. However, pulmonary pressures remained reduced at this point. Radionuclide ejection fraction showed a significant increase from 15.4 (1.5) to 21.9 (2.2)% (P less than 0.005) at the end of infusion, and maintained a significant increase at 1 h. Having demonstrated beneficial, acute haemodynamic effects in this study, further work should be undertaken with DPI 201-106 to investigate the effect of chronic treatment in patients with cardiac failure.

Adult↗
PubMed1988

Captopril-enhanced 99mTc DTPA scintigraphy in the detection of renal-artery stenosis.

The value of captopril-enhanced 99mTc DTPA scintigraphy as a screening test for renovascular disease was prospectively studied in 44 hypertensive patients suspected to have renal-artery stenosis. Renal impairment (plasma creatinine greater than 130 mumol/l) was present in 29 patients. At angiography 13 patients had unilateral stenosis, two bilateral stenosis, and 29 patients had no renovascular disease. Captopril induced a fall in split renal function in the kidney ipsilateral to the stenosis in all patients with unilateral disease (mean 52 +/- 23% to 44 +/- 21% of total renal function; P less than 0.001). A positive captopril scintigram (defined as a fall of 5% or more in split renal function) had a sensitivity of 85% and a specificity of 72% in the detection of unilateral renal-artery stenosis. Captopril-enhanced 99mTc DTPA scintigraphy is a promising non-invasive screening test for the detection of renal-artery stenosis.

Adult↗
PubMed1986

The role of the radioisotope phallogram in the investigation of vasculogenic impotence.

Patients complaining of impotence were investigated through a multi-disciplinary approach to define the factors involved. Radioisotope phallography was performed on all the patients using 99Tcm-labelled red blood cells (RBCs) and dynamic records of the variation in activity over the penis were obtained. During the course of the study an intravenous injection of a vasodilator (isoxsuprine HCl) was administered. An analysis of the data provided quantitative parameters for measuring the changes in penile blood flow and penile blood volume in response to the vasodilator injection. The results indicate that the radioisotope phallogram is useful both in the diagnosis of vasculogenic impotence and in indicating the method of treatment.

Adult↗
PubMed1985

Isotope phallogram: preliminary communication.

The isotope phallogram is an investigation which uses radioisotope-labelled red cells in the imaging of penile arterial blood flow. In a preliminary series of 12 impotent patients undergoing both internal iliac arteriography and isotope phallography, the penogram index described by Fannous et al. (1982) has been modified to derive an accurate indicator of vascular disease.

Arteries↗