False aneurysm of the abdominal aorta in Behçet's disease.
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Biomedical subjects
Publications and source records attributed to D J Allison.
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Pulmonary arteriovenous malformations (PAVMs) are uncommon lesions that can be treated by surgery or interventional radiology. Forty-four PAVMs in 11 patients were occluded by transcatheter coil embolization with only one symptomatic complication, deep venous thrombosis, attributable to the procedure. There was a significant improvement in symptoms and a reduction in pulmonary AV shunting in the 9 patients in whom embolization of all visible discrete lesions was successfully completed. Coil embolization is an effective alternative to other methods of treating PAVMs.
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Twenty-one patients with prostatic urethral obstruction who were unfit for surgery were treated with self-expandable stainless steel endoprostheses inserted under fluoroscopic guidance. The procedure was technically successful in all patients, although in one case a second stent was required 2 months later. One patient developed a urethral stricture in the 12-16 month follow up period. One case of epididymoorchitis and one case of septicaemia after stenting were treated successfully with antibiotics. Endoprostheses represent a satisfactory alternative to prostatectomy in high-risk patients.
The effects of percutaneous transcatheter embolization on pulmonary function and exercise capacity were assessed in 15 patients with pulmonary arteriovenous malformations (PAVM). Vital capacity (VC), FEV1, DLCO, SaO2, exercise performance, and right-to-left shunt (100% oxygen method) were measured before and 2 to 6 months after treatment. Surgical correction had been attempted in 9 patients prior to referral, and 11 had associated hereditary hemorrhagic telangiectasia (HHT). Lung function tests before intervention showed normal VC and FEV1/VC ratios, reduced DLCO (mean 71% predicted, range 36 to 123%), a resting supine SaO2 of 86% (range 67 to 95%) and mean shunt fraction of 33% (range 15 to 47%). Despite further marked falls in SaO2 on exertion, exercise capacity was well preserved. Following steel coil embolization of all PAVM with a feed vessel internal diameter greater than 3 mm (one to four sessions per patient), mean shunt fraction improved from 33 to 19% and resting SaO2 from 86 to 92% with no change in VC. A consistent improvement in diffusing capacity was seen only in patients with coexisting HHT. Exercise capacity increased in the majority (unchanged in 6), and SaO2 during maximal exercise improved in all except one patient. There were no long-term complications following embolization. These findings indicate that embolization of all macroscopic PAVM, undertaken primarily to reduce the risk of paradoxical embolization, is safe and results in substantial improvements in resting and exercise SaO2 without evidence of loss of normal lung. The right-to-left shunts remaining following embolization may reflect the presence of numerous microscopic PAVM in these patients.
If a hypertensive patient with renal artery stenosis (RAS) is to benefit from percutaneous transluminal renal angioplasty (PTRA) in terms of a sustained improvement in blood pressure control, one may postulate a demonstrable reduction in renal blood flow (RBF) to that kidney, reversible by PTRA. In a population of 32 hypertensive patients, RAS was present in 23 of 62 kidneys. Eleven of the 32 patients underwent renal revascularization, of whom 6 showed improvement in blood pressure control at 6 mo, i.e., had renovascular hypertension (RVH). There was no correlation between RBF and angiographic appearances of the renal artery. Furthermore, there was no significant difference between RBF in the stenosed kidneys of the patients with RVH compared with the stenosed kidneys of patients without RVH. Individual kidney RBF was 22% (s.d. 11) higher 1-3 wk after PTRA but the increase did not correlate with clinical outcome. Angiotensin converting enzyme (ACE) inhibition increased RBF by 25% (s.d. 25) of baseline flow before PTRA but the increase did not correlate with clinical outcome. Measurement of RBF is of limited value for the prediction of the long-term blood pressure response following PTRA.
Sixteen patients with pulmonary arteriovenous malformations (PAVM) have been treated by percutaneous transvenous coil embolization. In the ten patients who have had all their angiographically demonstrable PAVM's embolised there has been a reduction of right to left shunting from a mean of 28.1% to 13% and an improvement in mean arterial oxygen saturation from 87.4% to 92.4%. Eight of these ten patients now have oxygen saturations of more than 90%. All patients have shown symptomatic improvement. There have been three complications relating to the embolizations, none of which has been serious. Coil embolization of PAVM's is an effective, safe and well tolerated procedure. Embolization should be performed in all cases of PAVM's to prevent paradoxical embolization.
Portal-systemic shunts are effective in preventing haemorrhage from varices in portal hypertension, but at the price of hepatic encephalopathy. We describe the blockage of a splenorenal shunt using interventional radiology, in a patient with incapacitating chronic encephalopathy. The procedure successfully reversed encephalopathy, without haemodynamic disturbances or haemorrhage from recurrent varices and was associated with a return of the plasma amino acid profile towards normal, with a reduction in aromatic amino acids and an increase in branch chain amino acids. This observation supports the hypothesis that changes in plasma amino acid profiles in patients with portal-systemic shunting are due to the diversion of portal blood rather than the underlying chronic liver disease.
The Interventional Radiology Group of the Royal College of Radiologists sent a questionnaire to major hospitals in the United Kingdom in 1982 and 1987 in order to assess the impact of the introduction and growth of interventional procedures on patient management over the 5-year period and to consider the implications of these data for the future staffing and equipment requirements of radiology departments. In the 194 hospitals correctly completing the most recent survey, a total of 30,794 interventional procedures were performed in a 12 month period, representing an overall increase of 116% since the previous survey of 1982.
Twenty-eight pulmonary arteriovenous malformations in six patients were treated with coil embolization. The technique of embolization and the precautions taken to avoid complications are described. All patients had good relief of their symptoms and an improvement in arterial oxygenation. The observed complications were minor and our technique has now been modified to avoid these.
Forty-eight men with urodynamically proven bladder outflow tract obstruction (BOO) and 19 with retention secondary to benign prostatic hypertrophy were treated by balloon dilatation of the prostate as out-patients; 31 were dilated with 20 mm and 36 with 25 mm balloons. Of the 48 men with BOO, 37 had repeat cystometrograms at intervals ranging from 3 to 11 months after dilatation and 33 (89%) remained obstructed by urodynamic criteria. Of 6 who only had a peak flow rate assessment, 5 had a flow less than 12 ml/s. Of the 19 patients in retention only 3 were able to void and all are obstructed. Symptoms of hesitancy, poor stream, frequency and nocturia were improved in less than 50% of patients. No reliable correlation was found between objective response and balloon size, length of time of dilatation, prostate size or morphology, detrusor pressure or stability, or post-dilatation urethrogram appearances. Balloon dilatation to 25 mm is not adequate therapy for bladder outflow tract obstruction or urinary retention from prostatic hypertrophy.
The management of a patient with severe Cushing's syndrome due to ectopic ACTH produced by a medullary carcinoma of the thyroid is described. Initial treatment with maximal adrenolytic medical therapy and two attempts at bilateral adrenal venous infarction had failed to control the disease, and she was at that time unfit for surgery. Subsequent use of bilateral adrenal arterial embolization enabled medical therapy to produce sufficient control of the Cushing's syndrome to allow bilateral adrenalectomy to be performed successfully, with resultant cure of the excessive cortisol production.
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Hepatic embolization using the percutaneous transcatheter technique can provide valuable palliation of symptoms in patients with inoperable liver metastases. The method is not without complications and since its effect on patient survival is only modest the principal indication for its use is the amelioration of symptoms directly attributable to liver metastases such as local pain or the unpleasant humoral effects produced by secondary deposits from active endocrine tumours.
The clinical course and results of drug treatment for manifestations of the carcinoid syndrome are reviewed in 63 patients. The five-year actuarial survival in this group of patients was 48 per cent. The only markers of a poor prognosis that could be identified at diagnosis were marked weight loss and a high (over 1000 mumol/day) 5-hydroxyindole acetic acid excretion. The relative effectiveness of well-established drugs that either block 5-hydroxytryptamine synthesis or block 5-hydroxytryptamine receptors is reported, with respect to the different manifestations of the syndrome, and compared with a small group of patients treated with long-acting somatostatin analogue. In over one-third of patients, primary tumours were not detected on initial investigation, and in none of these did symptoms referrable to the primary site become apparent later.
We have described the clinical presentation of the commonest syndromes associated with hormone production by functioning pancreatic tumors. The role of the radiologist in tumor localization, staging, and treatment is discussed and the various imaging methods employed are examined individually. The problems of reviewing the world literature on such rare lesions are discussed and a tentative diagnostic algorithm is suggested.
Two recently reported large scale clinical surveys support the impression that the new non-ionic low osmolality iodinated radiographic contrast media are indeed significantly safer for intravascular use than conventional agents. These surveys will lend additional weight to the argument for the universal use of non-ionic agents despite their relatively high cost.