Angioplasty in atheromatous renovascular disease

Clinical Radiology (1991) 44, 139-140

Correspondence Letters are published at the discretion of the Editor. Opinions expressed by correspondents are not necessarily those of the Editor. Unduly long letters may be returned to the authors for shortening. Letters in response to a paper may be sent to the author of the paper so that the reply can be published in the same issue. Letters should be typed double spaced and should be signed by all authors personally. References should be given in the style specified in the Instruction to Authors at the front of the Journal CRITICAL E V A L U A T I O N O F T H E RADIAL H E A D C A P I T E L L U M VIEW IN A C U T E E L B O W T R A U M A W I T H AN EFFUSION SIR Drs M a n n s and Lee (1990) have written a well thought out article on the radial head - capitellum (RHC) view. We disagree that the R H C view m a y be misleading as it is well known that not all views will demonstrate a fracture, and this should not be held against the R H C view any more than the standard views. While accepting that the routine use of the R H C view is not justified, as the initial standard views m a y be sufficient, we continue to use it in cases of clinical or radiological doubt as a conclusive diagnosis is of value even if m a n a g e m e n t is not directly affected. In our prospective study in patients with a clinical suspicion of radial head injury, we concluded that the R H C view provided contributory diagnostic information in six cases (21% of identified fractures) (Grundy et al., 1985). -

P. G U E S T A. G R U N D Y

Department of Diagnostic Radiology St George's Hospital Blackshaw Road London SW17 OOT

References Grundy, A, Murphy, G, Barker, A, Guest, P & Jack, L (1985). The value of the radial head-capitellum view in radial head trauma. British Journal of Radiology, 58, 965-967. Manns, R A & Lee, J R (1990). Critical evaluation of the radial head capitellum view in acute elbow trauma with an effusion. Clinical Radiology, 42, 433-436.

they cite (Becker et al.) quotes a technical success rate of 90%, but this figure specifically excludes ostial lesions which are c o m m o n in A R A S and associated with a high recurrence rate (Wollenweber et al.). O f course, the quoted rate also takes no account of lesions found on angiography not thought to be amenable to angioplasty, and simply shows that the radiologists involved tended to undertake angioplasty in cases with a high likelihood of technical success. Second, the progressive nature of A R A S is said to justify intervention to preserve renal function. However, A R A S is only one manifestation of generalized vascular disease, which is also progressive. The diagnosis of A R A S does not predict the ultimate development of end-stage renal disease, and m a n y of these patients will die of cardio- or cerebral vascular disease before their kidneys fail (Isles et al.) The demonstration of m e a n reductions in serum creatinine levels is not synonymous with the prevention of ESRD. The precipitation of E S R D is a recognized side effect of angioplasty. We need to know if such risks of angioplasty in A R A S are outweighed by the potential benefits, and none of the work cited in the editorial sheds m u c h light on this. W h e n A R A S was aggressively sought and treated in one study the results were not encouraging although I0 patients with renal failure secondary to A R A S were identified, dialysis was delayed in only one, and one patient died of myocardial infarction shortly after angioplasty (ScoNe et al.). There m a y well be a role for angioplasty in a subset of patients with A R A S and steadily deteriorating renal function. Your editorial encourages a more widespread use of angioplasty, but we would like to see more convincing evidence that the benefits of dilation of the renal arteries outweigh the risks in patients with generalized atheromatous disease. J. M A I N H. LOOSE

Renal @rices Royal Victoria Infirmary Newcastle upon Tyne

Reply from the author SIR-May I t h a n k Drs Guest and G r u n d y for their c o m m e n t of a 'well thought out article'. They suggest that the radial h e a d - capitellum (RHC) view is diagnostically conclusive when the results of the article in question and others quoted in the literature do not support any such view. Second, they suggest that even if clinical m a n a g e m e n t is not affected the R H C view is useful. We are all guilty of occasions when we exercise such irrational behaviour but to advocate such a policy is in m y view wrong. In their own article (Grundy et al., 1985) they themselves imply the radial head - capitellum view m a y demonstrate a fracture which will alter management. Occult radial head fractures demonstrated by the R H C view alone are rare and of doubtful clinical relevance. R. A. M A N N S

Telford Hospital Apley Castle Telford Shropshire TF6 6TF

References Becker, GJ, Katzen, BT & Dake, M D (1989). Non-coronary angioplasty. Radiology, 170, 921-940. Isles, C, Main, J, O'Connell, JO, Brown, I, Findlay, J, Stewart, R & Wilkinson, R (1990). Survival associated with renovascular disease in Glasgow and Newcastle: A collaborative study. Scottish Medical Journal, 35, 70-73. Reidy, JF & Ritter, J M (1990). Angioplasty in atheromatous renovascular disease. Clinical Radiology, 42, 299-301. Scoble, JE, Maher, ER, Hamilton, G, Dick, R, Sweny, P & Moorhead, JF (1989). Atherosclerotic renovascular disease causing renal impairment - a case for treatment. Clinical Nephrology, 31, 119-122. Wollenweber, J, Sheps, S & Davis, G (1968). Cinical course of atherosclerotic renal vascular disease. American Journal of Cardiology, 21, 60-71.

Reply from the authors Reference Grundy, A, Murphy, G, Barker, A, Guest, P & Jack, L (1985). The value of the radial head - capitellum view in radial head trauma. British Journal of Radiology, 58, 965-967.

A N G I O P L A S T Y IN A T H E R O M A T O U S R E N O V A S C U L A R DISEASE S m - We would like to c o m m e n t on the recent editorial by Reidy and Ritter, Angioplasty in Atheromatous Renovascular Disease. We do not feel that the advocacy of an aggressive policy of intervention is supported by published results of the use of angioplasty. First, the editorial states that there is a high technical success rate of angioplasty for atheromatous renal artery stenosis (ALIAS). The paper

Sm In our editorial Angioplasty in Atheromatous Renal Vascular Disease we tried to throw some light on what we feel is a difficult and complex subject. We are pleased to be given the chance to comment on Drs Main and Loose's letter which we feel rather confuses the issue. In our concluding paragraph we advocated ' a n aggressive policy in seeking RAS in selected patients', and not an aggressive policy for intervention. We particularly drew attention to the lack of any controlled studies in renal angioplasty (PTRA). The problem arises in the hypertensive patient with severe renal artery stenosis (and normal renal function) when most physicians knowing the natural history of severe RAS are reluctant to withhold angioplasty aside from any possible benefit in the m a n a g e m e n t o f hypertension. Put another way, there is a feeling in such cases that the benefits o f P T R A outweigh (even though.this is not proven) the risks. We are well aware that patients with A R A S have diffuse arterial disease. Indeed, we drew particular attention to the risks o f associated coronary artery and cerebrovascular disease in

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our patients presenting with renal failure. Most would not exclude treatment on these grounds, especially when hypertension is likely to aggravate these conditions still further. The figure of 90% technical success cited in Becker's review is taken from the table of 15 reported series that does include ostial lesions as well as F M D . It need hardly be stated that the cases for P T R A are selected and that radiologists should only tackle cases where there is a reasonable likelihood of technical success, i.e. severe local stenoses and not extensive occlusions with small kidneys. It is our impression that the issue of ostial stenoses is overstated. These lesions are more commonly seen in patients presenting with renal failure who have more severe and diffuse disease. We along with others have drawn attention to the greater problems in performing P T R A in these patients with their higher risks o f strokes and myocardial ischaemia. It should not however be forgotten that this is the only treatable renal cause of chronic renal failure in older patients who are usually not candidates for transplantation or dialysis. There is a limited literature on P T R A in renal failure but what there is suggests a modest improvement in function does occur. Citing a further paper with only four attempted angioplasties does not really add to it. Every centre will have to work out a policy for investigating older patients with hypertension and renal failure and treating patients with A R A S , taking into account the views of their physicians and the experience of their vascular surgeons and interventional radiologists. We believe in an aggressive approach in seeking out patients with A R A S , as when properly employed in selected patients angioplasty offers a real therapeutic gain. J. F. R E I D Y J. M. R I T T E R *

Department of Radiology Guy's Hospital and *Department of Clinical Pharmacology United Medical and Dental Schools Guy's and St Thomas" Hospital London

A S I M P L E WAY T O E X P L A I N R A D I A T I O N

I propose a simple way to explain radiation. The quantity is called

ionizing radiation, which will often be shortened to radiation. The new unit for ionizing radiation is time - 'Background Equivalent Radiation Time' (BERT). B E R T is the number of days, weeks, m o n t h s or years that would give an adult the same 'effective dose equivalent' from natural or background radiation. In calculating the BERT I suggest using an a v e r a g e b a c k g r o u n d rate of 3 mSv (300 mrem) per year even though the background varies somewhat over the earth. (I thank my colleague Professor H. T. Richards for suggesting the name for the unit.) In describing radiation to the public BERT would not be mentioned. The a m o u n t of ionizing radiation would be expressed simply in terms of days, weeks or m o n t h s of natural radiation. For example, compare the information in the following statements: "Your X-ray study gave you about 100 millirems or 1 rosy of effective dose equivalent;' or 'Your X-ray study gave you radiation equivalent to about 4 months o f natural

radiation.' It is easy to use the new unit. Y o u have to remember that natural radiation to the public is about 300 m r e m or 3 mSv per year. Once you know the effective dose equivalent in mSv or mrem you can figure the days, weeks, m o n t h s or years of natural radiation. For example, the B E R T for 1 m r e m is roughly one day of natural radiation and the B E R T for 1 mSv is about 4 months. Radiation that strikes only part of the body, such as medical X-rays, is not as hazardous as the same a m o u n t of radiation to the whole body. For example, 100 m r e m to your lungs is equivalent to only 12 mrem of effective dose equivalent to the whole body. Other organs have similar factors to convert the dose equivalent to effective dose equivalent. Typical BERTs of ionizing radiation from medical radiographs with this new unit are: for a dental bitewing, about one week; for a chest radiograph, about 10 days; for a m a m m o g r a m , about 3 months; and for a barium enema radiograph study, about 1 year. The values vary greatly from one medical centre to another. The B E R T for the average a m o u n t of radiation to the public each year from diagnostic radiographs is about 7 weeks. O f course, some people receive m u c h more than others. The B E R T for the average a m o u n t of radiation we receive each year from nuclear power plants is less than one day of additional natural radiation even for people who live in the vicinity of a nuclear power plant. The B E R T for a trans-Atlantic jet flight is about five days. J. R. C A M E R O N

Sm The public has an exaggerated fear of even small a m o u n t s o f ionizing radiation, such as X-rays and radioactivity. The fear of radiation is made worse by not understanding the scientific words used to describe it. This letter describes a radiation unit based on natural radiation that is easily understood by the public.

Departments of Medical Physics, Radiology and Physics University of Wisconsin Madison W N 53706 USA