Journalrenovasculardisease.com

Journal of Renovascular Disease (2002) 1, 6–10
DOI: 10.1102/1473-1827.2002.0002
Controversies
A case of atheromatous renal artery stenosis with severe
hypertension: is surgical revascularisation appropriate?
Date accepted for publication 20 May 2002 Case History
In summary, this is a 62-year-old man with inade- quately controlled hypertension despite the usage of three A 62-year-old male was referred with a diagnosis of anti-hypertensive agents, who has a small left kidney renovascular disease. His past history included cervical resulting from left renal artery occlusion, a reasonable spondylosis, a transitional carcinoma of the bladder three sized right kidney although the upper pole artery is years previously and resistant hypertension for the last occluded resulting from failed angioplasty. The kidneys year. He was intolerant of a number of anti-hypertensive appear to have preserved renal function of 17 ml/min agents. An angiotensin converting enzyme inhibitor and 18 ml/min respectively and a serum creatinine of (ACEI) was added to the treatment regime followed by 249 µmol/l. The sizes of the renal arteries are not a decline in renal function to a plasma creatinine of clarified. Is the lower or upper pole right renal artery the 400 µmol/l. The creatinine fell on withdrawal of the main arterial blood supply or are they of equal size? Also, ACEI to 250 µmol/l. Ultrasound demonstrated a left we do not know the quality of the aorta, is it heavily kidney of 8.3 cm and right at 10.8 cm. A MRI scan showed an ostial stenotic lesion to the left kidney. He It is important to bear in mind that the current problem was referred for evaluation. On referral his blood pressure is the patient’s difficult to control hypertension and was 200/104 mm/Hg on three agents not including an not the level of renal function, which appears to be ACEI or Angiotensin II (AII) blocker. At angiography stable despite the occluded renal arteries. Clearly, blood the left renal artery was shown to be occluded. Two right supply to the kidneys from capsular and ureteric blood renal arteries were demonstrated. There was a stenosis arteries is currently sufficient to provide an adequate of the upper renal artery with the lower being normal.
combined GFR. What is not absolutely clear is whether An attempt was made to angioplasty the upper lesion the occlusion of the renal arteries will allow long-term but the guide wire could not cross the stenosis. No adequacy of blood supply to the kidneys, now that the flow could be demonstrated through the upper artery at latter are in the main protected from cholesterol emboli the end of the procedure. A subsequent single kidney from the aorta. Whether the kidneys continue to shrink glomerular filtration rate (SKGFR) found 17.3 ml/min down in size is not, therefore, certain. All kidneys that from the right kidney and 18.1 ml/min from the left I have biopsied when operating on for renovascular kidney. The radiologist did not feel that it was possible disease, have exhibited considerable damage due to to intervene in either of the two occluded arteries. The ischaemia and cholesterol embolisation. These renal patient was referred to a vascular surgeon for assessment.
changes may, and often do, progress despite surgical, His blood pressure was 170/96 on Indapamide, Labetolol radiological or medical management of hypertension.
and Methyl Dopa with a plasma creatinine of 249 µmol/l.
It is important to recognise that both kidneys are a problem and any management needs to deal with both.
The right kidney is, however, within normal size limits and preservation of that kidney is vital for long-termrenal preservation of function. There are several options Consultant Transplant and Vascular Surgeon, Royal Increase anti-hypertensive medication using additional Liverpool University Hospital, Liverpool, UK calcium channel blocker, metolazone or minoxidil etc.
This should resolve the hypertension although at the This paper is available online at http://www.journalrenovasculardisease.com. In the event of a change in the URL address, pleaseuse the DOI provided to locate the paper.
Atheromatous renal artery stenosis with severe hypertension expense of taking more tablets with increased chances disease often have extensive other vascular disease, of side-effects. Using ACEI or angiotensin II inhibitor including the coronary, carotid and peripheral arteries.
is likely to cause a reduction in renal blood flow and A MIBI scan/treadmill exercise test would be useful to will result in an increase in serum creatinine once again.
exclude such high risk cases. One of the problems of Of course the blood supply to the kidneys would remain surgical intervention remains post-operative myocardial indirect apart from that to the lower pole of the right infarction or stroke. Pre-operative risk assessment and full discussion with patient and physician is mandatory Surgical options are also available. Revascularisation before embarking on surgery. The mortality of past of both kidneys is possible although we do not know series of surgical series reflects the degree of pre- whether the right upper pole renal artery supplies a operative co-morbid assessment of patients. If best risk sufficient amount of renal parenchyma to be worthwhile cases are undertaken then a durable long-term result revascularising. Clearly, if the lower artery is the main can ensue. However, there will remain a need for supply to the right kidney, then the loss of the parenchyma long-term anti-hypertensive medication since the already supplied by upper pole artery can be ignored. The surgical damaged kidneys will not return to normal. However, options also depend also on the quality of the aortic the number of drugs used to control hypertension would wall—is it safe to clamp the aorta or is it too diseased be reduced. In addition, ACEI could be tentatively The safest option is to perform an extra-anatomical bypass to the renal arteries. The right upper pole arterycould be revascularised by a saphenous vein bypass from the hepatic artery and the left renal artery by usingthe splenic artery. Neither of these procedures involves Dr John Main
clamping the aorta and hence avoids left heart strain.
Consultant Nephrologist, James Cook University The spleen continues to be supplied by the short gastric arteries from the stomach. Alternatively, only one of theseprocedures may be necessary. If the right kidney upper Thank you for asking me to comment on this case, polar vessel is large, then revascularising this kidney which I think is difficult rather than controversial— would be most valuable and a hepato-renal bypass may clearly the options are to go for surgery or not and be best. The left kidney could be left alone since it is there are arguments in favour of either. Also, we need quite small. In this situation, the left kidney would still to remember the limitations of what we can learn from cause hypertension but this could be managed using an the outcome in a single case. If whichever path is finally chosen results in a ‘successful’ outcome, that is not Another extra-anatomical bypass could be performed the same as saying that the correct option was taken.
from the common iliac arteries to the renal arteries.
Any option has a chance of success and a chance of Again, aortic clamping would not be necessary. These failure, which we cannot now (or probably ever) calculate bypasses would be longer in length and would depend accurately. It is quite possible to miscalculate, opt for the on the quality of the inflow iliac arteries for blood supply.
If the patient is without significant cardiovascular risk A case such as this is particularly topical for two then an aortic procedure can be contemplated. The first reasons. Firstly, it highlights the enormous limitations of option would be to consider renal artery endarterectomy.
evidence-based medicine. EBM has nothing to offer us This involves clamping the aorta above and below the here—don’t bother to consult the Cochrane collobaration renal arteries and removing the intimal atherosclerotic or the latest issue of. Clinical evidence secondly, layer from the aortic ostia and the origins of the occluded everyone is now very interested in surgical outcomes. The renal arteries. This technique is practised in a few centres physicians can probably do what they want in this case only. There is a danger of intimal dissection down the without concern, but the surgeons have their mortality renal arteries and aorta if the endarterectomies are not rates to consider. In a rational environment, it would be performed properly and hence most surgeons avoid this obvious that such infrequent operations (in the UK) as this cannot be meaningfully audited for their outcomes. It The next alternative is a bilateral aorto-renal saphe- is not self-evident that consideration of surgical outcomes nous vein bypass. This procedure involves using one saphenous vein and its major branch, thus only a single What we can do here is examine the case in great detail anastomosis onto the aorta is required. Provided the aorta to see what we really know about this man. We also need is not heavily diseased, this option is attractive with only to carefully formulate the questions that are making the decision about intervention difficult. The nature of such It is imperative that further investigations to exclude a case means there is always some data missing in the significant cardiac disease is undertaken before surgery truncated summary. I’ll mention where this might have should be contemplated. Patients with renovascular Analysis of the case
diagnosis. Against the diagnosis is the asymmetry inkidney size.
At first glance this looked like just another case of If the renal impairment was solely due to ARAS, I’d atheromatous renal artery stenosis (ARAS) but it turns expect the left kidney to have a lower GFR, and the right out to have some quite interesting and unusual features.
kidney GFR to be closer to 25% of normal total—about The failure of magnetic resonance angiography will be 25 to 30 ml/min. I’d also expect the creatinine to have mentioned only to console those of us currently without risen after the unsuccessful angioplasty which occluded access to this technique. (Another explanation is that the artery occluded between MRA and definitive angiogra- Perhaps the likeliest scenario is a bit of both! The phy. If this was important, I’d expect to have seen a rise in left kidney had a longstanding ARAS, which encouraged serum creatinine, of which there is no mention in the case collateral growth. When the artery occluded, the kidney history). The split GFR results are fascinating—I would remained viable due to the collaterals but many nephrons not have guessed that the small kidney with one occluded were lost causing low GFR and shrinkage. The reason artery would have the same GFR as the big kidney with that the better blood supply to the right kidney is not asso- two arteries, one recently occluded but one unstenosed.
ciated with better GFR may be that there was insufficient I’m assuming that each of these arteries supplies about collateral growth and most of the upper pole died after oc- half the kidney. It is obvious therefore that all of the left clusion. The kidney size was estimated before occlusion.
kidney function and perhaps some of the right function A touch of athero-embolic disease might explain the less depends on renal blood flow through collateral vessels.
than perfect function in the lower half of the kidney.
One thing we would like to know is whether or not This picture would suggest that revascularisation will restoring blood supply through the main arteries would not change right upper pole function, but might improve improve renal function. There are some clues in the left kidney function. I don’t think a left renal biopsy history as given, and probably more clues not given.
would help—there is bound to be a lot of nephrosclerosis The adverse but reversible effect of ACE inhibition but the kidney is clearly viable. Further clues to help (ACEi) does not necessarily mean that surgical revascu- decide about the right would include a renogram or larisation will improve GFR. It could be that the GFR Doppler ultrasound to look at regional blood flow in that is angiotensin II dependent because of poor renal blood kidney. A lower pole biopsy wouldn’t help (that bit can’t flow through collaterals and that revascularisation would be improved). It is of course the case that the smaller the improve this. It could also be that the roughly 30% of kidney or the worse its function, the less likely benefit surviving nephrons are hyperfiltering, and the cessation will be seen with revascularisation [4,5]. I am choosing to of this following ACEi caused the rise in creatinine. Other not be over influenced by this because I think there is a explanations not pointing to reversible ischaemia include big difference between a small kidney beyond a stenosis a coincident degree of volume depletion, or simply too of say 50 to 90%, and a small kidney beyond an occlusion with a documented GFR of 18 ml/min. In the former cir- Whenever the contribution of ARAS to renal failure is cumstance, significant loss of nephrons in the absence of considered, we also have to think of the other common a very tight stenosis is probably a sign of athero-embolic problem in this setting which impairs GFR. This is an disease. This is the common scenario in many reports and ill-defined but increasingly recognised nephropathy due it is not surprising that these kidneys don’t stabilise after to a combination of hypertension and severe atheroma— intervention. The current case is very different.
probably to be called athero-embolic nephropathy [1].
So, in short, there is a possibility that successful This causes progressive renal failure and is not going revascularisation might improve GFR from 35 ml/min to to be helped by revascularisation. A kidney with ARAS is just as likely to have this as the cause of poorfunction [2]. It is vitally important to distinguish betweenrenal impairment due to low renal blood flow, which is Possible benefits of successful
therefore reversible by intervention, and renal impairment revascularisation
due to nephron loss because of other factors, which is notreversible. A recent study of split renal function in cases Revascularisation is not an end in itself. Would it help the of unilateral stenosis due to atheroma or fibromuscular patient? A modest increase in GFR in itself is unlikely disease shows an average of 18 ml/min less GFR in the to make a big difference to the patient or his prognosis.
non-stenotic kidney when atheroma was the cause [3].
It might reduce the risk of renal anaemia, which of So what do I think is going on here? If the course could be treated with EPO, at some expense, BP renal impairment was solely due to athero-embolic nephropathy, the creatinine should have been rising Would revascularisation reduce the risk of eventual steadily to the current level. The patient has an extensive end-stage renal disease? Quite possibly not in this case— medical history and probably has had lots of blood tests the kidneys are surviving with collateral supply and over the years—a reciprocal creatinine plot would be I haven’t seen any analysis of what happens to such interesting. A steady rise in creatinine would favour this Atheromatous renal artery stenosis with severe hypertension BP control might be helped, although it should be possibilities mean to them. A significant proportion will pointed out that the tablet burden in this case could be ask me to do whatever I think is for the best. Such a considerably eased by simply changing to once-a-day decision would be based on many factors which can never be addressed in this sort of exercise. If pre-operative Will the patient live longer? Possibly. I get the assessment was favourable (and I suspect it might well impression that high levels of angiotensin II are a not be), if the patient was keen on intervention, and if bad thing. Successful revascularisation addresses this a suitably skilled surgical team were available, then this problem both directly, by switching off the stimulus, and is case where surgery might have something to offer. In indirectly, by allowing use of ACEi or AIIR blockers. (In this particular case, because the benefits of surgery are the interests of fairness, it needs to be pointed out that not clearly defined in advance, it would not take much in the use of these might precipitate anaemia of a degree the way of extra anaesthetic/operative risk to dissuade me On balance, therefore, there is a sufficient possibility Whether or not surgery is performed, this patient has that revascularisation would help for us to consider the a high risk of coronary artery disease and should take aspirin and almost certainly an HMG CoA reductaseinhibitor.
Possible risks of surgery
I await the surgeon’s opinion with interest.
The information in the case summary doesn’t help us Conclusion
decide. There are two factors to consider—the patient,and the surgical team.
The left kidney has an occluded renal artery and a The concern with the patient relates to anaesthesia and GFR of 18 ml/min—presumably filtering blood from a possible sudden fluctuations in BP in either direction collateral supply. I don’t know of any studies that tell us in someone who could have critical stenoses of carotid, if revascularisation in this setting improves GFR, prevents coronary or mesenteric arteries. I would imagine that eventual end-stage renal failure, and/or allows ACE carotid dopplers and coronary angiography or some form inhibitor use without an acute decline in GFR. Given of testing for reversible ischaemia would be sensible.
that these are at least reasonable theoretical possibilities, The mesenteric vessels may have been visualised on intervention should be considered if the surgical expertise renal angiography. As the main renal arteries are already is available and significant vascular disease in other vital occluded, the risks of precipitating renal failure may be less than when trying to improve on a tight stenosis, and The function in the right kidney is similarly low despite principally related to episodes of hypotension.
adequate perfusion of the lower half. It seems less likely The surgical team will need to provide not only surgical that there is much to salvage in the upper half—a repeat expertise for this type of operation, but aggressive pre-, ultrasound scan and possibly renogram six weeks after peri- and post-operative management of BP and fluid state. This operation is rarely carried out in the UK. Thereare very few surgeons who could tell prospective patientsmeaningful results in similar previous cases.
References
[1] Suresh, M, Laboi, P, Mamtora, H, Kalra, PA. Relationship Decision time
of renal function to proximal renal arterial disease severity inatherosclerotic renovascular disease. Nephrol Dial Transplant Ultimately, my job here would be to tell the patient what [2] Farmer, CK, Reidy, J, Kalra, PA, Cook, GJ, Scoble, J. Individual he needs to know to allow him to decide. If testing kidney function in atherosclerotic nephropathy is not related to suggested he was reasonably fit for surgery, and if a the presence of renal artery stenosis. Lancet 1998; 352: 288–9.
good surgical team was available, I would summarise our [3] La Batide-Alanore, A, Azizi, M, Froissart, M, Raynaud, A, hopes for intervention as possibly improving his kidney Plouin, P-F. Split renal function outcome after renal angioplastyin patients with unilateral renal artery stenosis. J Am Soc Nephrol function (which may or may not make him feel any different), but more importantly allowing us to use the [4] Beutler, JJ, Van Ampting, JM, Van De Ven, PJ et al. Long term best drugs in this setting to control BP and prevent future effects of arterial stenting on kidney function for patients with related problems, i.e. ACEi or AIIRa. Unfortunately, the ostial atherosclerotic renal artery stenosis and renal insufficiency.
J Am Soc Nephrol 2001; 12: 1475–81.
surgery would carry a small but not insignificant risk of [5] Harden, PN, MacLeod, MJ, Rodger, RS et al. Effect of renal major complication including death, stroke, heart attack, artery stenting on progression of renovascular renal failure.
renal failure and peripheral or mesenteric ischaemia.
Other than the risks, the strongest reason not to proceedwould simply be that surgery might well make no Case Management
difference to how he felt or his future health. Clearly,in such a complex case, there will be a large variation The patient was reviewed by a vascular surgeon.
between patients in how they interpret what the various The major issue addressed was the fate of the function in the occluded kidney as his kidney had There appears to be preservation of function in the significant function. The patient had had a left aorto left with a decrement in the right. This may have renal bypass graft. The SKGFR are shown below: been the result of the attempted angioplasty to the right upper vessel. Post-operatively the patient sufferedan episode of pancreatitis after discharge but is at present well. Although now on two agents, the blood pressure is well controlled. The clinicians involved felt sufficiently confident for one of these agents to be an

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