renal artery stenosis: stent not help

interventional therapy for renal artery stenosis (RAS) has been largely discredited, to my mind, since the publication of the ASTRAL study (NEJM 2009: 361:1953), which reported on 806 patients with atherosclerotic renovascular disease randomized to revascularization plus medical therapy or medical therapy alone and found that over 5 years the rate of progression of renal disease was no different, there was no difference in systolic blood pressure with minimal difference in diastolic blood pressure, but slightly more meds were used in the medication only group.  However of note, serious complications occurred in 23 patients in the revascularization group including 2 deaths and 3 amputations.  Conclusion was that substantial risks were associated with revascularization with no evident worthwhile clinical benefit.

a study just reported at the American Heart Association, the CORAL trial, confirmed this earlier study (see htn RAS stent vs med CORAL nejm 2013 in dropbox or DOI: 10.1056/NEJMoa1310753). in this study, 947 patients with atherosclerotic RAS and either systolic hypertension and taking 2 or more antihypertensives or chronic kidney disease were randomized to medical therapy plus renal artery stenting or medical therapy alone.  Primary endpoint was a composite of death from cardiovascular or renal causes, MI, stroke, hospitalization for CHF, progressive renal insufficiency, or need for renal replacement therapy.  Patients were followed for 43 months.  RAS was defined as severe if 80-99% stenosis of the renal artery or stenosis of 60-80% with a systolic pressure gradient of at least 20 mmHg.  Medical therapy was either with candesartan, with or without hydrochlorothiazide, or combination pill of amlodipine/atorvastatin (adjusting meds/doses to achieve blood pressure goal).  Target blood pressure was less than 140/90, but less than 130/80 in those with diabetes or chronic kidney disease.   Median age of the patient was 69, half male, 7% African ancestry.  Median systolic blood pressure was 150 and 50% had at least stage III chronic kidney disease.  In the group with stenting, 11 had the complication of arterial dissection. 

 Results:

--At baseline patients were taking a mean of 2.1 antihypertensive meds.  No significant difference by the end of the study between the groups, with both taking approximately 3.5 meds.  Systolic blood pressure declined in the medication only group by 15.6 mmHg, and 16.6 in the stent group.

--There was no significant difference in occurrence of primary composite endpoint between the stent group, at 35.1%, and the medication only group, at 35.8%.

--subgroup analysis showed no difference between groups if the creatinine was more or less than 1.6, GFR more or less than 45, systolic blood pressure at baseline more or less than 160 mmHg, age more less than 70, maximal renal artery stenosis of more or less than 80%, or if the patient had diabetes, was male or female, or of African ancestry

--review of the study proved a bit difficult.  Very hard to figure of which blood pressure medicines and in which order they were given.  Not only did I look at the supplementary appendix online, but I also looked at the 2006 American Heart Journal article in which they described the methodology of the study.  The best I could figure is that they started with candesartan as the primary drug and then added other meds to control blood pressure, without listing dosages or order of addition in the initial 2006 paper or in this study, but per a specific (hidden) algorithm.  the use of the amlodipine/atorvastatin combo is a tad perplexing as well. i suspect they are anticipating another publication about lipid control.

so, hard to know exactly many of the parameters of the study (which meds used, etc), which is pretty unusual for an NEJM article.  but, the conclusion is pretty consistent: we have really good drugs now to control hypertension, and that should be the approach to those with or without RAS.  At this point, i would be hesitant even to work up patients for RAS, since it would not really alter the therapy. the medical therapy included the use of the angiotensin receptor blocker with or without a thiazide type diuretic and the addition of and Lodine as needed for blood pressure control patient's also received antiplatelet therapy and atorvastatin for management of lipids and diabetes was managed per routine clinical practice. (this approach only applies to atherosclerotic RAS, not fibromuscular RAS as seen in young people).

this study was supported by the national heart, lung and blood Institute, though 8 of the authors reported significant conflicts of interest from drug or medical device companies