November 22, 2009

Revascularization versus Medical Therapy for Renal-Artery Stenosis

ASTRAL Investigators, Wheatley K, Ives N, Gray R, Kalra PA, Moss JG, Baigent C, Carr S, Chalmers N, Eadington D, Hamilton G, Lipkin G, Nicholson A, Scoble J.   N Engl J Med.   2009 Nov 12;361(20):1953-62

This randomized, non-blinded study of patients with renovascular disease compared renal artery revascularization plus medical therapy vs medical therapy alone.  Those in the revascularization arm experience an increased rate of serious complications with no reduction in pre-defined clinical endpoints.

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Abstract:

BACKGROUND: Percutaneous revascularization of the renal arteries improves patency in atherosclerotic renovascular disease, yet evidence of a clinical benefit is limited. METHODS: In a randomized, unblinded trial, we assigned 806 patients with atherosclerotic renovascular disease either to undergo revascularization in addition to receiving medical therapy or to receive medical therapy alone. The primary outcome was renal function, as measured by the reciprocal of the serum creatinine level (a measure that has a linear relationship with creatinine clearance). Secondary outcomes were blood pressure, the time to renal and major cardiovascular events, and mortality. The median follow-up was 34 months. RESULTS: During a 5-year period, the rate of progression of renal impairment (as shown by the slope of the reciprocal of the serum creatinine level) was -0.07x10(-3) liters per micromole per year in the revascularization group, as compared with -0.13x10(-3) liters per micromole per year in the medical-therapy group, a difference favoring revascularization of 0.06x10(-3) liters per micromole per year (95% confidence interval [CI], -0.002 to 0.13; P=0.06). Over the same time, the mean serum creatinine level was 1.6 micromol per liter (95% CI, -8.4 to 5.2 [0.02 mg per deciliter; 95% CI, -0.10 to 0.06]) lower in the revascularization group than in the medical-therapy group. There was no significant between-group difference in systolic blood pressure; the decrease in diastolic blood pressure was smaller in the revascularization group than in the medical-therapy group. The two study groups had similar rates of renal events (hazard ratio in the revascularization group, 0.97; 95% CI, 0.67 to 1.40; P=0.88), major cardiovascular events (hazard ratio, 0.94; 95% CI, 0.75 to 1.19; P=0.61), and death (hazard ratio, 0.90; 95% CI, 0.69 to 1.18; P=0.46). Serious complications associated with revascularization occurred in 23 patients, including 2 deaths and 3 amputations of toes or limbs. CONCLUSIONS: We found substantial risks but no evidence of a worthwhile clinical benefit from revascularization in patients with atherosclerotic renovascular disease. (Current Controlled Trials number, ISRCTN59586944.)

Renal Artery Stenosis, Vascular Disease/Calcification
  • Mario T. Parise M.D.

    There are many problems with this paper. To start,the follow up of this study is only 34 months. How is one able to acertain a deterioration curve for Scr in the medical group in only 34 months? For example; a 70 yo 8o Kg male has a 95% osteal leison. If his GRF is 70% at age 70 and that lesion is allowed to close his GRF would be in the neighborhood of 35% when it closes as he lost 50% of his existing frnal function. I would agree that this would be unlikely to happen in 34 months however, I would expect him to loose function in ten years undoubtedly. Simply, this study shows no difference between groups in 34 months which in my opinion is to short to tell anything.
    With regard to the complications cited, my first questions are; how many different M.D.’s were involved in the stenting and what was there level of training? I am a nephrologist and have referred over 500 cases to a single skilled cardiology collegue since 1993. On one occasion we had a mottled toe which resolved quickly. I can not for the life of me fathom limb loss and death as complications with this relatively simple procedure.
    We are aware that our experience is anectdotal however, we have attempted to participate in the “CORAL” study to no avail and have approached two professors to assist us in publishing our experience. I am hopefull that we will be able to publish these data soon. M.T.Parise M.D.