Kidney Diseases Beyond Nephrology What’s new in hypertension 2009?

Treatment of renovascular hypertension remains a topic of much dispute. The simplistic approach says that if a renal artery stenosis (RAS) causes hypertension, invasive therapy will cure the patient. That approach overlooks that patients with atherosclerotic RAS as a rule exhibit widespread vascular disease of other organs leading to premature death that is barely influenced by the blood pressure. In addition, long-standing hypertension tends to perpetuate itself independent of the initiating mechanism. Previous randomized trials, showing that percutaneous transluminal angioplasty (PTA) in addition to antihypertensive drug therapy does not result in additional benefits, were criticized because no stents were used. Bax et al. [1] report a randomized controlled trial comparing optimal medical therapy with or without PTA and stent placement in 140 people with hypertension with an eGFR <80 ml/min (mean 45 ml/min at inclusion) and ostial RAS of >50% of luminal diameter, unilateral or bilateral (bilateral in about half). The primary outcome was a decrease in eGFR by >20% after a followup of 2 years that was not different between the groups; however, the confidence interval was wide (HR 0.73, CI 0.33–1.63). There were three deaths in the PTA group and one cholesterol embolism resulting in permanent dialysis although the PTA was performed in only 10 institutions, requiring radiologists with at least 10 years of PTA experience. While this review is written, a further paper from the ASTRAL investigators (N Engl J Med 2009; November 12 issue) on 806 patients with atherosclerotic renovascular disease randomized to medical therapy with or without additional percutaneous revascularization was published. No worthwhile clinical benefit but substantial risks with PTA were found. Revascularization was associated with a slightly slower decline in GFR and no difference in death or major renal and cardiovascular outcomes. However, serious complications in 23 of 806 patients, including 2 deaths and 3 amputations of toes or limbs, were observed. In conjunction with previous reports, these new studies provide no support whatsoever for PTA and stent treatment of atherosclerotic stenosis, including ostial stenosis, to preserve renal function or to lower blood pressure apart from very special circumstances, e.g. tight stenosis of a single kidney. Needless to say that many will continue to offer PTA and stent to patients with RAS because every trial has its limitations, performing a PTA is challenging and its vascular ‘cosmetic’ effects can be impressive to the patient. We can only hope that high revenues of PTA for caregivers and hospitals, as they are compared to conservative treatment in many health care systems, are not driving the continued and ill-indicated use of PTA.