Balloon angioplasty versus medical therapy for hypertensive patients with renal artery obstruction

  • Review
  • Intervention

Authors


Abstract

Background

Atherosclerotic renal artery stenosis is the most common cause of secondary hypertension. Balloon angioplasty is widely used for the treatment of hypertensive people with renal artery stenosis.

Objectives

To compare the effectiveness of balloon angioplasty (with and without stenting) with medical therapy on blood pressure control, renal function, frequency of renovascular complications and side effects in hypertensive people with atherosclerotic renal artery stenosis.

Search methods

The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last search June 2008) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library 2008, Issue 2. Bibliographies were also reviewed and trial authors contacted for more information.

Selection criteria

Randomised controlled trials (RCTs) comparing balloon angioplasty with medical therapy in hypertensive people with haemodynamically significant renal artery stenosis (greater than 50% reduction in luminal diameter) and minimum follow-up of six months.

Data collection and analysis

Data were extracted independently concerning trial design, participants, interventions and outcome measures. Data quality precluded a formal meta-analysis to assess the effect on blood pressure, renal function, number and defined daily doses of antihypertensive drugs. Peto's odds ratios and corresponding 95% confidence intervals (CI) were calculated for dichotomous outcomes, e.g. vessel patency and renovascular complications.

Main results

Three RCTs involving 210 participants met the inclusion criteria. In unselected participants, there was a consistent but statistically non significant trend towards lower blood pressure in the balloon angioplasty group. Those treated with balloon angioplasty required less antihypertensive drugs in two trials and were more likely to have patent renal arteries after 12 months (OR 4.2, 95% CI 1.8 to 9.8). There were no differences in renal function. There were significantly fewer cardiovascular and renovascular complications in participants treated with angioplasty (OR 0.32, 95% CI 0.15 to 0.70; test for heterogeneity p > 0.1).

Authors' conclusions

Available data are insufficient to conclude that balloon angioplasty is superior to medical therapy in lowering blood pressure of people with renal artery stenosis and pharmacologically controlled blood pressure. Where hypertension is refractory to medical therapy, there is weak evidence that balloon angioplasty lowers blood pressure more effectively than medical therapy. Balloon angioplasty appears to be safe and shows fewer cardiovascular and renovascular complications. Randomised controlled trials are needed to compare the effect of balloon angioplasty and medical therapy on the preservation of renal function in the long term.

Plain language summary

Balloon angioplasty versus medical therapy for patients with renal artery obstruction and high blood pressure

Atherosclerosis can cause narrowing and hardening of the main blood vessel supplying the kidneys (renal artery stenosis) and resulting high blood pressure. Even using drugs that lower blood pressure (antihypertensives), atherosclerotic renal artery narrowing tends to progress. Poor blood flow results in a lack of oxygen (renal ischaemia) and loss of kidney function, causing kidney failure and death. Currently, possible treatments are medical treatment with blood pressure lowering drugs, insertion of a balloon-like tube which is inflated to open up the renal artery (balloon angioplasty, with and without stents), insertion of a tube to open up the artery with stents, and surgery to reconstruct the artery. The review authors identified three controlled trials in which a total of 210 adults were randomized to have balloon angioplasty or drug treatment only. Those treated with balloon angioplasty required less antihypertensive drugs in two trials and were more likely to have open renal arteries after 12 months. The data were insufficient to show that one treatment was better than the other in lowering blood pressure. Renal function was similar with balloon angioplasty and drug treatment. Balloon angioplasty appears to be safe and there were fewer cardiovascular and renovascular complications in participants treated with angioplasty. Where high blood pressure is not reduced sufficiently with drugs, balloon angioplasty may help.

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