Abstract: Eight RCTs involving 2222 participants with renal artery stenosis were included in the review. The overall quality of evidence included in this review was moderate. Limited pooling of results was possible due to the variable presentation of some of the trial outcomes. Meta-analysis of the four studies reporting change in diastolic blood pressure (BP) found a small improvement in diastolic BP in the angioplasty group (MD -2.00 mmHg; 95% CI -3.72 to -0.27) whilst the meta-analysis of the five studies reporting change in systolic BP did not find any evidence of significant improvement (MD -1.07 mmHg; 95% CI -3.45 to 1.30). There was no significant effect on renal function as measured by serum creatinine (MD -7.99 µmol/L; 95% CI -22.6 to 6.62). Meta-analysis of the three studies that reported the mean number of antihypertensive drugs found a small decrease in antihypertensive drug requirements for the angioplasty group (MD -0.18; 95% CI -0.34 to -0.03). Repeat angiography was only performed on a small number of participants in a single trial and it was therefore not possible to comment on restenosis of the renal artery following balloon angioplasty. Based on the results of the seven studies that reported cardiovascular and renal clinical outcomes there were no differences in cardiovascular (OR 0.91; 95% CI 0.75 to 1.11) or renal adverse events (OR 1.02; 95% CI 0.75 to 1.38) between the angioplasty and medical treatment groups. A small number of procedural complications of balloon angioplasty were reported (haematoma at the site of catheter insertion (6.5%), femoral artery pseudoaneurysm (0.7%), renal artery or kidney perforation or dissection (2.5%) as well as peri-procedural deaths (0.4%)). No side effects of medical therapy were reported. The available data are insufficient to conclude that revascularisation in the form of balloon angioplasty, with or without stenting, is superior to medical therapy for the treatment of atherosclerotic renal artery stenosis in patients with hypertension. However, balloon angioplasty results in a small improvement in diastolic blood pressure and a small reduction in antihypertensive drug requirements. Balloon angioplasty appears safe and results in similar numbers of cardiovascular and renal adverse events to medical therapy.

Plain-language summary: The review authors identified eight controlled trials in which a total of 2222 adults were randomised to have balloon angioplasty or drug treatment only. The overall quality of the evidence was considered to be moderate because the methodological quality of the studies varied substantially and two of the studies had not provided sufficient data to be able to assess their risk of bias. Overall, the data were insufficient to show that one treatment was better than the other for preventing loss of kidney function or restenosis of the renal artery. Those treated with balloon angioplasty may require fewer antihypertensive drugs or lower doses and experience a slight improvement in diastolic but not systolic blood pressure. Balloon angioplasty appears to be safe and there were similar numbers of renal and cardiovascular adverse events in participants treated with either approach. A small number of procedural complications of balloon angioplasty were reported (collection of blood outside the blood vessel at the site of catheter insertion (6.5%), dilated groin artery (0.7%), renal artery or kidney perforation or tear (2.5%) as well as deaths shortly before, during or after the procedure (0.4%)). No side effects of medical therapy were reported.