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Guidelines recommend endovascular therapy (EVT) for severe (>75% on angiography) renal artery stenosis (RAS). We sought to determine whether the populations studied could have influenced the lack of benefit of EVT in RAS.
Pub Med, Cochrane and EMBASE were systematically reviewed until November 2015 for all RCTs comparing EVT to medical therapy (MT) for RAS. Primary outcomes: systolic blood pressure and anti-hypertensive medication reduction. Secondary outcomes: worsening renal function, morbidity, mortality, heart failure, and stroke. We used random effect analysis according to the Cochrane-Handbook of Systematic Reviews and RevMan 5.2 for statistical analysis.
Seven RCTs with 2126 patients were included: 1036 EVT and 1085 MT. 35-65% of patients did not have severe RAS. There was no difference in change of systolic blood pressure (0.45±1.85, p=0.64). There was a significant decrease in the mean amount of anti-hypertensive medication in the EVT group (0.24±0.12, p<0.001). There were no differences in worsening of renal function, morbidity and mortality, heart failure and stroke.
Our analysis suggests that the apparent lack of added benefit of EVT for RAS could be largely secondary to selection bias, given the percentage of patients with mild to moderate RAS that were included and treated. Based on available data, trials studying EVT for severe RAS are warranted and should be designed to only include the appropriate patients. These well-designed studies are ultimately likely to “awaken the force”.