Objective performance goals of safety and blood pressure efficacy for clinical trials of renal artery bare metal stents in hypertensive patients with atherosclerotic renal artery stenosis

Abstract

To provide safety and performance goals for prospective single-arm trials of bare metal renal artery stenting in patients with resistant hypertension associated with high grade atherosclerotic renal artery stenosis. To date, there have been no US Pre-Market Approval (PMA) bare metal renal stent device trials which have focused on improvement of blood pressure control as a primary effectiveness endpoint. Analysis of subject-level data from three large industry sponsored pre-market approval (PMA) trials was performed. Hypertensive patients (≥ 155 mmHg) with a ≥ 50% atherosclerotic renal artery stenosis were included. Thirty day and 9-month systolic and diastolic blood pressure measurements, renal function and 9-month duplex ultrasound assessment of renal artery patency were analyzed. Initial data analysis of 600 patients from the 3 PMA trials identified 286 patients who met inclusion criteria. The mean baseline systolic blood pressure was 177.8 ± 19.3 mmHg with a mean 68.1% diameter renal artery stenosis. Nine months after successful stenting, the mean SBP was 156.7 ± 24.1 mmHg; the 9 month restenosis rate was 14.4%. Based on the statistical modeling of these data and a priori established performance criteria, the co-primary endpoints of 9 month reduction in blood pressure and in-stent restenosis are proposed. The reduction in blood pressure will be analyzed as a continuous variable and will be compared to this performance goal.