REFORM 9-Month Data Support Cook's Formula Stent to Treat Renal Artery Stenosis After Suboptimal Angioplasty

July 24, 2013—Robert M. Bersin, MD, et al published results from the REFORM study in Catheterization and Cardiovascular Interventions (2013;82:266–273). REFORM is a prospective, single-arm, multicenter clinical study of the safety and effectiveness of the Formula balloon-expandable stent (Cook Medical, Bloomington, IN) for treating atherosclerotic renal artery stenosis (RAS) after suboptimal angioplasty.

The REFORM investigators concluded that the Formula stent was safe and effective in treating atherosclerotic RAS following suboptimal angioplasty.

As noted in the study background, when clinically indicated, an interventional approach with renal angioplasty and stent implantation is the preferred method for revascularization of atherosclerotic RAS, which can cause hypertension and ischemic nephropathy.

As summarized Catheterization and Cardiovascular Interventions, REFORM studied stent implantation with the Formula device after suboptimal percutaneous transluminal renal angioplasty. The study enrolled 100 patients who had atherosclerotic ostial renal artery lesions with 18-mm lengths and a residual stenosis > 50% after angioplasty. The primary endpoint was 9-month primary patency.

The REFORM investigators found that the 9-month primary patency rate was 91.7%. The 9-month major adverse event rate was 2.2%. Mean systolic blood pressure was significantly decreased at follow-up (from 150 ± 21 mm Hg at baseline to 141 ± 21 mm Hg at 9 months; P = .003). The mean serum creatinine (SCr) level and mean estimated glomerular filtration rate (eGFR) were not significantly different at 9 months.

A clinically meaningful improvement in renal function (25% increase in eGFR or 0.5 mg/dl decrease in SCr) was observed in 9% of patients at 1 month and 12% of patients at 9 months. A clinically meaningful decline in renal function (25% decrease in eGFR or 0.5 mg/dl increase in SCr) was observed in only 3% of patients at 1 month and 7% of patients at 9 months, reported the investigators in Catheterization and Cardiovascular Interventions.