Restenting and angioplasty decrease renal artery in-stent restenosis to less than 10%, study finds.
WASHINGTON, D.C.—Restenting and angioplasty are both highly effective for treating renal artery in-stent stenosis, according to findings presented here at the Society of Interventional Radiology’s 33rd Annual Scientific Meeting. Findings also suggest that in-stent restenosis may be associated with stent fractures.
Researchers at Mount Sinai Medical Center in New York reviewed 325 stents in 221 consecutive patients who underwent renal artery stent placement for atherosclerotic renal artery stenosis over a period of seven years. Renal artery stenting has evolved into first-line therapy for ostial atherosclerotic renal artery stenosis, but a major limitation of this therapy is the relatively high rate of in-stent restenosis (ISR), the investigators observed. No formal consensus exists regarding the optimum therapy for renal artery ISR.
Of the 221 patients, 38 (24 males and 14 females) underwent treatment of 50 stenosed renal artery stents. These patients had a mean age of 72 years (range, 55-89 years). The mean time for initial stent implantation was 6.7 months (range, 3-13 months). The mean stent diameter of the initial stent implantation was 5.4 mm.
Forty restenotic lesions were treated with new stent placement and six were treated with balloon angioplasty. Both therapies were successful at reducing the ISR to less than 10%. The primary patency rates were 100% at one month, 96% at six months, and 92% at 12 months. Four patients underwent treatment of a recurrent in-stent lesion with a drug-eluting stent, covered stent, or another bare metal stent.
Additionally, the investigators said they found fractures in about 10 stents (20%) at the time of re-intervention, a high rate that Robert A. Lookstein, MD, said was surprising.
Renal artery stent fracture is a poorly reported clinical problem and it is difficult to identify patients at high risk for this problem, he noted.
“Surveillance protocol for these patients now includes plain film radiographs to access for the presence of fractures during follow-up,” Dr. Lookstein said.
“These fractures need to be monitored more closely. It is clear from these data that renal artery stent fractures correlate with in-stent restenosis. Further studies are necessary to clarify the etiology of renal stent fractures, which patients are at risk for fracture, and the precise impact of renal stent fracture on the success of percutaneous renal artery stent procedure.”