Long-term clinical safety and efficacy of NIROYAL vs. NIR intracoronary stent

Restenosis in gold-coated renal artery stents

BACKGROUND

Gold coating improves stent visibility under fluoroscopy. This is particularly valuable for precise stent placement during renal artery stenting (RAS). There is conflicting evidence regarding restenosis with gold-coated stents. To evaluate the effect of gold coating on restenosis after renal stenting, we reviewed the results of all patients undergoing RAS in our practice.

METHODS

A retrospective cohort study of all patients undergoing RAS between June 2000 and September 2003 was performed. During this time, both gold-coated and stainless steel stents were used. Restenosis (>60% diameter) was determined by serial follow-up duplex exams (peak systolic velocity >180 cm/s and renal-aortic ratio >3.5). Restenosis rates were determined by using the Kaplan-Meier life-table method. Variables potentially affecting restenosis were evaluated with the log-rank test and Cox proportional hazards modeling.

RESULTS

RAS was performed in 97 arteries (78 patients). Gold-coated (NIRoyal) stents were placed in 59 arteries (48 patients). Stainless steel stents (Corinthian, Genesis, and Herculink) were placed in 38 arteries (34 patients). Patient demographics, indication for treatment, technical success, and complications did not differ between gold and stainless steel stent groups. Mean follow-up was 15 months for gold-coated stents and 18 months for stainless steel stents (NS). By life-table method, 1-year and 2-year freedom from restenosis rates were 84% and 78% in arteries treated with stainless steel stents versus 69% and 39% in those treated with gold-coated stents (P = .012, log-rank test). By multivariate analysis, only the use of gold-coated stents (P = .018; hazard ratio [HR], 3.3; 95% confidence interval [CI], 1.2 to 8.7) and bilateral disease (P = .046; HR, 2.3; 95% CI, 1.02 to 5.2) predicted restenosis. Stent diameter, patient demographics, and indication for RAS had no effect on restenosis by univariate analysis. According to American Heart Association criteria, 87% of patients in the stainless steel group had improved blood pressure at 1 year, compared with 77% in the gold-coated stent group (Kaplan-Meier; P = .042, log-rank test). There were no significant differences in the effect of RAS on serum creatinine levels between the two groups.

CONCLUSION

Gold-coated renal stents had a substantially higher rate of restenosis than stainless steel stents in our series. These findings have led us to abandon the use of gold-coated stents for RAS. Patients who have received gold-coated stents for the treatment of atherosclerotic renal artery stenosis should be followed closely for evidence of restenosis.

The NUGGET study: NIR ultra gold-gilded equivalency trial

This study should clarify whether the gold-coated NIROYAL stent is equivalent to the stainless steel NIR stent. Patients were randomized to either NIR stent (n = 298) or a NIROYAL stent (n = 305). The primary endpoint was the minimum lumen diameter of the target lesion at 6 months postprocedure. Secondary endpoints focused on clinical events. At 30 days, adverse events were similar in both groups. At 6 months, the minimal lumen diameter was 1.83/1.64 mm (P < 0.001; 95% CI = 0.08-0.30) and the angiographic restenosis rate was 20.6%/37.7% (P < 0.001; 95% CI = -24.7 to -9.3) for NIR/NIROYAL. The 6-month MACE rates were NIR 7.4% and NIROYAL 10.5% (95% CI = -7.7 to 1.4). Compared to stainless steel stent, the NIROYAL stent demonstrated a smaller minimal lumen diameter, a higher late loss (i.e., higher neointimal hyperplasia in spite of a significantly better initial gain), with higher restenosis and similar MACE rates at 6 months.