Everolimus-Eluting Stents in Patients With Bare-Metal and Drug-Eluting In-Stent Restenosis: Results From a Patient-Level Pooled Analysis of the RIBS IV and V Trials

BACKGROUND

Treatment of patients with drug-eluting stent (DES) in-stent restenosis (ISR) is more challenging than that of patients with bare-metal stent ISR. However, the results of everolimus-eluting stents (EES) in these distinct scenarios remain unsettled.

METHODS AND RESULTS

A pooled analysis of the RIBS IV (Restenosis Intra-Stent of Drug-Eluting Stents: Paclitaxel-Eluting Balloon vs Everolimus-Eluting Stent) and RIBS V (Restenosis Intra-Stent of Bare Metal Stents: Paclitaxel-Eluting Balloon vs Everolimus-Eluting Stent) randomized trials was performed using patient-level data to compare the efficacy of EES in bare-metal stent ISR and DES-ISR. Inclusion and exclusion criteria were identical in both trials. Results of 94 patients treated with EES for bare-metal stent ISR were compared with those of 155 patients treated with EES for DES-ISR. Baseline characteristics were more adverse in patients with DES-ISR, although they presented later and more frequently with a focal pattern. After intervention, minimal lumen diameter (2.22±0.5 versus 2.38±0.5 mm, P=0.01) was smaller in the DES-ISR group. Late angiographic findings (89.3% of eligible patients), including minimal lumen diameter (2.03±0.7 versus 2.36±0.6 mm, P<0.001) and diameter stenosis (23±22 versus 13±17%, P<0.001) were poorer in patients with DES-ISR. Results were consistent in the in-segment and in-lesion analyses. On multiple linear regression analysis, minimal lumen diameter at follow-up remained significantly smaller in patients with DES-ISR. Finally, at 1-year clinical follow-up (100% of patients), mortality (2.6 versus 0%, P<0.01) and need for target vessel revascularization (8 versus 2%, P=0.03) were higher in the DES-ISR group.

CONCLUSIONS

This patient-level pooled analysis of the RIBS IV and RIBS V randomized clinical trials suggests that EES provide favorable outcomes in patients with ISR. However, the results of EES are less satisfactory in patients with DES-ISR than in those with bare-metal stent ISR.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifiers: NCT01239953 and NCT01239940.

Restenosis of the Coronary Arteries: Past, Present, Future Directions

Restenosis is a pathologic response to vascular injury, characterized by neointimal hyperplasia and progressive narrowing of a stented vessel segment. Although advances in stent design have led to a dramatic reduction in the incidence of restenosis, it continues to represent the most common cause of target lesion failure following percutaneous coronary intervention. Efforts to maximize restenosis prevention, through careful consideration of modifiable risk factors and an individualized approach, are critical, as restenosis, once established, can be particularly difficult to treat. Novel approaches are on the horizon that have the potential to alter the natural history of this stubborn disease.

“Bare Metal” Stent Placement Complications: Interventional Treatment

The rapid implementation of stents in standard practice and expansion of the indication for their utilization also introduced a new problem: in-stent restenosis. Management of patients with restenosis after stent implantation is still considered an important clinical problem. Although balloon angioplasty is still one of the prefered strategies that provide satisfactory results and a low incidence of complication, repeat stenting with “drug eluting” stents or “drug balloon” angioplasty become a very atractive methods of treatment for selected lesions and patients.

Impact of catheter size on reliability of quantitative coronary angiographic measurements (comparison of 4Fr and 6Fr catheters)

To evaluate the feasibility of catheter down sizing for QCA, the reliability of a 4Fr catheter as a calibration device was evaluated. Repeated coronary angiograms of 9 lesions were obtained using 4Fr and 6Fr catheters under otherwise identical conditions. The calibration factor was measured 10 times by 4Fr and 6Fr catheters. QCA measurements including minimal lumen diameter (MLD), interpolated normal reference (Int N), percent diameter stenosis (%DS), and lesion length (LL) were performed by two technicians twice with a 3-month interval. The intraobserver and interobserver variability of each parameter was evaluated using intraclass correlation coefficients (ICCs). Mean of mean SD of calibration factor was significantly larger in 4Fr than in 6Fr in 9 lesions. The mean of mean coefficient of variance was significantly larger in 4Fr catheters vs in 6Fr catheters. A 6Fr catheter showed excellent reliability for both intraobserver and interobserver variability in MLD, Int N, %DS, and LL. In contrast, 4Fr showed that reliability in intraobserver variability depended on the analyst. Although reliability of interobserver variability in Int N measured by the 4Fr catheter was >0.80, the value was less than that by the 6Fr catheter. Taking these results into consideration, 4Fr catheters are less reliable than 6Fr catheters when measuring QCA data especially for follow-up data that need most accurate measurements of MLD and %DS. It would be better to use a 6Fr catheter to evaluate QCA measurements such as acute gain, late loss, restenosis rate, and device size.