Drug-eluting balloons versus drug-eluting stents for the management of in-stent restenosis: A meta-analysis of randomized and observational studies

A potential strategy for in-stent restenosis: Inhibition of migration and proliferation of vascular smooth muscle cells by Cu ion

The in-stent restenosis (ISR) often happens after the implantation of metal stents, including both bare metal stents (BMSs) and drug-eluting stents (DESs). Drug release from DESs could reduce significantly the occurrence of ISR but also suppress the revascularization and cause thrombosis. In this study, the effect of Cu ion in a range of 0 to 500 μM on the migration and proliferation of rat aortic smooth muscle cells (RASMCs) was investigated by a series of in vitro experiments including wound-healing assay, cell viability assay and flow cytometric analysis. It has been found that the critical concentration of Cu ion should be at least 250 μM in order to significantly inhibit the migration of RASMCs and the proliferation of RASMCs were impeded by every dose of Cu ion used in this study. In addition, the protein level of caspase-3 was upregulated by 250 μM and 500 μM Cu²⁺ exposure, which might be the main reason for RASMCs apoptosis. Thus, it is proposed that ISR might be prevented by the constant release of Cu ion.

A case of coronary artery disease with rapid progress triggered by stent implantation

Drug-eluting stents (DESs) have a low prevalence of in-stent restenosis. However, we describe a patient with coronary artery disease with rapid progress, which might have been triggered by implantation of a DES. The patient was a 72-year-old woman who was first admitted to hospital with non-ST-segment elevated myocardial infarction and had a DES implanted after coronary angiography showed severe stenosis of the left circumflex artery. However, although she kept taking dual antiplatelet therapy, her condition deteriorated and she was admitted to hospital three more times. Angiography showed that the coronary stenosis had become more severe and was more severe not just in the stent-implanted segments, but also in other coronary arteries. Another DES and drug-eluted balloon were used. However, the stent-implanted and balloon-dilated segments became severely stenosed within 1 month. Tests for auto-immune diseases and allergies were negative. We speculate that the first DES triggered an unknown response of the coronary arteries and led to severe stenosis from the stent-implanted segment to the distal segment and other arteries.

Drug-eluting balloons versus new generation drug-eluting stents for the management of in-stent restenosis: an updated meta-analysis of randomized studies

Background

New-generation drug-eluting stents (DES) was more effective in the treatment of in-stent restenosis (ISR) compared with the first-generation DES. Drug-eluting balloons (DEB) and new-generation DES had been available strategies in treatment of bare-metal stents/DES ISR (BMS/DES-ISR). Six new randomized trials have recently examined the angiographic outcomes and one-year clinical outcomes of DEB and new generation DES in BMS/DES-ISR. However, the optimal management for BMS/DES-ISR lesions remains controversial.

Methods

We searched the randomized clinical trials evaluating the angiographic outcomes and one-year clinical outcomes of DEB and new-generation DES in patients with BMS/DES-ISR. The primary endpoints were the angiographic outcomes, including the minimal luminal diameter (MLD), diameter stenosis % (DS%), late lumen loss (LLL), and binary restenosis (BR).

Results

A total of six randomized clinical trials with 1177 BMS/DES-ISR patients were included in our meta-analysis. For angiographic outcomes, there were significantly less MLD and more DS% with DEB compared to new-generation DES (MLD: MD = -0.18, 95% CI: -0.31- -0.04, P < 0.001; DS%: MD = 5.68, 95% CI: 1.00-10.37, P < 0.001). Moreover, for one-year clinical outcomes, DEB was associated with a significant increase risk in target lesion revascularization (TLR) (RR = 2.93, 95% CI: 1.50-5.72, P = 0.002). However, DEB was associated with higher risks of major adverse cardiac event, target vessel revascularization, TLR, BR, and more DS% only in DES-ISR group.

Conclusions

DEB and new-generation DES have the similar clinical efficacy for the treatment of BMS-ISR. However, DES showed more MLD, less DS%, and a decreased risk of TLR for the treatment of DES-ISR.