Interpreting the Treatment of Restenosis in Stent From 8 Aspects

Elution stent (DES) can change the healing process after stent placement, reduce neointimal formation, and reduce the incidence of intra-stent restenosis (ISR) to 5%-10%. The incidence of ISR for second-generation DES Still similar. Recently, ISR treatment was summarized in a review published by Circ Cardiovasc Interv.

1. Medication

Some drugs have been used to reduce the recurrence rate of ISR (including abrilumab, oral sirolimus, oral glucocorticoids, and local injection of paclitaxel), but the efficacy is poor and related to adverse reactions.

1. Balloon angioplasty

Ordinary balloon angioplasty is a representative of the previous interventions of the bare metal stent (BMS) ISR and DES-ISR, but it is associated with edge-related complications and a high ISR recurrence rate (>50%).

In the ISR treatment caused by mechanical reasons, high-pressure balloon expansion is more important. High-pressure balloon angioplasty can be used for stent insufficiency, the pressure of non-compliant balloons can be as high as 40 atm, short non-compliant balloons or better, can prevent longitudinal pressure injuries, but should avoid edge-related complications, Prevent the balloon from sliding out of the stent.

1. Cutting and spinous balloon

The spinous process balloon was introduced to minimize the air pressure injury of the blood vessel wall and reduce the sliding of the traditional balloon when it was inflated at the scar tissue. The ISAR-DESIRE 4 randomized trial showed that in DES-ISR patients, the use of spinous process balloon before the use of drug balloon (DCB) can reduce the recurrence rate of ISR and reduce the loss of lumen compared with ordinary high-pressure balloon. The cutting balloon uses multiple blades to anchor the instrument to the lesion, which can cut the neointimal.

1. Ablation treatment (spin mill and laser)

Coronary artery rotatory ablation and excimer laser coronary ablation can both remove lesions and change plaque compliance. Although its clinical data in DES-ISR is limited, the rotation may benefit some patients with calcified neointimal atherosclerosis or patients with incompletely inflated with high-pressure balloon stents. The heat generated during the ablation process helps the stent to expand further, but it should avoid rotating to the metal particles and prevent the grinding head from embedding. Excimer laser coronary resection can destroy and modify plaque through thermal effects and shock waves. The available evidence indicates that in some cases, coronary rotatory aurectomy is the best choice for ISR pretreatment for stent insufficiency or calcified lesions.

1. Drug balloon

At present, DCB has not been approved for coronary artery therapy in the United States, but it has been widely used worldwide. The ESC guidelines clearly recommend that DCB can be used for ISR treatment (I, A). Treatment of ISR with DCB can avoid the insertion of additional metal layers, and lipophilic drugs (such as paclitaxel) in DCB can inhibit neointimal proliferation. A small sample size study has initially demonstrated the efficacy of sirolimus-coated DCB in the treatment of ISR, but randomized trials are still needed to verify it.

1. Place DES again

The meta-analysis showed that compared with angioplasty alone, when combined with DES, the target vessel revascularization rate of DES-ISR patients was reduced. Registration studies have shown that for patients with stent layers> 2 layers, the incidence of adverse events increased significantly when DCB was used to treat ISR. This suggests that we should avoid the placement of the third layer of stents.

At present, there is no clear evidence that which type of DES is suitable for DES-ISR treatment. Although the RIBS III trial showed that when changing the DES type, the patient's angiography and clinical results at 9 months were better, but there is no consensus on whether to change the DES type when treating DES-ISR.

1. Vascular Radiotherapy (VBT)

Brachytherapy provided local strontium 90 radiation can inhibit neointimal formation in the stent and reduce hyperplastic tissue response, but currently only a few institutions can provide VBT treatment. Negi et al. reported for the first time the use of VBT for ISR treatment. A total of 186 patients were included in the study. The target lesion revascularization at 6 months, 1 year, and 3 years were 3.3%, 12.1%, and 19.4%, respectively. The observational trials recently published by Varghese et al compared the outcomes of patients receiving VBT (197 cases) and patients receiving percutaneous coronary intervention (PCI) but not receiving VBT (131 cases). Studies have shown that the use of brachytherapy can reduce major adverse cardiac events. In addition, the excimer laser treatment before VBT may be better, but the relevant data is limited.

VBT is mainly used for the treatment of refractory ISR, such as when there are multiple stents. If necessary, VBT treatment can also be repeated, and the interval between two treatments should be no less than 12 months. However, because VBT treatment can delay endothelialization, patients need antiplatelet therapy for life.

In patients with restenosis after VBT treatment, DES treatment can increase the risk of stent thrombosis. At this time, VBT treatment can be selected again, or ordinary balloon angioplasty or DCB treatment.

1. Bioabsorbable stent

Bioresorbable vascular stent is a potential ISR treatment method, but there is no random data to confirm. Since the bioabsorbable vascular stent can provide better expansion effect than DCB, and the stent can be gradually absorbed afterwards, it can be used as an alternative to DES for ISR. The retrospective trials published by Moscarella et al. showed that bioabsorbable stents are similar to DES and DCB in the treatment of ISR. But so far, there are few research data in this area, and further research data is needed to evaluate its role in ISR.

In addition, the intravascular shock wave treatment currently under study to treat stent insufficiency, calcification lesion shock wave combined with spinal milling, and sirolimus-coated DCB, etc. may provide potential treatment for ISR treatment.