Treatment of drug-eluting stent restenosis

Paclitaxel-coated balloon catheter compared with drug-eluting stent for drug-eluting stent restenosis in routine clinical practice

AIMS

The aim of this study was to compare the efficacy between paclitaxel-coated balloon (PCB) and drug-eluting stent (DES) implantation for the treatment of DES restenosis in complex situations.

METHODS AND RESULTS

Data of patients who received revascularisation for DES restenosis between 2004 and 2011 were collected. A total of 683 patients with 777 lesions were analysed in this study (306 lesions treated by PCB, 471 lesions by DES). The use of PCB or DES was at the discretion of the operator. Angiographic outcomes at six to eight months and clinical outcomes at 12-month follow-up were compared between groups. The primary outcome was binary restenosis. Cox regression analysis with propensity score adjustment suggested that there were no significant differences between the two groups with respect to binary restenosis, target lesion revascularisation (TLR), and major adverse cardiac events. As for the angiographic endpoints, subgroup analysis was performed for several parameters. There was a significant trend favouring PCB with respect to binary restenosis and TLR in non-focal type lesions and bifurcation lesions.

CONCLUSIONS

Angiographic and clinical outcomes in the PCB group were similar to those in the repeat DES group. PCB seemed to offer more favourable results in non-focal type lesions and bifurcation lesions.

Late Restenosis After Both First-Generation and Second-Generation Drug-Eluting Stent Implantations Occurs in Patients With Drug-Eluting Stent Restenosis

Background—

There are currently inadequate data about whether late restenosis occurs after drug-eluting stent (DES) implantation in patients with DES restenosis.

Methods and Results—

We collected data for 608 patients who received revascularization for DES restenosis between 2004 and 2012 and analyzed 688 lesions: 359 lesions treated with a first-generation DES (first DES) and 329 lesions treated with a second-generation DES (second DES). Two serial angiographic follow-ups were routinely planned for the patients (at 8 and 20 months after the procedure). Early follow-up angiography was performed for 620 lesions (90.1%), and recurrent restenosis occurred in 84 lesions (25.8%) in the first DES group and in 72 lesions (24.5%) in the second DES group ( P =0.78). Target lesion revascularization was performed for 69 lesions (21.2%) in the first DES group and for 48 lesions (16.3%) in the second DES group ( P =0.15). Late follow-up angiography was performed for 438 (87.1%) of the remaining 503 lesions (excluding target lesion revascularization lesions), and late restenosis was found in 35 lesions (15.8%) in the first DES group and in 28 lesions (14.7%) in the second DES group ( P =0.79). Nonfocal-type restenosis, percentage diameter stenosis after the procedure, previous stent size ≤2.5 mm, and right coronary artery ostial lesion were independent predictors of early restenosis. Nonfocal-type restenosis, percentage diameter stenosis at early follow-up, and stent fracture were independent predictors of late restenosis.

Conclusions—

Late restenosis occurs after both first DES implantation and second DES implantation for DES restenosis.

Impact of Neointimal Calcifications on Acute Stent Performance during the Treatment of In-Stent Restenosis

Optical coherence tomography (OCT) has become the invasive imaging modality of choice for coronary stent assessment due to its unmatched spatial resolution. Neointimal calcification (NC) is a rare finding, observed in 5-10% of in-stent restenosis (ISR) neointima. The impact of NC on percutaneous coronary intervention of ISR is unknown. We therefore present the outcome of six unique cases of ISR and NC in which OCT was used to evaluate the impact of NC on the quality of stent-in-stent deployment for the treatment of ISR. This series demonstrates for the first time the impact of NC on stent expansion, a finding which might help guiding percutaneous coronary intervention for ISR with NC.

Comparison of 2-year outcomes of repeated second-generation drug-eluting stent implantation for focal-type versus nonfocal-type in-stent restenosis

BACKGROUND

Second-generation drug-eluting stents (DES) have been used widely to treat DES in-stent restenosis (ISR), which remains a clinical challenge. Knowledge of the outcomes of repeated second-generation DES implantation for focal versus nonfocal-type ISR is still missing.

METHODS

In the current study, 254 patients with DES-ISR were divided into focal or nonfocal groups according to their ISR angiographic types. All patients with ISR lesions included in the current study received second-generation DES. Treatment modalities for both groups were similar without any systematic bias toward either group. The primary endpoint of the study was the occurrence of major adverse cardiac events (MACEs) over a 2-year follow-up period. MACEs were defined as cardiac death, myocardial infarction, and target lesion revascularization.

RESULTS

The nonfocal-type group showed significantly greater incidence of MACEs than the focal-type group (38.3 vs. 24.1%; P=0.03), in which the occurrence of target lesion revascularization was more pronounced (32.3 vs. 18.4%; P=0.02). However, this group showed a higher incidence of type B2/C lesions (69.5 vs. 41.4%; P<0.01), with longer lesion length, and received significantly more and longer reimplanted stents than the focal-type group. Cox regression analysis indicated that nonfocal-type ISR was an independent predictor of MACEs (odds ratio 2.134, 95% confidence interval 1.173-3.884; P=0.014) after adjusting for all significant variables.

CONCLUSION

In the current study, second-generation DES is more effective in the treatment of focal-type DES-ISR than nonfocal-type ISR in terms of the occurrence of MACEs. Nonfocal-type ISR is an independent predictor of MACEs after the treatment of DES-ISR with second-generation DES.

Restenosis after PCI. Part 2: prevention and therapy

The techniques and materials used during percutaneous coronary intervention have advanced considerably over the past 3 decades, yet restenosis remains one of the major drawbacks of this procedure. Many innovative technologies, including drug-eluting stents, with or without specific polymers, and fully biodegradable stents have been and continue to be developed in the search for a safe and effective antirestenosis therapy. Remarkable advances in stent design and nanoparticle delivery systems ('nanovehicles') have already fueled revolutionary changes in the prevention and treatment of in-stent restenosis. In this Review we provide an overview of the latest innovations for optimizing outcomes of coronary stenting, and up-to-date information about prevention and treatment of in-stent restenosis.

In-stent restenosis

The introduction of coronary stents marked a major turning point in the practice of interventional cardiology. Whereas the efficacy of balloon angioplasty was challenged both by immediate mechanical complications and by a high incidence of restenosis, coronary stents offered cardiologists a means by which to not only augment immediate procedural success, but also to reduce the incidence of restenosis following coronary intervention. However, despite technological advances and an improved understanding of the restenotic process, the overall rate of in-stent restenosis following bare metal stent implantation remains high. Although the introduction of drug-eluting stents has further reduced the incidence of restenosis, the "real-world" application of drug-eluting stents in increasingly complex lesion and patient subsets has given way to the even greater clinical challenge of managing drug-eluting stent restenosis. Although the standard treatment of bare metal stent restenosis typically involves placement of a drug-eluting stent, the optimal therapeutic approach to drug-eluting stent restenosis remains less defined. The issue of in-stent restenosis (especially following implantation of a drug-eluting stent) remains a clinical challenge, and investigation into therapeutic options remains ongoing. As technology evolves, such investigation will likely incorporate novel approaches including drug-coated balloons novel stent designs.

Therapeutic strategy for in-stent restenosis based on the restenosis pattern after drug-eluting stent implantation

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the outcomes of repeated percutaneous coronary intervention (PCI) based on the restenosis pattern in drug-eluting stent (DES) failure.

SUBJECTS AND METHODS

From April 2003 to March 2006, all 67 patients (67 lesions) at our 3 centers who had DES in-stent restenosis (ISR) were enrolled. The patients were divided into 3 groups: group I had focal edge restenosis, group II had focal body restenosis, and group III had non-focal restenosis. All patients were treated with conventional PCI including plain old balloon angioplasty (POBA), cutting balloon angioplasty (CBA), and repeated DES implantation (Re-DES). Angiographic and clinical one year follow-up results for the 3 groups were evaluated.

RESULTS

Sixteen patients were enrolled in group I, 36 in group II, and 15 in group III. Baseline clinical and angiographic characteristics and the proportion of patients in each group receiving each type of treatment strategy were not significantly different among the groups. Within each group, a comparison of angiographic and clinical outcomes for each therapeutic modality revealed that restenosis rates were not statistically different. Although rates of major adverse cardiac events (MACE) were not statistically different between groups I and II, in group III, MACE were 3-fold higher for the POBA (4/4, 100.0%) and CBA (4/4, 100.0%) subgroups than for Re-DES (1/3, 33.3%) (p=0.06), but the differences did not reach statistical significance.

CONCLUSION

THE PRESENT STUDY SUGGESTS THAT TREATMENT OF DES ISR SHOULD BE INDIVIDUALIZED ACCORDING TO RESTENOSIS PATTERN: any PCI strategy appears appropriate for focal ISR patterns, while Re-DES might be a better choice for non-focal ISR patterns.

X-ray photoelectron emission microscopy and time-of-flight secondary ion mass spectrometry analysis of ultrathin fluoropolymer coatings for stent applications

Fluoropolymer plasma coatings have been investigated for application as stent coatings due to their chemical stability, conformability, and hydrophobic properties. The challenge resides in the capacity for these coatings to remain adherent, stable, and cohesive after the in vivo stent expansion, which can generate local plastic deformation of up to 25%. Plasma-coated samples have been prepared by a multistep process on 316L stainless steel substrates, and some coated samples were plastically deformed to mimic a stent expansion. Analyses were then performed by X-ray photoelectron spectroscopy (XPS), X-ray photoelectron emission microscopy (X-PEEM), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to determine the chemical and physical effects of such a deformation on both the coating and the interfacial region. While XPS analyses always showed a continuous coating with no significant effect of the deformation, TOF-SIMS and near-edge X-ray absorption fine structure (derived from X-PEEM) data indicated the presence of a certain density of porosity and pinholes in all coatings as well as sparse fissures and molecular fragmentation in the deformed ones. The smallness of the area fraction affected by the defects and the subtlety of the chemical changes could only be evidenced through the higher chemical sensitivity of these latter techniques.