Effect of oversized partial postdilatation on coatings of contemporary durable polymer-based drug-eluting stents: a scanning electron microscopy study

Three contemporary thin-strut drug-eluting stents implanted in severely calcified coronary lesions of participants in a randomized all-comers trial

OBJECTIVE

The objective was to assess the 2-year clinical performance of three drug-eluting stents in all-comer patients with severely calcified coronary lesions.

BACKGROUND

Severe lesion calcification increases cardiovascular event risk after coronary stenting, but there is a lack of data on the clinical outcome of all-comers with severely calcified lesions who were treated with more recently introduced drug-eluting stents.

METHODS

The BIO-RESORT trial (clinicaltrials.gov: NCT01674803) randomly assigned 3,514 all-comer patients to biodegradable polymer Synergy everolimus-eluting stents (EES) or Orsiro sirolimus-eluting stents (SES), versus durable polymer Resolute Integrity zotarolimus-eluting stents (ZES). In a post hoc analysis, we assessed 783 patients (22.3%) with at least one severely calcified target lesion.

RESULTS

At 2-year follow-up (available in 99% of patients), the main composite endpoint target vessel failure occurred in 19/252 (7.6%) of the EES and in 33/265 (12.6%) of the ZES-treated patients (p = .07). Target vessel failure occurred in 24/266 (9.1%) of the SES-treated patients (vs. ZES: p = .21). There was a difference in target vessel revascularization, which was required in EES in 6/252 (2.4%) patients and in ZES in 20/265 (7.7%) patients (p = .01); the target vessel revascularization rate in SES was 9/266 (3.4%, vs. ZES: p = .04). Multivariate analysis showed that implantation of EES, but not SES, was independently associated with lower target vessel revascularization rates than in ZES.

CONCLUSIONS

In BIO-RESORT participants with severely calcified target lesions, treatment with EES was associated with a lower 2-year target vessel revascularization rate than treatment with ZES.

The Proximal Optimisation Technique for Intervention of Coronary Bifurcations

The proximal optimisation technique (POT) has been proposed as a strategy to improve the results of stent scaffolding of bifurcation lesions. It is a straightforward technique whereby a short, appropriately-sized balloon is inflated in the main vessel just proximal to the carina. The technique has several advantages: it reduces the risk of side branch compromise related to shifting of the carina, it improves stent apposition in the proximal main vessel, and it facilitates side branch access after main vessel stent implantation. When treating bifurcations, final kissing balloon dilation (KBD) has traditionally been used routinely to optimise angiographic results. However, recent clinical data have questioned this philosophy and bench models have demonstrated several shortcomings of KBD. Instead, the optimal strategy may centre on performing POT, followed by side branch dilation, and completed with a final (re)-POT. The following review article describes how to perform POT and presents the evidence to support its' routine use.

Stent Coating Integrity of Durable and Biodegradable Coated Drug Eluting Stents

BACKGROUND

Coatings consisting of a polymer and drug are widely used in drug-eluting stents (DES) and are essential in providing programmable drug release kinetics. Among other factors, stent coating technologies can influence blood compatibility, affect acute and sub-acute healing, and potentially trigger a chronic inflammatory response.

OBJECTIVE

The aim of this study was to investigate the short-term (7 and 28 days) and long-term (90 and 180 days) coating integrity of the Xience Prime Everolimus-Eluting Stent (EES), Resolute Zotarolimus-Eluting Stent (ZES), Taxus Paclitaxel-Eluting Stent (PES), and Nobori Biolimus A9-Eluting Stent (BES) in a rabbit ilio-femoral stent model.

METHODS AND RESULTS

Stented arteries (n = 48) were harvested and the tissue surrounding the implanted stents digested away with an enzymatic solution. Results demonstrated that the majority of struts of EES were without any coating defects with a few struts showing minor defects. Similarly, for the ZES, most of the struts were without coating defects at all time points except at 180 days. The majority of PES demonstrated mostly webbing and uneven coating. In the BES group, the majority of strut coating showed polymer cracking.

CONCLUSION

Overall, the EES and ZES had fewer coating defects than the PES and BES. Coating defects, however increase over time for the ZES, whereas the percent of coating irregularities remained constant for the EES. These results provide, for the first time, a comparison of the long-term durability of these drug-eluting stent coatings in vivo.

Zotarolimus-eluting stent for the treatment of recurrent, severe carotid artery in-stent stenosis in the TARGET-CAS population

PURPOSE

To evaluate the safety and efficacy of a balloon-mounted drug-eluting stent (DES) for recurrent carotid in-stent stenosis (ISS).

METHODS

As part of our targeted carotid artery stenting (TARGET-CAS) protocol, neurological and ultrasound evaluations have been performed at 3, 6, and 12 months and then annually since 2001 in all carotid stent patients. For angiographically-confirmed >70% ISS, balloon angioplasty was performed as a first-line treatment. Recurrent ISS was treated with a 4.0-mm zotarolimus-eluting coronary stent (ZES) that was postdilated according to intravascular ultrasound imaging. Among the 1350 neuroprotected CAS procedures performed between January 2001 and March 2011, there were 7 (0.52%) patients (5 men; ages 51-72 years), all neurologically asymptomatic, with >70% recurrent ISS that occurred at 5 to 11 months after the initial balloon angioplasty treatment for ISS.

RESULTS

ZES implantation under distal embolic protection was technically successful and uncomplicated. Angiographic stenosis was reduced from 84.6%±7.5% to 10.7%±3.6% (p<0.01). In 5 patients with ZES implanted fully within the self-expanding carotid stent, duplex ultrasound follow-up (mean 17 months, range 6-36) revealed no evidence of restenosis or stent fracture/deformation. In the 2 other patients, the ZES had been implanted for distal edge ISS such that the ZES protruded beyond the original carotid stent. This protruding segment of the ZES demonstrated deformation/kinking in both; in one, this led to symptomatic stent occlusion.

CONCLUSION

The use of coronary ZES in the treatment of recurrent carotid ISS is feasible and appears effective provided the ZES is placed entirely within the original stent. Placement of a coronary ZES outside the carotid stent scaffold should be avoided.

Outcomes in patients undergoing multivessel percutaneous coronary intervention using sirolimus-eluting stents: a report from the e-SELECT registry

AIMS

Performing percutaneous coronary intervention (PCI) to multiple coronary lesions during the same procedure has potential economic and social advantages. However comprehensive outcome data of real world practice in a large population is limited. We aimed to compare short- and long-term outcomes between patients with multivessel coronary artery disease who either underwent single- or multivessel PCI within the e-SELECT registry.

METHODS AND RESULTS

The e-SELECT registry combines data collected at 320 medical centres in 56 countries where patients received CYPHER Select® or CYPHER Select® Plus sirolimus-eluting stent (SES). Rates of myocardial infarction and major adverse cardiac event (MACE) (defined as any death, myocardial infarction or target lesion revascularisation) were compared between patients undergoing single-vessel versus multivessel PCI. A total of 15,147 patients who satisfied the inclusion criteria were included in the e-SELECT registry. Two thousand two hundred and seventy-eight (2,278) subjects (15%) underwent multivessel PCI and 12,869 (85%) had single-vessel PCI. The mean age was higher in the multivessel PCI group (63 vs. 62 years, p<0.001) and there was a higher prevalence of diabetes mellitus (32.4 vs. 30.0%, p=0.02). Lesions were more complex in the single-PCI group while pre- and post-dilatation were less common in the multivessel PCI group. Myocardial infarction within the first 30 days post PCI was more common in the multivessel PCI group (1.9 vs. 0.8%, p<0.001) and most of the infarctions were periprocedural (1.3 vs. 0.6%, p=0.001). Mortality and myocardial infarction at one-year were higher in the multivessel PCI group resulting in a significantly higher MACE (6.1 vs. 4.6%, p=0.005).

CONCLUSIONS

Overall procedural and one year outcomes were excellent for both single- and multivessel procedures. However despite lower lesion complexity, performing multivessel PCI was associated with higher rates of periprocedural myocardial infarction and MACE when compared to single-vessel PCI in the e-SELECT registry.

Clinical Impact of Stent Design

The introduction and widespread adoption of drug-eluting stents into routine clinical practice has seen tremendous changes in the practice of interventional cardiology. For a prolonged period, manufacturers have focused research on drugs and polymers that are the key to the prevention of in-stent restenosis. However, stent platform design and its clinical implications have now come back to the fore. This has occurred for numerous reasons, but has primarily been driven by the need for modern stents to perform well in increasingly demanding clinical scenarios. This paper reviews the historical evolution of stent platform design. Current manufacturing processes and materials are also explored. Geometric stent construction and its implications for longitudinal stability and the longer term risks of stent fracture are reviewed. Finally, the implications of the specific stent chosen for different clinical applications including the treatment of bifurcations and left main disease are also summarised. This article will familiarise cardiologists with the crucial impact of each of these factors on modern day practice, as well as acute and long-term outcomes for patients.