In-Stent Restenosis due to Stent Recoil After Third-Generation Drug-Eluting Stent Implantation

Comparative Clinical Implications of Calcified versus Non-Calcified Tissue Protrusion After Coronary Stent Implantation

Purpose

The prognostic implications of calcified versus non-calcified tissue protrusions (TPs) following stent implantation remain undetermined. This study aimed to evaluate the differential clinical outcomes associated with calcified and non-calcified TP morphologies.

Patients and Methods

Employing intravascular ultrasound (IVUS), we identified calcified TPs as calcium fragment extrusions permeating the stent struts, while non-calcified TPs were characterized as plaque and/or thrombus extensions through the stent into the arterial lumen. The primary endpoint encompassed target lesion failure (TLF), comprising cardiac death, target vessel myocardial infarction, clinically driven target lesion revascularization (TLR), or stent thrombosis, assessed in patients with a follow-up period exceeding one year.

Results

Of 1033 patients subjected to pre- and post-intervention IVUS, 62 exhibited calcified TPs (6.0%), and 279 presented non-calcified TPs (27.0%), forming the basis of this analysis. Multivariable linear regression indicated calcified nodules as a significant predictor of calcified TP [Odds Ratio (OR) 2.47; 95% Confidence Interval (CI) 2.33 to 2.62; P <0.001], with ST-segment elevation myocardial infarction emerging as an inverse correlate [OR 0.82; 95% CI 0.73 to 0.93; P = 0.004]. Two-year data revealed a higher incidence of TLF in patients with calcified TPs versus their non-calcified counterparts (11.3% vs 2.2%, P <0.001), and a marked increase in clinically driven TLR (9.7% vs 1.4%, P <0.001). Calcified TPs were independently correlated with increased TLF risk in the adjusted model [Hazard Ratio (HR) 2.47; 95% CI 1.17 to 5.16; P = 0.027].

Conclusion

After drug-eluting stent implantation, IVUS-identified calcified TPs correlate with adverse clinical outcomes compared to non-calcified TP formations.

A novel double arrowhead auxetic coronary stent

A stent implantation is a standard medical procedure for treating coronary artery diseases. Over the years, various different designs have been explored for the stents which come with a range of limitations, including late in-stent restenosis (due to low radial strength), foreshortening, radial recoil, etc. Contrary, stents with auxetic design, characterized by a negative Poisson's ratio, display unique deformation characteristics that result in enhanced mechanical properties in terms of its radial strength, radial recoil, foreshortening, and more. In this study, we have analysed a novel double arrowhead (DA) auxetic stent that aims to overcome the limitations associated with traditional stents, specifically in terms of radial strength, foreshortening, and radial recoil. The parametric analysis was done initially on the DA's unit ring structure to optimize the design by evaluating the effect of three design parameters (angle, amplitude, and width) on the mechanical characteristics (radial strength and radial recoil) using finite element analysis. The width of the strut was found to be the primary determinant of the stent structure's properties. Consequently, the angle and width were found to have the least effect on altering the stent's mechanical properties. After performing the parametric analysis, optimal design factors were selected to design the full-length DA auxetic stent. The mechanical characteristics of the DA auxetic stent were assessed and compared in a case study with the Cypher™ commercial stent. The radial strength of DA auxetic stent was found to be 7.26 N/mm, which is more than double the Cypher™ commercial stent's radial strength. Additionally, the proposed stent possesses reduced radial recoil property and completely eliminates the stent foreshortening issue, which shows the superior mechanical properties of the proposed auxetic stent and its potential as a promising candidate for future stent designs.

Stent expansion in calcified coronary chronic total occlusions: The impact of different stent platforms

OBJECTIVES

To evaluate the stent expansion of the durable-polymer Zotarolimus-eluting stent (dp-ZES), the durable-polymer Everolimus-eluting stent (dp-EES), and the bioabsorbable-polymer Sirolimus-eluting stent (bp-SES) in calcified coronary chronic total occlusions (CTO).

BACKGROUND

The newer generation stents with ultrathin struts might raise concerns regarding reduced radial strength and higher stent recoil (SR) when implanted in calcified CTOs.

METHODS

Between January 2017 and June 2021 consecutive patients with CTO undergoing percutaneous coronary intervention with dp-ZES, dp-EES, or bp-SES were evaluated. The analysis was performed in calcific and in noncalcific CTOs. Quantitative coronary angiography analysis was used to assess diameter stenosis (DS), absolute and relative SR, absolute and relative focal SR, absolute and relative balloon deficit (BD), and absolute and relative focal BD. The primary endpoint was DS.

RESULTS

A total of 213 CTOs were evaluated, 115 calcific CTOs (dp-ZES:25, dp-EES:29, bp-SES:61) and 98 non-calcific CTOs (dp-ZES:41, dp-EES:11, bp-SES:46). In calcific CTOs, residual DS was lower in dp-ZES than in dp-EES and bp-SES (-1.00% [-6.50-6.50] vs. 13.00% [7.0-19.00] vs. 15.00% [5.00-20.00]; p < 0.001). Dp-ZES was also an independent predictor of residual DS ≤ 10% (OR 11.34, 95% CI 2.6-49.43, p = 0.001). Absolute and relative focal SR and absolute and relative SR were similar between dp-ZES, dp-EES, and bp-SES (p = 0.913, p = 0.890, p = 0.518, p = 0.426, respectively). In noncalcified CTOs, the residual DS was similar in the three groups (p = 0.340). High relative focal SR was less frequent in dp-ZES than in dp-EES and in bp-SES (19.5% vs. 54.5% vs. 37.0%; p < 0.048).

CONCLUSIONS

The three stent platforms demonstrated an overall low residual DS when implanted in CTOs. However, dp-ZES was associated with the lowest residual DS and identified as independent predictor of residual DS ≤ 10% in patients with calcific CTOs. Dp-ZES was associated with a lower incidence of high relative focal stent recoil, in noncalcific CTOs. Balloon deficit might be considerate as a surrogate for stent expansion in calcified CTOs.

Increased risk of adverse cardiovascular events by strict glycemic control after percutaneous coronary intervention (HbA1c < 6.5% at 2 years) in type 2 diabetes mellitus combined with acute coronary syndrome: a 5-years follow-up study

OBJECTIVE

This study assessed the association between HbA1c level measured 2 years after percutaneous coronary intervention (PCI) and long-term clinical outcomes in type 2 diabetes mellitus combined with acute coronary syndrome (ACS) who underwent PCI.

METHODS

This prospective observational study analyzed 2877 ACS patients with type 2 diabetes mellitus whose baseline HbA1c ≥ 7.0% and underwent PCI. All patients were divided into 6 groups according to the HbA1c level at 2 years after PCI. The clinical outcome was major adverse cardiovascular events (MACEs), defined as all-cause death, all myocardial infarction, any revascularization, congestive heart failure, ischemic stroke. The median follow-up duration was 4.1 years.

RESULTS

All 2877 patients were divided into 6 groups: 2-year after PCI HbA1c < 6.0% (n = 219), 6.0-6.5% (n = 348), 6.5-7.0% (n = 882), 7.0-7.5% (n = 567), 7.5-8.0% (n = 441), ≥8.0% (n = 420). The 5-year incidence rate of MACEs in HbA1c <6.0% and 6.0-6.5% groups were similar to 7.5-8.0% and ≥8.0% groups, which were significantly higher than in 6.5-7.0% and 7.0-7.5% groups (p = .044). The cumulative incidence rate of MACEs significantly differed among the groups (p = .046). Multivariate Cox regression analysis revealed a U-shaped relationship between 2-year HbA1c level after PCI and risk of MACEs. 2-year HbA1c <6.5% after PCI was an independent risk factor for MACEs in type 2 diabetes mellitus combined with ACS who underwent PCI (p < .001).

CONCLUSIONS

The findings indicated an increased risk of MACEs by strict glycemic control after PCI (2-year HbA1c < 6.5% after PCI) in type 2 diabetes mellitus combined with ACS who underwent PCI.

The incidence, natural history, and predictive factors for tissue protrusion after drug-eluting stent implantation

OBJECTIVES AND BACKGROUND

Although tissue protrusion (TP) between the stent struts after stent implantation has been implicate as a potential factor of stent failure, the incidence, natural history, and predictive factor of TP after stent implantation remains unclear. This prospective study evaluated the fate of TP after drug-eluting stent (DES) deployment using optical coherence tomography (OCT).

METHOD AND RESULT

This study analyzed TP for 42 lesions after DES in which three serial OCTs, including preprocedure, postprocedure, and 1-month after the procedure were performed. TP was classified into the five groups: (a) persistent, (b) progressive, (c) healed, (d) regressive, and (e) late-acquired. Immediately after the procedure, 100 TPs in 37 lesions (88%) were identified. Of those, 53 (53%) were persistent, 3 (3%) were progressive, 20 (20%) were healed, and 24 (24%) were regressed at 1-month follow-up. Seven TPs in five patients (13%) were observed only at 1-month follow-up (late-acquired).

CONCLUSION

In lesions with late-acquired TP, calcified nodule was identified as an underlying plaque morphology on preprocedural OCT. A serial OCT analysis found TP occurred not only immediately after DES implantation, but also 1-month after DES implantation.

The frequency and clinical characteristics of in-stent restenosis due to calcified nodule development after coronary stent implantation

The purpose of this study was to evaluated the clinical characteristics of calcified nodule-like in-stent restenosis (ISR) lesions using optical coherence tomography (OCT) in vivo. A total of 124 ISR lesions that were treated with a repeat coronary intervention under OCT guidance were included in this analysis. ISR neointimal morphology was classified as "calcified nodule-like ISR", that appeared as a high-backscattering protruding mass with an irregular surface covered by signal-rich bands, or "non-calcified nodule-like ISR". The maximum arc and thickness of calcium behind the stent struts was also measured. Of the 124 ISR lesions, calcified nodule-like ISR was observed in 11 lesions (9%). OCT analysis data showed that the maximum arc of calcium and the maximum calcium thickness behind the stent were significantly larger in the calcified nodule-like ISR lesions than in the non-calcified nodule-like ISR lesions (269 ± 51 vs. 179 ± 92°, p < 0.01 and 989 ± 174 vs. 684 ± 241 μm, p < 0.01, respectively). The enlargement of the stent area was significantly larger in the calcified nodule-like ISR lesions than in the non-calcified nodule-like ISR lesions (1.6 ± 2.3 vs. 0.7 ± 1.3 mm², p = 0.02). As a result, the enlargement of the lumen area tended to be larger in the calcified group (2.8 ± 1.7 vs. 2.4 ± 1.3 mm², p = 0.3). Calcified nodule-like neointima within the stent could develop in approximately 10% of all ISR lesions, especially within stents deployed in severely calcified lesions.

Incidence, retrieval methods, and outcomes of intravascular ultrasound catheter stuck within an implanted stent: Systematic literature review

BACKGROUND

There have been no reviews regarding intravascular ultrasound (IVUS) catheter entrapment during percutaneous coronary intervention (PCI). This study investigated the incidence, retrieval methods, and outcomes of IVUS catheter stuck within implanted stents.

METHODS

Between January 2015 and July 2018, a total of 794 consecutive patients underwent PCI for coronary artery disease. Among them, 705 patients underwent stent implantation using IVUS. The patients with IVUS catheter entrapment in an implanted stent were investigated.

RESULTS

Ten patients (1.4%) suffered from an IVUS catheter stuck in an implanted stent. Among them, 7 patients had very tortuous lesions while 5 patients had severely calcified lesions. Seven patients (70%) underwent placement of the 3rd generation drug-eluting stent (DES), and the stent diameters were ≤2.5mm among 8 patients (80%). Retrieval methods were the buddy wire technique, the double guide catheter technique, covering the exit port of IVUS catheter with a balloon catheter, and covering with GuideLiner® catheter (Vascular Solutions Inc., Minneapolis, MN, USA). On multivariable analysis, the predictors of IVUS catheter entrapment were tortuous lesion [odds ratio (OR), 8.21; 95% confidence interval (CI), 2.19-30.7; p=0.002], 3rd generation DES (OR, 5.31; 95% CI, 1.08-26.1; p=0.021), and stent diameter ≤2.5mm (OR, 6.31; 95% CI, 1.29-30.8; p=0.010). Furthermore, we identified 6 cases of IVUS catheter entrapment through a systematic literature review.

CONCLUSIONS

The IVUS catheter was almost stuck in tortuous lesions and the 3rd generation DES with a small diameter. We could successfully retrieve it in all cases using various retrieval techniques.