Novel bioabsorbable polymer and polymer-free metallic drug-eluting stents

Natural History and Clinical Outcomes After ST-Segment Elevation Myocardial Infarction Without Stent Insertion

After restoration of coronary perfusion in patients presenting with ST-segment elevation myocardial infarction (STEMI), discrete severe stenotic coronary lesions are not always apparent. There remains ambiguity whether drug-eluting stent (DES) insertion or initial medical management is best practice. We sought to assess short-term clinical outcomes in patients presenting with STEMI without initial stent insertion. Patients who underwent percutaneous coronary intervention for STEMI between 2014 and 2020 were prospectively enrolled and assessed for inclusion. Patients presenting with in-stent restenosis or stent thrombosis, or who did not survive to hospital discharge were excluded. Of 13,871 patients presenting, 456 (3.3%) were treated without initial stenting. These patients were older than those treated with DES (66.1 ± 13.6 vs 62.3 ± 12.4 years, p <0.001), had higher rates of diabetes (23.5% vs 16.0%, p <0.001) and previous revascularization with either percutaneous coronary intervention (14.0% vs 7.3%, p <0.001) or coronary artery bypass graft (3.5% vs 1.8%, p = 0.008). Thirty-day mortality was elevated in patients treated without stenting compared to those receiving DES (4.2% vs 0.9%, p <0.001), as were rates of myocardial infarction (1.3% vs 0.5%, p = 0.026) and major adverse cardiac events (10.5% vs 2.4%, p <0.001). After propensity matching, a trend toward increased mortality remained (4.2% vs 2.0%, p = 0.055). In conclusion, a no-stenting initial strategy, compared with DES insertion, is associated with increased 30-day mortality in those presenting with STEMI without severe stenosis. These data suggest when appropriate, current-generation DES insertion should be undertaken.

Peri-Coronary Adipose Tissue Is a Predictor of Stent Failure in Patients Undergoing Percutaneous Coronary Intervention

PURPOSE

Coronary inflammation is postulated as a driver of atherosclerosis and dysfunctional arterial healing which may trigger stent failure. Pericoronary adipose tissue (PCAT) attenuation, detected on computer tomography coronary angiography (CTCA), is an emerging non-invasive marker of coronary inflammation. This propensity matched study assessed the utility of both lesion specific (PCATLesion) and standardized PCAT attenuation as assessed in the proximal RCA (PCATRCA) as a predictor of stent failure in patients undergoing elective percutaneous coronary intervention. This is the first study to our knowledge that assesses the association of PCAT with stent failure.

METHODS

Patients undergoing CTCA assessment for coronary artery disease with subsequent stent insertion within 60 days and repeat coronary angiography for any clinical reason within 5 years were included in the study. Stent failure was defined as binary restenosis of >50 % on quantitative coronary angiography analysis or stent thrombosis. Both PCATLesion and PCATRCA was assessed utilizing semi-automated proprietary software on baseline CTCA. Patients with stent failure were propensity matched utilizing age, sex, cardiovascular risk factors and procedural characteristics.

RESULTS

One hundred and fifty-one patients met inclusion criteria. Of these, 26 (17.2 %) had study-defined failure. A significant difference in PCATLesion attenuation between patients with and without failure was observed (-79.0 ± 12.6 vs. -85.9 ± 10.3HU, p = 0.035). There was no significant difference in PCATRCA attenuation between the two groups (-79.5 ± 10.1 vs -81.0 ± 12.3HU, p = 0.50). Univariate regression analysis showed PCATLesion attenuation was independently associated with stent failure (OR 1.06, 95 % CI 1.01-1.12, P = 0.035).

CONCLUSIONS

Patients with stent failure exhibit significantly increased PCATLesion attenuation at baseline. These data suggest that baseline plaque inflammation may be an important driver for coronary stent failure.

Clinical implications of inflammation in atheroma formation and novel therapies in cardiovascular diseases

Cardiovascular diseases (CVD) are the leading causes of death and disability in the world. Among all CVD, the most common is coronary artery disease (CAD). CAD results from the complications promoted by atherosclerosis, which is characterized by the accumulation of atherosclerotic plaques that limit and block the blood flow of the arteries involved in heart oxygenation. Atherosclerotic disease is usually treated by stents implantation and angioplasty, but these surgical interventions also favour thrombosis and restenosis which often lead to device failure. Hence, efficient and long-lasting therapeutic options that are easily accessible to patients are in high demand. Advanced technologies including nanotechnology or vascular tissue engineering may provide promising solutions for CVD. Moreover, advances in the understanding of the biological processes underlying atherosclerosis can lead to a significant improvement in the management of CVD and even to the development of novel efficient drugs. To note, over the last years, the observation that inflammation leads to atherosclerosis has gained interest providing a link between atheroma formation and oncogenesis. Here, we have focused on the description of the available therapy for atherosclerosis, including surgical treatment and experimental treatment, the mechanisms of atheroma formation, and possible novel therapeutic candidates such as the use of anti-inflammatory treatments to reduce CVD.

Primary percutaneous coronary intervention in CAD patients: A comparison of major adverse cardiovascular events of second- and third-generation drug-eluting stents

Background: Biodegradable polymer (BP) drug-eluting stents (DES) have been introduced as a novel solution to the problems of durable polymer (DP) stents. In Pakistan, very few studies are available for the treatment intervention in post-primary percutaneous coronary intervention (PPCI) patients. Our study will compare the major adverse cardiovascular events (MACEs) and their predictors in patients with coronary artery disease (CAD) undergoing PPCI with second- or third-generation DES. Methodology: An observational, retrospective, cohort study was carried out on CAD patients undergoing PPCI with either second- (DP-XIENCE Prime/XIENCE Xpedition) or third-generation (BP-BioMatrix NeoFlex/BioMatrix Alpha) DES. MACEs were assessed after 1 year of PPCI procedure in 341 patients and screened as per inclusion/exclusion criteria (167 in the second-generation group and 174 in the third-generation group). Results: The number of male patients (86.2%) was more than female patients in our study population. MACEs were reported in 4.19% patients after 1 year duration, and the percentage of MACEs was more in the second-generation DES group (4.77%) than in the third-generation group (3.44%); however, statistical analysis has not found any significant difference (p = 0.534). The rate of myocardial infarction (1.19% vs. 0.57%) and stent thrombosis (1.8% vs. 1.15%) was more in the second-generation DES group. However, restenosis (1.19% vs. 1.15%) and cardiac death (0.59% vs. 0.57%) were almost same in both groups. A significant association was found between MACEs and diabetes mellitus (p = 0.025), hypertension (p = 0.035), smoking (p = 0.008), and a family history of CAD (p = 0.018). Conclusion: BP-BioMatrix and DP-XIENCE DES have comparable clinical outcomes. Findings of the current study will assist the policy makers and healthcare providers in the rationalization of scarce resources and evidence-based patient care. However, longer follow-up studies are required for convincing results.

A Randomized Comparison of the Healing Response Between the Firehawk Stent and the Xience Stent in Patients With ST-Segment Elevation Myocardial Infarction at 6 Months of Follow-Up (TARGET STEMI OCT China Trial): An Optical Coherence Tomography Study

Background

The healing response of the Firehawk stent in patients with ST-segment elevation myocardial infarction (STEMI) remains unclear.

Aim

We compared the vascular healing of a biodegradable polymer sirolimus-eluting stent (Firehawk) vs. a durable polymer everolimus-eluting stent (Xience) at 6 months after percutaneous coronary intervention (PCI) in patients with STEMI.

Methods

In this prospective, multicenter, randomized, non-inferiority study, patients within 12 h of STEMI onset were randomized in a ratio of 1:1 to receive Firehawk or Xience stents. Optical coherence tomography (OCT) follow-up was performed 6 months after the index procedure and assessed frame by frame. The primary endpoint was the neointimal thickness (NIT) at 6 months evaluated by OCT. The safety endpoint was target lesion failure (TLF) at 12 months.

Results

The Firehawk stent was non-inferior to the Xience stent in terms of the neointimal thickness (73.03 ± 33.30 μm vs. 78.96 ± 33.29 μm; absolute difference: −5.94 [one-sided 95% lower confidence bound: −23.09]; P_{non−inferiority} < 0.001). No significant difference was observed between the Firehawk and Xience groups regarding the percentage of uncovered struts (0.55 [0.08, 1.32]% vs. 0.40 [0.21, 1.19]%, P = 0.804), the percentage of malapposed struts (0.17 [0.00, 1.52]% vs. 0.17 [0.00, 0.69]%, P = 0.662), and the healing score (1.56 [0.23, 5.74] vs. 2.12 [0.91, 3.81], P = 0.647). At 12 months, one patient in the Firehawk group experienced a clinically indicated target lesion revascularization. No other TLF events occurred in both groups. Independent risk factors of the NIT included body mass index, hyperlipidemia, B2/C lesions, thrombus G3–G5, thrombus aspiration, and postdilation pressure.

Conclusion

In patients with STEMI, Firehawk was non-inferior to Xience in vascular healing at 6 months. Both stents exhibited nearly complete strut coverage, moderate neointimal formation, and minimal strut malapposition.

Clinical Trial Number

NCT04150016.

Diabetes mellitus is independently associated with early stent thrombosis in patients undergoing drug eluting stent implantation: Analysis from the Victorian cardiac outcomes registry

BACKGROUND

Diabetes mellitus (DM) is a predictor of restenosis and late stent thrombosis (ST) in patients undergoing percutaneous coronary intervention (PCI) with drug-eluting-stents (DES). Real-world data on rates of early ST is lacking. We compared clinical outcomes of patients with and without DM from the Victorian cardiac outcomes registry.

METHODS

Consecutive patients undergoing PCI with DES were analyzed with primary outcome being ST at 30-days. Secondary outcomes including major adverse cardiovascular events (MACE) and all-cause mortality.

RESULTS

Of 43,209 patients included, 9730 (22.5%) had DM. At 30 days, DM was independently associated with higher rates of early ST (0.7% vs. 0.5%) OR 1.41 (95% confidence interval; 1.05-1.87, p = 0.02), MACE (4.1% vs. 3.5%, p = 0.004) and mortality (1.9% vs. 1.5%, p = 0.01). Increased risk was not simply due to treatment. Patients with DM requiring insulin were equally affected in regard to MACE (4.7% vs. 3.9%, p = 0.069) and mortality (1.9%, vs. 1.8%, p = 0.746). On National Death Index linkage, patients with DM had increased all-cause mortality over five-year follow-up (OR 1.69 CI 1.55-1.83, p = < 0.001).

CONCLUSION

In this large real-world-registry, DM was an independent predictor of early ST, MACE and mortality at 30 days. These data suggest additional therapeutic strategies are required to reduce the risk of early complications in patients with DM undergoing PCI with DES.

Cutting balloon angioplasty on branch pulmonary artery stenosis in pediatric patients

OBJECTIVES

To identify medium-term results following cutting balloon angioplasty (CBA) for branch pulmonary artery stenosis (PAS) and predictors of successful intervention.

BACKGROUND

CBA has emerged as a successful alternative therapy for PAS resistant to conventional balloon angioplasty techniques but there is little information on medium and long-term outcomes.

METHODS

This is a descriptive, single center, retrospective chart review of pediatric patients who underwent CBA for PAS at Arkansas Children's Hospital between May 2005 and December 2020. We reviewed demographics, procedural specifics, and 30-day complications.

RESULTS

Forty-four patients underwent pulmonary artery CBA on 114 pulmonary artery segments through 126 catheterization cases, totaling 148 CBA events. Thirty-three individual pulmonary arteries underwent repeat intervention. Average minimal luminal diameter increase from pre-CBA to end of follow-up was 57% (CI, 38%-75%). Absence of Tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries (TOF/PA/MAPCAs) and the absence of Alagille Syndrome, Williams Syndrome, or Arterial Tortuosity Syndrome (ATS) were associated with increased odds of sustained success by 70% (CI, 0.11-0.79) and 91% (CI, 0.02-0.56), respectively. Increasing the cutting balloon diameter-to-minimal luminal diameter ratio by 0.5 increased odds of successful intervention by 2.37-fold (CI, 1.7-3.3). Seven patients had 30-day complications including one death.

CONCLUSIONS

In the longest follow-up to date of children and adolescents who underwent CBA for branch PAS, we found that there was moderate medium-term success. Additionally, absence of TOF/PA/MAPCAs, absence of Alagille Syndrome, Williams Syndrome, or ATS, and high cutting balloon diameter-to-minimal luminal diameter ratio are predictors of sustained results.

Recent advances and directions in the development of bioresorbable metallic cardiovascular stents: Insights from recent human and in vivo studies

Over the past two decades, significant advancements have been made regarding the material formulation, iterative design, and clinical translation of metallic bioresorbable stents. Currently, magnesium-based (Mg) stent devices have remained at the forefront of bioresorbable stent material development and use. Despite substantial advances, the process of developing novel absorbable stents and their clinical translation is time-consuming, expensive, and challenging. These challenges, coupled with the continuous refinement of alternative bioresorbable metallic bulk materials such as iron (Fe) and zinc (Zn), have intensified the search for an ideal absorbable metallic stent material. Here, we discuss the most recent pre-clinical and clinical evidence for the efficacy of bioresorbable metallic stents and material candidates. From this perspective, strategies to improve the clinical performance of bioresorbable metallic stents are considered and critically discussed, spanning material alloy development, surface manipulations, material processing techniques, and preclinical/biological testing considerations. STATEMENT OF SIGNIFICANCE: Recent efforts in using Mg, Fe, and Zn based materials for bioresorbable stents include elemental profile changes as well as surface modifications to improve each of the three classes of materials.  Although a variety of alloys for absorbable metallic stents have been developed, the ideal absorbable stent material has not yet been discovered. This review focuses on the state of the art for bioresorbable metallic stent development. It covers the three bulk materials used for degradable stents (Mg, Fe, and Zn), and discusses their advances from a translational perspective. Strategies to improve the clinical performance of bioresorbable metallic stents are considered and critically discussed, spanning material alloy development, surface manipulations, material processing techniques, and preclinical/biological testing considerations.

Angioscopic assessments and clinical outcomes one year after polymer-free biolimus A9-coated coronary stent implantation

BACKGROUND

Polymer-free biolimus A9-coated coronary stent (DCS) has novel features which lead to the expectation of better arterial healing. However, comparisons of intravascular status between DCS and drug-eluting stents (DES), and robust real-word clinical assessments of DCS have been lacking to date.

METHODS

From September 2017 to September 2018, we evaluated the intra-vascular status of 74 DCS implanted in 55 lesions from 43 patients using coronary angioscopy (CAS) approximately one year after implantation from a cohort of 219 lesions in 158 patients. We set 239 second-generation durable-polymer DES (DP-DES) implanted in 211 lesions from 180 patients from a cohort of 2652 lesions in 1914 patients as the control. Angioscopic images were analyzed to determine (1) the dominant degree of neointimal coverage (NIC) over the stent; (2) the heterogeneity of NIC; (3) yellow color grade of the stented segment; and (4) the presence of intra-stent thrombus. The primary outcome was the incidence of thrombus and secondary outcomes were the other CAS findings, and the 1-year clinical outcomes which included target lesion revascularization (TLR) and major adverse cardiac events (MACE). To minimize inter-group differences in baseline characteristics, propensity score matching was performed for clinical outcomes.

RESULTS

Incidence of thrombus adhesion was similar in DCS and DP-DES groups (28.4% versus 22.6%, p=0.31). However, the dominant NIC grade was significantly higher in DCS (p<0.001), while NIC was more heterogeneous in DCS than in DP-DES (p=0.001). Maximum yellow color grade was similar (p=0.22). After propensity score matching, 202 lesion pairs from 146 patient pairs were retained for analysis. The cumulative incidence of TLR (4.6% versus 3.8%, p=0.38) and MACE (11.6% versus 11.7%, p=0.84) was similar for DCS and DP-DES.

CONCLUSIONS

DCS showed thrombus adhesion and clinical outcomes at 1 year similar to DP-DES. DCS can thus be used with similar safety and efficacy as DP-DES.

Drug-Eluting Stents and Balloons-Materials, Structure Designs, and Coating Techniques: A Review

Controlled drug delivery is a matter of interest to numerous scientists from various domains, as well as an essential issue for society as a whole. In the treatment of many diseases, it is crucial to control the dosing of a drug for a long time and thus maintain its optimal concentration in the tissue. Heart diseases are particularly important in this aspect. One such disease is an obstructive arterial disease affecting millions of people around the world. In recent years, stents and balloon catheters have reached a significant position in the treatment of this condition. Balloon catheters are also successfully used to manage tear ducts, paranasal sinuses, or salivary glands disorders. Modern technology is continually striving to improve the results of previous generations of stents and balloon catheters by refining their design, structure, and constituent materials. These advances result in the development of both successive models of drug-eluting stents (DES) and drug-eluting balloons (DEB). This paper presents milestones in the development of DES and DEB, which are a significant option in the treatment of coronary artery diseases. This report reviews the works related to achievements in construction designs and materials, as well as preparation technologies, of DES and DEB. Special attention was paid to the polymeric biodegradable materials used in the production of the above-mentioned devices. Information was also collected on the various methods of producing drug release coatings and their effectiveness in releasing the active substance.

Overview of the latest developments in the field of drug-eluting stent technology

Angioplasty with stent implantation is considered to be the basic treatment method of stenosis of blood vessels. The process of stent implantation changed through the years, from stents made only from metals, produced from polymers, to biodegradable ones and those which elute drugs. The purpose of this review is to outline the development of this medical procedure and present the advantages and disadvantages of each type of stent.

Recent advances in percutaneous coronary intervention

Percutaneous coronary intervention (PCI) continues to advance at pace with an ever-broadening indication. In this article we will review the recent technological advances in PCI that have enabled more complex coronary disease to be treated. The choice of revascularisation strategy must take into account the evidence-just because we can treat by PCI does not necessarily mean we should. When PCI is indicated, a safe, precision PCI approach guided by physiology, imaging and optimal lesion preparation should be the goal to obtain complete revascularisation and a durable long-term result. When these standards are adhered to, the outcomes can be excellent, in even complex coronary disease. We provide contemporary trial evidence to justify PCI and treatment algorithms that ensure optimal revascularisation decision making to achieve the best patient outcomes.

Impact of different coronary angioscopic findings on arterial healing one year after bioresorbable-polymer and second-generation durable-polymer drug-eluting stent implantation

BACKGROUND

The advantage of using bioresorbable-polymer drug-eluting stent (BP-DES) compared with second-generation durable-polymer drug-eluting stent (2G DP-DES) still remains controversial in clinical situations. The purpose of this study to evaluate the degree of re-endothelialization and the prevalence of high-grade yellow-colored plaque (YCP), which might concern arterial healing after BP-DES and 2G DP-DES implantation using a high-resolution coronary angioscopy (CAS).

METHODS

In total, 104 DESs (52: 2G DP-DES and 52: BP-DES) were prospectively observed using CAS 12±1 months after coronary intervention. The grade of neointimal coverage (NIC) over the stent was scored on a 4-point scale from 0 (no coverage) to 3 (complete coverage). YCP grade was also scored on a 4-point scale as 0 (white) to 3 (intensive yellow). High-grade YCP was defined as maximum grade ≥2. Moreover, the prevalence of high-grade YCP and the incidence of thrombus were investigated.

RESULTS

BP-DES revealed better dominant NIC grade and less NIC heterogeneity than 2G DP-DES (p=0.0001 and p=0.015, respectively). The prevalence of high-grade YCP was lower for BP-DES than for 2G DP-DES (p=0.05). However, the incidence of thrombus was not significantly different (p=0.41). Multivariate analysis identified that low-density lipoprotein cholesterol levels [odds ratio (OR), 1.03; 95% Confidence Interval (CI): 1.01-1.06, p=0.01] and the usage of BP-DES [OR, 0.36; 95% CI: 0.14-0.91, p=0.03] as independent predictors of high-grade YCP.

CONCLUSIONS

Compared with 2G DP-DES, BP-DES was less heterogeneous and well-covered NIC and less prevalence of the high-grade YCP implying optimal arterial healing.

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.

One-year clinical results of the NANO registry: A multicenter, prospective all-comers registry study in patients receiving implantation of a polymer-free sirolimus-eluting stent

OBJECTIVES

We aimed to evaluate the safety and efficacy of Nano+™ (Lepu Medical, Beijing, China) stent implantation in all-comer patients at the 1-year follow-up.

BACKGROUND

The Nano+™ stent is a novel polymer-free sirolimus-eluting stent polymer that employs nanoporous stent surface technology to control drug-delivery. The Nano+™ stent is one of the most widely used drug-eluting stent (DES) in China.

METHODS

A total of 2,481 consecutive patients were included in the multicenter and prospective NANO registry. In this study, the primary endpoint was target lesion failure (TLF) at 1-year follow-up, defined as a composite of cardiac death, target vessel nonfatal myocardial infarction (TV-MI), and clinically driven target lesion revascularization (TLR). The safety endpoint was the occurrence of definite or probable stent thrombosis (ST).

RESULTS

Up to 40.2% of patients presented with acute myocardial infarction (AMI). A total of 63.9% of the 2,904 lesions were American College of Cardiology/American Heart Association (ACC/AHA) type B2 or C lesions. One-year follow-up data were available for 98.4% of patients. The 1-year rate of TLF was 3.1% with rates of 1.3, 1.8, and 0.4% for clinically driven TLR, cardiac death, and TV-MI, respectively. ST occurred in 0.4% of patients. Diabetes mellitus, AMI, left ventricular ejection fraction <40% and long lesions (>40 mm) were independent predictors of 1-year TLF.

CONCLUSIONS

The 1-year clinical outcomes were excellent for Nano+™ polymer-free SES implantation in an all-comer patient population. Follow-up will be extended up to 5 years, to further elucidate the potential long-term clinical benefits.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02929030.

Biodegradable-Polymer Versus Polymer-Free Drug-Eluting Stents for the Treatment of Coronary Artery Disease

BACKGROUND/PURPOSE

Biodegradable-polymer (BP) and polymer-free (PF) drug eluting stents (DES) were developed to reduce the risk of delayed arterial healing observed with durable-polymer (DP) platforms. Although trials demonstrate BP-DES and PF-DES are non-inferior to DP-DES, there is limited data directly comparing these technologies. We performed a meta-analysis to assess the efficacy and safety of BP-DES versus PF-DES for the treatment of coronary artery disease.

METHODS/MATERIALS

Electronic searches were performed identifying randomized trials comparing BP-DES with PF-DES. Co-primary efficacy endpoints were target vessel revascularization (TVR), target lesion revascularization (TLR) and angiographic in-stent late lumen loss (LLL). Co-secondary safety endpoints were all-cause death, myocardial infarction (MI) and stent thrombosis (ST).

RESULTS

Of 208 studies, 5 met inclusion criteria including 1975 patients. At mean follow-up (14 ± 5 months), BP-DES were associated with significantly reduced rates of TVR (OR 0.58, 95%CI 0.37-0.92, p = 0.02), TLR (4.7% vs 9.5%) (OR 0.48, 95%CI 0.31-0.75, p = 0.001) and in-stent LLL (pooled mean difference -0.20 mm, 95%CI -0.24 to -0.16, p < 0.001). There was no difference in safety, including all-cause death (OR 1.24, 95%CI 0.68-2.28, p = 0.48), MI (OR 0.92, 95%CI 0.54-1.56, p = 0.75) or ST (OR 1.58, 95%CI 0.67-3.73, p = 0.30).

CONCLUSIONS

These data suggests that BP-DES are more efficacious when compared with PF-DES for the treatment of CAD.