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

Long-term outcomes following ultrathin vs thin-strut drug-eluting stents for percutaneous coronary intervention: an updated systematic review and meta-analysis of randomized control trials

OBJECTIVES

Current thin-strut 2nd generation drug eluting stents (DES) are considered as optimal standard of care for revascularization of coronary artery disease (CAD) patients undergoing percutaneous coronary intervention (PCI). Ultrathin (≤ 70 μm strut thickness) strut DES have recently been shown to reduce target lesion failure (TLF) compared to thin-strut DES. Therefore, in order to assess the validity of improved outcomes associated with ultrathin-strut DES, we conducted an updated meta-analysis that includes recently published follow-ups of previously conducted randomized controlled trials (RCTs).

METHODS

MEDLINE and Scopus were queried from their inception to May 2024 to identify studies comparing outcomes between ultrathin and current thin-strut 2nd generation DES groups. A random-effects meta-analysis was conducted to derive risk ratios (RR) from dichotomous data. The primary endpoint was long-term TLF defined as a composite of cardiac death, target vessel myocardial infarction (TV-MI) and clinically driven target lesion revascularization (CD-TLR). The secondary outcome was target-vessel failure (TVF) defined as a composite of cardiac death, TV-MI and clinically driven target-vessel revascularization (CD-TVR).

RESULTS

A total of 17 RCTs (n=22141) with a mean follow-up of 34 months were included. The risk of TLF was significantly lowered in the ultrathin DES group in comparison to thin-strut DES. A significant decrease was also noted in rates of TVF, CD-TLR and CD-TVR in the ultrathin DES vs thin-strut DES group.

CONCLUSION

The results of our analysis demonstrate a significantly reduced risk of TLF in the ultrathin DES group in comparison with thin-strut DES. Ultrathin DES was also associated with a significantly decreased risk of TVF, CD-TLR and CD-TVR.

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.

Drug-Eluting Stents: Technical and Clinical Progress

Drug-eluting stents (DES) demonstrated superior efficacy when compared to bare metal stents and plain-old balloon angioplasty and are nowadays used in almost all percutaneous revascularization procedures. The design of the stent platforms is constantly improving to maximize its efficacy and safety. Constant development of DES includes adoption of new materials used for scaffold production, new design types, improved overexpansion abilities, new polymers coating and, finally, improved antiproliferative agents. Especially nowadays, with the immense number of available DES platforms, it is crucial to understand how different aspects of stents impact the effect of their implantation, as subtle differences between various stent platforms could impact the most important issue-clinical outcomes. This review discusses the current status of coronary stents and the impact of stent material, strut design and coating techniques on cardiovascular outcomes.

Does the use of polymer-free drug eluting stents improve clinical outcomes of patients undergoing percutaneous coronary interventions?

BACKGROUND

Implantation of drug eluting stents (DES) is the mainstay treatment for patients requiring percutaneous coronary intervention (PCI). The polymer coating of DES has been associated with inflammatory response, increased arterial injury and long-term in-stent restenosis and thrombosis. Polymer-free stents (PFS) were designed to overcome limitations of polymer-coated stents (PCS). Our aim was to compare clinical outcomes of patients undergoing PCI with PFS versus contemporary PCS.

METHODS

This is a prospective, open-label registry study enrolling consecutive all-comers patients admitted to a single center and undergoing PCI using contemporary DES. Clinical outcomes were compared between patients treated with PFS and PCS. The primary endpoint was target lesion revascularization (TLR) at 12 months. Subgroup analyses were conducted for diabetic and nondiabetic patients.

RESULTS

Overall, 1664 patients were included: 928 (55.8%) of which were treated with PFS and 736 (44.2%) with PCS for 2046 and 1462 lesions, respectively. At 12 months, TLR rates were not significantly different between the groups (1.7% vs. 2.3% for PFS and PCS, respectively, P = 0.48). The use of PFS did not improve clinical outcomes among diabetic patients in comparison with PCS. Target vessel revascularization and major adverse cardiac events rates were also similar between groups, regardless of diabetes status.

CONCLUSION

Newer generation DES offer excellent results in diabetic and nondiabetic patients without significant differences in outcomes between PCS and PFS.

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.

Long-term follow-up after ultrathin vs. conventional 2nd-generation drug-eluting stents: a systematic review and meta-analysis of randomized controlled trials

AIMS

Contemporary 2nd-generation thin-strut drug-eluting stents (DES) are considered standard of care for revascularization of patients undergoing percutaneous coronary intervention. A previous meta-analysis of 10 randomized controlled trials (RCTs) with 11 658 patients demonstrated a 16% reduction in the 1-year risk of target lesion failure (TLF) with ultrathin-strut DES compared with conventional 2nd-generation thin-strut DES. Whether this benefit is sustained longer term is not known, and newer trial data may inform these relative outcomes. We therefore sought to perform an updated systematic review and meta-analysis of RCTs comparing clinical outcomes with ultrathin-strut DES (≤70 µm strut thickness) with conventional 2nd-generation thin-strut DES.

METHODS AND RESULTS

We performed a random-effects meta-analysis of all RCTs comparing ultrathin-strut DES to conventional 2nd-generation thin-strut DES. The pre-specified primary endpoint was long-term TLF, a composite of cardiac death, myocardial infarction (MI), or clinically driven target lesion revascularization (CD-TLR). Secondary endpoints included the components of TLF, stent thrombosis (ST), and all-cause death. There were 16 eligible trials in which 20 701 patients were randomized. The weighted mean follow-up duration was 2.5 years. Ultrathin-strut DES were associated with a 15% reduction in long-term TLF compared with conventional 2nd-generation thin-strut DES [relative risk (RR) 0.85, 95% confidence interval (CI) 0.76-0.96, P = 0.008] driven by a 25% reduction in CD-TLR (RR 0.75, 95% CI 0.62-0.92, P = 0.005). There were no significant differences between stent types in the risks of MI, ST, cardiac death, or all-cause mortality.

CONCLUSIONS

At a mean follow-up of 2.5 years, ultrathin-strut DES reduced the risk of TLF, driven by less CD-TLR compared with conventional 2nd-generation thin-strut DES, with similar risks of MI, ST, cardiac death, and all-cause mortality.

Heparin/poly-l-lysine nanoplatform with growth factor delivery for surface modification of cardiovascular stents: The influence of vascular endothelial growth factor loading

The rapid re-endothelialization of the vascular stent surface is desirable for preventing thrombosis or reducing restenosis. Many biological factors that promote the biological behavior of endothelial cells have been used for the surface modification of stents. Vascular endothelial growth factor (VEGF), which plays an important role in angiogenesis, induces strong vascular growth. In this study, we investigated different VEGF concentrations (50 to 500 ng/ml) to determine the optimum concentration for biocompatibility. First, VEGF-loaded heparin/poly-l-lysine (Hep-PLL) nanoparticles were created by electrostatic interactions. Then, the VEGF-loaded nanoparticles were immobilized on dopamine-coated 316 L stainless steel (SS) surfaces. The physical and chemical properties of the modified surface were characterized and the biocompatibility was evaluated in vitro. The results indicated that the VEGF-loaded nanoparticles were immobilized successfully on the 316LSS surface, as evidenced by the results of Alcian Blue staining and water contact angle (WCA) measurements. The low platelet adhesion and activation indicated that the modified surfaces had good blood compatibility. The modified surfaces showed a good inhibitory effect on smooth muscle cells, indicating that they inhibited tissue hyperplasia. In addition, the modified surfaces significantly promoted endothelial cell adhesion, proliferation, migration, and biological activity, especially VEGF concentration was 350 ng/ml (NPV350). The optical VEGF concentration of the surface modified Hep-PLL nanoparticles was 350 ng/ml. The proposed method shows promise for potential applications for cardiovascular devices.