Acute thrombogenicity of fluoropolymer coated stents versus competitive drug-eluting stents under single antiplatelet therapy

Durable versus biodegradable polymer drug-eluting stents in all-comers

BACKGROUND

Drug-eluting stents (DESs) have become the gold standard of coronary angioplasty since their inception in 2002. Biodegradable polymer DESs (BP-DESs) have been postulated to be superior to durable polymer DESs (DP-DESs) due to their more biocompatible polymer. To date, no study has shown the superiority of one type of polymer compared with the other. We aimed to compare outcomes between a broad range of second-generation DP-DES and BP-DES in an all-comer population.

METHODS

We analysed data from 2824 patients who underwent percutaneous coronary intervention (PCI) with BP-DES or DP-DES in the Cardio-FR database. Of these, 2079 (1286 DP-DES and 793 BP-DES) met the inclusion and exclusion criteria and completed a 2-year follow-up: The primary outcome was the device-oriented composite endpoint (DOCE) of cardiac death, non-fatal target vessel myocardial infarction and target lesion revascularisation.

RESULTS

Mean age was 67 years, with 75% male. Despite the DP-DES group exhibiting significantly higher rates of risk factors, such as arterial hypertension (63.1% vs 57.5%, p=0.010), a greater average number of stents implanted per patient (1.72±0.92 vs 1.63±0.84, p=0.040), more acute coronary syndrome (ACS) (55.1% vs 50.2%, p=0.031) and a higher rate of post-dilatation (42.2% vs 35.2%, p<0.001), the rate of acute stent thrombosis (ST) was significantly lower than in the BP-DES group (HR 0.240, 95% CI 0.075 to 0.766; p=0.016). This difference remained significant even after adjusting for covariates using a Cox proportional hazards model and performing a win ratio analysis (4.09, 95% CI 1.28 to 13.09; p=0.018). Despite this increased rate of acute ST, there was no difference in DOCE (12.1% vs 14.5%, OR 1.218, 95% CI 0.926 to 1.600; p=0.158) between the two groups up to 2 years.

CONCLUSION

Clinical follow-up up to 2 years shows similar outcomes between BP-DES and DP-DES. The rate of acute ST is higher in patients with BP-DES.

Dual antiplatelet therapy duration and stent type in patients with high bleeding risk: A systematic review and network meta-analysis

BACKGROUND

It is uncertain whether the efficacy and safety of dual antiplatelet therapy (DAPT) in patients with high bleeding risk (HBR) vary according to DAPT duration and stent type (eg, durable polymer drug-eluting stents (DP-DESs), biodegradable polymer DESs (BP-DESs), or polymer-free drug-coated stents (PF-DCSs)). We aimed to study the stent type and DAPT duration appropriate for patients with HBR.

METHODS

PubMed and EMBASE were searched until October 2023. Randomized controlled trials (RCTs) involving patients with HBR that compared standard DAPT (6-12 months) with DP- or BP-DES versus short DAPT (≤3 months) with DP- or BP-DES or PF-DCS or bare-metal stent (BMS) were identified. The primary efficacy outcome was major adverse cardiovascular events (MACEs), defined as cardiovascular death, myocardial infarction (MI), and stroke. The primary safety outcome was major bleeding. Secondary outcomes included MI and stent thrombosis (ST). We performed a network meta-analysis using a random effects model.

RESULTS

Thirteen RCTs with a total of 19,418 patients with HBR were included. Compared to standard DAPT with DP-DES, short DAPT with BMS was associated with a higher risk of MACE and MI. For major bleeding, short DAPT strategies were associated with a lower risk than standard DAPT strategies (e.g. short DAPT with DP-DES vs standard DAPT with DP-DES; HR[95% CI]: 0.48[0.28-0.82]). Interestingly, the use of BP-DES was associated with a higher risk of ST than DP-DES (e.g. standard DAPT with BP-DES vs short DAPT with DP-DES; HR[95% CI]: 2.65[1.03-6.79]).

CONCLUSIONS

In patients with HBR who underwent percutaneous coronary intervention, a short DAPT strategy with DP-DES should be used since it offers the best combination of efficacy and safety.

Challenges and advances in device-related thrombus in left atrial appendage occlusion

Oral anticoagulation therapy (OAC) is a mainstay for mitigating stroke and other embolic events in patients with atrial fibrillation (AF). Despite the demonstrated efficacy of OAC in reducing events, many patients are unable to tolerate OAC due to bleeding risks. Left atrial appendage occlusion (LAAO) devices were developed as implantable technologies to moderate stroke risk in patients with intolerance to OAC. Despite clinical data supporting near-comparable protection against thromboembolic events with OAC, device-related thrombus formation has emerged as a critical complication following LAAO that remains a potential limitation to the safety and efficacy of LAAO. Improved biocompatibility of LAAO devices with fluoropolymers, a well-established stent-coating technology used to reduce thrombus formation and promote endothelialization, may optimize outcomes after LAAO.

Comparison of thrombogenicity in different types of drug-eluting stents during transition from DAPT to SAPT

BACKGROUND

During the transition from dual antiplatelet therapy (DAPT) to single antiplatelet therapy (SAPT), previous studies have raised concerns about a rebound effect. We compared platelet and inflammatory cell adhesion on different types of stents in the setting of clopidogrel presence and withdrawal.

METHODS

In Experiment 1, three pigs were administered with DAPT, that is, clopidogrel and acetylsalicylic acid (ASA), for 7 days. Each animal underwent an extracorporeal carotid arteriovenous shunt model implanted with fluoropolymer-coated everolimus-eluting stent (FP-EES), biodegradable-polymer sirolimus-eluting stent (BP-SES), and biodegradable-polymer everolimus-eluting stents (BP-EES). In Experiment 2, two pigs were administered DAPT, clopidogrel was then withdrawn at day 7, and SAPT with ASA was continued for next 21 days. Then flow-loop experiments with the drawn blood from each time point were performed for FP-EES, BioLinx-polymer zotarolimus-eluting stents (BL-ZES), and BP-EES. The rebound effect was defined as the statistical increase of inflammation and platelet adhesion assessed with immunohistochemistry on the stent-strut level basis from baseline to day-14 or 28.

RESULTS

Both experiments showed platelet adhesion value was highest in BP-EES, while the least in FP-EES during DAPT therapy. There was no increase in platelet or inflammatory cell adhesion above baseline values (i.e., no therapy) due to the cessation of clopidogrel on the stent-strut level. Monocyte adhesion was the least for FP-EES with the same trend observed for neutrophil adhesion.

CONCLUSIONS

No evidence of rebound effect was seen after the transition from DAPT to SAPT. FP-EES demonstrated the most favorable antithrombotic and anti-inflammatory profile regardless of the different experimental designs.

Enhanced Thromboresistance and Endothelialization of a Novel Fluoropolymer-Coated Left Atrial Appendage Closure Device

BACKGROUND

Device-related thrombus (DRT) after left atrial appendage closure (LAAC) procedures is a rare but potentially serious event. Thrombogenicity and delayed endothelialization play a role in the development of DRT. Fluorinated polymers are known to have thromboresistant properties that may favorably modulate the healing response to an LAAC device.

OBJECTIVES

The goal of this study was to compare the thrombogenicity and endothelial coverage (EC) after LAAC between the conventional uncoated WATCHMAN FLX (WM) and a novel fluoropolymer-coated WATCHMAN FLX (FP-WM).

METHODS

Canines were randomized for implantation with WM or FP-WM devices and given no postimplant antithrombotic/antiplatelet agents. The presence of DRT was monitored by using transesophageal echocardiography and verified histologically. The biochemical mechanisms associated with coating were assessed by using flow loop experiments to quantify albumin adsorption, platelet adhesion, and porcine implants to quantify EC and the expression of markers of endothelial maturation (ie, vascular endothelial-cadherin/p120-catenin).

RESULTS

Canines implanted with FP-WM exhibited significantly less DRT at 45 days than those implanted with WM (0% vs 50%; P < 0.05). In vitro experiments showed significantly greater albumin adsorption (52.8 [IQR: 41.0-58.3] mm2 vs 20.6 [IQR: 17.2-26.6] mm2; P = 0.03) and significantly less platelet adhesion (44.7% [IQR: 27.2%-60.2%] vs 60.9% [IQR: 39.9%-70.1%]; P < 0.01) on FP-WM. Porcine implants showed significantly greater EC by scanning electron microscopy (87.7% [IQR: 83.4%-92.3%] vs 68.2% [IQR: 47.6%-72.8%]; P = 0.03), and higher vascular endothelial-cadherin/p120-catenin expression after 3 months on FP-WM compared with WM.

CONCLUSIONS

The FP-WM device showed significantly less thrombus and reduced inflammation in a challenging canine model. Mechanistic studies indicated that the fluoropolymer-coated device binds more albumin, leading to reduced platelet binding, less inflammation, and greater EC.

Overcoming challenges in refining the current generation of coronary stents

INTRODUCTION

Late stent thrombosis caused by delayed vascular healing and prolonged local inflammation were major drawbacks of 1^st generation drug-eluting stents (DES). Strut design, biocompatibility of polymer, and drug-release profiles were improved in 2^nd and 3rdgeneration DES. Accordingly, the indications for percutaneous coronary intervention with DES have been expanded to more complex patients and lesions. Despite these improvements, significant barriers such as greater flexibility in the duration of dual-antiplatelet therapy (DAPT) as well as reducing long-term stent-related events remain. To achieve ideal short- and long-term results, these existing limitations need to be overcome.

AREAS COVERED

We will discuss the current limitations of coronary DES and how they might be overcome from pathological and clinical viewpoints.

EXPERT OPINION

Optimizing DAPT duration after stent implantation and prevention of in-stent neoatherosclerosis are two major issues in current DES. Overcoming these drawbacks is a prerequisite toward achieving better short- and long-term clinical outcomes. New technologies including platform design, polymer types, and anti-proliferative agent itself might lead to further improvements. Although the initial experience with bioresorbable scaffold/stents (BRS) was disappointing, positive results of clinical studies regarding novel BRS are raising expectations. Overall, further device innovation is desired for overcoming the limitations of current DES.

Comparison between biodegradable- and durable-polymer everolimus-eluting stents in hemodialysis patients with coronary artery disease

To investigate the clinical outcomes after biodegradable-polymer (BP) and durable-polymer (DP) everolimus-eluting stent (EES) implantation in hemodialysis (HD) patients with coronary artery disease. We enrolled 221 consecutive HD patients successfully treated with EES implantation for coronary lesions. Over the following 2 years, we assessed the incidence of target lesion revascularization (TLR) and major adverse cardiac event (MACE), defined as the composite endpoint of TLR, all-cause mortality, or myocardial infarction. We performed a propensity-score matching analysis and collected follow-up coronary angiography data. There were 91 patients in the BP-EES group and 130 in the DP-EES group. Male sex and diabetes rates were significantly lower in the BP-EES group than in the DP-EES group. A debulking device was less frequently used in the BP-EES group than in the DP-EES group (7.6% vs. 21.5%, p = 0.006). TLR occurred in 38 patients, while stent thrombosis was observed in 3 patients; 19 patients died. TLR and MACE rates at 2 years were comparable between the two groups (19.2% in the BP-EES group vs. 20.4% in the DP-EES group, p = 0.73 and 26.9% vs. 34.2%, p = 0.93, respectively). In the propensity-score-matched cohort, TLR and MACE rates were similar between the two groups (19.2% in the BP-EES group vs. 18.1% in the DP-EES group, p = 0.69, and 26.9% vs. 30.2%, p = 0.66, respectively). Restenosis rates at follow-up angiography were similar between the two groups (p = 0.79). In hemodialysis patients, BP-EES and DP-EES showed similar 2-year clinical outcomes.