|Year : 2023 | Volume
| Issue : 1 | Page : 1-5
The outcome of ultrathin-strut biodegradable polymer-coated sirolimus-eluting stents in coronary artery disease patients – A feasibility study
Prashanth Panduranga, Azzam Mohammed
Department of Cardiology, National Heart Center, Royal Hospital, Muscat, Sultanate of Oman
|Date of Submission||20-May-2022|
|Date of Acceptance||17-Jan-2023|
|Date of Web Publication||23-Feb-2023|
Dr. Prashanth Panduranga
Department of Cardiology, National Heart Center, Royal Hospital, Post Box 1331, Muscat-111
Sultanate of Oman
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Drug-eluting coronary stents with ultrathin struts and biodegradable polymers have been shown to reduce inflammation, neointimal proliferation, and thrombus formation, leading to less early and late complications in patients with coronary artery disease as compared to thinner strut and durable polymer second-generation stents. In Oman, currently, second-generation stents are used for all patients.
Objective: The purpose of this feasibility study was to evaluate the clinical safety and performance of ultrathin-strut (60 μm) biodegradable polymer-coated sirolimus-eluting stents in an all-comers patient population.
Methods: This was a prospective, observational, single-center, and single-arm investigator-initiated study from August 2018 to August 2019. Inclusion criteria: 18 years of age, patients with symptomatic coronary artery disease indicated for percutaneous coronary intervention, and stenting of at least one coronary lesion. All patients were followed clinically or telephonically at 12 months after the index procedure.
Results: A total of 88 patients were recruited in the study, but 10 patients were lost to follow-up and hence excluded from the analysis. The overall mean age was 63 ± 13 years and 78% were males. The main comorbid conditions were hypertension (58%), diabetes mellitus (49%), and hyperlipidemia (26%). Fifty-three percent presented with unstable angina or non-ST elevation myocardial infarction (MI), 10% with ST elevation MI, recent MI 16%, 18% with stable angina, and 1.3% in cardiogenic shock. The mean left ventricular ejection fraction of the cohort was 46 ± 14%. Angiographically, Type A lesions were seen in 25%, Type B in 32%, and Type C in 42%. Left anterior descending stenting was done in 44%, right coronary artery in 32%, left circumflex artery in 14%, left main in 5%, and graft stenting in 4%. Device success was 96%. Procedural success was seen in 97% of patients. At 1-year follow-up, 93% were asymptomatic; overall device-oriented clinical events were 6.8% including cardiac death in 2.7%, target-vessel MI in 2.7%, and target-lesion revascularization in 1.3% which all occurred in uncontrolled diabetic patients.
Conclusions: At index admission and 1 year, ultrathin-strut biodegradable polymer-coated sirolimus-eluting stent study showed low device-related adverse clinical events which are comparable to published data for the second-generation stents. This feasibility study shows that these stents can be used in all types of stent-indicated patients with added advantages of biodegradable polymer and ultrathin struts. In addition, measures to prevent, diagnose, and control diabetes need to be taken in Oman as this cohort of patients develop ST after stenting.
Keywords: Biodegradable polymer, stent, ultrathin strut
|How to cite this article:|
Panduranga P, Mohammed A. The outcome of ultrathin-strut biodegradable polymer-coated sirolimus-eluting stents in coronary artery disease patients – A feasibility study. Heart Views 2023;24:1-5
|How to cite this URL:|
Panduranga P, Mohammed A. The outcome of ultrathin-strut biodegradable polymer-coated sirolimus-eluting stents in coronary artery disease patients – A feasibility study. Heart Views [serial online] 2023 [cited 2023 Mar 24];24:1-5. Available from: https://www.heartviews.org/text.asp?2023/24/1/1/370259
| Introduction|| |
Second-generation drug-eluting stents (DESs) with thin struts (<100 μm) and durable polymer are known to reduce myocardial infarction (MI) and in-stent thrombosis (IST) when compared to first-generation thick strut (~140 μm) durable polymer stents. However, several studies have demonstrated late or very late stent thrombosis (ST) due to polymer-mediated inflammatory or hypersensitivity reactions together with delayed healing and incomplete re-endothelialization.,, This led to the development of DES with ultra-thinner struts (defined as strut thickness <70 μm) and biodegradable polymers which have controlled release of drug elution and gradual degradation of the polymer, which has been shown to reduce inflammation, neointimal proliferation, and thrombus formation, leading to less early and late complications in patients with coronary artery disease. In addition, there is added advantage of increased deliverability of the stent in complex lesions and reduced very late ST. In Oman, currently, second-generation stents are used for all patients.
The purpose of this feasibility study was to evaluate the clinical safety and performance of ultrathin-strut (60 μm) biodegradable polymer-coated sirolimus-eluting stents in an all-comers patient population.
This is a prospective, observational, single-center, and single-arm investigator-initiated study from August 2018 to August 2019 with follow-up up to August 2020 at National Heart Center, Royal Hospital, Oman.
Eighteen years of age; patients with symptomatic coronary disease including stable angina and acute coronary syndromes; patients with a clinical indication for percutaneous coronary intervention (PCI) and stenting of at least one coronary lesion, visually confirmed on coronary angiography were included in the analysis.
Patients have a known hypersensitivity or contraindication to aspirin, clopidogrel, heparin, cobalt chromium, sirolimus, or contrast media; patients scheduled to undergo elective noncardiac surgery within 6 months postindex PCI; and Incomplete data on follow-up were excluded from the analysis.
Coronary angioplasty and stenting were done as per the standard practice from either the femoral or radial approach. All new patients received dual-antiplatelet therapy (DAPT), including a loading dose of aspirin (300 mg) and clopidogrel (600 mg). Transferred patients from other hospitals were on aspirin 75 mg once daily and clopidogrel 75 mg once daily. Procedural anticoagulation was achieved with unfractionated heparin and intraprocedural administration of glycoprotein IIb/IIIa inhibitor (tirofiban) was used at the operator's discretion. All patients were advised to maintain DAPT (aspirin 75 mg daily lifelong and clopidogrel 75 mg daily for 1 year) after the procedure. CE-approved sirolimus-eluting Supraflex (S-flex) stent was implanted for the culprit lesion. Other lesions have additional stents at the operator's discretion.
Device-oriented composite endpoint (DOCE): A composite endpoint of cardiac death, target vessel MI, and target lesion revascularization (TLR). Reinterventions inside the stent or within 5 mm proximally or distally to the stent were defined as TLR.
Device success (Up to discharge)
Successful delivery and deployment of the stent (s) at the intended target lesion and successful withdrawal of the stent delivery system with the attainment of final residual stenosis of <20% by visual estimation.
Procedure success (Up to 7 days after procedure)
Successful delivery and deployment of stent (s) without the occurrence of an ischemia-driven major cardiac event during the hospital stay to a maximum of the first 7-day postindex procedure. Stent thrombosis rates according to Academic Research Consortium classification.
Data were collected from the electronic medical records and entered in the case report form. All clinically relevant baseline variables were recorded. The procedural and clinical in-hospital data were collected from the case records. The Ministry of Health ethical approval was obtained (Ethical approval No: SRC#91/2018). All patients were followed clinically or telephonically at 12 months after the index procedure, and their electronic medical records were reviewed and recorded.
Statistical analyses were done for risk factors, clinical presentation, angiographic profile, PCI details, number of stents used, medication use, and in-hospital and 1-year outcome following PCI. Baseline characteristics of patients are summarized in terms of frequencies and percentages for the categorical variables and by means and standard deviation for the continuous variables. All data were processed using the SPSS Statistics (SPSS Statistics Inc., Chicago, Illinois, USA) software version 15.
| Results|| |
A total of 88 patients were recruited in the study, but 10 patients were lost to follow-up and hence excluded from the analysis. Among the 78 patients, in three patients, stent could not be delivered at the intended target lesion resulting in a device success of 96%. [Table 1] shows the baseline characteristics of patients. The overall mean age was 63 ± 13 years and 78% were males. The main comorbid conditions were hypertension (58%), diabetes mellitus (49%), and hyperlipidemia (26%). Fifty-three percent presented with unstable angina or non-ST elevation MI, 10% with ST elevation MI, recent MI 16%, 18% with stable angina, and 1.3% in cardiogenic shock. The mean left ventricular ejection fraction of the cohort was 46 ± 14%. [Table 2] shows the angiographic data. A total of 87 stents were implanted (1.16 ± 0.4 stents per patient) in 75 patients. In three patients with very calcific anatomy, which needed debulking but was unavailable, the stent was attempted to cross but could not.
|Table 1: Baseline characteristics of 75 percutaneous coronary intervention patients|
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|Table 2: Angiographic characteristics of 75 percutaneous coronary intervention patients|
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Angiographically, the majority of patients had type B/C lesions. Type A lesions were seen in 25%, Type B in 32%, and Type C in 42%. Left anterior descending stenting was done in 44%, right coronary artery in 32%, left circumflex artery in 14%, left main in 5%, and graft stenting in 4%. [Figure 1] shows the in-hospital outcome. Procedural success was seen in 97% of patients. There was one in-hospital death due to coronary perforation and an S-flex stent was used as a bailout in addition to other stents implanted; another patient had intracerebral bleed secondary to over-anticoagulation which was managed conservatively and recovered. [Figure 2] shows 1-year outcomes.
|Figure 1: In-hospital outcome (%). TV-MI: Target vessel myocardial infarction, TLR: Target lesion revascularization, ICH: Intracerebral hemorrhage|
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|Figure 2: One-year outcome (%). TV-MI: Target vessel myocardial infarction, TLR: Target lesion revascularization, ICH: Intracerebral hemorrhage|
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At 1-year follow-up, 93% were asymptomatic and overall DOCE was 6.8% including cardiac death in 2.7%, target-vessel MI in 2.7%, and target-lesion revascularization in 1.3%. Definite or probable IST occurred in three patients who were all diabetics (4%) and compliant with DAPT. Two patients had early probable IST with one of them dying suddenly and another lysed but expired due to cardiogenic shock. The third patient had late definite IST treated percutaneously. ISR was seen in 2.7%.
| Discussion|| |
The current study demonstrates that ultrathin strut bioabsorbable polymer stent uses in Oman coronary artery all-comer population be safe and effective for 1 year. Overall DOCE was low similar to published second-generation contemporary stents. However, the DOCE was mainly driven by ST which could be due to the high prevalence of diabetes mellitus.
Royal Hospital/National Heart Center is one of three public tertiary care hospitals in Oman that commonly use second-generation stents for all patients. Second-generation thin strut stents improved flexibility and delivery, with good radial strength and less thrombogenic when compared to thick strut first-generations tents. Furthermore, studies were done to find whether ultrathin-strut DES are better than contemporary stents and these trials showed that ultrathin-strut DES were associated with a 16% reduction in target lesion failure and was also associated with lower rates of ST. In addition to ultrathin strut thickness, studies were done to find whether biodegradable polymers compared to durable polymers improve clinical outcomes, and the results were positive.,,,,
The S-flex stent is an ultrathin (60 μm) cobalt-chromium sirolimus-eluting coronary stent with biodegradable polymer and in many studies has proven safety and efficacy in real-world patients with complex anatomy as in this study.,
Targeted therapy with a localized abluminal groove, low-dose sirolimus-eluting, biodegradable polymer coronary stent (TARGET) all-comers trial comparing a low-dose sirolimus-eluting stent, Firehawk® (MicroPort, Shanghai, China) to the Xience stent, the device success rate reported was 92.4% and 94.8%, respectively. In this study, the device success rate of S-flex was 96%.
In this study, baseline characteristics showed a high-risk cohort of patients with 58% of the patients having hypertension, 49% diabetes mellitus, and a majority of patients having Type B2/C lesions (74.0%).
In the S-flex UK registry, 24% of patients were diabetic indicating a high prevalence of diabetes in Oman patients who were stented. In the S-flex UK registry of 469 patients, at 12 months, the overall major adverse cardiac events (MACE) was 3.9%, there was no definite ST, 1 (0.2%) probable ST, and 3 (0.6%) possible ST which is lower than the current study which could be attributed to a high prevalence of diabetes mellitus in Oman.
In the landmark treatment of atherosclerotic lesions (TALENT) trial from 23 European countries with a head-to-head comparison of S-flex stent versus Xience, the most commonly used second-generation stent, 720 patients received S-flex stent, and 715 patients received Xience stent. At 12 months, the DOCE had occurred in 4.9% in the S-flex group and 5.3% in the Xience group (P for noninferiority < 0.001). Definite or probable ST was 0.8 and 0.9%, respectively. In the TALENT 2-year outcome study, at 2 years, in the intention to treat data set, DOCE occurred in 6.9% of patients treated with S-flex and 7.9% of patients treated with Xience (P = 0.491). The rate of definite/probable ST was also not different between the two stent arms (1.1% vs. 1.3%, P = 0.813).
In a study of S-flex stents, optical coherence tomography analysis showed 98.1% strut coverage at 6 months while it was 91.5% and 94.1% in the PROMUS Element and Xience DES, respectively., In the same study, the S-flex stent had a healing index (percentage of uncovered struts and incomplete stent apposition) of 4.8 which is excellent when compared to the healing index of the biolimus A9-eluting BioMatrix stent at 35, zotarolimus-eluting resolute stent at 18.7, and everolimus-eluting Xience stents at 10.8,, which all reduce the risk of ST.
The major limitation of this study is a nonrandomized observational study of a small patient population with the inherent limitations of such studies. However, the study intended to test the feasibility of this stent in Oman. Furthermore, a few patients lost to follow-up. We were unable to contact some patients from other nationalities as they traveled back home.
| Conclusions|| |
At index admission and 1 year, an ultrathin-strut biodegradable polymer-coated sirolimus-eluting stent study showed low device-related adverse clinical events which are comparable to published data for the second-generation stents. This feasibility study shows that these stents can be used in all types of stent-indicated patients with added advantages of biodegradable polymer and ultrathin struts. In addition, measures to prevent, diagnose, and control diabetes need to be taken in Oman as this cohort of patients develop ST after stenting.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]