Abstract
Aim
Self-expanding stents represent a re-emerging option for percutaneous coronary interventions. Their application covers a wide spectrum of angiographic situations, i.e., coronary bifurcations, acute coronary syndromes with large thrombotic burden and stenosis of ectatic coronaries. We review our experience with self-expanding stents for different clinical and angiographic indications, with long clinical follow-up.
Methods
From 2011 to 2013 we used self-expanding STENTYS® stents in 40 consecutive patients followed-up for death from any cause and from cardiovascular cause, myocardial infarction, target lesion revascularization (TLR), stent thrombosis (mean 21 ± 13 months).
We also revised rate of procedural outcomes, acute stent thrombosis and TLR in patients treated with conventional stents for similar clinical/angiographic situations, in the same period at our institution.
Results
We identified three anatomical settings of STENTYS® use: coronary bifurcations with proximal/distal main branch diameter discrepancy (55% of cases), massive thrombotic burden in the setting of acute coronary syndrome (35% of cases) and stenosis of ectatic coronaries (15%). We observed one death related to acute heart failure and 1 case (2.5%) of acute stent thrombosis (2.5% in the control group). During follow-up 2 cases of stent restenosis leading to TLR (5%) occurred (6.25% in the control group).
Conclusions
According to our real life experience, self-expanding STENTYS® stents appear to be an effective tool for different angiographic situations in which they may be preferable to balloon-expandable stents, showing a low rate of complications and good results at long term follow-up.
Highlights
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STENTYS use in different and complex angiographic situations is revised.
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Optimal results in bifurcation lesions as compared with balloon-expandable stents
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Use in acute coronary syndrome with huge thrombotic burden
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Treatment of coronary stenosis in coronary artery ectasia
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Low rate of target lesion revascularization at long term follow-up
1
Introduction
Balloon-expandable stents represent the well-established gold standard technology for percutaneous coronary intervention (PCI) in different angiographic situations. Self-expanding devices were the stents first used in the pioneering era of PCI , but were then replaced by balloon-expanding stents due to a lower rate of stent thrombosis, a more accurate control of dimensions and deployment , and reduced vessel trauma . In recent years, a re-discovery of self-expanding stents has occurred due to improvements in materials and technology, as well as the need to better treat specific angiographic situations. The self-expanding STENTYS® stent is a nitinol (nickel–titanium alloy) stent with a conical shape that, upon deployment, exerts a constant outward force, being very different from the sharp wire ends of the eighty’s self-expanding stents. This device was at first designed for coronary bifurcations as it overcomes the limitation of diameter discrepancy in the main branch and, due to its platform, may be easily crossed thus permitting optimal scaffolding of the side branch. In the OPEN I trial, the first-in-man study, STENTYS® showed excellent procedural success and a relatively low MACE rate, with low late lumen loss; disconnectable struts offered excellent access for side branch stenting with increased gains in stent area over time .
Soon after, STENTYS® was tested in the setting of acute myocardial infarction as its characteristics allow deployment at lower pressures with gentle expansion of the stent during the first 3 days after PCI. This may result in a lower degree of initial barotrauma, and less intrastent and edge dissections with a potential lower occurrence of stent thrombosis and a better conformability for vasoconstricted vessels during myocardial infarction . In the APPOSITION II trial, strut malapposition at 3 days was significantly lower in patients allocated to self-expanding stents compared to balloon-expanding stents.
Coronary artery ectasia (CAE) represents a possible further application of self-expanding stents. CAE is defined as a dilatation of an arterial segment to a diameter 1.5 times larger than that of the adjacent normal coronary artery ; it is a condition that can be found in 3–8% of angiographic series. Only few data have been reported in the literature , showing favorable results with STENTYS®, as confirmed also by intracoronary imaging techniques.
In this study, we aim to report our real life experience with the use of self-expanding STENTYS® in different angiographic and clinical situations, with a long term clinical follow-up.
2
Methods
2.1
Patient population
The aim of this single center study was to assess safety and efficacy of STENTYS® use in an all-comers population with long term clinical follow-up. STENTYS® was used for different clinical (from stable coronary disease to acute coronary syndromes including STEMI) and angiographic indications (coronary bifurcations, massive thrombotic burden, CAE). STENTYS® use was left to operator’s discretion. Patients received 250 mg of aspirin before the intervention or were already receiving long-term treatment. A clopidogrel loading dose of 600 mg was administered in patients who did no present with acute coronary syndrome. In acute coronary syndrome, patients received ticagrelor or prasugrel, unless absolute contraindications to their use were present. Dual-antiplatelet therapy was recommended for at least 1 month in stable patients and for 12 months in NSTEMI and STEMI. Procedural anticoagulation was achieved with unfractioned heparin (70 UI/kg). The local ethics committee approved the research protocol and informed consent was obtained from all patients.
2.2
Study procedure
The STENTYS® coronary stent available at our institution was a self-expanding, nitinol, bare-metal stent with a nominal strut width of 68 μm. The stent lengths were 22 and 27 mm with diameters suitable for vessels with reference vessel diameters between 2.5 and 3.0 mm (small), 3.0 and 3.5 mm (medium), and 3.5 and 4.0 mm (large). The decision to perform pre- and post-dilatation as well as manual thromboaspiration in case of acute thrombotic occlusions, was left to the operator’s discretion.
Lesion length and vessel reference diameter were assessed using online quantitative coronary angiography or visual estimation.
2.3
Primary outcome measures
The primary endpoint was major adverse cardiac events occurrence (MACE; all-cause death, myocardial infarction [MI], target lesion revascularization [TLR] and stent thrombosis). Patients were followed up by telephone or hospital visit. No patient was lost to follow-up. Information regarding time and cause of death was obtained from death certificates, post-mortem reports or by contacting family doctors. Academic Research Consortium (ARC) definitions were used for the evaluation of stent thrombosis.
2.4
Statistical analysis
Continuous variables are presented as means ± standard deviations, while categorical variables are presented as counts and percentages.
We revised our historical series of, respectively, primary angioplasty (about 300/year) and coronary bifurcations PCI with provisional balloon expanding stents in the main branch (about 110/year), for the period 2011–2013. We extracted two groups of patients treated with conventional stents in order to match them with patients who received STENTYS for coronary bifurcations or thrombotic occlusion, respectively. We extracted 36 patients treated with conventional stents for acute thrombotic occlusion (3:1 with the STENTYS group). This group was matched with the STENTYS group for age, gender, coronary segment involved and proximal diameter. All patients had TIMI flow = 0 at baseline. The rate of final TIMI < 3 flow was calculated for both the entire historical group and the control group. We also extracted 44 patients treated with conventional stents for coronary bifurcations (2:1 with the STENTYS group). This group was matched with the STENTYS group for age, gender, Medina classification of the bifurcation lesion. The rate of side branch residual stenosis was calculated for both the entire historical group and the control group. The rate of acute/late stent thrombosis as well as of TLR for both the entire historical group and the aggregate of the two control groups were calculated. Chi-square analysis was used for comparison between self-expanding STENTYS/balloon expanding stents event rates.
2
Methods
2.1
Patient population
The aim of this single center study was to assess safety and efficacy of STENTYS® use in an all-comers population with long term clinical follow-up. STENTYS® was used for different clinical (from stable coronary disease to acute coronary syndromes including STEMI) and angiographic indications (coronary bifurcations, massive thrombotic burden, CAE). STENTYS® use was left to operator’s discretion. Patients received 250 mg of aspirin before the intervention or were already receiving long-term treatment. A clopidogrel loading dose of 600 mg was administered in patients who did no present with acute coronary syndrome. In acute coronary syndrome, patients received ticagrelor or prasugrel, unless absolute contraindications to their use were present. Dual-antiplatelet therapy was recommended for at least 1 month in stable patients and for 12 months in NSTEMI and STEMI. Procedural anticoagulation was achieved with unfractioned heparin (70 UI/kg). The local ethics committee approved the research protocol and informed consent was obtained from all patients.
2.2
Study procedure
The STENTYS® coronary stent available at our institution was a self-expanding, nitinol, bare-metal stent with a nominal strut width of 68 μm. The stent lengths were 22 and 27 mm with diameters suitable for vessels with reference vessel diameters between 2.5 and 3.0 mm (small), 3.0 and 3.5 mm (medium), and 3.5 and 4.0 mm (large). The decision to perform pre- and post-dilatation as well as manual thromboaspiration in case of acute thrombotic occlusions, was left to the operator’s discretion.
Lesion length and vessel reference diameter were assessed using online quantitative coronary angiography or visual estimation.
2.3
Primary outcome measures
The primary endpoint was major adverse cardiac events occurrence (MACE; all-cause death, myocardial infarction [MI], target lesion revascularization [TLR] and stent thrombosis). Patients were followed up by telephone or hospital visit. No patient was lost to follow-up. Information regarding time and cause of death was obtained from death certificates, post-mortem reports or by contacting family doctors. Academic Research Consortium (ARC) definitions were used for the evaluation of stent thrombosis.
2.4
Statistical analysis
Continuous variables are presented as means ± standard deviations, while categorical variables are presented as counts and percentages.
We revised our historical series of, respectively, primary angioplasty (about 300/year) and coronary bifurcations PCI with provisional balloon expanding stents in the main branch (about 110/year), for the period 2011–2013. We extracted two groups of patients treated with conventional stents in order to match them with patients who received STENTYS for coronary bifurcations or thrombotic occlusion, respectively. We extracted 36 patients treated with conventional stents for acute thrombotic occlusion (3:1 with the STENTYS group). This group was matched with the STENTYS group for age, gender, coronary segment involved and proximal diameter. All patients had TIMI flow = 0 at baseline. The rate of final TIMI < 3 flow was calculated for both the entire historical group and the control group. We also extracted 44 patients treated with conventional stents for coronary bifurcations (2:1 with the STENTYS group). This group was matched with the STENTYS group for age, gender, Medina classification of the bifurcation lesion. The rate of side branch residual stenosis was calculated for both the entire historical group and the control group. The rate of acute/late stent thrombosis as well as of TLR for both the entire historical group and the aggregate of the two control groups were calculated. Chi-square analysis was used for comparison between self-expanding STENTYS/balloon expanding stents event rates.
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