Long-term endothelial dysfunction after coronary artery stenting

Coronary vasomotion after treatment with drug-coated balloons or drug-eluting stents: a prospective, open-label, single-centre randomised trial

BACKGROUND

Although recent studies have reported that drug-coated balloons (DCB) are non-inferior to drug-eluting stents (DES) for the treatment of native coronary arteries in a specific population, there is no available information concerning vasomotion after treatment with DCB.

AIMS

The aim of this study was to prospectively compare coronary vasomotion in patients with small coronary artery disease treated with DCB versus DES.

METHODS

Forty-two native lesions (2.0-3.0 mm) treated in our institution were randomly assigned to the DCB arm (n=19) or the bioabsorbable polymer everolimus-eluting stents arm (n=23) after successful predilation. At eight months after treatment, endothelium-dependent and -independent vasomotion was evaluated with intracoronary infusions in incremental doses of acetylcholine (right coronary artery: low dose 5 μg, high dose 50 μg; left coronary artery: low dose 10 μg, high dose 100 μg) and nitroglycerine (200 μg). The mean lumen diameter of the distal segment, beginning 5 mm and ending 15 mm distal to the edge of the treated segment, was quantitatively measured by angiography.

RESULTS

The luminal dimension in the treated segment did not differ between groups at the follow-up angiography. The vasoconstriction after acetylcholine infusion was less pronounced in the DCB arm than in the DES arm (low-dose: 6±13% vs -3±18%, p=0.060; high-dose: -4±17% vs -21±29%, p=0.035). The response to nitroglycerine did not differ between groups (17±13% vs 17±22%, p=0.929).

CONCLUSIONS

Vasoconstriction after acetylcholine infusion in the peri-treated region was less pronounced in the DCB arm than in the DES arm, suggesting that endothelial function in treated coronary vessels could be better preserved by DCB than by new-generation DES.

The impact of percutaneous peripheral interventions on endothelial function

Background: Treatment of symptomatic peripheral artery disease (PAD) through endovascular interventions is the primary revascularization strategy. Interventions restore perfusion but may cause severe injury to the vascular endothelium, which regulates vascular tone. Endothelial dysfunction is involved in the progression of cardiovascular disease, with higher incidences of vascular events. We aimed to determine the impact of percutaneous interventions on change in endothelial function. Patients and methods: Endothelial function was determined using flow-mediated dilation (FMD) before, the day after lower limb intervention with paclitaxel-coated balloons or stent guided interventions and after a six-month follow-up in the target limb, control limb and the systemic circulation in 42 PAD patients aged 70.2±9 years and 66% men. Additionally, macro- and microvascular function were assessed. Results: In PAD patients aged 70.2±9 years and 66% men, we observed an immediate enhancement of macro-, microvascular and endothelial function after endovascular treatment (FMD of superficial femoral artery (SFA) 3.7±0.2% to 4.1±0.1%, n=42, p=0.02), a sustained long-term improvement after 6-months (FMD SFA 3.7±0.2% to 4.2±0.1%, n=42, p=0.01), and moreover an improved systemic endothelial function (FMD brachial artery 4.3±0.1% to 4.7±0.2, n=42, p=0.01) following peripheral interventions. Subgroup analysis however revealed that following paclitaxel-based percutaneous intervention, the paclitaxel dosage applied was inversely related to the chronic improvement in local endothelial function (r=-0.6, n=22, p=0.005) without evidence for systemic effects (r=-0.25, p=0.27). Conclusions: We demonstrate an improved local and systemic endothelial function after treatment of atherosclerotic peripheral disease with a distinguished response after endovascular intervention with higher dosage of applied paclitaxel restraining the benefits. Further studies have to determine the optimal interventional strategy with respect to different treatment modalities to maintain vessel functions.

Bridging Therapy for Acute Stroke as the Initial Manifestation of Takayasu Arteritis: A Case Report and Review of Literature

Takayasu arteritis (TA) is a chronic inflammatory disease involving the aorta and its principal branches. Acute ischaemic stroke (AIS) as the initial manifestation of TA is uncommon. There is little evidence on the efficacy of bridging therapy for AIS induced by TA. A 23-year-old Chinese woman with a suspected stroke presented to our hospital with sudden onset of right-sided weakness, right facial palsy, and aphasia that occurred 1 hour ago. After physical and ancillary examinations, recombinant tissue plasminogen activator was administered to the patient, which led to partial recovery. Her neurological function deteriorated with a large salvageable ischaemic penumbra on computed tomography perfusion. Cerebrovascular angiography showed multiple stenoses in the brachiocephalic trunk, the beginning of the right common carotid artery (CCA), and the bilateral subclavian arteries, as well as occlusion of the left CCA and its branches. Mechanical thrombectomy of the left middle cerebral artery was performed immediately. Percutaneous transluminal balloon angioplasty of the left CCA followed by stent implantation of the proximal left CCA was then performed. A diagnosis of TA was made based on the findings. The patient’s neurological deficit fully recovered with immunosuppressants at the 3 month-follow-up. We report a rare case of a patient with TA initially presenting with AIS treated with bridging therapy with full recovery of neurological function. Bridging therapy should be taken into consideration for AIS in patients with TA. Further study is needed in this regard.

Endothelial Dysfunction and Coronary Vasoreactivity - A Review of the History, Physiology, Diagnostic Techniques, and Clinical Relevance

The fervency for advancement and evolution in percutaneous coronary intervention has revolutionised the treatment of coronary artery disease. Historically, the focus of the interventional cardiologist was directed at the restoration of luminal patency of the major epicardial coronary arteries, yet whilst this approach is evolving with much greater utilisation of physiological assessment, it often neglects consideration of the role of the coronary microcirculation, which has been shown to clearly influence prognosis. In this review, we explore the narrative of the coronary circulation as more than just a simple conduit for blood but an organ with functional significance. We review organisation and physiology of the coronary circulation, as well as the current methods and techniques used to examine it. We discuss the studies exploring coronary artery endothelial function, appreciating that coronary artery disease occurs on a spectrum of disorder and that percutaneous coronary intervention has a latent effect on the coronary circulation with long-term consequences. It is concluded that greater recognition of the coronary artery endothelium and mechanisms of the coronary circulation should further guide revascularisation strategies.

Role of acetylcholine spasm provocation test as a pathophysiological assessment in nonobstructive coronary artery disease

Coronary angiography (CAG) sometimes shows nonobstructive coronary arteries in patients with suspected angina or acute coronary syndrome (ACS). The high prevalence of nonobstructive coronary artery disease (CAD) in those patients has recently been reported not only in Japan but also in Western countries, and is clinically attracting attention. Coronary spasm is considered to be one of the leading causes of both suspected stable angina and ACS with nonobstructive coronary arteries. Coronary spasm could also be associated with left ventricular dysfunction leading to heart failure, which could be improved following the administration of calcium channel blockers. Because we rarely capture spontaneous attacks of coronary spasm with electrocardiograms or Holter recordings, an invasive diagnostic modality, acetylcholine (ACh) provocation test, can be useful in detecting coronary spasm during CAG. Furthermore, we can use the ACh-provocation test to identify high-risk patients with coronary spasm complicated with organic coronary stenosis, and then treat with intensive care. Nonobstructive CAD includes not only epicardial coronary spasm but also microvascular spasm or dysfunction that can be associated with recurrent anginal attacks and poor quality of life. ACh-provocation test could also be helpful for the assessment of microvascular spasm or dysfunction. We hope that cardiologists will increasingly perform ACh-provocation test to assess the pathophysiology of nonobstructive CAD.

Changes in Index of Microcirculatory Resistance during PCI in the Left Anterior Descending Coronary Artery in Relation to Total Length of Implanted Stents

Aim

To investigate the relationship between stent length and changes in microvascular resistance during PCI in stable coronary artery disease (CAD).

Methods and Results

We measured fractional flow reserve (FFR), index of microcirculatory resistance (IMR), and coronary flow reserve (CFR) before and after stenting in 42 consecutive subjects with stable coronary artery undergoing PCI with stent in the LAD. Patients that had very long stent length (38–78 mm) had lower FFR before stenting than patients that had long (23–37 mm) and moderate (12–22 mm) stent length (0.59 (±0.16), 0.70 (±0.12), and 0.75 (±0.07); p=0.002). FFR improved after stenting and more so in subjects with very long stent length compared to long and moderate stent length (0.27 (s.d ± 16), 0.15 (s.d ± 0.12), and 0.12 (s.d ± 0.07); p for interaction = 0.013). Corrected IMR (IMR_corr) increased after stenting in subjects who had very long stent length, whereas IMR_corr was lower after stenting in subjects who had long or moderate stent length (4.6 (s.d. ± 10.7), −1.4 (s.d. ± 9,9), and −4.2 (s.d. ± 7.8); p for interaction = 0.009).

Conclusions

Changes in IMR during PCI in the LAD in stable CAD seem to be related to total length of stents implanted, possibly influencing post-PCI FFR. Larger studies are needed to confirm the relationship.

Prior Percutaneous Coronary Interventions May Be Associated With Increased Mortality After Coronary Bypass Grafting: A Meta-Analysis

There is conflicting evidence for adverse outcomes after coronary artery bypass surgery (CABG) with prior percutaneous intervention (PCI). A literature search was performed from 1998 to 2017 and articles with primary or secondary outcomes of survival, major adverse cardiovascular events (MACE), and myocardial infarction in CABG patients with prior PCI were included. Forest plots were generated from odds ratios for survival, MACE, and myocardial infarction for unmatched and propensity-matched data. Heterogeneity between studies was assessed for all outcomes using I². Funnel plots were generated for early survival, survival at 5 years, survival at >5 years, and MACE. Thirty-one studies were included over 18 years with 194,544 patients without PCI prior to CABG and 23,519 patients (12.09%) with prior PCI. Prior PCI did not adversely affect survival among the included studies (inverse rate ratio: 1.12, 95% confidence interval: 0.98-1.27, P = 0.110. MACE was significantly worse for those with prior PCI (odds ratio: 1.26, confidence interval: 1.02-1.55, P = 0.03). The relative risk of mortality associated with prior PCI has decreased significantly over the last 2 decades. Studies with higher percentage of prior PCI patients had higher relative mortalities. There was significant heterogeneity between studies for the treatment effects. PCI prior to CABG in recent times does not adversely affect survival despite adverse early and late MACE rates. However, high institutional rates of prior PCI may be associated with increasing mortality after CABG.

Endothelial Function: A Short Guide for the Interventional Cardiologist

An impaired function of the coronary endothelium is an important determinant of all stages of atherosclerosis, from initiation, to mediation of functional phenomena—such as spasm and plaque erosion, to atherothrombotic complications. Endothelial function is modified by therapies, including stent implantation. Finally, endothelial function changes over time, in response to physical stimuli and pharmocotherapies, and its assessment might provide information on how individual patients respond to specific therapies. In this review, we describe the role of the endothelium in the continuum of coronary atherosclerosis, from the perspective of the interventional cardiologist. In the first part, we review the current knowledge of the role of endothelial (dys)function on atherosclerotic plaque progression/instabilization and on the mechanisms of ischemia, in the absence of coronary artery stenosis. In the second part of this review, we describe the impact of coronary artery stenting on endothelial function, platelet aggregation, and inflammation.

Comparison of endothelial cell attachment on surfaces of biodegradable polymer-coated magnesium alloys in a microfluidic environment

Polymeric coatings can provide temporary stability to bioresorbable metallic stents at the initial stage of deployment by alleviating rapid degradation and providing better interaction with surrounding vasculature. To understand this interfacing biocompatibility, this study explored the endothelial-cytocompatibility of polymer-coated magnesium (Mg) alloys under static and dynamic conditions compared to that of non-coated Mg alloy surfaces. Poly (carbonate urethane) urea (PCUU) and poly (lactic-co-glycolic acid) (PLGA) were coated on Mg alloys (WE43, AZ31, ZWEKL, ZWEKC) and 316L stainless steel (316L SS, control sample), which were embedded into a microfluidic device to simulate a vascular environment with dynamic flow. The results from attachment and viability tests showed that more cells were attached on the polymer-coated Mg alloys than on non-coated Mg alloys in both static and dynamic conditions. In particular, the attachment and viability on PCUU-coated surfaces were significantly higher than that of PLGA-coated surfaces of WE43 and ZWEKC in both static and dynamic conditions, and of AZ31 in dynamic conditions (P<0.05). The elementary distribution map showed that there were relatively higher Carbon weight percentages and lower Mg weight percentages on PCUU-coated alloys than PLGA-coated alloys. Various levels of pittings were observed underneath the polymer coatings, and the pittings were more severe on the surface of Mg alloys that corroded rapidly. Polymer coatings are recommended to be applied on Mg alloys with relatively low corrosion rates, or after pre-stabilizing the substrate. PCUU-coating has more selective potential to enhance the biocompatibility and mitigate the endothelium damage of Mg alloy stenting.

Treatment of Danhong Injection Combined with Naoxintong Capsule in Acute Coronary Syndrome Patients Undergoing PCI Operation: Study for a Randomized Controlled and Double-Blind Trial

Objective

This double-blind and randomized placebo-controlled trial evaluated the safety and efficacy of Danhong injection combined with Naoxintong capsule in patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI).

Methods

ACS patients scheduled to undergo PCI (n = 130) were equally and randomly apportioned to either a treatment or control group. After PCI, the treatment group received Danhong injection combined with Naoxintong capsule for 12 weeks, while the control group was given placebo. Both groups were otherwise treated with conventional secondary prevention of coronary artery disease. The groups were primarily evaluated for clinical efficacy and cardiovascular events. Evaluative indicators of safety included adverse events, platelet count, and liver, renal, and blood coagulation functions.

Result

No cardiovascular events or adverse reactions were observed in either group. The treatment group demonstrated better signs of clinical efficacy, including left ventricular ejection fraction, higher nitric oxide levels, and lower levels of endothelin-1 (ET-1) and von Willebrand factor (VWF).

Conclusion

ACS patients treated with Danhong injection combined with Naoxintong capsule after PCI demonstrated better improvement with regard to markers associated with atherosclerosis and adverse cardiovascular events, without apparent adverse effects. Thus, Danhong injection combined with Naoxintong capsule was safe and effective for treating ACS patients after PCI.

Multianalysis with optical coherence tomography and vasomotion in everolimus-eluting stents and everolimus-eluting biovascular scaffolds: the MOVES trial

Aims

To compare endothelium-dependent vasomotor function and vascular healing 15 months after implantation of two new-generation drug-eluting stents and biovascular scaffolds (BVS).

Methods and results

A total of 28 patients previously treated with a SYNERGY stent (bioabsorbable polymer everolimus-eluting stents (BP-EES)), a PROMUS stent (persistent polymer everolimus-eluting stents (PP-EES)) or an ABSORB (BVS) underwent control coronary angiography, 15 months after implantation, coupled with optical coherence tomography imaging and supine bicycle exercise. Intracoronary nitroglycerin was administered after exercise testing. Coronary vasomotor response was assessed using quantitative coronary angiography at rest, during supine bicycle exercise and after nitroglycerin. The primary end point was the percent change in mean lumen diameter compared with baseline. Secondary end points were strut coverage and apposition.There were no significant differences in vasomotor response between the three treatment groups. Patients with PP-EES showed significant vasoconstriction of the proximal peristent segment at maximum exercise (P=0.02). BP-EES (2.7%, 95% CI 0 to 5.5) and BVS (3.2%, 95% CI 0 to 6.7) showed less uncovered struts than PP-EES (12.1%, 95% CI 2.9 to 21.3, P=0.02 and 0.09, respectively). Complete strut apposition was more frequently seen with BP-EES (99.6%, 95% CI 99.2 to 100) than with BVS (98.9%, 95% CI 98.2 to 99.6, P=0.04) or PP-EES (95.0%, 95% CI 91.6 to 98.5, P=0.001).

Conclusion

BVS and thin strut BP-EES have a reassuring vasomotion profile, suggesting minimal endothelial dysfunction 15 months after implantation.

Preserved endothelial vasomotor function after everolimus-eluting stent implantation

AIMS

To compare the degree of endothelial dysfunction (ED) in patients treated with everolimus-eluting stent (EES) versus bare metal stent (BMS) implantation.

METHODS AND RESULTS

This is an observational study. A total of 30 elective patients (15 treated with EES and 15 with BMS) were recruited. All patients underwent coronary angiography and intracoronary acetylcholine (Ach) test at different doses at six months after stent implantation. Quantitative coronary angiography analysis was performed to evaluate the changes in mean luminal diameter (MLD) of the segments distal to the distal stent edge after increasing doses of Ach. Both EES and BMS groups had similar baseline characteristics except for stent length (18.6±2.5 vs. 16.5±2.5 mm; p=0.033) and diameter (3.1±0.2 vs. 3.4±0.3 mm; p=0.007). The vasomotion test showed that EES had 3.14% of MLD decrease after Ach infusion and BMS had 2.35% of vasoconstriction (p=0.62). After adjustment for baseline characteristics, no statistical difference was observed between groups.

CONCLUSIONS

In our study EES implantation was associated with a low degree of ED and had a similar vasomotion response as compared to BMS. Prospective randomised investigations are warranted to confirm these findings.

Endothelial dysfunction and coronary artery disease: a state of the art review

Atherosclerotic coronary artery disease (CAD) is a major cause of morbidity and mortality in the developed world. Endothelial dysfunction plays an important role in the development of atherosclerosis and predicts cardiovascular (CV) outcomes independent of conventional CV risk factors. In recent years, there have been tremendous improvements in the pharmacological prevention and management of CAD. In this review, the pathophysiology of endothelial dysfunction in relation to CAD is discussed and various techniques of invasive and noninvasive assessments of peripheral and coronary endothelial function described. In addition, evidence for the association of endothelial dysfunction and CV outcomes has been examined and finally the role of therapeutic interventions in endothelial dysfunction has been discussed.

The results of treatment in renal artery stenosis due to Takayasu disease: comparison between surgery, angioplasty, and stenting. A monocentrique retrospective study

PURPOSE

To evaluate retrospectively and compare the long-term patency and the antihypertensive effect of open surgery, angioplasty, and stent insertion of the renal artery stenosis due to Takayasu's arteritis.

PATIENTS AND METHODS

We retrospectively analyzed and compared the effects on blood pressure and permeability of the renal artery over 23 patients (age ranging from 16 to 60 years, mean 33.9 years); with renovascular hypertension caused by Takayasu's arteritis. those patients underwent surgical treatment (11 arteries) or endovascular (19) including angioplasty (11) and stenting (8) for 30 stenotic renal arteries.

RESULTS

Technical success was 96.7% (29/30) without major complications (but longer period of hospitalization among patients who had surgery). In the last follow-up CT angiography (mean 60 ± 36 months), restenosis was 18.2% (2/11) in the surgery, 9% (1/11) in the angioplasty, and 62.5% (5/8) in the stenting. Rate of the permeability of the surgery was 100%, 90.9% , 81.8%, the permeability of the angioplasty was 100%, 90.9%, 90.9%, primary patency rate stenting was 62.5%, 37.5%, 37.5%, assists permeability was 87.5%, 75%, 50% at 1, 3 and 5 years, respectively. In the clinical follow-up (mean 60 ± 37.8 months, range 48-96 months) beneficial effects on blood pressure were achieved into 91.3% of patients (21/23), and there was no significant difference between patients who have been treated by surgery and angioplasty alone and the patients who received a stent in at least one renal artery.

CONCLUSION

Angioplasty has shown better long-term patency and a similar clinical benefit of renovascular hypertension in renal artery stenosis caused by Takayasu's arteritis compared with the surgery and the stenting. We suggest that stenting should be reserved in case of clear failure of the angioplasty. The surgery is our choice for patients who do not meet the indication of endovascular treatment or failure of this treatment.

Core-shell PVA/gelatin electrospun nanofibers promote human umbilical vein endothelial cell and smooth muscle cell proliferation and migration

Cardiovascular disease is the leading cause of death in the world. In this study, coaxial electrospinning is employed to fabricate fibers in a core-shell structure with polyvinyl alcohol (PVA) in the core and gelatin in the shell for evaluation as a potential vascular tissue engineering construct. PVA, a synthetic polymer, provides mechanical strength to the biocompatible and weak gelatin sheath. The HUVEC (human umbilical vein endothelial cells) and rSMC (rat smooth muscle cells) demonstrated a flattened morphology with multiple attachment sites on the gelatin and coaxial scaffolds, with an increase in cell spreading seen as mechanical stiffness of the scaffold increased. Additionally, HUVEC had an increase in migration on the coaxial scaffolds, which was attributed to the increase in stiffness; however, this increase in migration was not seen with the rSMC, which had the highest outward migration on the flat surfaces (tissue culture polystyrene and gelatin film). Overall, these scaffolds are appealing substrates for vascular tissue engineering applications.

STATEMENT OF SIGNIFICANCE

The worldwide burden of cardiovascular disease presents an ongoing need and opportunity for creating a variety of vascular prostheses. Fabrication of novel scaffolds and constructs for these are needed, providing strength and biological properties facilitating endothelial (EC) and smooth muscle (SMC) cell attachment, migration, and integration. Using electrospinning we formed 3D core:shell nanofibers and examined their effectiveness as substrates for EC and SMC attachment and growth, compared to a 2D (flat) substrate. We found that ECs attached and grew best on 3D core:shell fibers, whereas SMCs favored 2D gelatin surfaces. Interestingly, we found that EC attachment, migration and growth correlated and improved with increasing fiber stiffness. These materials and insights may foster novel vascular prostheses development.

Comparison of endothelium-dependent and -independent vasomotor response after abluminal biodegradable polymer biolimus-eluting stent and persistent polymer everolimus-eluting stent implantation (COMPARE-IT)

BACKGROUND

Drug-eluting stents (DES) have been associated with local endothelial dysfunction in the segments proximal and distal to the stent (peristent segments) and increased thrombotic risk in long term follow-up. Little data exists on endothelial function post-implantation of new DES with biodegradable polymer. The aim of our study was to compare the local endothelial function assessed by exercise induced coronary vasomotion after implantation of a biolimus A9-eluting stent with biodegradable polymer (BES) with an everolimus-eluting stent with durable polymer (EES).

METHODS

Coronary vasomotion was evaluated with quantitative coronary angiography at rest and during supine bicycle exercise in nine patients with EES and thirteen patients with BES, 16 months after stent implantation. Mean luminal diameter of the stent, peristent segments, and of a control vessel were determined at rest, during exercise, and after the administration of nitroglycerine.

RESULTS

The control vessel showed exercise-induced vasodilatation in both groups (EES: +6.4±5.5%, p=0.07; BES: +7.8±10.1%, p=0.07). Vasomotion in the stented vessel segment was abolished. There was exercise-induced vasoconstriction in both groups in the segments proximal (EES: -9.6±4.5%; p=0.03; BES: -4.3±5.4%, p=0.02) and distal to the stent (EES: -3.2±9.3%; p=0.41, BES -8.6±8.0%, p<0.01). Sublingual nitroglycerin was associated with maximal vasodilatation of the peristent segments in both groups.

CONCLUSION

Alike DES with durable polymer, stents with a biodegradable polymer are associated with exercise-induced paradoxical coronary vasoconstriction of the peristent segments. This data suggests that endothelial dysfunction after DES implantation is not primarily caused by the durability of the polymer coating.

Hemocompatibility of Poly(vinyl alcohol)-Gelatin Core-Shell Electrospun Nanofibers: A Scaffold for Modulating Platelet Deposition and Activation

In this study, we evaluate coaxial electrospun nanofibers with gelatin in the shell and poly(vinyl alcohol) (PVA) in the core as a potential vascular material by determining fiber surface roughness, as well as human platelet deposition and activation under varying conditions. PVA scaffolds had the highest surface roughness (Ra=65.5±6.8 nm) but the lowest platelet deposition (34.2±5.8 platelets) in comparison to gelatin nanofibers (Ra=36.8±3.0 nm and 168.9±29.8 platelets) and coaxial nanofibers (1 Gel:1 PVA coaxial, Ra=24.0±1.5 nm and 150.2±17.4 platelets. 3 Gel:1 PVA coaxial, Ra=37.1±2.8 nm and 167.8±15.4 platelets). Therefore, the chemical structure of the gelatin nanofibers dominated surface roughness in platelet deposition. Due to their increased stiffness, the coaxial nanofibers had the highest platelet activation rate, rate of thrombin formation, in comparison to gelatin and PVA fibers. Our studies indicate that mechanical stiffness is a dominating factor for platelet deposition and activation, followed by biochemical signals, and lastly surface roughness. Overall, these coaxial nanofibers are an appealing material for vascular applications by supporting cellular growth while minimizing platelet deposition and activation.

Evolving management of patients treated by drug-eluting stent: prevention of late events

SUMMARY

Drug eluting stents (DES) were introduced in clinical practice to overcome the problem of in-stent restenosis (ISR) that limited the overall efficacy of percutaneous coronary revascularization with bare metal stent (BMS). Long-term outcome data confirm a sustained benefit of DES as compared with BMS. However, this benefit is mainly evident in the first year of follow-up. Indeed, DES-related events may extend over this time, due to late events (late ISR and/or very late stent thrombosis). Prevention of late failure of DES may become a specific therapeutic target.

Head-to-head comparison of sirolimus-eluting stent versus bare metal stent evaluation of the coronary endothelial dysfunction in the same patient presenting with multiple coronary artery lesions: the CREDENTIAL study

OBJECTIVES

To assess the endothelial dysfunction (ED) after bare metal stents (BMS) and sirolimus eluting stents (SES) implantation in the same patient, overcoming the confounding role of individual variables.

BACKGROUND

SES reduce restenosis rate compared to BMS but causes more ED. ED is a potentially unsafe phenomenon, since it is the first step in the cascade of atherosclerosis. Studies showing more pronounced ED with drug eluting stents than BMS involved different series of patients, making the comparison difficult because endothelial function (EF) is responsive to many risk factors.

METHODS

we designed a prospective comparison of 6 months post-deployment EF of SES versus BMS implanted in the same patient, but in different coronary segments. Forty-eight lesions were randomly assigned on a 1:1 allocation using block sizing of 4 according to a computer-generated sequence (SAS System, Version 9.1) basis to treatment with SES or BMS. The EF was evaluated by measuring vessel diameter variation in the stented segment, before and after selective intracoronary infusion of acetylcholine (iiAch).

RESULTS

In eligible patients, the relative magnitudes of major vasoconstriction were 2.6, 2.9, 4.6, and 3.1 at 5 mm proximal and 5, 10 and 20 mm distal to the stent edge. Overall, a 3.5-fold major distal vasoconstriction after iiAch of SES vs. BMS was calculated.

CONCLUSIONS

in the same patients, but treating different coronary segments, SES implantation induces a higher rate of vasoconstriction compared to BMS. The increased vasoconstriction after iiAch is an indicator of ED.

Time course of endothelium-dependent and -independent coronary vasomotor response to coronary balloons and stents. Comparison of plain and drug-eluting balloons and stents

OBJECTIVES

This study sought to determine the time dependency of the endothelium-dependent and -independent vascular responses after percutaneous coronary intervention (PCI) with drug-eluting (DEB) or plain balloons, bare-metal (BMS), and drug-eluting (DES) stents, or controls.

BACKGROUND

Long-term endothelial dysfunction after DES implantation is associated with delayed healing and late thrombosis.

METHODS

Domestic pigs underwent PCI using DEB or plain balloon, BMS, or DES. The dilated and stented segments, and the proximal reference segments of stents and control arteries were explanted at 5-h, 24-h, 1-week, and 1-month follow-up (FUP). Endothelin-induced vasoconstriction and endothelium-dependent and -independent vasodilation of the arterial segments were determined in vitro and were related to histological results.

RESULTS

DES- and BMS-treated arteries showed proneness to vasoconstriction 5 h post-PCI. The endothelium-dependent vasodilation was profoundly (p < 0.05) impaired early after PCI (9.8 ± 3.7%, 13.4 ± 9.2%, 5.7 ± 5.3%, and 7.6 ± 4.7% using plain balloon, DEB, BMS, and DES, respectively), as compared with controls (49.6 ± 9.5%), with slow recovery. In contrast to DES, the endothelium-related vasodilation of vessels treated with plain balloon, DEB, and BMS was increased at 1 month, suggesting enhanced endogenous nitric oxide production of the neointima. The endothelium-independent (vascular smooth muscle-related) vasodilation decreased significantly at 1 day, with slow normalization during FUP. All PCI-treated vessels exhibited imbalance between vasoconstriction-vasodilation, which was more pronounced in DES- and BMS-treated vessels. No correlation between histological parameters and vasomotor function was found, indicating complex interactions between the healing neoendothelium and smooth muscle post-PCI.

CONCLUSIONS

Coronary arteries treated with plain balloon, DEB, BMS, and DES showed time-dependent loss of endothelial-dependent and -independent vasomotor function, with imbalanced contraction/dilation capacity.

Location-dependent coronary artery diffusive and convective mass transport properties of a lipophilic drug surrogate measured using nonlinear microscopy

PURPOSE

Arterial wall mass transport properties dictate local distribution of biomolecules or locally delivered dugs. Knowing how these properties vary between coronary artery locations could provide insight into how therapy efficacy is altered between arterial locations.

METHODS

We introduced an indocarbocyanine drug surrogate to the lumens of left anterior descending and right coronary (LADC; RC) arteries from pigs with or without a pressure gradient. Interstitial fluorescent intensity was measured on live samples with multiphoton microscopy. We also measured binding to porcine coronary SMCs in monoculture.

RESULTS

Diffusive transport constants peaked in the middle sections of the LADC and RC arteries by 2.09 and 2.04 times, respectively, compared to the proximal and distal segments. There was no statistical difference between the average diffusivity value between LADC and RC arteries. The convection coefficients had an upward trend down each artery, with the RC being higher than the LADC by 3.89 times.

CONCLUSIONS

This study demonstrates that the convective and diffusive transport of lipophilic molecules changes between the LADC and the RC arteries as well as along their length. These results may have important implications in optimizing drug delivery for the treatment of coronary artery disease.

Deformationally dependent fluid transport properties of porcine coronary arteries based on location in the coronary vasculature

OBJECTIVE

Understanding coronary artery mass transport allows researchers to better comprehend how drugs or proteins move through, and deposit into, the arterial wall. Characterizing how the convective component of transport changes based on arterial location could be useful to better understand how molecules distribute in different locations in the coronary vasculature.

METHODS AND RESULTS

We measured the mechanical properties and wall fluid flux transport properties of de-endothelialized (similar to post-stenting or angioplasty) left anterior descending (LADC) and right (RC) porcine coronary arteries along their arterial lengths. Multiphoton microscopy was used to determine microstructural differences. Proximal LADC regions had a higher circumferential stiffness than all other regions. Permeability decreased by 198% in the LADC distal region compared to other LADC regions. The RC artery showed a decrease of 46.9% from the proximal to middle region, and 51.7% from the middle to distal regions. The porosity increased in the intima between pressure states, without differences through the remainder of the arterial thickness.

CONCLUSIONS

We showed that the permeabilities and mechanical properties do vary in the coronary vasculature. With variations in mechanical properties, overexpansion of stents can occur more easily while variations in permeability may lead to altered transport based on location.

The long-term effect of coronary stenting on epicardial and microvascular endothelial function

BACKGROUND

Coronary stents, drug-eluting stents in particular, have been linked to coronary epicardial endothelial dysfunction after implantation. However, less is known about their impact on coronary microvascular function and their long-term effects on the vasculature.

METHODS AND RESULTS

We evaluated 71 patients (mean age, 53.0±10.1 years) with chest pain and angiographically nonsignificant coronary artery disease 17.1±17.1 months after left anterior descending coronary artery stenting. Seventy-one age- and sex-matched patients (mean age, 53.0±10.3 years) with chest pain but no prior coronary intervention served as controls. Coronary blood flow in response to the endothelium-dependent vasodilator acetylcholine as well as the microvascular (endothelium-independent) coronary flow reserve in response to intracoronary adenosine were evaluated. Quantitative coronary angiography was used to study epicardial diameter changes to acetylcholine. Microcirculatory function was not significantly different between the stenting and control groups (median [interquartile range] coronary flow reserve, 2.9 [2.5-3.4] versus 3.0 [2.4-3.4] mL/min, P=0.24; change of coronary blood flow, 34.9% [-34.4% to 90.0%] versus 54.7% [-5.6% to 104.6%], P=0.18). Both groups exhibited epicardial endothelial dysfunction (-23.0% [-47.4% to -7.6%] versus -20.0% [-40.0% to 0.0%], P=0.4). Results did not differ between patients with drug-eluting stents (n=46) and patients with bare-metal stents (n=24).

CONCLUSIONS

This study demonstrates that in patients with coronary arteries in which a stent has been placed, coronary microcirculatory and epicardial vascular function are not significantly different from that of an age- and sex-matched population with similar symptoms but nonsignificant coronary artery disease.

Late Positive Remodeling and Late Lumen Gain Contribute to Vascular Restoration by a Non-Drug Eluting Bioresorbable Scaffold

Background—

The interplay between mechanical dilatation, resorption, and arterial response following implantation of bioresorbable scaffolds is still poorly understood.

Methods and Results—

Long-term geometric changes in porcine coronary arteries in relation to gradual degradation of bioresorbable scaffolds were assessed in comparison with bare metal stents (BMS). Intravascular ultrasound (IVUS)-derived lumen, outer stent/scaffold, and reference vessel areas were evaluated in 94 polymer scaffolds and 46 BMS at 5 days and 3, 6, 12, 18, 24, and 55 months, in addition to polymer scaffold radial crush strength and molecular weight (M W ) at 3, 6, and 12 months. BMS outer stent area and lumen area remained constant through 55 months ( P =0.05, but within 1 standard deviation of 100%, and P =0.58, respectively), while significant increases were exhibited by polymer-scaffolded vessels with the maximum late lumen gain at 24 months, paralleled by the outer scaffold area increase, and then remaining at that increased level at 55 months ( P <0.01). By 12 months polymer scaffolds experienced significant reductions in radial strength and M W , while the animals underwent the largest weight gain. At 3 months and beyond, the patency ratio (lumen area/reference vessel area) of BMS remained constant (0.71 to 0.85, P =0.49). In contrast, that of polymer scaffolds increased and approached 1 ( P =0.13).

Conclusions—

Bioresorbable polymer scaffolds allow restoration of the treated segment's ability to remodel outward to achieve level lumen transition between reference vessel and scaffold-treated regions, a process mediated by animal growth and scaffold degradation. This also introduces a challenge to standard analyses of IVUS outcomes relying on constant stent diameters over time.

Rescue of arterial function by angiotensin-(1-7): towards improvement of endothelial function by drug-eluting stents

PURPOSE

To explore the hypothesis that stent placement decreases dilator function of various arteries outside the stented segment and that angiotensin- (1-7) improves this function, and to assess the contribution of dilator signal compounds. A further objective was to test the hypothesis that on-stent delivery of Ang-(1-7) reduces neointima formation and improves endothelial function.

METHODS

Abdominal aortic stenting or sham operation was performed in the rat four weeks after stenting and treatment with intravenous saline or Ang-(1-7) infusion (24 mug/kg/h); vasomotor function in isolated thoracic aorta and brachial and iliac artery was measured in organ baths. Furthermore, Ang-(1-7)-eluting stents were designed and placed in rat abdominal aorta. Neointima formation and aortic function were tested after four weeks.

RESULTS

Relaxation of the thoracic aorta to metacholine was decreased after stenting compared with shams due to a decrease in nitric oxide-mediated response (67% reduction in maximal NO-dependent response). Ang-(1-7) restored the response mainly through increased prostaglandin- and possibly also endothelial-derived hyperpolarising factor-mediated relaxation. Relaxation in the brachial artery decreased after stenting (maximal response dropped by 50%), whilst contractions to phenylephrine increased. Ang-(1-7) normalised vasomotor function. Iliac artery function remained unaltered after stenting but Ang-(1-7) increased maximal relaxations by 65%. Delivery of Ang-(1-7) by means of a drug-eluting stent improved endothelial function.

CONCLUSION

Stenting differentially affects dilator and contractile function in various arterial beds. Ang-(1-7) both improves dilator function and normalises contractile function. Delivery of protective peptides such as Ang-(1-7) from the stent is a new therapy option that merits further development and exploration. (Neth Heart J 2008;16:293-8.).

Preventing restenosis in early drug-eluting stent era: recent developments and future perspectives

Restenosis is the major limitation of the successful therapy of percutaneous coronary intervention (PCI) for patients with coronary artery disease. The problem was appreciated in the late 1970s to early 1980s. Only in recent years, anti-restenotic therapy has achieved a breakthrough with the development of drug-eluting stents. Here, we provide an overview about pathological mechanisms of restenosis after PCI. Present therapeutic approaches to overcome restenosis and recent clinical results are revisited, and some major concerns in the post-drug-eluting stent era are discussed.

Selective endothelin A-receptor blockade attenuates coronary microvascular dysfunction after coronary stenting in patients with type 2 diabetes

BACKGROUND

Endothelin-1 may be involved in the development of diabetic microangiopathy. We studied the effect of endothelin-1 blockade on myocardial microcirculation during coronary stenting.

PATIENTS AND METHODS

Patients with type 2 diabetes and stable coronary artery disease undergoing elective percutaneous coronary intervention (PCI) were randomized to bolus dose of 500 mg bosentan (n = 4), a dual endothelin receptor blocker, or intracoronary administration of 0.03 mmol BQ123 (n = 6), a selective endothelin A-receptor blocker, or placebo (n = 5), respectively. Coronary flow reserve (CFR) was measured immediately post-PCI. CFR was also measured in five nondiabetic controls post-coronary stenting.

RESULTS

Patients in the placebo group had (P < 0.05) lower values of CFR (2.3 +/- 1.2) as compared to those who received endothelin blockade (n = 10; 3.1 +/- 0.7) and nondiabetic controls (4.9 +/- 2.3). Patients who received BQ123 showed significantly higher CFR (3.3 +/- 0.5; P < 0.05) as compared to those on placebo. Nondiabetic patients had significantly higher CFR as compared to patients with diabetes (4.9 +/- 2.3 and 2.8 +/- 1.0, respectively; P < 0.05).

CONCLUSION

Coronary microvascular dysfunction is present during coronary stenting in patients with type 2 diabetes and may be reversed by selective endothelin A-receptor blockade. Targeting endothelin system may be of importance in protecting the myocardium against ischemic events during elective PCI in type 2 diabetic patients.

Initial evidence for the return of coronary vasoreactivity following the absorption of bioabsorbable magnesium alloy coronary stents

AIMS

To investigate the endothelium independent coronary smooth muscle vasomotor function four months after implantation of magnesium alloy absorbable metal stents (AMS) as part of the Progress-AMS clinical trial (n = 5), compared with a control group of patients implanted with permanent metal stents (PMS) (n = 10) undergoing follow-up angiography, but who were free from angiographic restenosis.

METHODS AND RESULTS

Quantitative coronary angiogram (QCA) using an automated edge detection system was performed before and after the administration of 2 mg intracoronary isosorbide dinitrate (ISDN). The vessel diameter was measured at 0.2 mm intervals throughout the stented segments and a 1 cm proximal reference segment. The cross sectional area (CSA) was calculated before and after the ISDN, averaged and the percentage change measured. Reference segments demonstrated preserved vasomotor function in all cases: +13.28% (AMS) versus +17.15% (PMS), p = 0.39. The mean percentage increase in CSA for the stented segment was +6.78% for the AMS versus -1.30% for PMS, p = 0.003.

CONCLUSION

These data demonstrate that four months after AMS implantation vasomotor function in reference segments is no different to that observed with PMS. However in contrast to PMS, within the AMS-stented segments there is demonstrable vasodilatation. These observations may have important implications for future stent design.

The first report of late stent thrombosis leading to acute myocardial infarction in patient receiving the new endothelial progenitor cell capture stent

The endothelial progenitor cell (EPC) capture stent is a stainless steel coronary stent covered with antibodies specific to EPC's surface antigens, designed to promote the faster formation of a functional endothelial lining. This may prevent both stent thrombosis and restenosis as well as reduce the need of prolonged double antiplatelet therapy. Here we report a case of late (156 days after implantation) EPC capture stent thrombosis and re-stenosis of a second EPC capture stent occurring both in the same patient after withdrawal of clopidogrel. Intravascular ultrasound performed during his acute admission showed undersizing of the stent with thrombosis. The present case raises the question about the safety of the EPC capture stent and the need to prolong at least for 6 months double antiplatelet therapy also in patients receiving this new stent.

Reversible defects on myocardial perfusion imaging early after coronary stent implantation: a predictor of late restenosis

PURPOSE

If coronary artery was treated with optimal stent implantation, myocardial perfusion in the territory supplied by a dilated coronary artery should be not reversible. However, several studies have demonstrated reversible perfusion in the territory supplied by a coronary artery with an optimally implanted stent. The main objective of this study was to evaluate the incidence of reversible defects detected by M-SPECT early after optimal PTCA with stent implantation. Its second objective was to determine the predictive value of detecting reversible defects after stent implantation for late restenosis.

METHODS

About 66 patients that underwent M-SPECT within 24 h of successful PTCA with stent implantation were included. All patients were followed up clinically and angiographically. The incidence of reversible perfusion defects on M-SPECT and the rate of late restenosis in target coronary arteries were evaluated retrospectively.

RESULTS

Reversible perfusion defects on M-SPECT were observed in 26% of the patients and in 36% of lesions following successful PTCA with stent implantation. The incidence of late restenosis was significantly higher in patients and lesions with reversible perfusion defects (47% vs. 18%). According to binary logistic regression analysis, the presence of a reversible perfusion defects was the only independent predictor of late restenosis.

Chest Symptoms Following Coronary Stenting in the First 10 Weeks of Recovery

Background: Most patients experience the benefits of PTCA and stent quickly, with reduction in symptoms and improvement in functional status, however many patients experience chest symptoms post-procedure.

Objective: To describe the pattern and characteristics of post-stent chest symptoms in cardiac rehabilitation participants.

Methods: A prospective descriptive study assessing the pattern and presence of chest symptoms in coronary artery stent recipients ( N = 129) four and ten weeks post-procedure. Patients were interviewed at cardiac rehabilitation or by the phone using a specifically developed questionnaire which incorporated the McGill Pain Questionnaire.

Results: Most participants were male, aged on average 60.5 years and received two stents, most often drug eluting. Post-stent chest symptoms were common, experienced by two thirds of patients (68%) at some time during the 10 weeks post-discharge. Chest symptoms were recurrent, with 33% having symptoms on both occasions and occurred more often in younger patients ( p < .00). Patients described their symptoms as discomforting and used the descriptors dull, tight, sharp, pressing and flickering. Chest symptoms tended to be brief and/or intermittent (65%) lasting from a few seconds to a few minutes (63%). Most patients felt their symptoms were related to their stent (75%) and were unsure what to do. A small number (5%) interpreted their symptoms as ischaemic and presented to the hospital (4%).

Conclusions: Post-stent chest symptoms are frequent and recurrent out to 10 weeks post-discharge. Although symptoms tended to be brief and intermittent, the location and quality of these symptoms may overlap with existing chest pain guidelines, making it difficult for patients to interpret. Cardiac rehabilitation staff are in an ideal position to support and inform stent recipients about appropriate responses to these symptoms.

Presence of asymmetric dimethylarginine gradients across high-grade lesions in patients with coronary artery disease

BACKGROUND

Asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide synthase, is a systemic marker of endothelial dysfunction. Although experimental evidence indicates that asymmetric dimethylarginine may play an important role in atherogenesis, local asymmetric dimethylarginine levels have not been measured in vivo.

OBJECTIVES

We sought to determine whether: (i) asymmetric dimethylarginine is elevated locally at sites of coronary lesions, (ii) systemic asymmetric dimethylarginine concentrations correlate with local levels, and (iii) percutaneous coronary intervention produces immediate local asymmetric dimethylarginine elevation.

METHODS

In patients undergoing percutaneous coronary intervention (n=15), blood samples were obtained from a peripheral venous site, the coronary ostium proximal to the lesion and the coronary vessel distal to the lesion, before percutaneous coronary intervention. Samples were also obtained distal to the coronary lesion immediately after percutaneous coronary intervention and from the peripheral venous line 24 h after percutaneous coronary intervention.

RESULTS

Asymmetric dimethylarginine gradients were present across the coronary bed: local asymmetric dimethylarginine (micromol/l) was significantly higher distal to coronary lesions compared with proximally (2.39+/-1.27 vs. 1.52+/-0.68, P=0.005), and to systemic venous levels (2.39+/-1.27 vs. 1.17+/-0.72, P=0.001). Local asymmetric dimethylarginine did not increase immediately after percutaneous coronary intervention (1.88+/-0.89 vs. 2.39+/-1.27, P=0.11). Peripheral venous percutaneous coronary intervention levels 24 h after percutaneous coronary intervention were similar to baseline values (1.17+/-1.2 vs. 1.17+/-0.72, P=0.98).

CONCLUSION

Asymmetric dimethylarginine gradients exist across coronary lesions, suggesting asymmetric dimethylarginine release at the plaque site. Local asymmetric dimethylarginine accumulation may contribute to the endothelial dysfunction associated with high-grade coronary lesions. Peripheral asymmetric dimethylarginine is a marker of generalized endothelial dysfunction, but our findings highlight its limitation in detecting focal injury.

Impaired endothelial vasomotor function after sirolimus-eluting stent implantation

BACKGROUND

Sirolimus inhibits endothelial cell proliferation in vitro, but although the sirolimus-eluting stent (SES) is widely used because of the very low rates of in-stent restenosis, the influence of SES on coronary endothelial vasomotor function in humans is not well known.

METHODS AND RESULTS

The present study included 21 patients treated with SES, and 12 patients treated with conventional bare metal stent (BMS). Endothelium-dependent vasomotor function was evaluated 6 months after stent implantation, using intracoronary acetylcholine infusion. Changes in diameter at the 5-mm proximal and distal edges of the stent, and at the control segment were assessed by quantitative coronary angiography. To evaluate native endothelial function, an intracoronary acetylcholine test was performed before stenting. In the 21 SES patients acetylcholine infusion at 10(-8) mol/L and 10(-7) mol/L produced significant vasoconstriction in the proximal stent segment (-11.3+/-10.3%, and -14.1+/-11.3%, respectively) and the distal stent segment (-13.7+/-9.3%, and -17.5+/-12.5%, respectively). In contrast, in the 12 BMS patients, acetylcholine infusion at the same concentrations did not produce a vasoconstrictive response in the proximal stent segment (5.0+/-8.2% and 4.9+/-9.1%, respectively) or the distal stent segment (4.2+/-7.6% and 5.1+/-7.7%, respectively). Intracoronary nitroglycerin induced a similar grade of vasodilation in the peri-stent area in both groups. Local endothelial function before SES implantation showed no vasoconstrictive response.

CONCLUSIONS

In contrast to vasodilation in BMS patients, SES implantation in the peri-stent area resulted in a vasoconstrictive response to acetylcholine. SES implantation may impair endothelial function in humans.

Angioscopic evaluation of neointima coverage: sirolimus drug-eluting stent versus bare metal stent

BACKGROUND

The process of neointima formation after bare metal stent (BMS) implantation has been previously elucidated by angioscopic observations; however, that after drug-eluting stent (DES) implantation has not been clarified. Therefore, we compared the angioscopic appearance of neointima over DESs with that over BMSs 6 months after implantation.

METHODS AND RESULTS

Patients who received an implantation of a BMS (n = 13) or a sirolimus DES (n = 24) were included in this study. Angiographic and angioscopic examinations were performed at 6 months. The color of the stented lesion (white or yellow), coverage of stent by neointima (not covered, covered by a thin layer, or buried under neointima), and thrombus at the stented lesion (presence or absence) were angioscopically evaluated. Of the 24 lesions in which a DES was implanted, 11 (46%) had a part where the stent strut had no coverage, 21 (88%) had a part where it was covered by a thin layer, and 11 (46%) had a part where it was buried under neointima. Of the 13 lesions in which a BMS was implanted, 1 (8%) lesion had a part where the stent strut had no coverage, 4 (31%) lesions had a part where it was covered by a thin layer, and 13 (100%) lesions had a part where it was buried under neointima. The prevalence of a stent buried under neointima (46% vs 100%, P = .001) was lower and that of thrombus (42% vs 8%, P = .03) was higher in DES-implanted lesions as compared with BMS-implanted lesions. The prevalence of thrombus (64% vs 17%, P = .005) was higher in the yellow area than in the white area when a DES was implanted.

CONCLUSION

Sirolimus DESs, as compared with BMSs, were poorly covered by neointima and were accompanied by thrombus especially when there was a yellow plaque under the stents. Thus, the thrombogenic potential in DES-implanted lesions may be sustained by the inhibition of neointima formation over thrombogenic plaques.