Intravascular Lithotripsy for Treatment of Calcified Coronary Artery Disease

Intravascular lithotripsy (IVL) uses acoustic shock waves in a balloon-based delivery system to modify severely calcified atherosclerotic coronary vascular lesions in preparation for stent implantation. IVL results in circumferential and longitudinal calcium fracture, which improves transmural vessel compliance and facilitates subsequent stent expansion without requiring high-pressure balloon dilation. Clinical trials have demonstrated IVL to be safe (low rates of major adverse cardiac events in hospital and to 1 year; low rates of severe angiographic complications), effective (high rates of procedural success), and easy to use (little or no learning curve) when applied in the treatment of severely calcified coronary arteries.

[Perioperative Antiplatelet Therapy in Patients with Coronary Stents Undergoing Elective Non-Cardiac Surgery]

Among patients undergoing elective non-cardiac surgery (NCS), those with coronary stent implants are gradually becoming a patient group that cannot be easily overlooked. Previous history of heart disease, coronary stents and antiplatelet agents expose these patients to dual perioperative risks of thrombosis and bleeding. Formulating appropriate plans for perioperative antiplatelet therapy will help reduce the risks and ensure the safety of patients. We herein reviewed and analyzed various aspects of perioperative antiplatelet therapy for patients with coronary stent implants undergoing elective NCS, and discussed prospective research directions in the field.

Revascularization Strategies for Multivessel Coronary Artery Disease in the Elderly Population

BACKGROUND

Prospective trials comparing coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) for the treatment of multivessel coronary disease (MVCAD) have included mostly younger patients. We compared treatment strategies in the elderly population.

MATERIALS AND METHODS

We performed a propensity-score-matched comparison of patients ≥75 y who underwent isolated CABG or PCI for MVCAD between 2011 and 2018, excluding those with prior cardiac surgery and/or significant left main disease. The primary outcome was 5-year Kaplan Meier survival, and secondary outcomes included readmissions and major adverse cardiovascular and cerebrovascular events (MACCE).

RESULTS

Propensity-matching yielded 536 patients (266 PCI and 266 CABG). Rates of complete revascularization of all stenotic lesions were higher in the CABG arm (86.8% versus 21.8%; P < 0.001). Thirty-d mortality was similar between cohorts, though PCI recipients had shorter hospital stay and greater likelihood of discharge to home. Unadjusted one- (89.1% versus 88.4%) and 5-year (73.8% versus 60.1%) survival were both higher in patients who underwent CABG (P = 0.0332). Patients undergoing CABG had reduced, but nonsignificant cumulative incidence of all-cause hospital readmission and MACCE at 5 y. Subgroup analysis of patients 80 y or older revealed similar late survival benefit with CABG when compared to PCI. Among patients undergoing CABG, there did not appear to be any 5-year benefits from multi-arterial grafting.

CONCLUSIONS

Despite longer hospitalization and higher rate of nonhome discharge, CABG was associated with improved late survival over PCI in the elderly population. Cardiac surgeons should be included in the multidisciplinary evaluation of older patients with MVCAD.

Percutaneous coronary intervention of totally occluded coronary venous bypass grafts: An exercise in futility?

BACKGROUND

Percutaneous coronary intervention (PCI) of diseased saphenous vein grafts (SVG) continues to pose a clinical challenge. Current PCI guidelines give a class III recommendation against performing PCI on chronically occluded SVG. However, contemporary outcomes after SVG intervention have incrementally improved with distal protection devices, intracoronary vasodilators, drug-eluting stents, and prolonged dual antiplatelet therapy.

AIM

To reassess the procedural and long-term outcomes of PCI for totally occluded SVG with contemporary techniques.

METHODS

This was a retrospective observational study conducted at a single university hospital. The study population consisted of 35 consecutive patients undergoing PCI of totally occluded SVG. Post-procedure dual antiplatelet therapy was continued for a minimum of one year and aspirin was continued indefinitely. Clinical outcomes were assessed at a mean follow-up of 1221 ± 1038 d. The primary outcome was freedom from a major adverse cardiac event (MACE) defined as the occurrence of any of the following: death, myocardial infarction, stroke, repeat bypass surgery, repeat PCI, or graft reocclusion.

RESULTS

The study group included 29 men and 6 women with a mean age of 69 ± 12 years. Diabetes was present in 14 (40%) patients. All patients had Canadian Heart Classification class III or IV angina. Clinical presentation was an acute coronary syndrome in 34 (97%) patients. Mean SVG age was 12 ± 5 years. Estimated duration of occlusion was acute (< 24 h) in 34% of patients, subacute (> 24 h to 30 d) in 26%, and late (> 30 d) in 40%. PCI was initially successful in 29/35 SVG occlusions (83%). Total stent length was 52 ± 35 mm. Intraprocedural complications of distal embolization or no-reflow occurred in 6 (17%) patients. During longer term follow-up, MACE-free survival was only 30% at 3 years and 17% at 5 years.

CONCLUSION

PCI of totally occluded SVG can be performed with a high procedural success rate. However, its clinical utility remains limited by poor follow-up outcomes.

Evolution of antithrombotic therapy in patients undergoing percutaneous coronary intervention: a 40-year journey

Since its introduction in 1977, percutaneous coronary intervention has become one of the most commonly performed therapeutic procedures worldwide. Such widespread diffusion, however, would have not been possible without a concomitant evolution of the pharmacotherapies associated with this intervention. Antithrombotic agents are fundamental throughout the management of patients undergoing coronary stent implantation, starting from the procedure itself to the long-term prevention of cardiovascular events. The last 40 years of interventional cardiology have seen remarkable improvements in both drug therapies and device technologies, which largely reflected a progressive understanding of the pathophysiological mechanisms of coronary artery disease, as well as procedure- and device-related adverse events. The purpose of this article is to provide an overview of the important milestones in antithrombotic pharmacology that have shaped clinical practice of today while also providing insights into knowledge gaps and future directions.

Bivalirudin and sirolimus co-eluting coronary stent: Potential strategy for the prevention of stent thrombosis and restenosis

Localized drug delivery with sustained elution characteristics from nanocarrier coated stents represents a viable therapeutic approach to circumvent concerns related to coronary stent therapy. We fabricated a Sirolimus (SRL) and Bivalirudin (BIV) releasing nanoparticles (NPs) coated stent for concurrent mitigation of vascular restenosis and acute stent thrombosis. SRL NPs were prepared by nanoprecipitation method whereas the BIV vesicles were generated using hydrophobic ion pair approach followed by micellization phenomenon. MTT assay and confocal microscopic analysis indicated superior anti-proliferative activity and higher cellular uptake of SRL NPs into human coronary artery smooth muscle cells, respectively. DSC and ATR-FTIR techniques confirmed the formation of complex between BIV and phosphatidylglycerol via some weak physical interactions. More than 2 fold rise in log P value was obtained for DSPG-BIV at 3:1 M ratio compared with native BIV solution. The SAXS analysis indicated formation of oligolamellar vesicles of DSPG-BIV complex which was preferentially entrapped into lipophilic lamellae of vesicles. APTT, PT, and TT tests revealed that the BIV vesicles caused significant prolongation of clotting time compared to native BIV solution. The SEM analysis showed uniform and defect free stent coating. In vitro release study demonstrated that SRL and BIV were eluted in a sustained manner from coated stents.

Bifunctional polymer brush-grafted coronary stent for anticoagulation and endothelialization

At present, cardiovascular stent intervention faces clinical complications such as delayed endothelialization, late thrombosis and restenosis after implantation. In this work, a kind of bifunctional polymer brush-grafted coronary stent with anticoagulant and endothelial functions was developed. First, a block copolymer brush with zwitterionic structure consisting of sulfoethyl methacrylate (SBMA) and glycidyl methacrylate (GMA) was surface-induced grafted onto the surface of bare metal coronary stent by atom transfer radical polymerization. The diethylenetriamine NONOate (DETA NONOate), acted as nitric oxide (NO) donor to promote endothelialization, was then attached to polyglycidyl methacrylate (PGMA) brush by a reactive epoxy group to produce NO. The process of chemical modification and the release behavior of NO were characterized in detail. Moreover, the results of anticoagulant test, cytotoxicity test, endothelial cells (ECs) proliferation test and animal experiment of this bifunctional polymer brush-grafted coronary stent we proposed indicate that the zwitterion modified and NO supplied bifunctional coatings has good anticoagulant property, no cytotoxicity and significant endothelialization effect. This work opens the door to combine biological activity of NO and anticoagulant effect of zwitterions, which has great potential to address post-operative side effects associated with restenosis and late stent thrombosis.

Intracoronary Imaging for Assessment of Vascular Healing and Stent Follow-up in Bioresorbable Vascular Scaffolds

Bioresorbable Vascular Scaffolds (BVS) are polymer-based materials implanted in the coronary arteries in order to treat atherosclerotic lesions, based on the concept that once the lesion has been treated, the material of the implanted stent will undergo a process of gradual resorption that will leave, in several years, the vessel wall smooth, free of any foreign material and with its vasomotion restored. However, after the first enthusiastic reports on the efficacy of BVSs, the recently published trials demonstrated disappointing results regarding long-term patency following BVS implantation, which were mainly attributed to technical deficiencies during the stenting procedure. Intracoronary imaging could play a crucial role for helping the operator to correctly implant a BVS into the coronary artery, as well as providing relevant information in the follow-up period. This review aims to summarize the role of intracoronary imaging in the follow-up of coronary stents, with a particular emphasis on the role of intravascular ultrasound and optical coherence tomography for procedural guidance during stent implantation and also for follow-up of bioabsorbable scaffolds.

Did India's price control policy for coronary stents create unintended consequences?

In February 2017, India capped the retail price of coronary stents and restricted the channel margin to bring Percutaneous Transluminal Coronary Angioplasty (PTCA) procedure, which uses coronary stents, within reach of millions of patients who previously could not afford it. Prior research shows that care providers respond to such regulations in a way that compensates for their loss in profits because of price control. Therefore, price control policies often introduce unintended consequences, such as distortions in clinical decision making. We investigate such distortions through empirical analysis of claims data from a representative public insurance program in the Indian state of Karnataka. Our data comprises 25,769 insurance claims from 69 private and seven public hospitals from February 2016 to February 2018. The public insurance context is ideal for investigating distortions in clinical decisions as the price paid by patients, and thereby access to the treatment, does not change after price control. We find that the change in the average volume of PTCA procedures per hospital per month after price control disproportionately increased when compared to the change in the clinical alternative - Coronary Artery Bypass Graft (CABG) procedures. This increase corresponds to 6% of the average number of PTCA procedures and 28% of the average number of CABG procedures before the price control. In addition, disproportionate increase in PTCA procedures occurred only among private hospitals, indicating the possibility of profit-maximization intentions driving the clinical choices. Such clinical distortions can have negative implications for patient health outcomes in the long run. We discuss alternative policies to improve access and affordability to healthcare products and services which are likely to not suffer from similar distortions.

Future Balloon-Expandable Stents: High or Low-Strength Materials?

PURPOSE

Recent progress in material science allows researchers to use novel materials with enhanced capabilities like optimum biodegradability, higher strength, and flexibility in the design of coronary stents. Considering the wide range of mechanical properties of existing and newfangled materials, finding the influence of variations in mechanical properties of stent materials is critical for developing a practical design.

METHODS

The sensitivity of stent functional characteristics to variations in its material plastic properties is obtained through FEM modeling. Balloon-expandable coronary stent designs: Absorb BVS, and Xience are examined for artificial and commercial polymeric, and metallic materials, respectively. Standard tests including (1) the crimping process followed by stent implantation in an atherosclerotic artery and (2) the three-point bending test, have been simulated according to ASTM standards.

RESULTS

In Absorb BVS, materials with higher yield stress than PLLA have similar residual deflection and maximum bending force to PLLA, which is not the case for Xience stent and Co-Cr. Moreover, elevated yield stress significantly reduces stent flexibility only in Xience stent. For both stents, with different degree of influence, an increase in yield or ultimate stress improves stent radial strength and stiffness and reduces arterial stress and plastic strain of stent, which consequently enhances the stent mechanical performance. Contrarily, yield or ultimate stress elevation increases stent recoil which adversely affects stent performance.

CONCLUSION

Using high-strength materials has a double-edged sword effect on the stent performance and existing uncertainty in the precise estimate of stent mechanical properties adversely affects the reliability of numerical models' predictions.

Multi-Objective Optimization Design of Balloon-Expandable Coronary Stent

PURPOSE

Recent studies suggested that suboptimal delivery and longitudinal stent deformation can result in in-stent restenosis. Therefore, the purpose of this paper was to study the effect of stent geometry on stent flexibility and longitudinal stiffness (LS) and optimize the two metrics simultaneously. Then, the reliable and accurate relationships between metrics and design variables were established.

METHODS

A multi-objective optimization method based on finite element analysis was proposed for the investigation and improvement of stent flexibility and LS. The relative influences of design variables on the two metrics were evaluated on the basis of the main effects. Three surrogate models, namely, the response surface model (RSM), radial basis function neural network (RBF), and Kriging were employed and compared.

RESULTS

The accuracies of the three models in fitting flexibility were nearly similar, although Kriging made more accurate prediction in LS. The link width played important roles in flexibility and LS. Although the flexibility of the optimal stent decreased by 13%, the LS increased by 48.3%.

CONCLUSIONS

The obtained results showed that the multi-objective optimization method is efficient in predicting an optimal stent design. The method presented in this paper can be useful in optimizing stent design and improving the comprehensive mechanical properties of stents.

A novel method of inducing thrombosis in target arteries using coronary stents for therapeutic occlusion

OBJECTIVES

Peripheral artery embolizations are often required for therapeutic purposes. The therapeutic embolizations are usually performed using embolization particles and coils. These procedures are also associated with complications. Coils and their delivery cables, and the expertise are not always available in all catheterization centers. Hence, a novel, simple controlled technique for arterial closure would be useful in emergency settings.

RESULTS

Following is a report of seven cases where embolization was performed successfully on an emergency basis after stenting using coronary stents for better closure of the target artery. Six patients underwent bronchial artery embolization for recurrent massive hemoptysis, and one another patient had pseudoaneurysm following percutaneous nephrolithotomy, and presented with hematuria and persistent and increasing blood discharge in drainage catheter. The stents were deployed in the target artery using 6F Judkin's diagnostic catheter over the 014 wires, which are easily available in all cardiac catheterization laboratories. This is a novel method to establish a metal platform inside the target arteries using coronary stents for better closure of the target arteries in combination with embolization techniques. The procedures were performed as lifesaving measures when small coils and the delivery cables were not available at the time of the procedures.

Inflammatory markers in dependence on the plasma concentration of 37 fatty acids after the coronary stent implantation

Using the regression model building the relationships between the concentration of 37 fatty acids of blood plasma phospholipids of 41 patients with coronary artery disease after coronary stent implantation, the inflammatory response and oxidative stress markers were estimated. The dynamics of the inflammatory response and the oxidative stress was indicated by measuring plasma concentrations of highly sensitive C-reactive protein, interleukin-6, serum amyloid A and malondialdehyde before, 24h after stent implantation. The multiple linear regression analysis was preceded by an exploratory data analysis, principal component analysis, factor analysis and cluster analysis, which proved a hidden internal relation of 37 fatty acids. The concentration of cerotic acid (C26:0) has been positively associated with an increase of malondialdehyde concentration after stent implantation, while the concentrations of tetracosatetraenoic (C24:4 N6) and nonadecanoic (C19:0) acids were associated with decrease of lipoperoxidation. The increase of interleukin-6 during the 24h after implantation was associated with higher levels of pentadecanoic acid (C15:0) and lower levels of α-linolenic acid (C18:3 N3). Regression models found several significant fatty acids at which the strength of the parameter β for each fatty acid on selected markers of C-reactive protein, malondialdehyde, interleukin-6 and serum amyloid A was estimated. Parameter β testifies to the power of the positive or negative relationship of the fatty acid concentration on the concentration of selected markers. The influencing effect of the cerotic acid (C26:0) concentration in plasma phospholipids exhibiting parameter β=140.4 is, for example, 3.5 times higher than this effect of n-3 tetracosapentaenoic acid (C24:5 N3) with β=40.0. Composition of fatty acids in plasma phospholipids shows spectrum of fatty acids available for intercellular communication in systemic inflammatory response of organism and should affect clinical outcomes.

Bioresorbable Scaffolds in Coronary Intervention: Unmet Needs and Evolution

Bioresorbable scaffolds (BRS) represent a novel paradigm in the 40-year history of interventional cardiology. Restoration of cyclic pulsatility and physiologic vasomotion, adaptive vascular remodeling, plaque regression, and removal of the trigger for late adverse events are expected BRS benefits over current metallic drug-eluting stents. However, first-generation BRS devices have significant manufacturing limitations and rely on optimal implantation technique to avoid experiencing an excess of clinical events. There are currently at least 22 BRS devices in different stages of development, including many trials of device iterations with thinner (<150 µm) struts than first-generation BRS. This article reviews the outcomes of commercially available and potentially upcoming BRS, focusing on the most recent stages of clinical development and future directions for each scaffold type.

Palliative treatment of coronary "atherosclerotic cancer" by drug-eluting or bare-metal stents: From oculo-stenotic reflex period to age of precision medicine

Medications and treatments are said to have a palliative effect if they relieve symptoms without having a curative effect on the underlying disease such as atherosclerosis or cancer. Some authors speculated that atherosclerotic coronary artery disease (CAD) could be considered a "cancer of the coronary arterial wall". Although the percutaneous coronary intervention (PCI) has proven to be effective in decreasing mortality rates among patients with acute coronary syndromes, the previous meta-analyses of PCI versus optimal medical therapy for stable CAD have not been able to demonstrate a reduction in major adverse cardiac outcomes. However, few cardiologists discussed the evidence-based benefits of angiogram and PCI for stable CAD, and some implicitly or explicitly overstated the benefits. Recently, the precision medicine is defined as an evidence-based approach that uses innovative tools and biological and data science to customize disease prevention, detection, and treatment, and improve the effectiveness and quality of patient care. Providing patients with accurate and complete information appears to be an effective way to combat the reliance on the oculostenotic reflex. The foundation of precision medicine is the ability to tailor therapy based upon the expected risks and benefits of treatment for each individual patient. As said by Doctor William Osler, "The good physician treats the disease; the great physician treats the patient who has the disease."

Longitudinal deformation of a third generation zotarolimus eluting stent: “The concertina returns!”

In the current case series we describe two cases of longitudinal stent deformation in ostial lesions treated with a new generation zotarolimus eluting stent and review current literature on longitudinal stent deformation. Historically not a common occurrence, longitudinal deformation occurred mainly in Promus Element everolimus eluting stents, which had only two rather than the commonly used 3 links between stent rings. Longitudinal deformation commonly occurs secondary to compression of the proximal edge of the stent by either the guide catheters, or intravascular balloons and imaging catheters. The degree of deformation however, depends on the longitudinal strength and design of the stent.

Bioresorbable Scaffolds: Current Evidences in the Treatment of Coronary Artery Disease

Percutaneous coronary revascularization strategies have gradually progressed over a period of last few decades. The advent of newer generation drug-eluting stents has significantly improved the outcomes of Percutaneous Coronary Intervention (PCI) by substantially reducing in-stent restenosis and stent thrombosis. However, vascular inflammation, restenosis, thrombosis, and neoatherosclerosis due to the permanent presence of a metallic foreign body within the artery limit their usage in complex Coronary Artery Disease (CAD). Bioresorbable Scaffolds (BRS) represent a novel approach in coronary stent technology. Complete resorption of the scaffold liberates the treated vessel from its cage and restores pulsatility, cyclical strain, physiological shear stress, and mechanotransduction. In this review article, we describe the advances in this rapidly evolving technology, present the evidence from the pre-clinical and clinical evaluation of these devices, and provide an overview of the ongoing clinical trials that were designed to examine the effectiveness of BRS in the clinical setting.

A retrospective study showing the extent of compliance with perioperative guidelines in patients with coronary stents with regard to double antiplatelet therapy

STUDY OBJECTIVE

To evaluate perioperative dual antiplatelet therapy management in patients with previously placed coronary stents.

DESIGN

Retrospective medical record review.

SETTING

Academic medical center.

PATIENTS

A total of 1891 surgical cases performed at Vanderbilt University Medical Center in 2012 were evaluated using a perioperative database. Of these, 161 had complete data records that were evaluated using 2 evidence-based and expert opinion-supported protocols.

INTERVENTIONS

N/A.

MEASUREMENTS

This study is meant to evaluate perioperative antiplatelet management decisions in patients with coronary stents.

MAIN RESULTS

Management decisions were consistent with guidelines regarding antiplatelet therapy in 13% (21/161) of patients. Of the 87% (140/161) of cases where decisions were not consistent, 88% (123/140) were due to discontinuing aspirin preoperatively when there was not a high risk of surgical bleeding.

CONCLUSIONS

This study revealed suboptimal adherence to current perioperative antiplatelet management guidelines in patients with coronary stents. The lack of adherence to current guidelines is concerning and could be used to support the notion of an anesthesiologist-led Perioperative Surgical Home.

The History of Coronary Stenting

The history of coronary angioplasty began with the groundbreaking work of Andreas Grüntzig, who was the first to use balloon-expandable catheters for the treatment of flow-limiting atherosclerotic coronary artery lesions. Thereafter, early investigators tested self-expanding springs as a solution to abrupt closure and restenosis seen with balloon angioplasty but these devices suffered from difficult delivery and a high complication rate. Julio Palmaz and Richard Schatz introduced the first balloon-expandable stent as a mechanical support to improve vessel patency. Their pioneering work launched a new era in the treatment of coronary artery disease.

Coating Techniques and Release Kinetics of Drug-Eluting Stents

Implantation of drug-eluting stents (DESs) via percutaneous coronary intervention is the most popular treatment option to restore blood flow to occluded vasculature. The many devices currently used in clinic and under examination in research laboratories are manufactured using a variety of coating techniques to create the incorporated drug release platforms. These coating techniques offer various benefits including ease of use, expense of equipment, and design variability. This review paper discusses recent novel DES designs utilizing individual or a combination of these coating techniques and their resulting drug release profiles.

[Coronary stent evaluation with cardiac CT: Literature review]

Since the introduction of the 64-generation scanners, the accuracy and robustness of the diagnosis of coronary artery disease has progressed. The main advantage of cardiac CT is the exclusion of coronary artery disease by its excellent negative predictive value. Currently, cardiac CT applications extend thanks to innovations both in terms of technological development systems scanner or stents implanted. This is a literature review of stent evaluation with cardiac CT.

Comparison of long-term safety and efficacy outcomes after drug-eluting and bare-metal stent use across racial groups: Insights from NHLBI Dynamic Registry

BACKGROUND

Long-term data on outcomes after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) and bare-metal stent (BMS) across racial groups are limited, and minorities are under-represented in existing clinical trials. Whether DES has better long-term clinical outcomes compared to BMS across racial groups remains to be established. Accordingly, we assessed whether longer-term clinical outcomes are better with DES compared to BMS across racial groups.

METHODS

Using the multicenter National Heart, Lung, and Blood Institute (NHLBI)-sponsored Dynamic Registry, 2-year safety (death, MI) and efficacy (repeat revascularization) outcomes of 3326 patients who underwent PCI with DES versus BMS were evaluated.

RESULTS

With propensity-score adjusted analysis, the use of DES, compared to BMS, was associated with a lower risk for death or MI at 2 years for both blacks (adjusted Hazard Ratio (aHR)=0.41, 95% CI 0.25-0.69, p<0.001) and whites (aHR=0.67, 95% CI 0.51-0.90, p=0.007). DES use was associated with a significant 24% lower risk of repeat revascularization in whites (aHR=0.76, 95% CI 0.60-0.97, p=0.03) and with nominal 34% lower risk in blacks (aHR=0.66, 95% CI 0.39-1.13, p=0.13).

CONCLUSION

The use of DES in PCI was associated with better long-term safety outcomes across racial groups. Compared to BMS, DES was more effective in reducing repeat revascularization in whites and blacks, but this benefit was attenuated after statistical adjustment in blacks. These findings indicate that DES is superior to BMS in all patients regardless of race. Further studies are needed to determine long-term outcomes across racial groups with newer generation stents.

Numerical investigations of the haemodynamic changes associated with stent malapposition in an idealised coronary artery

The deployment of a coronary stent near complex lesions can sometimes lead to incomplete stent apposition (ISA), an undesirable side effect of coronary stent implantation. Three-dimensional computational fluid dynamics (CFD) calculations are performed on simplified stent models (with either square or circular cross-section struts) inside an idealised coronary artery to analyse the effect of different levels of ISA to the change in haemodynamics inside the artery. The clinical significance of ISA is reported using haemodynamic metrics like wall shear stress (WSS) and wall shear stress gradient (WSSG). A coronary stent with square cross-sectional strut shows different levels of reverse flow for malapposition distance (MD) between 0mm and 0.12 mm. Chaotic blood flow is usually observed at late diastole and early systole for MD=0mm and 0.12 mm but are suppressed for MD=0.06 mm. The struts with circular cross section delay the flow chaotic process as compared to square cross-sectional struts at the same MD and also reduce the level of fluctuations found in the flow field. However, further increase in MD can lead to chaotic flow not only at late diastole and early systole, but it also leads to chaotic flow at the end of systole. In all cases, WSS increases above the threshold value (0.5 Pa) as MD increases due to the diminishing reverse flow near the artery wall. Increasing MD also results in an elevated WSSG as flow becomes more chaotic, except for square struts at MD=0.06 mm.

Coronary artery disease associated with severe mitral and tricuspid valve regurgitation after left pneumonectomy: report of a successful hybrid procedure

The literature concerning heart surgery after pneumonectomy is still poor. Moreover, there is still a lack of a standardized approach to such a patient in the decision-making process. Here, we report a case of a patient who had previously had left pneumonectomy for malignancy and who had coronary artery disease and mitral and tricuspid regurgitation treated with a hybrid procedure.

Single coronary artery originating from the right aortic sinus without a left anterior descending and circumflex artery in conventional swine

Single coronary artery is a rare coronary artery anomaly. Very few previous reports of this anatomical malformation in swine have been found. A 22 kg Yorkshire X Landrace F1 crossbred castrated male swine was presented for enrollment in a coronary stent implantion study. Coronary angiography revealed a single coronary artery arising from the right aortic sinus. The right coronary artery and anomalous left coronary artery were implanted with novel coronary stents without any side effects.

In vitro hemocompatibility and vascular endothelial cell functionality on titania nanostructures under static and dynamic conditions for improved coronary stenting applications

The usefulness of nanoscale topography in improving vascular response in vitro was established previously on hydrothermally modified titanium surfaces. To propose this strategy of surface modification for translation onto clinically used metallic stents, it is imperative that the surface should be also hemocompatible: an essential attribute for any blood-contacting device. The present in vitro study focuses on a detailed hemocompatibility evaluation of titania nanostructures created through an alkaline hydrothermal route on metallic Ti stent prototypes. Direct interactions of TiO2 nanocues of various morphologies with whole blood were studied under static conditions as well as using an in vitro circulation model mimicking arterial flow, with respect to a polished Ti control. Nanomodified stent surfaces upon contact with human blood showed negligible hemolysis under constant shear and static conditions. Coagulation profile testing indicated that surface roughness of nanomodified stents induced no alterations in the normal clotting times, with insignificant thrombus formation and minimal inflammatory reaction. Endothelialized nanomodified Ti surfaces were found to inhibit both activation as well as aggregation of platelets compared with the control surface, with the endothelium formed on the nanosurfaces having an increased expression of anti-thrombogenic genes. Such a nanotextured Ti surface, which is anti-thrombogenic and promotes endothelialization, would be a cost-effective alternative to drug-eluting stents or polymer-coated stents for overcoming in-stent restenosis.

Patients with ischemic heart disease

Ischemic heart disease (IHD) occurs when myocardial oxygen supply is not adequate for myocardial oxygen demand. Patients with IHD who are undergoing surgery are at risk for development of perioperative cardiac events (PCEs), and this risk depends on the type of surgery, the presence of clinical risk factors, and functional status of the patients. Appropriate perioperative management of medications such as dual antiplatelet therapy and β-blockers has a significant impact on outcomes. Perioperative management decisions should be communicated clearly between the surgeon, cardiologist, and anesthesiologist in charge of the patient. Appropriate perioperative management reduces the incidence of PCEs.

Techniques and material used in the percutaneous treatment of chronic coronary occlusions. Data from the CIBELES study

INTRODUCTION

In recent years, various specific techniques and materials have been developed for the treatment of coronary chronic total occlusions (CTO).

OBJECTIVE

To evaluate the current situation in the treatment of CTO (techniques and material) in our setting.

METHODS

We evaluated data on techniques and material used in the CIBELES (ChronIc coronary occlusion treated By EveroLimus Eluting Stent) trial, a randomized comparison of sirolimus- and everolimus-eluting stents in 207 patients with CTO in 13 centers in Spain and Portugal.

RESULTS

A radial approach was used in 23% of patients, and retrograde techniques were used in only 5%. A high number of balloons were used (2.2±0.9 per patient). Microcatheters were used in 33% of patients, and post-dilatation balloons in only 25%. The mean number of stents implanted per patient was 2.1±1.0, with a mean total stent length of 49±24 mm. Other devices and techniques used were: Tornus penetration catheter in 4% of patients, rotational atherectomy in 2%, and cutting balloon in 1%. Intracoronary ultrasound was used in only 6% of patients. In 34% of cases, operators used guidewires that were not specifically for CTO. Considerable variability between centers was detected in the use of different techniques, the highest and lowest variability being observed in the use of intracoronary ultrasound and the use of CTO guidewires, respectively.

CONCLUSIONS

In the CIBELES trial, techniques and devices specifically designed for the treatment of CTO were used in a relatively low proportion of patients. Considerable variability between centers was detected.