Revascularization interventions for ischemic heart disease

Effect of ivabradine on structural and functional changes of myocardium and NT-proBNP levels in patients with stable coronary heart disease after coronary stenting

OBJECTIVE

Aim: To investigate the effect of ivabradine on the hemodynamics and contractility of the myocardium and the features of NT-pro-BNP production in patients with stable ischemic heart disease after endovascular revascularization of the myocardium depending on the number of affected coronary arteries during 12 months of therapy.

PATIENTS AND METHODS

Materials and Methods: The object of the study was 120 patients with stable coronary artery disease: angina pectoris of functional class III with heart failure IIA FC III with preserved and moderately reduced ejection fraction of the left ventricle, who underwent coronary artery stenting. The examined patients were randomized according to the number of affected coronary vessels and the method of treatment.

RESULTS

Results: Ivabradine in patients with stable ischemic heart disease after 12 months of therapy had a significant beneficial effect on the structural and functional parameters of the myocardium (contributed to the reverse remodeling of the left ventricle), which did not depend on the number of stented coronary arteries (p<0.05). In patients with stented one coronary artery, all structural and functional indicators of the heart after 12 months of treatment reached the values of practically healthy individuals from the control group. The use of ivabradine in patients with stable ischemic heart disease with heart failure with preserved and intermediate ejection fraction of the left ventricle after coronary stenting made it possible to ensure the correction of a number of clinical and pathogenetic links of the disease, which generally contributed to the improvement of metric and volumetric parameters of the heart.

CONCLUSION

Conclusions: Ivabradine made it possible to significantly increase the effectiveness of standard therapy, which was manifested by a faster recovery of the geometry and contractility of the left ventricle. Therefore, the use of ivabradine along with standard therapy was appropriate for such a contingent of patients. The management of patients with stable coronary heart disease should combine adequate (surgical and pharmacological) treatment of the underlying disease, further individual medication correction of symptoms and circulatory disorders inherent in coronary heart disease and heart failure.

Pilot of a consumer based anti-stigma mentorship program for nursing students

Purpose

Nurses and nursing students often hold stigmatizing attitudes toward patients with mental illness, contributing to poor health outcomes. To address this, direct contact with persons with lived experience in mental illness (i.e. consumers) has been integrated into training curricula. This has shown decreased negative attitudes and increased empathy, but gains are not typically maintained at follow-up. The purpose of this paper is to explore acceptability (i.e. feasibility, process and fidelity) and stigmatizing attitudes of nursing students after the completion of a mentor-based direct-contact curriculum to decrease stigmatizing attitudes toward persons with mental illness.

Design/methodology/approach

A five-week manualized contact-based mentorship program, with a mentor (i.e. consumer)–mentee (i.e. student) pairs implemented as a supplement to the clinical curriculum for 23 baccalaureate-nursing students. Feasibility (i.e. attendance), acceptability, fidelity and stigmatizing attitudes were evaluated. The Error Choice Test and the Attribution Questionnaire (AQ-9) were used to assess stigmatizing attitudes.

Findings

Feasibility was 100 percent for face-to-face meetings and participants were satisfied with the integration of the program into their curriculum, indicating high acceptability. A repeated measures ANOVA yielded significant findings for stigmatizing attitudes (F (2, 21)=6.96, p<0.02, η2=0.23). This suggests that a consumer-led mentoring program may reduce mental health stigma within student-nursing populations. The AQ-9 did not yield significant results.

Research limitations/implications

This study lacked a comparison group. Future research should include a randomized controlled trial.

Originality/value

This study demonstrates capacity for high feasibility and acceptability for an anti-stigma curriculum in this educational context.

Drug-eluting stents in multivessel coronary artery disease: cost effectiveness and clinical outcomes

Multivessel coronary artery disease is more often treated either with coronary artery bypass surgery (CABG) or percutaneous coronary intervention (PCI) with stenting. The advent of drug-eluting stent (DES) has changed the revascularization strategy, and caused an increase in the use of DES in multivessel disease (MVD), with reduced rate of repeat revascularization compared to conventional bare metal stent. The comparative studies of DES-PCI over CABG have shown comparable safety; however, the rate of major adverse cerebrovascular and cardiac events and repeat revascularization was significantly higher with DES-PCI at long term. In diabetic patients with MVD, concern of repeat revascularization with DES-PCI is persistent. More recent, one-year economic outcomes have reported that the CABG is favored among patients with high angiographic complexity. The higher rate of repeat revascularization with DES-PCI in MVD would lead to increased economic burden on patient at long term besides bearing high cost of DES. In diabetic MVD patients, CABG is associated with having better clinical outcomes and being more cost-effective approach when compared to DES-PCI at long term.

Exploring cell compatibility of a fibronectin-functionalized physically crosslinked poly(vinyl alcohol) hydrogel

Physically crosslinked poly(vinyl alcohol) (PVA) hydrogels prepared using a low-temperature thermally cycled process have tunable mechanical properties that fall within the range of soft tissues, including cardiovascular tissue. An approach to render it hemocompatible is by endothelization, but its hydrophilic nature is not conducive to cell adhesion and spreading. We investigated the functionalization reaction of this class of PVA hydrogel with fibronectin (FN) for adhesion and spreading of primary porcine radial artery cells and vascular endothelial cells. These are cells relevant to small-diameter vascular graft development. FN functionalization was achieved using a multistep reaction, but the activation step involving carbonyl diimidazole normally required for chemically crosslinked PVA was found to be unnecessary. The reaction resulted in an increase in the elastic modulus of the PVA hydrogel but is still well within the range of cardiovascular tissue. Confocal microscopy confirmed the adhesion and spreading of both cell types on the PVA-FN surfaces, whereas cells failed to adhere to the PVA control. This is a first step toward an alternative for the realization of a synthetic replacement small-diameter vascular graft.

Blood Flow Changes in Normal and Ischemic Myocardium During Topically Applied Negative Pressure

BACKGROUND

Topical negative pressure (TNP) therapy has been adopted as a first-line treatment for wound healing. One of the mechanisms by which TNP improves healing is by stimulating blood flow to the wound edge. Among patients with ischemic heart disease, it is of great importance to improve the microvascular blood flow in the myocardium during episodes of ischemia to protect the myocardium from infarction. The present study was designed to elucidate the effect of TNP on microvascular blood flow in the myocardium.

METHODS

Six pigs underwent median sternotomy. The microvascular blood flow in the myocardium was recorded, before and after the application of TNP, by using laser Doppler velocimetry. Analyses were performed before left anterior descending artery (LAD) occlusion (normal myocardium), after 20 minutes of LAD occlusion (ischemic myocardium), and after 20 minutes of reperfusion (reperfused myocardium).

RESULTS

TNP at -0 mm Hg increased microvascular blood flow in the normal myocardium from 14.7 +/- 3.9 perfusion units (PU) before to 25.8 +/- 6.1 PU after TNP application (p < 0.05), in the ischemic myocardium from 7.2 +/- 1.5 PU before to 13.8 +/- 2.6 PU after TNP application (p < 0.05), and in the reperfused myocardium from 10.8 +/- 2.0 PU before to 19.3 +/- 5.6 PU after TNP application (p < 0.05).

CONCLUSIONS

TNP increases the microvascular blood flow significantly in normal, ischemic, and reperfused myocardium and may provide a novel therapeutic tool in the treatment of ischemic myocardium.

The polyvinyl alcohol-bacterial cellulose system as a new nanocomposite for biomedical applications

Finding materials suitable for soft tissue replacement is an important aspect for medical devices design and fabrication. There is a need to develop a material that will not only display similar mechanical properties as the tissue it is replacing, but also shows improved life span, biocompatibility, nonthrombogenic, and low degree of calcification. Polyvinyl alcohol (PVA) is a hydrophilic biocompatible polymer with various characteristics desired for biomedical applications. PVA can be transformed into a solid hydrogel with good mechanical properties by physical crosslinking, using freeze-thaw cycles. Hydrophilic bacterial cellulose (BC) fibers of an average diameter of 50 nm are produced by the bacterium Acetobacter xylinum, using a fermentation process. They are used in combination with PVA to form biocompatible nanocomposites. The resulting nanocomposites possess a broad range of mechanical properties and can be made with mechanical properties similar to that of cardiovascular tissues, such as aorta and heart valve leaflets. The stress-strain properties for porcine aorta are matched by at least one type of PVA-BC nanocomposite in both the circumferential and the axial tissue directions. A PVA-BC nanocomposite with similar properties as heart valve tissue is also developed. Relaxation properties of all samples, which are important for cardiovascular applications, were also studied and found to relax at a faster rate and to a lower residual stress than the tissues they might replace. The new PVA-BC composite is a promising material for cardiovascular soft tissue replacement applications.

Changing treatment patterns for coronary artery revascularization in Canada: the projected impact of drug eluting stents

Background

To evaluate current treatment patterns for coronary artery revascularization in Canada and explore the potential impact of drug eluting stents (DES) on these treatment patterns.

Methods

Eleven cardiologists at multiple Canadian academic centers completed a questionnaire on coronary artery revascularization rates and treatment patterns.

Results

Participating physicians indicated slightly higher rates of PTCA, CABG, and stent implantation than reported in CCN publications. Participants estimated that 24% of all patients currently receiving bare metal stents (BMS) would receive DES in the first year following DES approval in Canada, although there was a large range of estimates around this value (5% to 65%). By the fifth year following DES approval, it was estimated that 85% of BMS patients would instead receive DES. Among diabetic patients, estimates ranged from 43% in the first year following approval to 91% in the fifth year. For all patients currently receiving CABG, mean use of DES instead was estimated at 12% in the first year to 42% at five years; rates among diabetic patients currently undergoing CABG were 17% in the first year to 49% in the fifth year.

Conclusions

These results suggest a continued increase in revascularization procedures in Canada. Based on the panel's responses, it is likely that a trend away from CABG towards PTCA will continue in Canada, and will be augmented by the availability of DES as a treatment option. The availability of DES as a treatment option in Canada may change the threshold at which revascularization procedures are considered.

External heating of stents by radio waves: pilot studies in rabbit aorta

PURPOSE

This experiment was designed to assess the feasibility of radio frequency energy delivered by a prototype radio frequency generator inductive heating device (REVAX) positioned external to the body, for transient heating of stents after arterial implant.

METHODS AND MATERIALS

Twenty-one New Zealand White rabbits underwent stenting of their infrarenal aorta. Nine rabbits were stented and immediately placed in the REVAX for external stent heating with internal temperature probes in place. Twelve rabbits were stented and 3 days later either heated or placed in the generator as a sham for 20 min. The animals were terminated 28 days later.

RESULTS

The REVAX was able to heat the aortic stents in a controlled fashion; in Phase II experiments, the stent temperature was raised to 42 degrees C for 20 min. In Phase I mild necrosis was noted at the stent struts. In Phase II, necrosis and mineralization of the media was seen at the stent struts, and evidence of neointimal suppression was observed.

CONCLUSION

This study demonstrated that external heating of stents in a blood vessel in a live animal via radio frequency energy is feasible. Further studies will be needed to assess whether any specific heating regimen might inhibit fibrocellular neointimal hyperplasia.