Restenosis after Angioplasty

Self-care in coronary heart disease patient and caregiver dyads (HEARTS-IN-DYADS)-Protocol of a multicenter longitudinal study

Self-care performed by patients and the caregiver contribution to this self-care are essential for improving cardiovascular outcomes; however, so far, no studies have sufficiently investigated this field in Italy. This paper describes a research protocol of a multi-center longitudinal study designed to investigate the self-care of patients affected by coronary heart disease (CHD), the caregiver's contribution to this self-care, the predictors of patient and caregiver self-care, the mediating role of self-efficacy, and the self-care outcomes. Data collection will be performed across seven Italian inpatient settings at baseline and 3 and 6 months from enrollment. Multilevel modeling and actor partner interdependence models will be implemented on a sample of 330 patient-caregiver dyads to adjust for the interdependence of measurements. The study received approval from an ethics committee in Italy and was financed in January 2021 by a grant from the Solidal Foundation in Alessandria. This research will advance the knowledge about the self-care process in CHD. The results will guide research and clinical practice by identifying variables sensitive to educational interventions.

Role of inflammatory cytokines in genesis and treatment of atherosclerosis

Atherosclerosis demonstrates an increased rate of vascular smooth muscle cells (VSMC) plasticity characterized by switching from the differentiated contractile phenotype to a de-differentiated synthetic state. In healthy blood vessels, phenotypic switching represents a fundamental property of VSMC in maintaining vascular homeostasis. However, in atherosclerosis, it is an initial and necessary step in VSMC-derived foam cell formation. These foam cells play a decisive role in atherosclerosis progression since approximately half of all the foam cells are of VSMC origin. Our recent work showed that interferon-gamma (IFN-γ), a primary inflammatory cytokine in progressive atherosclerosis, mediates VSMC phenotype switching exclusively through upregulating mini-tryptophanyl-tRNA synthetase (mini-TrpRS). Here, we discuss the pro-atherosclerotic implication of this phenomenon that inevitably occurs in the context of a more complex regulation mediated by IFN-γ. An emerging therapeutic option for patients with progressive atherosclerosis is also discussed.

Photoactive Pore Matrix for In Situ Delivery of a Photosensitizer in Vascular Smooth Muscle Cells Selective PDT

In this study we present the porous silica-based material that can be used for in situ drug delivery, offering effective supply of active compounds regardless its water solubility. To demonstrate usability of this new material, three silica-based materials with different pore size distribution as a matrix for doping with Photolon (Ph) and Protoporphyrin IX (PPIX) photosensitizers, were prepared. These matrices can be used for coating cardiovascular stents used for treatment of the coronary artery disease and enable intravascular photodynamic therapy (PDT), which can modulate the vascular response to injury caused by stent implantation-procedure that should be thought as an alternative for drug eluting stent. The FTIR spectroscopic analysis confirmed that all studied matrices have been successfully functionalized with the target photosensitizers. Atomic force microscopy revealed that resulting photoactive matrices were very smooth, which can limit the implantation damage and reduce the risk of restenosis. No viability loss of human peripheral blood lymphocytes and no erythrocyte hemolysis upon prolonged incubations on matrices indicated good biocompatibility of designed materials. The suitability of photoactive surfaces for PDT was tested in two cell lines relevant to stent implantation: vascular endothelial cells (HUVECs) and vascular smooth muscle cells (VSMC). It was demonstrated that 2 h incubation on the silica matrices was sufficient for uptake of the encapsulated photosensitizers. Moreover, the amount of the absorbed photosensitizer was sufficient for induction of a phototoxic reaction as shown by a rise of the reactive oxygen species in photosensitized VSMC. On the other hand, limited reactive oxygen species (ROS) induction in HUVECs in our experimental set up suggests that the proposed method of PDT may be less harmful for the endothelial cells and may decrease a risk of the restenosis. Presented data clearly demonstrate that porous silica-based matrices are capable of in situ delivery of photosensitizer for PDT of VSMC.

Inhibition of p110δ PI3K prevents inflammatory response and restenosis after artery injury

Inflammatory cells play key roles in restenosis upon vascular surgical procedures such as bypass grafts, angioplasty and stent deployment but the molecular mechanisms by which these cells affect restenosis remain unclear. The p110δ isoform of phosphoinositide 3-kinase (PI3K) is mainly expressed in white blood cells. Here, we have investigated whether p110δ PI3K is involved in the pathogenesis of restenosis in a mouse model of carotid injury, which mimics the damage following arterial grafts. We used mice in which p110δ kinase activity has been disabled by a knockin (KI) point mutation in its ATP-binding site (p110δD910A/D910A PI3K mice). Wild-type (WT) and p110δD910A/D910A mice were subjected to longitudinal carotid injury. At 14 and 30 days after carotid injury, mice with inactive p110δ showed strongly decreased infiltration of inflammatory cells (including T lymphocytes and macrophages) and vascular smooth muscle cells (VSMCs), compared with WT mice. Likewise, PI-3065, a p110δ-selective PI3K inhibitor, almost completely prevented restenosis after artery injury. Our data showed that p110δ PI3K plays a main role in promoting neointimal thickening and inflammatory processes during vascular stenosis, with its inhibition providing significant reduction in restenosis following carotid injury. p110δ-selective inhibitors, recently approved for the treatment of human B-cell malignancies, therefore, present a new therapeutic opportunity to prevent the restenosis upon artery injury.

Recurrent angina after coronary angioplasty: mechanisms, diagnostic and therapeutic options

Recurrent angina in patients who underwent percutaneous coronary intervention is defined as recurrence of chest pain or chest discomfort. Careful assessment is recommended to differentiate between non-cardiac and cardiac causes. In the case of the latter, recurrent angina occurrence can be related to structural ('stretch pain', in-stent restenosis, in-stent thrombosis, incomplete revascularization, progression of coronary atherosclerosis) or functional (coronary micro-vascular dysfunction, epicardial coronary spasm) causes. Even though a complete diagnostic algorithm has not been validated, ECG exercise testing, stress imaging and invasive assessment of coronary blood flow and coronary vaso-motion (i.e. coronary flow reserve, provocation testing for coronary spasm) may be required. When repeated coronary revascularization is not indicated, therapeutic approaches should aim at targeting the underlying mechanism for the patient's symptoms using a variety of drugs currently available such as beta-blockers, calcium-channel blockers, ivabradine or ranolazine.

Wingspan stents for the treatment of symptomatic atherosclerotic stenosis in small intracranial vessels: safety and efficacy evaluation

BACKGROUND AND PURPOSE

Until now, endovascular treatment of symptomatic atherosclerotic stenosis in small intracranial arteries (≤2.5 mm) was limited. We evaluated the safety and efficacy of the treatment by using Wingspan stents in arteries of this caliber.

MATERIALS AND METHODS

From March 2007 to July 2010, 53 symptomatic intracranial stenoses with narrowing of at least 50% in 53 patients were treated by using Wingspan stents. Clinical manifestations and imaging features were recorded.

RESULTS

The technical success rate was 98.1%. There were no serious complications, with the exception of 1 patient who experienced a small cerebral hemorrhage caused by perforation of microwire. Thirty-nine patients (74%) were available for follow-up imaging with DSA. ISR was documented in 13 of these patients, including 2 patients with symptomatic ISR. The median length of the vascular lesions was 5.39 mm, and patients whose vascular lesions were longer than 5.39 mm had a much higher incidence of ISR than patients whose vascular lesions were shorter than 5.39 mm (53% versus 15%, respectively). The median ratio of the reference artery diameter to the stent diameter was 0.78, and patients whose ratio was smaller than 0.78 had a much higher incidence of ISR than patients whose ratio was larger than 0.78 (53% versus 15%, respectively).

CONCLUSIONS

In our series, percutaneous transluminal angioplasty and stent placement of small intracranial arteries by using Wingspan stents was safe. The ISR rate was relatively high; most patients having ISR were asymptomatic. Further follow-up is needed to assess the long-term efficacy of this procedure.

In vitro photodynamic therapy with chlorin e6 leads to apoptosis of human vascular smooth muscle cells

Percutaneous coronary intervention has become the most common and widely implemented method of heart revascularization. However, the development of restenosis remains the major limitation of this method. Photodynamic therapy (PDT) recently emerged as a new and promising method for the prevention of arterial restenosis. Here the efficacy of chlorin e6 in PDT was investigated in vitro using human vascular smooth muscle cells (TG/HA-VSMCs) as one of the cell types crucial in the development of restenosis. PDT-induced cell death was studied on many levels,including annexin V staining, measurement of the generation reactive oxygen species (ROS) and caspase-3 activity,and assessment of changes in mitochondrial membrane potential and fragmentation of DNA. Photosensitization of TG/HA-VSMCs with a 170 lM of chlorin e6 and subsequent illumination with the light of a 672-nm diode laser(2 J/cm2) resulted in the generation of ROS, a decrease in cell membrane polarization, caspase-3 activation, as well as DNA fragmentation. Interestingly, the latter two apoptotic events could not be observed in photosensitized and illuminated NIH3T3 fibroblasts, suggesting different outcomes of the model of PDT in various types of cells. The results obtained with human VSMCs show that chlorin e6 may be useful in the PDT of aerial restenosis, but its efficacy still needs to be established in an animal model.

Effect of cilostazol on in-stent neointimal hyperplasia after coronary artery stenting: a quantative coronary angiography and volumetric intravascular ultrasound study

BACKGROUND

This study was designed to investigate the efficacy of cilostazol on the prevention of in-stent neointimal hyperplasia as measured by both quantitative coronary angiography (CAG) and volumetric intravascular ultrasound (IVUS).

METHODS AND RESULTS

Fifty-nine patients (39 men, age 62 years) undergoing elective coronary stenting were randomly assigned to receive aspirin plus clopidogrel or ticlopidine (Group I, n=28, 30 lesions) or aspirin plus clopidogrel or ticlopidine plus cilostazol (Group II, n=31, 35 lesions). CAG and IVUS were performed and repeated at 6 months to assess the primary endpoints of minimal luminal diameter (MLD) and in-stent neointimal hyperplasia volume. Follow-up CAG was performed on all patients and follow-up IVUS study was available for 50 lesions in 48 patients (24 lesions in Group I, 26 in Group II). There were no significant differences in the baseline angiographic data between the 2 groups. At 6 months follow-up, in-stent MLD was 1.90+/-0.76 mm in Group I and 2.41+/-0.85 mm in Group II (p=0.006). Volumetric IVUS at 6 months demonstrated that in-stent intimal hyperplasia volume per stent length was 2.2+/-1.4 mm3/mm in Group I and 1.0+/-0.5 mm3/mm in Group II (p=0.001).

CONCLUSIONS

Triple antiplatelet therapy including cilostazol seems to be more effective at preventing in-stent neointimal hyperplasia than a dual antiplatelet regimen.

Effects of Diffusion Coefficients and Struts Apposition Using Numerical Simulations for Drug Eluting Coronary Stents

In the context of drug eluting stent, we present two-dimensional numerical models of mass transport of the drug in the wall and in the lumen to study the effect of the drug diffusion coefficients in the three principal media (blood, vascular wall, and polymer coating treated as a three-compartment problem) and the impact of different strut apposition configurations (fully embedded, half embedded, and not embedded). The different conditions were analyzed in terms of their consequence on the drug concentration distribution in the arterial wall. We apply the concept of the therapeutic window to the targeted vascular wall region and derive simple metrics to assess the efficiency of the various stent configurations. Although most of the drug is dispersed in the lumen, variations in the blood flow rate within the physiological range of coronary blood flow and the diffusivity of the drug molecule in the blood were shown to have a negligible effect on the amount of drug in the wall. Our results reveal that the amount of drug cumulated in the wall depends essentially on the relative values of the diffusion coefficients in the polymer coating and in the wall. Concerning the strut apposition, it is shown that the fully embedded strut configuration would provide a better concentration distribution.

Building bridges between academic research and policy formulation: the PRUFE framework - an integral part of Ontario's evidence-based HTPA process

Healthcare expenditure in Ontario has been escalating at increasing rates and a growing proportion of this has come from medical devices and other technologies. A comprehensive evidence-based process for the assessment of new health technologies in Ontario was recently established (the Health Technology Policy Analysis [HTPA] process). Requests for funding for new technologies are directed through a department of the Ministry called the Medical Advisory Secretariat (MAS) who, using a systematic and evidence-based approach, provides information on the safety, effectiveness, and cost effectiveness of the technology to the Ontario Health Technology Advisory Committee (OHTAC). If the OHTAC determines that the evidentiary base for making recommendations is too uncertain, a request is made to reduce this uncertainty through the conduct of a 'real world' Ontario-based study. The Program for Assessment of Technology in Health (PATH) reduction of Uncertainty through Field Evaluation (PRUFE) framework is an iterative process for collecting new information, updating prior knowledge and providing new 'real world' evidence back to the Ministry regarding the cost effectiveness of new health technologies. MAS/OHTAC has undertaken evidence-based analyses for >50 new technologies. The PRUFE framework has been successful for reducing uncertainty and controlling healthcare expenditures while providing access and improving patient outcomes.

Vascular brachytherapy in renal artery restenosis

PURPOSE OF REVIEW

As renal artery stenting becomes more commonly performed, the prevalence of renal artery in-stent restenosis will increase. Intracoronary brachytherapy is the only adjuvant therapy that has been shown to reduce the incidence of recurrent restenosis. This review addresses the mechanisms that make brachytherapy an effective tool for restenosis and its application to renal arteries.

RECENT FINDINGS

To date, the literature on renal artery brachytherapy for restenosis consists of several singular case reports and two case series. The first series of 13 patients had a 20% restenosis rate 1 year after brachytherapy, when Doppler ultrasound was used for follow-up monitoring. A report of a series of 5 patients, published this year, used surrogate markers for assessing efficacy as endpoints and found a similar restenosis rate.

SUMMARY

These series and case reports demonstrate that renal brachytherapy is feasible and safe. Comments on efficacy must await a randomized trial or accumulation of more anecdotal data.

Rationale and design of the randomized, multicenter, cilostazol for RESTenosis (CREST) trial

Restenosis of a segment of diseased coronary artery following metallic stenting is a common clinical problem and a major limitation of the procedure. Systemic pharmacologic interventions to deal with this problem have met with little success. Several small studies suggest that cilostazol, a phosphodiesterase III inhibitor whose pharmacologic properties include antiplatelet, antithrombotic, and vasodilatory effects; a beneficial effect on serum lipids; and in vitro inhibition of smooth muscle cell proliferation, may help prevent platelet aggregation and impede the accumulation of new intimal tissue in the stented artery. The Cilostazol for RESTenosis (CREST) trial will aim to evaluate more definitively the ability of cilostazol to prevent restenosis following uncomplicated stent implantation for de novo coronary artery stenosis. In this randomized, double-blind, multicenter study, 700 patients will receive clopidogrel, aspirin, and either cilostazol or placebo after successful intracoronary stent implantation. The primary endpoint is minimal luminal diameter (MLD) of the first lesion stented after 6 months; secondary endpoints include MLD in all lesions, mean percent diameter stenosis, target lesion revascularization, and major angiographic endpoints. Safety endpoints are abnormal complete blood count and liver function tests at 1, 3, and 6 months. The trial has been initiated, and enrollment is anticipated to be concluded in 2003. Cilostazol has properties that may reduce or avert in-stent coronary restenosis. The CREST trial is a large, rigorously conducted trial that may corroborate the favorable effects of cilostazol on coronary stent restenosis suggested by earlier studies.

Effects of external gamma radiation on femoral artery reimplantation in rats: morphometrical analyzes

PURPOSE: To investigate the effects of external gamma radiation on rat femoral artery reimplant. METHODS: Sixty-two male Wistar rats were distributed in two groups I (Control) and II (Irradiated), both formed by three observation subgroups: 2 (10 animals), 7 (11) and 21(10) postoperative days (PO). The right femoral artery of each animal was split up and reimplanted (end-to-end anastomosis), through microsurgery technique. In the first PO day group II animals were irradiated with a single dose of 15Gy, external source. The histological analysis, qualitative and descriptive analysis, was accomplished through hematoxylin and eosin (HE), Verhoeff and Masson trichromium methodology. Morphometric analysis was realized in the same slides used to histological analysis stained by HE. Computer software was used to quantify morphological alterations of the vascular wall, by processing captured images from a microscope. It was analyzed the intimal layer (intimal hyperplasia and endothelium cells formation) and the nuclei percentage of smooth muscular cell in the medium layer and in the intima hyperplasia. The data were treated applying the statistical tests: Fisher's exact, Chi-square, Mann-Whitney, Kruskal-Wallis and analysis of variance (p < .05). RESULTS: The patency graft was observed by microscope distal to the autograft in 93.5% (29/31). It was observed that the gamma-radiation reduced the degree of covering of the vascular wall for the neo-formed endothelium. The nuclei percentage of smooth muscular cells, in the media, was smaller compared to control animals, although it was no significant for the studied sample size. The irradiated group showed a significant lower luminal stenosis and the intimal hyperplasia occurrence. In this group the percentage of smooth muscular cells proliferation, in the media, were significantly lower for 7 and 21 days of observation. CONCLUSION: The external single dose of 15 Gy gamma-radiation delivered at first postoperative day may inhibit the endothelial cells regeneration and the percentage of lumen stenosis and prevents intimal hyperplasia, in the 2, 7 and 21 PO on femoral artery autograft in rats.

Five-year clinical follow-up after intracoronary radiation: results of a randomized clinical trial

BACKGROUND

Several clinical trials indicate that intracoronary radiation is safe and effective for treatment of restenotic coronary arteries. We previously reported 6-month and 3-year clinical and angiographic follow-up demonstrating significant decreases in target lesion revascularization (TLR) and angiographic restenosis after gamma radiation of restenotic lesions. The objective of this study was to document the clinical outcome 5 years after treatment of restenotic coronary arteries with catheter-based iridium-192 (192Ir).

METHODS AND RESULTS

A double-blind, randomized trail compared 192Ir to placebo sources in patients with restenosis after coronary angioplasty. Over a 9-month period, 55 patients were enrolled; 26 were randomized to 192Ir and 29 to placebo. At 5-year follow-up, TLR was significantly lower in the 192Ir group (23.1% versus 48.3%; P=0.05). There were 2 TLRs between years 3 and 5 in patients in the 192Ir group and none in patients in the placebo group. The 5-year event-free survival rate (freedom from death, myocardial infarction, or TLR) was greater in 192Ir-treated patients (61.5% versus 34.5%; P=0.02).

CONCLUSIONS

Despite apparent mitigation of efficacy over time, there remains a significant reduction in TLR at 5 years and an improvement in event-free survival in patients treated with intracoronary 192Ir. The early clinical benefits after intracoronary gamma radiation with 192Ir seem durable at 5-year clinical follow-up.

The cost-effectiveness of beta-radiation therapy for treatment of in-stent restenosis: an analysis at 290-day follow-up

PURPOSE

We studied the cost-effectiveness of percutaneous coronary intervention (PCI) plus beta-radiation (Radiotherapy) vs. PCI alone for treating in-stent restenosis.

METHODS AND MATERIALS

We analyzed medical resource data collected at US sites during the Intimal Hyperplasia Inhibition with beta In-stent Trial (INHIBIT) to compare the incremental costs between Radiotherapy and PCI alone for each repeat target lesion revascularization (TLR) avoided. Costs were assigned for cardiac-related medical services using the Medicare payer perspective.

RESULTS

Radiotherapy increased initial inpatient costs by US$3360 (P<.001). In the Radiotherapy and PCI alone groups, the mean per-patient rates for TLR were 0.13 vs. 0.30 (P=.001), and mean per-patient total costs were US$19,286 vs. US$18,349 (P<.001), respectively. The incremental cost of Radiotherapy relative to PCI alone was US$5512 per TLR avoided, which compares favorably to the observed mean per-patient cost of treating restenosis (US$16,852).

CONCLUSIONS

beta-radiation is a cost-effective adjunct to PCI in treating patients with in-stent restenosis.