The Coronary Sinus Reducer; 5-year Dutch experience.

BACKGROUND: Refractory angina is a growing and major health-care problem affecting millions of patients with coronary artery disease worldwide. The Coronary Sinus Reducer (CSR) is a device that may be considered for the relief of symptoms of refractory angina. It causes increased venous pressure leading to a dilatation of arterioles and reduced arterial vascular resistance in the sub-endocardium. This study describes the 5­year Dutch experience regarding safety and efficacy of the CSR. METHODS: One hundred and thirty-two patients with refractory angina were treated with the CSR. The primary efficacy endpoint of the study was Canadian Cardiovascular Society (CCS) class improvement between baseline and 6­month follow-up. The primary safety endpoint was successful CSR implantation in the absence of any device-related events. RESULTS: Eighty-five patients (67%) showed improvement of at least 1 CCS class and 43 patients (34%) of at least 2 classes. Mean CCS class improved from 3.17 ± 0.61 to 2.12 ± 1.07 after implantation (P < 0.001). The CSR was successfully implanted in 99% of the patients and only minor complications during implantation were reported. CONCLUSION: The CSR is a simple, safe, and effective option for most patients with refractory angina. However, approximately thirty percent of the patients showed no benefit after implantation. Future studies should focus on the exact underlying mechanisms of action and reasons for non-response to better identify patients that could benefit most from this therapy.

The ethnicity-specific association of biomarkers with the angiographic severity of coronary artery disease.

BACKGROUND: Risk factor burden and clinical characteristics of patients with coronary artery disease (CAD) differ among ethnic groups. We related biomarkers to CAD severity in Caucasians, Chinese, Indians and Malays. METHODS: In the Dutch-Singaporean UNICORN coronary angiography cohort (n = 2033) we compared levels of five cardiovascular biomarkers: N-terminal pro-brain natriuretic peptide (NTproBNP), high-sensitivity C-reactive protein (hsCRP), cystatin C (CysC), myeloperoxidase (MPO) and high-sensitivity troponin I (hsTnI). We assessed ethnicity-specific associations of biomarkers with CAD severity, quantified by the SYNTAX score. RESULTS: Adjusted for baseline differences, NTproBNP levels were significantly higher in Malays than in Chinese and Caucasians (72.1 vs. 34.4 and 41.1 pmol/l, p < 0.001 and p = 0.005, respectively). MPO levels were higher in Caucasians than in Indians (32.8 vs. 27.2 ng/ml, p = 0.026), hsTnI levels were higher in Malays than in Caucasians and Indians (33.3 vs. 16.4 and 17.8 ng/l, p < 0.001 and p = 0.029) and hsTnI levels were higher in Chinese than in Caucasians (23.3 vs. 16.4, p = 0.031). We found modifying effects of ethnicity on the association of biomarkers with SYNTAX score. NTproBNP associated more strongly with the SYNTAX score in Malays than Caucasians (ß 0.132 vs. ß 0.020 per 100 pmol/l increase in NTproBNP, p = 0.032). For MPO levels the association was stronger in Malays than Caucasians (ß 1.146 vs. ß 0.016 per 10 ng/ml increase, p = 0.017). Differing biomarker cut-off levels were found for the ethnic groups. CONCLUSION: When corrected for possible confounders we observe ethnicity-specific differences in biomarker levels. Moreover, biomarkers associated differently with CAD severity, suggesting that ethnicity-specific cut-off values should be considered.

Heart failure with preserved ejection fraction in women: the Dutch Queen of Hearts program.

Heart failure (HF) poses a heavy burden on patients, their families and society. The syndrome of HF comes in two types: with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). The latter is on the increase and predominantly present in women, especially the older ones. There is an urgent need for mortality-reducing drugs in HFpEF, a disease affecting around 5 % of those aged 65 years and over. HFpEF develops in patients with risk factors and comorbidities such as obesity, hypertension, diabetes, COPD, but also preeclampsia. These conditions are likely to drive microvascular disease with involvement of the coronary microvasculature, which may eventually evolve into HFpEF. Currently, the diagnosis of HFPEF relies mainly on echocardiography. There are no biomarkers that can help diagnose female microvascular disease or facilitate the diagnosis of (early stages of) HFpEF. Recently a Dutch consortium was initiated, Queen of Hearts, with support from the Netherlands Heart Foundation, with the aim to discover and validate biomarkers for diastolic dysfunction and HFpEF in women. These biomarkers come from innovative blood-derived sources such as extracellular vesicles and circulating cells. Within the Queen of Hearts consortium, we will pursue female biomarkers that have the potential for further evolution in assays with point of care capabilities. As a spin-off, the consortium will gain knowledge on gender-specific pathology of HFpEF, possibly opening up novel treatment options.

Plasma extracellular vesicle protein content for diagnosis and prognosis of global cardiovascular disease.

Cardiovascular disease is a major public health problem worldwide. Its growing burden is particularly ominous in Asia, due to increasing rates of major risk factors such as diabetes, obesity and smoking. There is an urgent need for early identification and treatment of individuals at risk of adverse cardiovascular events. Plasma extracellular vesicle proteins are novel biomarkers that have been shown to be useful in the diagnosis, risk stratification and prognostication of patients with cardiovascular disease. Ongoing parallel biobank initiatives in European (the Netherlands) and Asian (Singapore) populations offer a unique opportunity to validate these biomarkers in diverse ethnic groups.

Carotid atherosclerotic plaques stabilize after stroke: insights into the natural process of atherosclerotic plaque stabilization.

OBJECTIVE: Rupture of unstable atherosclerotic plaques is the pathological substrate for acute ischemic events. Underlying cellular and molecular characteristics of plaque rupture have been studied extensively. However, the natural course of symptomatic plaque remodeling after ischemic events is relatively unexplored. METHODS AND RESULTS: Atherosclerotic carotid plaques were obtained from 804 symptomatic (stroke=204 and TIA=426) and asymptomatic (n=174) patients undergoing carotid endarterectomy. The presence of macrophages, smooth muscle cells (SMC), collagen, calcification, and lipid-core size were assessed histologically. At protein level, inflammatory mediators (interleukin [IL]-2, IL-4, IL-5, IL-8, IL-10, IL-12p70, interferon-gamma [INF-gamma], tumor necrosis factor-alpha [TNF-alpha], matrix degrading proteinases (MMPs), and an apoptosis marker (caspase-3) were determined. We associated plaque characteristics with time elapsed between the latest event and surgery. Early after stroke and TIA, plaques revealed an unstable phenotype. After stroke, the content of macrophages decreased significantly with time (P=0.02), whereas SMC content tended to increase. At protein level, IL-6, IL-8 expression levels and caspase activity strongly decreased after stroke or TIA. CONCLUSIONS: Symptomatic carotid lesions remodel into more stable plaques over time after stroke. Changes in IL-6 and IL-8 and caspase preceded the decrease of macrophages. These temporal phenotypic plaque alterations should be taken into account for biomarker and therapeutic target validation studies using human atherosclerotic plaques.

Predictive risk factors for restenosis after remote superficial femoral artery endarterectomy.

OBJECTIVES: Restenosis following remote superficial femoral artery endarterectomy (RSFAE) remains a challenging problem. The determinants predicting failure are lacking. This study investigated patient characteristics with predictive value for restenosis during the first year after RSFAE. DESIGN: A prospective cohort study. MATERIALS AND METHODS: A total of 90 patients post-RSFAE were studied for the occurrence of restenosis (peak systolic velocity ratio >or= 2.5) in the first 12 months postoperatively. At baseline, clinical parameters were recorded. Vessel size was measured on the basis of plaque perimeter in the culprit lesion and lumen diameter on perioperative digital subtraction angiography. RESULTS: In 57 patients (63%), a restenotic lesion was diagnosed within 12 months following surgery. Patients with longer time interval between start of ischaemic walking complaints and RSFAE revealed a significantly higher incidence of restenosis (hazard ratio (HR) = 1.3 (1.05-1.52) per 4 years). Small plaque perimeter and small superficial femoral artery (SFA) diameter on angiography were significantly associated with restenosis (HR = 0.54 (0.34-0.88) per 10 mm and HR = 0.46 (0.27-0.78) per 1.5 mm, respectively). In multivariate analysis, age, duration of ischaemic walking complaints and lumen diameter were independently associated with increased risk of restenosis after RSFAE. CONCLUSIONS: This study provides evidence that age, vessel size and duration of ischaemic walking complaints before RSFAE are predictive values for restenosis after RSFAE.

[Differences between men and women in the composition of atherosclerotic plaque, as an explanation for the lower success rate of carotid endarterectomy in women]. / Verschillen in samenstelling van de atherosclerotische plaque tussen mannen en vrouwen als verklaring voor het geringere succes van carotisendarteriëctomie bij vrouwen.

OBJECTIVE: To determine whether men and women differ in the histological characteristics of plaque material removed at carotid endarterectomy. DESIGN: Observational and descriptive. METHODS: Carotid endarterectomy plaque specimens obtained from 45 degrees consecutive patients (135 women, 315 men) were assessed for the presence of macrophages, smooth muscle cells, collagen, calcifications, and luminal thrombus by means ofimmunohistochemical staining. The plaques were categorised in 3 phenotypes according to the overall presentation of histological characteristics and the lipid level. Protein was isolated from the plaques to determine the interleukin-6 (IL-6) and IL-8 concentrations and the activity of matrix metalloproteinase-8 (MMP-8) and MMP-9. RESULTS: Atheromatous plaques (> 40% fat) were less frequently observed in women than in men (22 versus 40%; p < 0.001). In addition, more women than men had a low macrophage staining (18 versus 11%; p = 0.05) and strong smooth muscle cell staining (38 versus 24%; p = 0.001). Compared with men, women had a lower plaque concentration of IL-8 and lower MMP-8 activity. The observed differences were most pronounced in the asymptomatic group. An atheromatous plaque occurred in 9% of asymptomatic women compared to 39% ofasymptomatic men (p = 0.02). Moreover, a large proportion of plaques obtained from asymptomatic women showed high smooth muscle cell content (53 versus 30%; p = 0.03) and high collagen content (55 versus 24%; p = 0.003). All relations between gender and plaque characteristics, except for MMP-8, remained the same in a multivariate analysis that was adjusted for clinical presentation and other cardiovascular risk factors. CONCLUSION: Women with a carotid stenosis had more stable plaques than men, independent of clinical presentation and cardiovascular risk profile. Asymptomatic women demonstrated the highest prevalence of stable plaques. These findings may explain why women benefit less from carotid endarterectomy than men.

Identification of genes potentially involved in disease transformation of CML.

In patients with chronic myeloid leukemia (CML) who do not reach a (near) complete cytogenetic response, the disease progresses over several years from an indolent, chronic phase into a rapidly fatal blast crisis. Events that are responsible for this transformation process are largely unknown. To identify changes in gene expression that occurred during the course of the disease, we performed cDNA subtraction on sequentially stored peripheral blood mononuclear cell pellets, collected throughout the course of disease of a single CML patient. In total, 32 differentially expressed sequences were identified, of which 27 corresponded to known genes. On quantitative PCR, eight of these genes, YWHAZ, GAS2, IL8, IL6, PBEF1, CCL4, SAT and MMRN, showed comparable differential expression in additional CML patient samples. This set of genes can be considered as a starting point for further research on causes of disease transformation in CML and may lead to new targets in the treatment of resistant CML.

Toll-like receptor 2 stimulation induces intimal hyperplasia and atherosclerotic lesion development.

BACKGROUND: Toll like receptors (Tlr) are essential in activation of the innate immune system. We recently described that peptidoglycan, an exogenous Tlr2 specific ligand, is present in human atherosclerotic plaques and associated with histological markers for plaque vulnerability. Also, endogenous Tlr2 ligands can be expressed in atherosclerotic tissues. Here, we determined whether Tlr2 stimulation promotes pro-inflammatory cytokine/chemokine production in vitro and augments neointima formation and development of atherosclerotic plaques in vivo. METHODS AND RESULTS: We detected Tlr2 using Western blot and RT-PCR in human coronary arteries and primary adventitial fibroblasts. RNAse protection assay demonstrated significant induction of IL-1, IL-6, IL-8 and MCP-1 mRNA after Tlr2 stimulation in human adventitial fibroblasts in vitro. ELISA demonstrated induction of IL-6, IL-8 and MCP-1. In vivo application of Pam(3)Cys-SK(4), a synthetic Tlr2 ligand, on femoral arteries of C57BL/6 wild type (WT) mice using a peri-adventitial cuff, significantly enhanced neointima formation compared to control arteries. This increased inflammatory response was not observed in Tlr2 knockout (Tlr2-/-) mice. In ApoE knockout mice (ApoE-/-), application of the same Tlr2 ligand led to a significant increase in atherosclerotic plaque development. CONCLUSION: Local arterial Tlr2 stimulation induced neointima and atherosclerotic plaque formation in mouse femoral arteries. Tlr2 stimulation may be an important mediator in arterial occlusive disease.

Carotid atherosclerotic plaque characteristics are associated with microembolization during carotid endarterectomy and procedural outcome.

BACKGROUND AND PURPOSE: During carotid endarterectomy (CEA), microemboli may occur, resulting in perioperative adverse cerebral events. The objective of the present study was to investigate the relation between atherosclerotic plaque characteristics and the occurrence of microemboli or adverse events during CEA. METHODS: Patients (n=200, 205 procedures) eligible for CEA were monitored by perioperative transcranial Doppler. The following phases were discriminated during CEA: dissection, shunting, release of the clamp, and wound closure. Each carotid plaque was stained for collagen, macrophages, smooth muscle cells, hematoxylin, and elastin. Semiquantitative analyses were performed on all stainings. Plaques were categorized into 3 groups based on overall appearance (fibrous, fibroatheromatous, or atheromatous). RESULTS: Fibrous plaques were associated with the occurrence of more microemboli during clamp release and wound closure compared with atheromatous plaques (P=0.04 and P=0.02, respectively). Transient ischemic attacks and minor stroke occurred in 5 of 205 (2.4%) and 6 of 205 (2.9%) patients, respectively. Adverse cerebral outcome was significantly related to the number of microembolic events during dissection (P=0.003) but not during shunting, clamp release, or wound closure. More cerebrovascular adverse events occurred in patients with atheromatous plaques (7/69) compared with patients with fibrous or fibroatheromatous plaques (4/138) (P=0.04). CONCLUSIONS: Intraoperatively, a higher number of microemboli were associated with the presence of a fibrous but not an atheromatous plaque. However, atheromatous plaques were more prevalent in patients with subsequent immediate adverse events. In addition, specifically the number of microemboli detected during the dissection phase were related to immediate adverse events.

Modulation of collagen turnover in cardiovascular disease.

Collagen fibers are the most abundant components of the extracellular matrix in arteries and myocardium. Disturbances in the collagen turnover (synthesis and degradation) have been linked to inflammatory diseases including cardiovascular pathological syndromes. In the myocardium, changes in collagen turnover may result in ventricle dilatation and subsequent contractile dysfunction. In arteries, collagen synthesis and degradation are associated with the progression of atherosclerotic disease and intimal hyperplasia following injury. Collagen synthesis is tightly regulated at several levels: synthesis of procollagens, suitable folding of polypeptides, secretion and cross-linking of mature fibers. On the other hand, degradation of newly synthesised procollagen and mature collagen fibers depends on the action of Matrix-Metalloproteinases (MMPs). The major role of collagen turnover in cardiovascular disorders has stimulated the search for pharmacological agents that interfere with collagen turnover at different levels. These drugs can theoretically act through modulation of the synthesis of procollagens or by interference with their post-translational modifications. Another group of pharmacological agents inhibit collagen breakdown (MMP inhibitors). Beneficial effects of compounds that target collagen metabolism have been reported. Unfortunately, many of these compounds also give rise to serious adverse effects due to interference with vital biological processes in which collagen plays an important role. In this paper, we will review cardiovascular diseases in which altered local collagen turnover is a key feature. Subsequently, the effect of compounds that have been developed and tested to modulate collagen synthesis, cross-linking or breakdown will be discussed.

Matrix metalloproteinases: a therapeutic target in cardiovascular disease.

Cardiovascular disease is the leading cause of death in Western society. Extracellular matrix turnover is important in many cardiovascular pathologies, such as arterial remodeling, plaque rupture, restenosis, aneurysm formation and heart failure. Matrix metalloproteinases (MMPs) belong to a group of zinc and calcium dependent proteases and cause breakdown of the extracellular matrix. MMP inhibitors have been developed and tested for their effect on the outcome of oncological disease [1]. Recent preclinical research revealed that these MMP inhibitors could also have great potential in the field of cardiovascular disease. This preclinical research has encouraged investigators to design and start the first clinical studies with cardiovascular endpoints. In the present paper, the various aspects of MMP participation in cardiovascular disease will be summarized. Preclinical animal studies that demonstrated the effect and potential of applicable MMP inhibitors on different cardiovascular disease entities will be discussed. We will specifically focus on the role of MMPs and the potential of their inhibitors in de novo atherosclerotic plaque destabilization, arterial remodeling, restenosis after ballon angioplasty and stenting, aneurysm formation and heart failure. We conclude that MMP inhibitors are likely to be useful in the development of pharmacological approaches to reduce cardiovascular death, considering the positive outcomes after usage of MMP inhibitors in restenosis and arterial remodeling.

[Remodelling of the arterial wall: a determinant of luminal stenosis and a factor with prognostic significance]. / Remodellering van de vaatwand: een determinant van lumenstenosering en een factor met prognostische betekenis.

A structural transversal change in artery size is a type of arterial remodelling. Luminal stenosis in atherosclerosis is not only determined by plaque increase, but also by remodelling of the vessel wall. Expansive remodelling prevents luminal stenosis by atherosclerotic plaque progression, whereas constrictive remodelling increases luminal stenosis. Expansive remodelling is associated with lesions that are frequently observed at sites of acute manifestations of atherosclerotic disease, such as myocardial infarction, and it is therefore a negative prognostic feature. Constrictive remodelling is associated with stable plaque lesions. Remodelling of the vessel wall also plays a role after interventions such as balloon angioplasty, heart transplantation and bypass surgery. For example, the most important determinant of restenosis after balloon angioplasty is constrictive remodeling.

Methods in molecular cardiology: suppression subtraction hybridisation.

Identification of differentially expressed genes in pathological tissues may provide more insight into the molecular mechanism involved in the development or progression of disease. Suppression subtraction hybridisation (SSH) allows the identification of novel, differentially expressed genes without prior knowledge about gene expression patterns or functional and biochemical protein characteristics. This review provides a general overview of the SSH method and gives two examples of SSH in the cardiovascular field.

Methods in molecular cardiology: quantitative real-time polymerase chain reaction.

Changes in mRNA expression levels occur during physiological and pathological processes in the cardiovascular system. An increase in DNA transcription results in increased mRNA levels and will subsequently cause an increase in levels of proteins that regulate processes inside and outside the cell. To determine alterations in mRNA levels, traditional methods such as Northern blotting and ribonuclease protection assay can be used; however, large amounts of RNA are necessary and the methods are very labour intensive. In this review, we focus on one of the newest advancements in polymerase chain reaction (PCR) technology, real-time or quantitative PCR, using small amounts of RNA to determine expression levels. We discuss the technique in general and describe two different approaches.

Increased amount of bone marrow-derived smooth muscle-like cells and accelerated atherosclerosis in diabetic apoE-deficient mice.

AIMS: Atherosclerotic plaque development is accelerated in patients with diabetes. Bone marrow-derived smooth muscle-like cells have been detected in neointima and diabetes has a numerical and functional effect on circulating vascular progenitor cells. We hypothesized that an increased number of bone marrow-derived smooth muscle-like cells correlates with accelerated atherosclerosis in diabetic apoE-deficient mice. METHODS: ApoE(-/-) mice were subjected to total body irradiation and transplanted with bone marrow cells from GFP-transgenic mice. Mice were rendered diabetic by streptozotocin injection and examined after 4, 8, 11 and 15 weeks of diabetes. RESULTS: Diabetic mice showed a larger plaque area and a higher number of smooth muscle-like cells compared to non-diabetic mice at 11 and 15 weeks after diabetes induction. Bone marrow-derived smooth muscle-like cells were detected in atherosclerotic plaques of both diabetic and control mice, but numbers were higher in plaques of diabetic mice 11 weeks after induction of diabetes. The higher number of bone marrow-derived smooth muscle-like cells in plaque was associated with an increase in in vitro differentiation of smooth muscle-like cells from spleen mononuclear cells in diabetic mice. CONCLUSIONS: Diabetes increases the number of bone marrow-derived smooth muscle-like cells in atherosclerotic plaques and the differentiation of mononuclear cells towards smooth muscle-like cells, which may contribute to accelerated atherosclerotic plaque development in diabetic apoE(-/-) mice.

Biobanking in atherosclerotic disease, opportunities and pitfalls.

Cardiovascular disease is the leading cause of death in Western countries and current research is still focusing on optimizing therapeutic approaches in the battle against this multifactorial disease. Concepts regarding the pathogenesis of many cardiovascular diseases originate from observations of human atherosclerotic tissue obtained from autopsies or during vascular surgery. These observations have helped us to disentangle the pathophysiology of atherosclerosis. However, identifying vulnerable patients, those prone to developing cardiovascular complications, remains difficult. The search for predictive cardiovascular biomarkers continues and large, well organized biobanks are needed to discover or validate novel biomarkers. Biobanks are an extremely valuable resource that enables us to study the influence of both genetic and environmental factors on the development of multifactorial diseases such as atherosclerosis. This review will focus on the advantages and pitfalls in atherosclerotic biobanking.

New predictors of adverse cardiovascular events following vascular surgery.

With the aging population and the increasing number of patients suffering from diabetes, the incidence of clinical manifestations of atherosclerotic disease is rising. Risk factors for development of atherosclerosis have been described and it is a challenge to develop risk scores that can be applied for individual patients. Specific predictors for progression of atherosclerosis and secondary manifestations of the disease are lacking. The search for new serological and genetic markers predictive for cardiovascular events is an emerging research field. Local plaque instability can give rise to thromboembolic cardiovascular events, which suggests that certain information might be enclosed in local atherosclerotic tissue. Because of the systemic character of atherosclerosis, it can be hypothesized that local plaque characteristics encompass information of other atherosclerotic lesions throughout the vascular tree. Biobank studies with a longitudinal design have been initiated to investigate the link between characteristics of local atherosclerotic tissue and outcome during follow up. These studies might reveal new insights in predictors for cardiovascular outcome for vascular patients at an individual level.

Atherosclerotic lesion development and Toll like receptor 2 and 4 responsiveness.

BACKGROUND: Toll like receptors (TLR) have been recognized for their role in atherosclerotic lesion development and progression. Endogenous TLR ligands that are also expressed in atherosclerotic tissues have been shown to promote atherosclerosis in mice. Since repetitive stimulation of TLR induces an attenuated inflammatory response, we hypothesized that the TLR response is altered during atherosclerosis development, due to chronic exposure to endogenous ligands. METHODS AND RESULTS: We examined five groups of both ApoE-/- and C57Bl/6 mice aged 5, 10, 15, 25 and 40 weeks. In ApoE-/- mice with advanced stages of atherosclerosis, levels of mRNA encoding TLR2 and TLR4, the endogenous TLR ligands EDA and hsp60 as well as intracellular TLR-regulating mediators, like IRAK-M, were increased. Systemic TLR cell surface expression on circulating monocytes and EDA plasma levels were significantly increased in ApoE-/- mice with advanced atherosclerosis. We also observed that the endogenous TLR ligand EDA was capable of activating the TLR-signaling pathway in white blood cells. During the plaque progression stage however, stimulation of TLR2 and TLR4 in blood samples attenuated MIP-1 alpha and RANTES release in atherosclerotic mice. CONCLUSION: During atherosclerotic lesion development, TLR2 and TLR4 expression increases in atherosclerotic plaques and on circulating blood cells. However, with advanced stages of atherosclerotic disease, circulating blood cells become less responsive to TLR ligation, which may be due to chronic TLR engagement by endogenous EDA.