The objective of this study was to examine the value of stress-echocardiography in patients with paradoxical low-flow, low-gradient (PLFLG) aortic stenosis (AS). The projected aortic valve area ...(AVAProj ) at a normal flow rate was calculated in 55 patients with PLFLG AS. In the subset of patients (n = 13) who underwent an aortic valve replacement within 3 months after stress echocardiography, AVAProj correlated better with the valve weight compared to traditional resting and stress echocardiographic parameters of AS severity (AVAProj : r = −0.78 vs. other parameters: r = 0.46 to 0.56). In the whole group (N = 55), 18 (33%) patients had an AVAProj >1.0 cm2 , being consistent with the presence of pseudo severe AS. The AVAProj was also superior to traditional parameters of stenosis severity for predicting outcomes (hazard ratio: 1.32/0.1 cm2 decrease in AVAProj ). In patients with PLFLG AS, the measurement of AVAproj derived from stress echocardiography is helpful to determine the actual severity of the stenosis and predict risk of adverse events.
Abstract Many developments have occurred since the publication of the widely-used 2009 Canadian Cardiovascular Society (CCS) Dyslipidemia guidelines. Here, we present an updated version of the ...guidelines, incorporating new recommendations based on recent findings and harmonizing CCS guidelines with those from other Societies. The G rading of R ecommendations A ssessment, D evelopment and E valuation (GRADE) system was used, per present standards of the CCS. The total cardiovascular disease Framingham Risk Score (FRS), modified for a family history of premature coronary disease, is recommended for risk assessment. Low-density lipoprotein cholesterol remains the primary target of therapy. However, non-high density lipoprotein cholesterol has been added to apolipoprotein B as an alternate target. There is an increased emphasis on treatment of higher risk patients, including those with chronic kidney disease and high risk hypertension. The primary panel has recommended a judicious use of secondary testing for subjects in whom the need for statin therapy is unclear. Expanded information on health behaviours is presented and is the backbone of risk reduction in all subjects. Finally, a systematic approach to statin intolerance is advocated to maximize appropriate use of lipid-lowering therapy. This document presents the recommendations and principal conclusions of this process. Along with associated Supplementary Material that can be accessed online, this document will be part of a program of knowledge translation. The goal is to increase the appropriate use of evidence-based cardiovascular disease event risk assessment in the management of dyslipidemia as a fundamental means of reducing global risk in the Canadian population.
The present article represents the 2009 update of the Canadian Cardiovascular Society guidelines for the diagnosis and treatment of dyslipidemia and prevention of cardiovascular disease in the adult.
Abstract Familial hypercholesterolemia (FH) is the most common genetic disorder causing premature cardiovascular disease and death. Heterozygous FH conservatively affects approximately 1:500 ...Canadians, and the more serious homozygous form affects approximately 1:1,000,000 Canadians, although these numbers might be underestimated. Of approximately 83,500 Canadians estimated to have FH, most are undiagnosed, which represents a simultaneous public health deficit and opportunity, because early treatment of heterozygous FH can normalize life expectancy. Diagnostic algorithms for FH incorporate increased plasma low-density lipoprotein cholesterol, pathognomonic clinical features, and family history of early cardiovascular disease and hyperlipidemia. DNA-based detection of causative mutations in FH-related genes can help with diagnosis. Maximizing diagnosis and treatment of FH in Canada will involve a multipronged approach, including: (1) increasing awareness of FH among health care providers and patients; (2) creating a national registry for FH individuals; (3) setting standards for screening, including cascade screening in affected families; (4) ensuring availability of standard-of-care therapies, in particular optimization of plasma low-density lipoprotein cholesterol levels and timely access to future validated therapies; (5) promoting patient-based support and advocacy groups; and (6) forming alliances with international colleagues, resources, and initiatives that focus on FH. This document aims to raise awareness of FH nationally, and to mobilize knowledge translation, patient support, and availability of treatment and health care resources for this underrecognized, but important medical condition.
Lipoprotein(a) (Lpa) is the preferential lipoprotein carrier of oxidized phospholipids (OxPLs) and a well-established genetic risk factor for calcific aortic valve stenosis (CAVS). Whether Lp(a) ...predicts aortic valve microcalcification in individuals without CAVS is unknown. Our objective was to estimate the prevalence of elevated Lp(a) and OxPL levels in patients with CAVS and to determine if individuals with elevated Lp(a) but without CAVS have higher aortic valve microcalcification.
We recruited 214 patients with CAVS from Montreal and 174 patients with CAVS and 108 controls from Québec City, Canada. In a second group of individuals with high (≥75 nmol/L, n = 27) or low (<75 nmol/L, n = 28) Lp(a) levels, 18F-sodium fluoride positron emission tomography/computed tomography was performed to determine the difference in mean tissue-to-background ratio (TBR) of the aortic valve.
Patients with CAVS had 62.0% higher Lp(a) (median = 28.7, interquartile range 8.2-116.6 vs 10.9 3.6-28.8 nmol/L,
0.0001), 50% higher OxPL-apolipoprotein-B (2.2 1.3-6.0 vs 1.1 0.7-2.6 nmol/L,
0.0001), and 69.9% higher OxPL-apolipoprotein(a) (7.3 1.8-28.4 vs 2.2 0.8-8.4 nmol/L,
0.0001) levels compared with individuals without CAVS (all
0.0001). Individuals without CAVS but elevated Lp(a) had 40% higher mean TBR compared with individuals with low Lp(a) levels (mean TBR = 1.25 ± 0.23 vs 1.15 ± 0.11,
= 0.02).
Elevated Lp(a) and OxPL levels are associated with prevalent CAVS in patients studied in an echocardiography laboratory setting. In individuals with elevated Lp(a), evidence of aortic valve microcalcification by 18F-sodium fluoride positron emission tomography/computed tomography is present before the development of clinically manifested CAVS.
Lipoprotein(a) (Lpa), which consists of a low-density lipoprotein (LDL) bound to apolipoprotein(a), is one of the strongest genetic risk factors for atherosclerotic cardiovascular diseases. Few ...studies have performed hypothesis-free direct comparisons of the Lp(a) and the LDL proteomes. Our objectives were to compare the Lp(a) and the LDL proteomic profiles and to evaluate the effect of lifelong exposure to elevated Lp(a) or LDL cholesterol levels on the plasma proteomic profile.
We performed a label-free analysis of the Lp(a) and LDL proteomic profiles of healthy volunteers in a discovery (n = 6) and a replication (n = 9) phase. We performed inverse variance weighted Mendelian randomization to document the effect of lifelong exposure to elevated Lp(a) or LDL cholesterol levels on the plasma proteomic profile of participants of the INTERVAL study.
We identified 15 proteins that were more abundant on Lp(a) compared with LDL (serping1, pi16, itih1, itih2, itih3, pon1, podxl, cd44, cp, ptprg, vtn, pcsk9, igfals, vcam1, and ttr). We found no proteins that were more abundant on LDL compared with Lp(a). After correction for multiple testing, lifelong exposure to elevated LDL cholesterol levels was associated with the variation of 18 plasma proteins whereas Lp(a) did not appear to influence the plasma proteome.
Results of this study highlight marked differences in the proteome of Lp(a) and LDL as well as in the effect of lifelong exposure to elevated LDL cholesterol or Lp(a) on the plasma proteomic profile.
La lipoprotéine(a) (Lpa), qui est constituée d’une lipoprotéine de basse densité (LDL) liée à une apolipoprotéine(a), est l’un des plus importants facteurs de risque génétiques de survenue d’une maladie cardiovasculaire athéroscléreuse. Peu d’études comparatives directes sans hypothèse ont porté sur le protéome de la Lp(a) et celui des LDL. Nos objectifs étaient de comparer les profils protéomiques de la Lp(a) et des LDL et d’évaluer l’effet d’une exposition à vie à un taux élevé de Lp(a) ou de cholestérol LDL sur le profil protéomique plasmatique.
Nous avons réalisé une analyse sans marquage des profils protéomiques de la Lp(a) et des LDL chez des volontaires en bonne santé dans le cadre d’une phase de découverte (n = 6) et d’une phase de réplication (n = 9). Pour rendre compte de l’effet d’une exposition à vie à un taux élevé de Lp(a) ou de cholestérol des LDL sur le profil protéomique plasmatique des participants de l’étude INTERVAL, nous avons utilisé une analyse de randomisation Mendélienne avec pondération par l’inverse de la variance.
Nous avons relevé 15 protéines associées en plus grande abondance à la Lp(a) qu’aux LDL (serping1, pi16, itih1, itih2, itih3, pon1, podxl, cd44, cp, ptprg, vtn, pcsk9, igfals, vcam1 et ttr). Nous n’avons noté aucune protéine associée en plus grande abondance aux LDL qu’à la Lp(a). Après correction pour tenir compte de la multiplicité des tests, l’exposition à vie à un taux élevé de cholestérol LDL a été associée à la variation de 18 protéines plasmatiques, tandis que le taux de Lp(a) ne semblait pas influencer le protéome plasmatique.
Les résultats de notre étude font ressortir les différences marquées entre le protéome de la Lp(a) et celui des LDL, ainsi qu’entre l’effet sur le profil protéomique plasmatique de l’exposition à vie à un taux élevé de cholestérol LDL et celui de l’exposition à vie à un taux élevé de Lp(a).
It has been previously demonstrated that a new index of aortic stenosis (AS) severity derived from dobutamine stress echocardiography (DSE), the projected aortic valve area (AVA) at a normal ...transvalvular flow rate (AVA(proj)), is superior to traditional Doppler echocardiographic indices to discriminate true severe from pseudosevere low-gradient AS. The objectives of this study were to prospectively validate the diagnostic and prognostic value of AVA(proj) in a large series of patients and to propose a new clinically applicable simplified method to estimate AVA(proj).
AVA(proj) was calculated in 142 patients with low-flow AS using 2 methods. In the conventional method, AVA was plotted against mean transvalvular flow (Q) at each stage of DSE, and AVA at a standardized flow rate of 250 ml/s was projected from the slope of the regression line fitting the plot of AVA versus Q: AVA(proj) = AVA(rest) + slope x (250 - Q(rest)). In the simplified method, using this equation, the slope of the regression line was estimated by dividing the DSE-induced change in AVA from baseline to the peak stage of DSE by the change in Q.
There was a strong correlation between AVA(proj) calculated by the two methods (r = 0.95, P < .0001). Among the 142 patients, 52 underwent aortic valve replacement and had underlying AS severity assessed by the surgeon. Conventional and simplified AVA(proj) demonstrated similar performance in discriminating true severe from pseudosevere AS (percentage of correct classification of AVA(proj) < or = 1 cm(2), 94% and 92%, respectively) and were superior to traditional dobutamine stress echocardiographic indices (percentage of correct classification, 60%-77%). Both conventional and simplified AVA(proj) correlated well with valve weight (r = 0.52 and r = 0.58, respectively), whereas traditional dobutamine stress echocardiographic indices did not. In the 84 patients who were treated medically, conventional AVA(proj) < or = 1.2 cm(2) (hazard ratio, 1.65; P = .02) and simplified AVA(proj) < or = 1.2 cm(2) (hazard ratio, 2.70; P < .0001) were independent predictors of mortality. Traditional dobutamine stress echocardiographic indices were not predictive.
In patients with low-flow AS, AVA(proj) better predicts underlying AS severity and patient outcomes than traditional dobutamine stress echocardiographic indices. Simplified AVA(proj) is easier to calculate than conventional AVA(proj), facilitating the use of AVA(proj) in clinical practice.
Abstract Cardiovascular disease (CVD) is one of the leading causes of morbidity and mortality worldwide, and dyslipidemia constitutes a major risk factor for CVD and premature atherosclerosis. ...Therapies to reduce the plasma levels of atherogenic lipoproteins are well established interventions that decrease CVD risk. However, treatment of dyslipidemia with the most widely used lipid-lowering drugs (ie, statins and ezetimibe) often fails to protect a significant proportion of patients from cardiovascular risk. The development of several novel therapies to treat lipid-related disorders and their associated risks is ongoing and includes the following: (1) reducing plasma levels of atherogenic lipoproteins using proprotein convertase subtilisin/kexin type 9 inhibitors, antisense inhibitors of Apolipoprotein (Apo)(a), microsomal triglyceride transfer protein inhibitors, antisense oligonucleotides of ApoB for inhibiting very low-density lipoprotein production, and inhibitors of angiopoietin-like protein 3 or ApoC-III for triglyceride-rich lipoprotein management upstream of low-density lipoprotein production as well as gene replacement therapy to improve low-density lipoprotein and triglyceride-rich lipoprotein clearance; and (2) emerging therapies that target high-density lipoprotein (HDL) and reverse cholesterol transport using cholesteryl ester transfer protein inhibitors, HDL peptide mimetics, and autologous infusion of pre-β HDLs. Clinical trials of several of these emerging therapies are currently being conducted. Despite the potential efficacy of these new therapies in CVD prevention, their costs might limit their use because of limited reimbursement funds. Therefore, the real challenge facing the next generation of lipid-lowering agents will most likely be accessibility, reflecting a new paradigm that applies to almost all emerging therapies for any disease in the era of precision medicine.
Abstract Researchers from the Cholesterol Treatment Trialists' (CTT) Collaboration have argued for maximal lowering of low-density lipoprotein cholesterol (LDL-C) by the use of pharmacologic agents, ...with the strongest evidence coming from the five comparison statin studies in their second meta-analysis. The CTT meta-analysis has many strengths but also a number of limitations, which have not been discussed and which, given the clinical implications, require consideration. Among these are: (1) the impact and validity of including revascularizations within a composite primary end point; (2) the inclusion of the A-Z study, whose design does not allow for valid comparisons of two statin regimens; (3) the fact that baseline LDL-C levels in the comparison studies were not low enough to test whether statin therapy reduces risk significantly in groups with an initial low LDL-C; and, most important, (4) authors of the five studies compared doses at the extremes of statin regimens. However, the clinical choice is not between the lowest and the greatest dose of a statin statin regimens, for example, between 10 and 80 mg atorvastatin, but, more realistically, between intermediate and high dose, that is, between 40 and 80 mg atorvastatin. On the basis of the CTT meta-analysis, we calculate that any potential gain from increasing the dose from 40 to 80 mg atorvastatin would be very small, at best a further 2% further reduction in clinical events. The increase in dose, unfortunately, would likely be associated with increased side effects and decreased compliance. Accordingly, whether net benefit would be demonstrable cannot be assumed. It follows that definitive evidence supporting maximal lowering of LDL-C or maximal dose of statins is still lacking and guidelines, if they are to be evidence-based, should acknowledge this uncertainty.
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