Steven R. Jones

Coronary Artery Calcium Progression: An Important Clinical Measurement?: A Review of Published Reports

Baseline coronary artery calcification (CAC) accurately identifies coronary atherosclerosis and might improve prediction of future cardiac events. Serial assessment of CAC scores has been proposed for monitoring atherosclerosis progression and for assessing the effectiveness of medical therapies aimed at reducing cardiac risk. However, whether knowledge of progression of CAC scores over time further improves risk prediction is unclear. Several trials relating medical therapies to CAC progression have been performed without any formal guidelines on the definition of CAC progression and how it is best quantified. We conducted a comprehensive review of published reports on CAC progression. Increased CAC progression is associated with many known cardiac risk factors. We found that CAC progression correlates with worsening atherosclerosis and may facilitate prediction of future cardiac events. These findings support the notion that slowing CAC progression with therapeutic interventions might provide prognostic benefit. However, despite promising early data, such interventions (most notably with statin therapy) have not been shown to slow the progression of CAC in any randomized controlled trial to date, outside of post hoc subgroup analyses. Thus, routine quantification of CAC progression cannot currently be recommended in clinical practice. First, standards of how CAC progression should be defined and assessed need to be developed. In addition, there remains a need for further studies analyzing the effect of other cardiac therapies on CAC progression and cardiac outcomes.

Statin intolerance - an attempt at a unified definition. Position paper from an International Lipid Expert Panel.

Statins are one of the most commonly prescribed drugs in clinical practice. They are usually well tolerated and effectively prevent cardiovascular events. Most adverse effects associated with statin therapy are muscle-related. The recent statement of the European Atherosclerosis Society (EAS) has focused on statin associated muscle symptoms (SAMS), and avoided the use of the term ‘statin intolerance’. Although muscle syndromes are the most common adverse effects observed after statin therapy, excluding other side effects might underestimate the number of patients with statin intolerance, which might be observed in 10–15% of patients. In clinical practice, statin intolerance limits effective treatment of patients at risk of, or with, cardiovascular disease. Knowledge of the most common adverse effects of statin therapy that might cause statin intolerance and the clear definition of this phenomenon is crucial to effectively treat patients with lipid disorders. Therefore, the aim of this position paper was to suggest a unified definition of statin intolerance, and to complement the recent EAS statement on SAMS, where the pathophysiology, diagnosis and the management were comprehensively presented.

Friedewald-estimated versus directly measured low-density lipoprotein cholesterol and treatment implications.

OBJECTIVES The aim of this study was to compare Friedewald-estimated and directly measured low-density lipoprotein cholesterol (LDL-C) values. BACKGROUND LDL-C is routinely estimated by the Friedewald equation to guide treatment; however, compatibility with direct measurement has received relatively little scrutiny, especially at levels <70 mg/dl now targeted in high-risk patients. METHODS We examined 1,340,614 U.S. adults who underwent lipid profiling by vertical spin density gradient ultracentrifugation (Atherotech, Birmingham, Alabama) from 2009 to 2011. Following standard practice, Friedewald LDL-C was not estimated if triglyceride levels were ≥ 400 mg/dl (n = 30,174), yielding 1,310,440 total patients and 191,333 patients with Friedewald LDL-C <70 mg/dl. RESULTS Patients were 59 ± 15 years of age and 52% were women. Lipid distributions closely matched those in the National Health and Nutrition Examination Survey. A greater difference in the Friedewald-estimated versus directly measured LDL-C occurred at lower LDL-C and higher triglyceride levels. If the Friedewald-estimated LDL-C was <70 mg/dl, the median directly measured LDL-C was 9.0 mg/dl higher (5th to 95th percentiles, 1.8 to 15.4 mg/dl) when triglyceride levels were 150 to 199 mg/dl and 18.4 mg/dl higher (5th to 95th percentiles, 6.6 to 36.0 mg/dl) when triglyceride levels were 200 to 399 mg/dl. Of patients with a Friedewald-estimated LDL-C <70 mg/dl, 23% had a directly measured LDL-C ≥ 70 mg/dl (39% if triglyceride levels were concurrently 150 to 199 mg/dl; 59% if triglyceride levels were concurrently 200 to 399 mg/dl). CONCLUSIONS The Friedewald equation tends to underestimate LDL-C most when accuracy is most crucial. Especially if triglyceride levels are ≥ 150 mg/dl, Friedewald estimation commonly classifies LDL-C as <70 mg/dl despite directly measured levels ≥ 70 mg/dl, and therefore additional evaluation is warranted in high-risk patients.

Comparison of a Novel Method vs the Friedewald Equation for Estimating Low-Density Lipoprotein Cholesterol Levels From the Standard Lipid Profile

IMPORTANCE In clinical and research settings worldwide, low-density lipoprotein cholesterol (LDL-C) is typically estimated using the Friedewald equation. This equation assumes a fixed factor of 5 for the ratio of triglycerides to very low-density lipoprotein cholesterol (TG:VLDL-C); however, the actual TG:VLDL-C ratio varies significantly across the range of triglyceride and cholesterol levels. OBJECTIVE To derive and validate a more accurate method for LDL-C estimation from the standard lipid profile using an adjustable factor for the TG:VLDL-C ratio. DESIGN, SETTING, AND PARTICIPANTS We used a convenience sample of consecutive clinical lipid profiles obtained from 2009 through 2011 from 1,350,908 children, adolescents, and adults in the United States. Cholesterol concentrations were directly measured after vertical spin density-gradient ultracentrifugation, and triglycerides were directly measured. Lipid distributions closely matched the population-based National Health and Nutrition Examination Survey (NHANES). Samples were randomly assigned to derivation (n = 900,605) and validation (n = 450,303) data sets. MAIN OUTCOMES AND MEASURES Individual patient-level concordance in clinical practice guideline LDL-C risk classification using estimated vs directly measured LDL-C (LDL-CD). RESULTS In the derivation data set, the median TG:VLDL-C was 5.2 (IQR, 4.5-6.0). The triglyceride and non-high-density lipoprotein cholesterol (HDL-C) levels explained 65% of the variance in the TG:VLDL-C ratio. Based on strata of triglyceride and non-HDL-C values, a 180-cell table of median TG:VLDL-C values was derived and applied in the validation data set to estimate the novel LDL-C (LDL-CN). For patients with triglycerides lower than 400 mg/dL, overall concordance in guideline risk classification with LDL-CD was 91.7% (95% CI, 91.6%-91.8%) for LDL-CN vs 85.4% (95% CI, 85.3%-85.5%) for Friedewald LDL-C (LDL-CF) (P < .001). The greatest improvement in concordance occurred in classifying LDL-C lower than 70 mg/dL, especially in patients with high triglyceride levels. In patients with an estimated LDL-C lower than 70 mg/dL, LDL-CD was also lower than 70 mg/dL in 94.3% (95% CI, 93.9%-94.7%) for LDL-CN vs 79.9% (95% CI, 79.3%-80.4%) for LDL-CF in samples with triglyceride levels of 100 to 149 mg/dL; 92.4% (95% CI, 91.7%-93.1%) for LDL-CN vs 61.3% (95% CI, 60.3%-62.3%) for LDL-CF in samples with triglyceride levels of 150 to 199 mg/dL; and 84.0% (95% CI, 82.9%-85.1%) for LDL-CN vs 40.3% (95% CI, 39.4%-41.3%) for LDL-CF in samples with triglyceride levels of 200 to 399 mg/dL (P < .001 for each comparison). CONCLUSIONS AND RELEVANCE A novel method to estimate LDL-C using an adjustable factor for the TG:VLDL-C ratio provided more accurate guideline risk classification than the Friedewald equation. These findings require external validation, as well as assessment of their clinical importance. The implementation of these findings into clinical practice would be straightforward and at virtually no cost. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01698489.

Dyslipidemia, Coronary Artery Calcium, and Incident Atherosclerotic Cardiovascular Disease Implications for Statin Therapy From the Multi-Ethnic Study of Atherosclerosis

Background— Worldwide clinical practice guidelines for dyslipidemia emphasize allocating statin therapy to those at the highest absolute atherosclerotic cardiovascular disease (CVD) risk. Methods and Results— We examined 5534 Multi-Ethnic Study of Atherosclerosis (MESA) participants who were not on baseline medications for dyslipidemia. Participants were classified by baseline coronary artery calcium (CAC) score (>0, ≥100) and the common clinical scheme of counting lipid abnormalities (LA), including low-density lipoprotein cholesterol ≥3.36 mmol/L (130 mg/dL), high-density lipoprotein cholesterol <1.03 mmol/L (40 mg/dL) for men or <1.29 mmol/L (50 mg/dL) for women, and triglycerides ≥1.69 mmol/L (150 mg/dL). Our main outcome measure was incident CVD (myocardial infarction, angina resulting in revascularization, resuscitated cardiac arrest, stroke, cardiovascular death). Over a median follow-up of 7.6 years, more than half of events (55%) occurred in the 21% of participants with CAC ≥100. Conversely, 65% of events occurred in participants with 0 or 1 LA. In those with CAC ≥100, CVD rates ranged from 22.7 to 29.5 per 1000 person-years across LA categories. In contrast, with CAC=0, CVD rates ranged from 2.7 to 5.9 per 1000 person-years across LA categories. Individuals with 0 LA and CAC ≥100 had a higher event rate compared with individuals with 3 LA but CAC=0 (22.7 versus 5.9 per 1000 person-years). Similar results were obtained when we classified LA using data set quartiles of total cholesterol/high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, non–high-density lipoprotein cholesterol, or low-density lipoprotein particle concentration and guideline categories of low-density lipoprotein cholesterol or non–high-density lipoprotein cholesterol. Conclusions— CAC may have the potential to help match statin therapy to absolute CVD risk. Across the spectrum of dyslipidemia, event rates similar to secondary prevention populations were observed for patients with CAC ≥100. # Clinical Perspective {#article-title-26}Background— Worldwide clinical practice guidelines for dyslipidemia emphasize allocating statin therapy to those at the highest absolute atherosclerotic cardiovascular disease (CVD) risk. Methods and Results— We examined 5534 Multi-Ethnic Study of Atherosclerosis (MESA) participants who were not on baseline medications for dyslipidemia. Participants were classified by baseline coronary artery calcium (CAC) score (>0, ≥100) and the common clinical scheme of counting lipid abnormalities (LA), including low-density lipoprotein cholesterol ≥3.36 mmol/L (130 mg/dL), high-density lipoprotein cholesterol <1.03 mmol/L (40 mg/dL) for men or <1.29 mmol/L (50 mg/dL) for women, and triglycerides ≥1.69 mmol/L (150 mg/dL). Our main outcome measure was incident CVD (myocardial infarction, angina resulting in revascularization, resuscitated cardiac arrest, stroke, cardiovascular death). Over a median follow-up of 7.6 years, more than half of events (55%) occurred in the 21% of participants with CAC ≥100. Conversely, 65% of events occurred in participants with 0 or 1 LA. In those with CAC ≥100, CVD rates ranged from 22.7 to 29.5 per 1000 person-years across LA categories. In contrast, with CAC=0, CVD rates ranged from 2.7 to 5.9 per 1000 person-years across LA categories. Individuals with 0 LA and CAC ≥100 had a higher event rate compared with individuals with 3 LA but CAC=0 (22.7 versus 5.9 per 1000 person-years). Similar results were obtained when we classified LA using data set quartiles of total cholesterol/high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, non–high-density lipoprotein cholesterol, or low-density lipoprotein particle concentration and guideline categories of low-density lipoprotein cholesterol or non–high-density lipoprotein cholesterol. Conclusions— CAC may have the potential to help match statin therapy to absolute CVD risk. Across the spectrum of dyslipidemia, event rates similar to secondary prevention populations were observed for patients with CAC ≥100.

HDL cholesterol subclasses, myocardial infarction, and mortality in secondary prevention: the lipoprotein investigators collaborative

AIMS High-density lipoprotein (HDL) is highly heterogeneous and the link of its subclasses to prognosis remains controversial. We aimed to rigorously examine the associations of HDL subclasses with prognosis in secondary prevention. METHODS AND RESULTS We collaboratively analysed data from two, complementary prospective cohorts: the TRIUMPH study of 2465 acute myocardial infarction patients, and the IHCS study of 2414 patients who underwent coronary angiography. All patients had baseline HDL subclassification by vertical-spin density gradient ultracentrifugation. Given non-linearity, we stratified by tertiles of HDL-C and its two major subclasses (HDL2-C, HDL3-C), then compared multivariable-adjusted hazard ratios for mortality and mortality/myocardial infarction. Patients were middle-aged to elderly (TRIUMPH: 58.2 ± 12.2 years; IHCS: 62.6 ± 12.6 years), and the majority were men (TRIUMPH: 68.0%; IHCS: 65.5%). IHCS had lower mean HDL-C levels (34.6 ± 10.1 mg/dL) compared with TRIUMPH (40 ± 10.6 mg/dL). HDL3-C accounted for >3/4 of HDL-C (mean HDL3-C/HDL-C 0.78 ± 0.05 in both cohorts). During 2 years of follow-up in TRIUMPH, 226 (9.2%) deaths occurred, while death/myocardial infarction occurred in 401 (16.6%) IHCS patients over 5 years. No independent associations with outcomes were observed for HDL-C or HDL2-C. In contrast, the lowest tertile of HDL3-C was independently associated with >50% higher risk in each cohort (TRIUMPH: with middle tertile as reference, fully adjusted HR for mortality of HDL3-C, 1.57; 95% CI, 1.13-2.18; IHCS: fully adjusted HR for mortality/myocardial infarction, 1.55; 95% CI, 1.20-2.00). CONCLUSION In secondary prevention, increased risk for long-term hard clinical events is associated with low HDL3-C, but not HDL2-C or HDL-C, highlighting the potential value of subclassifying HDL-C.

Analysis of vitamin D levels in patients with and without statin-associated myalgia - A systematic review and meta-analysis of 7 studies with 2420 patients

INTRODUCTION Vitamin D (vit D) deficiency may be associated with an increased risk of statin-related symptomatic myalgia in statin-treated patients. The aim of this meta-analysis was to substantiate the role of serum vitamin D levels in statin-associated myalgia. METHODS The search included PUBMED, Cochrane Library, Scopus, and EMBASE from January 1, 1987 to April 1, 2014 to identify studies that investigated the impact of vit D levels in statin-treated subjects with and without myalgia. Two independent reviewers extracted data on study characteristics, methods and outcomes. Quantitative data synthesis was performed using a fixed-effect model. RESULTS The electronic search yielded 437 articles; of those 20 were scrutinized as full texts and 13 studies were considered unsuitable. The final analysis included 7 studies with 2420 statin-treated patients divided into subgroups of patients with (n=666 [27.5%]) or without (n=1754) myalgia. Plasma vit D concentrations in the symptomatic and asymptomatic subgroups were 28.4±13.80ng/mL and 34.86±11.63ng/mL, respectively. The combination of data from individual observational studies showed that vit D plasma concentrations were significantly lower in patients with statin-associated myalgia compared with patients not manifesting this side effect (weighted mean difference -9.41ng/mL; 95% confidence interval: -10.17 to -8.64; p<0.00001). CONCLUSIONS This meta-analysis provides evidence that low vit D levels are associated with myalgia in patients on statin therapy. Randomized controlled trials are necessary to establish whether vitamin D supplementation reduces the risk for statin-associated myalgia.

Low-Risk Lifestyle, Coronary Calcium, Cardiovascular Events, and Mortality: Results From MESA

Unhealthy lifestyle habits are a major contributor to coronary artery disease. The purpose of the present study was to investigate the associations of smoking, weight maintenance, physical activity, and diet with coronary calcium, cardiovascular events, and mortality. US participants who were 44-84 years of age (n = 6,229) were followed in the Multi-Ethnic Study of Atherosclerosis from 2000 to 2010. A lifestyle score ranging from 0 to 4 was created using diet, exercise, body mass index, and smoking status. Coronary calcium was measured at baseline and a mean of 3.1 (standard deviation, 1.3) years later to assess calcium progression. Participants who experienced coronary events or died were followed for a median of 7.6 (standard deviation, 1.5) years. Participants with lifestyle scores of 1, 2, 3, and 4 were found to have mean adjusted annual calcium progressions that were 3.5 (95% confidence interval (CI): 0.0, 7.0), 4.2 (95% CI: 0.6, 7.9), 6.8 (95% CI: 2.0, 11.5), and 11.1 (95% CI: 2.2, 20.1) points per year slower, respectively, relative to the reference group (P = 0.003). Unadjusted hazard ratios for death by lifestyle score were as follows: for a score of 1, the hazard ratio was 0.79 (95% CI: 0.61, 1.03); for a score of 2, the hazard ratio was 0.61 (95% CI: 0.46, 0.81); for a score of 3, the hazard ratio was 0.49 (95% CI: 0.32, 0.75); and for a score of 4, the hazard ratio was 0.19 (95% CI: 0.05, 0.75) (P < 0.001 by log-rank test). In conclusion, a combination of regular exercise, healthy diet, smoking avoidance, and weight maintenance was associated with lower coronary calcium incidence, slower calcium progression, and lower all-cause mortality over 7.6 years.

Statin therapy and plasma coenzyme Q10 concentrations—A systematic review and meta-analysis of placebo-controlled trials

Statin therapy may lower plasma coenzyme Q10 (CoQ10) concentrations, but the evidence as to the significance of this effect is unclear. We assessed the impact of statin therapy on plasma CoQ10 concentrations through the meta-analysis of available RCTs. The literature search included selected databases up to April 30, 2015. The meta-analysis was performed using either a fixed-effects or random-effect model according to I(2) statistic. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence interval (CI). The data from 8 placebo-controlled treatment arms suggested a significant reduction in plasma CoQ10 concentrations following treatment with statins (WMD: -0.44 μmol/L, 95%CI: -0.52, -0.37, p<0.001). The pooled effect size was robust and remained significant in the leave-one-out sensitivity analysis. Subgroup analysis suggested that the impact of statins on plasma CoQ10 concentrations is significant for all 4 types of statins studied i.e. atorvastatin (WMD: -0.41 μmol/L, 95%CI: -0.53, -0.29, p<0.001), simvastatin (WMD: -0.47 μmol/L, 95% CI: -0.61, -0.33, p<0.001), rosuvastatin (WMD: -0.49 μmol/L, 95%CI: -0.67, -0.31, p<0.001) and pravastatin (WMD: -0.43 μmol/L, 95%CI: -0.69, -0.16, p=0.001). Likewise, there was no differential effect of lipophilic (WMD: -0.43 μmol/L, 95%CI: -0.53, -0.34, p<0.001) and hydrophilic statins (WMD: -0.47 μmol/L, 95%CI: -0.62, -0.32, p<0.001). With respect to treatment duration, a significant effect was observed in both subsets of trials lasting <12 weeks (WMD: -0.51 μmol/L, 95%CI: -0.64, -0.39, p<0.001) and ≥12 weeks (WMD: -0.40 μmol/L, 95%CI: -0.50, -0.30, p<0.001). The meta-analysis showed a significant reduction in plasma CoQ10 concentrations following treatment with statins. Further well-designed trials are required to confirm our findings and elucidate their clinical relevance.

Nonalcoholic fatty liver disease and serum lipoproteins: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE While nonalcoholic fatty liver disease (NAFLD) is associated with the metabolic syndrome, it is not known if NAFLD plays an independent role in the atherogenic dyslipidemia phenotype. METHODS AND RESULTS The Multi-Ethnic Study of Atherosclerosis (MESA) is a population-based prospective cohort study of adults free of clinical cardiovascular disease at enrollment. We tested for a relationship between NAFLD, defined as a liver/spleen (L/S) attenuation ratio of <1 on a non-contrast cardiac CT scan, and multiple measures of fasting serum lipoprotein size, cholesterol and particle concentrations. NAFLD was present in 569 (17%) of 3362 participants. After adjustment for multiple metabolic risk factors, adiposity and measures of insulin resistance (HOMA-IR), NAFLD was independently associated with higher fasting serum triglycerides and lower serum HDL-C. Despite a lack of association with LDL-C, NAFLD was associated with higher LDL particle concentration and lower LDL particle size. Modeling the L/S ratio as a continuous variable, a severity dependent association was observed between atherogenic lipoprotein abnormalities and NAFLD. CONCLUSION In a large, multi-ethnic, gender balanced cohort, CT-diagnosed NAFLD was associated with the atherogenic dyslipidemia phenotype in a dose dependent fashion. These relationships persisted after adjustment for several metabolic risk factors and HOMA-IR, suggesting a possible independent pathophysiologic role between NAFLD and dyslipidemia.