Cardiac biomarkers in acute coronary syndromes

Cardiac biomarkers play a significant role in the diagnosis, risk assessment, and management of patients with acute coronary syndromes (ACS). Several biomarkers identify different components of the pathophysiology of ACS: troponins are markers of myocyte necrosis, natriuretic peptides reflect neurohormonal activation and myocardial dysfunction, and C-reactive protein reflects various inflammatory processes. Whilst there are a number of established and novel biomarkers to assess ischemia, necrosis and myocardial dysfunction in coronary artery disease, it is probable that no single biomarker will emerge that provides appropriate information for all clinical settings of ACS. This suggests that ongoing efforts in plasma-based biomarker research should concentrate on the use of a multimarker approach to enhance our diagnosis, prognostic assessment, and management of patients with suspected ACS, as compared with using individual markers alone. It is recommended that current practice involve the selective use of biomarkers in patients in whom a more complete assessment of risk is desired. At present, routine biomarker measurement is not advocated until further data become available, which will support the benefit of specific therapeutic interventions

Impact of smoking on cardiovascular outcomes in patients with stable coronary artery disease

Aims: Smoking is a major preventable risk factor for cardiovascular disease and mortality. However, the ‘smoker’s paradox’ suggests that it is associated with better survival after acute myocardial infarction. We aimed to investigate the impact of smoking on mortality and cardiovascular outcomes in patients with stable coronary artery disease. Methods: The international CLARIFY registry included 32,703 patients with stable coronary artery disease between 2009 and 2010. Among the 32,378 patients included in the present analysis, Cox proportional hazards models (adjusted for age, sex, geographic region, prior myocardial infarction, and revascularization status) were used to estimate associations between smoking status and outcomes. Patients were stratified as follows: 41.3% of patients never smoked, 12.5% were current smokers and 46.2% were former smokers. Results: Current smokers were younger than never-smokers and former smokers (59 vs. 66 and 64 years old, respectively, p < 0.0001). There were more men among current or former smokers compared with never-smokers. Compared with never-smokers, both current and former smokers were at higher risk of all-cause death (hazard ratio = 1.96 and 1.37) and cardiovascular death (hazard ratio = 1.92 and 1.38) within five years (all p < 0.05). Similarly graded and increased risks were present for myocardial infarction and the composite of cardiovascular death, myocardial infarction and stroke (all p < 0.05). Conclusion: In contrast to the ‘smoker’s paradox’, current smokers with stable coronary artery disease have a greatly increased risk of future cardiovascular events, including mortality, compared with never-smokers. In former smokers, cardiovascular risk remains elevated albeit at an intermediate level between that of current and never-smokers, reinforcing the importance of smoking cessation. (ISRCTN43070564)

Management of pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a potentially lethal disease mainly affecting young females. Although the precise mechanism of PAH is unknown, the past decade has seen the advent of many new classes of drugs with improvement in the overall prognosis of the disease. Unfortunately the therapeutic options for PAH in South Africa are severely limited. The Working Group on PAH is a joint effort by the South African Heart Association and the South African Thoracic Society tasked with improving the recognition and management of patients with PAH. This article provides a brief summary of the disease and the recommendations of the first meeting of the Working Group

Comparative assessment of absolute cardiovascular disease risk characterization from non-laboratory-based risk assessment in South African populations

Background: All rigorous primary cardiovascular disease (CVD) prevention guidelines recommend absolute CVD risk scores to identify high- and low-risk patients, but laboratory testing can be impractical in low- and middle-income countries. The purpose of this study was to compare the ranking performance of a simple, non-laboratory-based risk score to laboratory-based scores in various South African populations. Methods: We calculated and compared 10-year CVD (or coronary heart disease (CHD)) risk for 14,772 adults from thirteen cross-sectional South African populations (data collected from 1987 to 2009). Risk characterization performance for the non-laboratory-based score was assessed by comparing rankings of risk with six laboratory-based scores (three versions of Framingham risk, SCORE for high- and low-risk countries, and CUORE) using Spearman rank correlation and percent of population equivalently characterized as ‘high’ or ‘low’ risk. Total 10-year non-laboratory-based risk of CVD death was also calculated for a representative cross-section from the 1998 South African Demographic Health Survey (DHS, n = 9,379) to estimate the national burden of CVD mortality risk. Results: Spearman correlation coefficients for the non-laboratory-based score with the laboratory-based scores ranged from 0.88 to 0.986. Using conventional thresholds for CVD risk (10% to 20% 10-year CVD risk), 90% to 92% of men and 94% to 97% of women were equivalently characterized as ‘high’ or ‘low’ risk using the non-laboratory-based and Framingham (2008) CVD risk score. These results were robust across the six risk scores evaluated and the thirteen cross-sectional datasets, with few exceptions (lower agreement between the non-laboratory-based and Framingham (1991) CHD risk scores). Approximately 18% of adults in the DHS population were characterized as ‘high CVD risk’ (10-year CVD death risk >20%) using the non-laboratory-based score. Conclusions: We found a high level of correlation between a simple, non-laboratory-based CVD risk score and commonly-used laboratory-based risk scores. The burden of CVD mortality risk was high for men and women in South Africa. The policy and clinical implications are that fast, low-cost screening tools can lead to similar risk assessment results compared to time- and resource-intensive approaches. Until setting-specific cohort studies can derive and validate country-specific risk scores, non-laboratory-based CVD risk assessment could be an effective and efficient primary CVD screening approach in South Africa

Candidate gene polymorphisms related to lipid metabolism in Asian Indians living in Durban, South Africa.

BACKGROUND & OBJECTIVES: Asian Indians have been shown to have a high prevalence of metabolic syndrome (MetS), related to insulin resistance and possibly genetic factors. The aim of this study was to determine the genetic patterns associated with MetS in Asian Indians living in Durban, South Africa. METHODS: Nine hundred and ninety nine participants from the Phoenix Lifestyle Project underwent clinical, biochemical and genetic assessment. MetS was diagnosed according to the harmonized definition. The apolipoprotein A5 Q139X, lipoprotein lipase (LPL) Hinf I, human paraoxonase 1 (PON1) 192Arg/Gln, cholesteryl ester transfer protein (CETP) Taq1B, adiponectin 45T>G and leptin (LEP) 25CAG were genotyped by real-time polymerase chain reaction in participants with and without MetS. Univariate-unadjusted and multivariate-adjusted relations were conducted for all analyses. RESULTS: The prevalence of MetS was high (49.0%). More females had MetS than males (51.0 vs 42.8%). There was no significant difference in the distribution of genotypes between participants with MetS and those without. Males with the MetS who had the adiponectin TG genotype and human paraoxonase 1 AA genotype were more likely to have reduced high-density lipoprotein cholesterol (HDL-C) (P=0.001) and higher systolic blood pressure (P=0.018), respectively. INTERPRETATION & CONCLUSIONS: About half of the Asian Indians living in Phoenix had MetS. No association between the polymorphisms studied and the risk for MetS was observed. The adiponectin TG genotype may be associated with reduced HDL-C and the human paraoxonase 1 AA genotype with hypertension in males. This suggested that lifestyle factors were the major determinant for MetS in this ethnic group and the genetic risk might be related to its component risk factors than to MetS as an entity