Left ventricular mass and correlated atherosclerotic risk factors in young adolescents: report from Chin-Shan community cardiovascular study in Taiwan

Task force on: 'Early markers of atherosclerosis: influence of age and sex'

Atherosclerosis and its complications are the most important causes of death all over the world, especially in Western countries. Diet habits, modern stress life, smoking, sedentary way of life and an involvement of genetic pattern of individuals lead to a sure degeneration of quality of life increasing the risk of atherosclerosis development. For this reason, the main purpose of actual medicine is to identify all the markers that could allow the physicians to evaluate the first moments of the development of this dangerous pathological process. The aim is to reduce the speed of its evolution, trying to delay indefinitely the risk coming from the morphological alterations of the vessels. 'Endothelium function' could allow physicians to detect the first moment of the natural history of atherosclerosis process. Its impairment is the first step in the degeneration of vascular structures. Many methods [flow-mediated vasodilatation (FMD); antero-posterior abdominal aorta diameter (APAO); intima-media thickness of the common carotid artery (CCA-IMT); arterial stiffness; and so on] try to evaluate its function, but many limitations come from general population characteristics. A standardization of the methods should take into account individuals' peculiarities. Two elements, not modifiable, should be taken into account for vascular evaluation: age and sex. The aim of this review is to outline the linkage among age, sex and instrumental evaluation of patients considered for a noninvasive assessment of their cardiovascular risk profile.

Left atrial dimension and risk of stroke in women without atrial fibrillation: the Chin-Shan Community Cardiovascular Cohort study

BACKGROUND

Evidence on the relationship between left atrial dimension and cardiovascular events is inconclusive. We explored the association between left atrial dimension and stroke and all-cause death in an ethnic Chinese population.

METHODS

We recruited 1,937 subjects undertaking echocardiographic examination without prior atrial fibrillation/stroke in the Chin-Shan Community Cardiovascular Cohort study. Left atrial dimension indexed by body mass index was used as left atrial dimension index (LADI) for analysis. The end points were stroke and all-cause death. A multivariate Cox regression analysis was used to estimate the relative risks between participants stratified by tertile of LADI within each gender.

RESULTS

During a median follow-up of 11.9 years, 21,733 person-years were accrued and 114 subjects with stroke and 364 all-cause deaths were identified. The adjusted relative risk of stroke was 2.44 (95% CI, 1.11 to 5.36, P for trend = 0.029) among women in the upper tertile of LADI compared with women in the lower tertile of LADI. Further adjusting for left ventricular mass index attenuated the relationship of LADI to stroke (adjusted relative risk 2.11, 95% CI, 0.88 to 5.02, P for trend = 0.09). In men, tertile of LADI was not associated with stroke. LADI was not associated with risk of all-cause death in both genders.

CONCLUSIONS

We found an association between increased LADI and incident stroke in women but not in men in this ethnic Chinese population. LADI was not associated with all-cause death in both genders.

Aortic root dimension as an independent predictor for all-cause death in adults <65 years of age (from the Chin-Shan Community Cardiovascular Cohort Study)

BACKGROUND

Evidence on aortic root dimension for predicting cardiovascular morbidity and mortality is inconclusive. This cohort study sought to characterize the predictive power of aortic root dimension on cardiovascular morbidity and mortality in an ethnic Chinese population.

METHODS

We recruited 1,851 participants in the Chin-Shan Community Cardiovascular Cohort (CCCC) study who had received echocardiography without previous cardiovascular events. Aortic root dimension was measured by M-mode echocardiography and indexed by body surface area to obtain aortic root dimension index (AOI). The end points were all-cause death and incident cardiovascular events including coronary heart disease and stroke over a median follow-up of 11.9 years.

RESULTS

Although tertiles of AOI was associated with an increased risk of cardiovascular events and all-cause death in univariate analysis, the significance diminished after adjusting for age variable (P for trend = 0.11 for cardiovascular events; P for trend = 0.23 for all-cause death). In subgroup analysis, we found a significant association between tertiles of AOI and risk of all-cause death in the final multivariate Cox regression model in adults <65 years. The adjusted relative risk was 1.88 (95% CI, 1.04 to 3.40) in participants in the upper tertile of AOI compared with participants in the lower tertile (P for trend = 0.037). In adults > or = 65 years, tertile of AOI was not associated with all-cause death (P for trend = 0.14). Tertiles of AOI was not associated with cardiovascular events throughout this study.

CONCLUSION

Our study showed a significant association between AOI and all-cause death in adults <65 years in an ethnic Chinese population. (Echocardiography 2010;27:487-495).

Left ventricular mass and risk of cardiovascular events and all-cause death among ethnic Chinese--the Chin-Shan Community Cardiovascular Cohort study

BACKGROUND

We conducted this cohort study involving ethnic Chinese population to explore the association between left ventricular mass and cardiovascular events and all-cause death, and to define the cutoff value of left ventricular mass for risk stratification.

METHODS

We evaluated 2604 participants aged ≥35years in the Chin-Shan Community Cardiovascular Cohort (CCCC) study who had received echocardiography without previous cardiovascular events. Left ventricular mass was divided by body surface area to obtain left ventricular mass index (LVMI). The end-points were all-cause death and incident cardiovascular events including coronary heart disease and stroke over a median follow-up of 14.4years.

RESULTS

By multivariate Cox regression analyses, a linear relationship between LVMI and cardiovascular events was found (adjusted hazard ratio 2.01, 95% CI, 1.11 to 3.63, for the highest quintile of LVMI compared with the lowest quintile, p for trend=0.001). A J-shape relationship between LVMI and all-cause death was observed, with the test for a linear relationship being rejected (p=0.003). The adjusted hazard ratios of all-cause death were significantly lower in the second quintile (0.58, 95% CI, 0.40 to 0.84) and in the third quintile (0.68, 95% CI, 0.47 to 0.96) of LVMI compared with the lowest quintile. The proposed cut-off value of LVMI was 105g/m(2) for prediction of cardiovascular events.

CONCLUSION

A linear relationship between LVMI and cardiovascular events, and a J-shape relationship between LVMI and all-cause death were found. The cut-off value derived from our Chinese population was lower than the frequently applied value derived from Caucasian population.

Impact of heart failure and left ventricular function on long-term survival--report of a community-based cohort study in Taiwan

BACKGROUND

There is little community-based information on heart failure (HF) prognosis in ethnic Chinese populations, in whom there is a low prevalence of coronary heart disease.

AIMS

To study the impact of HF and left ventricular function on long-term all-cause mortality.

METHODS AND RESULTS

This community-based prospective cohort study included 2660 subjects (1215 men, 1445 women, mean age 54.4+/-11.9 years) over a 10 year follow-up period. The prevalence of HF was 5.5%. Hypertension was the most common factor related to HF. The five and ten year all-cause mortality was higher in the HF/preserved LVEF group (14.1% and 24.4%) and the HF/impaired LVEF group (29.2% and 48.2%) than in the HF-free group (6.0% and 14.6%, p<0.0001 for both). In multivariable Cox analyses, controlling for sex, LV mass, atrial fibrillation, hypertension, coronary heart disease, HF/preserved LVEF and HF/impaired LVEF were important predictors of all-cause mortality (p=0.007).

CONCLUSIONS

Hypertension is a major heart failure related disease. HF and LV systolic dysfunction are associated with a significant increase in all-cause mortality in an ethnic Chinese population.

The association of left ventricular mass with blood pressure, cigarette smoking and alcohol consumption; data from the LARGE Heart study

BACKGROUND

Left ventricular mass is a risk factor for cardiovascular morbidity and mortality. Although factors associated with elevated left ventricular mass have been sought and studied extensively in elderly and in diseased subjects, few studies have examined the young and healthy. The aim of this study was to examine the possible influence of lifestyle on left ventricular mass in a large group of young men.

METHODS

Left ventricular mass was assessed using cardiovascular magnetic resonance in 541 healthy Caucasian male army recruits. Anthropometric, lifestyle and blood pressure data were collected.

RESULTS

Mean unadjusted left ventricular mass and left ventricular mass indexed to body surface area were 163.8+/-24.9 g and 86.6+/-10.2 g m(-2) respectively. In univariate analysis, age, height, weight, alcohol consumption, systolic blood pressure, diastolic blood pressure and indices of physical activity were positively associated with unadjusted left ventricular mass (all P<0.02). By contrast, smoking was associated with lower mean left ventricular mass; never smoked 167.5+/-25.8 g vs ex-smokers 159.1+/-25.2 g vs current smokers 161.0+/-23.1 g (P=0.007). Multivariate analysis revealed weight, systolic blood pressure, smoking status and indices of physical activity to be independent predictors of left ventricular mass.

CONCLUSIONS

Our data confirm an association of age, body weight, height, physical activity, diastolic and systolic blood pressure with left ventricular mass. In addition, unexpectedly, we have found smoking is associated with lower left ventricular mass in a large sample of young healthy men. Although the latter association may result from confounding effects, such an interesting observation deserves further investigation.

Heritability and major gene effects on left ventricular mass in the Chinese population: a family study

Background

Genetic components controlling for echocardiographically determined left ventricular (LV) mass are still unclear in the Chinese population.

Methods

We conducted a family study from the Chin-San community, Taiwan, and a total of 368 families, 1145 subjects, were recruited to undergo echocardiography to measure LV mass. Commingling analysis, familial correlation, and complex segregation analysis were applied to detect component distributions and the mode of inheritance.

Results

The two-component distribution model was the best-fitting model to describe the distribution of LV mass. The highest familial correlation coefficients were mother-son (0.379, P < .0001) and father-son (0.356, P < .0001). Genetic heritability (h²) of LV mass was estimated as 0.268 ± 0.061 (P < .0001); it decreased to 0.153 ± 0.052 (P = .0009) after systolic blood pressure adjustment. Major gene effects with polygenic components were the best-fitting model to explain the inheritance mode of LV mass. The estimated allele frequency of the gene was 0.089.

Conclusion

There were significant familial correlations, heritability and a major gene effect on LV mass in the population-based families.

Pulse pressure, aortic regurgitation and carotid atherosclerosis: a comparison between hypertensives and normotensives

Pulse pressure (PP) has often been associated with cardiovascular morbidity and mortality. Patients with aortic regurgitation (AR) often have increased PP. The aim of this study is to investigate the associations among PP, AR and extracranial carotid artery (ECCA) carotid atherosclerosis (CA) in hypertensives and age- and sex-matched normotensives. Two hundred and sixty-three hypertensive patients and 270 normotensive subjects from the Chin-Shan Community Cardiovascular Cohort participated in this study in 1996. CA, expressed as maximal common carotid artery intima-media thickness (IMT) > or = 75th percentile and ECCA plaque score > 6, was measured using high-resolution B-mode ultrasonography. The presence of AR was assessed by echocardiography, and their relationships with CA were evaluated. Results showed measurements of CA significantly associated with increased PP. Presence of AR associated with CA, but this relationship was attenuated after controlling for age. Multivariate logistic regression analyses revealed that an ECCA score > 6 significantly increase the risk in conjunction with PP, age and smoking in hypertensives. Correspondingly, CA increased with age, smoking and left ventricular hypertrophy on electrocardiography but not PP in normotensives. In conclusion, higher PP is strongly associated with CA in patients with hypertension. In terms of risk stratification, PP is more important in hypertensives than in normotensives which seem to imply that pulsatile haemodynamic component of BP is crucial in association with atherosclerosis.

Segregation analysis of apolipoprotein A1 levels in families of adolescents: a community-based study in Taiwan

Background

Apolipoprotein (Apo) A1 is a protective factor for cardiovascular events. This study aimed to perform complex segregation analyses of Apo A1 levels in families of adolescents systematically ascertained from the junior high school students in a rural community. Both siblings and parents of the adolescent probands were recruited for the study. Apo A1 concentrations were measured by turbidimetric immunoassay methods. After adjustment for gender, age, body mass index, smoking and drinking status, residual values of Apo A1 were subjected to subsequent analyses.

Results

Significant mother-father and parent-offspring correlations were found. Commingling analyses indicated that a four-component distribution model was needed to account for the Apo A1 variation. Segregation analysis using regressive models revealed that the best-fit model of Apo A1 was a model of environmental effect plus familial correlation (heritability = 23.9%), in which a significant mother-father correlation existed. Models containing major gene effect could be rejected.

Conclusion

These results suggest that variations of Apo A1 levels in the normal range, especially during adolescence, are likely to be influenced by multiple factors without significant contribution from major genes.