Preclinical systolic dysfunction relating to ankle-brachial index among high-risk PAD population with preserved left ventricular ejection fraction

Peripheral artery disease (PAD) shares common clinical risk factors, for example, endothelial dysfunction, with preserved ejection fraction (LVEF) heart failure (HFpEF). Whether PAD is associated with preclinical systolic dysfunction and higher HF risk among individuals presenting preserved LVEF remains uncertain. We retrospectively included outpatients with at least one known or established cardiovascular (CV) risk factor with LVEF ≥ 50%. Patients were categorized into high risk and low risk of developing PAD (PAD vs Non-PAD) by ankle-brachial index (ABI) (≤ 0.90 or > 1.4) and further stratified based on their history of HFpEF (HFpEF vs. Non-HFpEF), resulting in the formation of four distinct strata. Preclinical systolic dysfunction was defined using dedicated speckle-tracking algorithm. A total of 2130 consecutive patients were enrolled in the study, with a median follow-up of 4.4 years. The analysis revealed a higher prevalence of high risk of developing PAD in patients with HFpEF compared to those without HFpEF (25.1% vs. 9.4%). Both high risk of developing PAD and HFpEF were independently associated with preclinical systolic dysfunction (global longitudinal strain, GLS ≥ - 18%) (odds ratio, OR: 1.38; 95% confidence interval, CI: 1.03-1.86). In comparison to patients at low risk of developing PAD without HFpEF (Non-PAD/Non-HFpEF group), those categorized as having a high risk of developing PAD with HFpEF (PAD/HFpEF group) exhibited the most impaired GLS and a heightened susceptibility to heart failure hospitalization (hazard ratio, HR: 6.51; 95% CI: 4.43-9.55), a twofold increased risk of all-cause mortality (HR: 2.01; 95% CI: 1.17-3.38), cardiovascular mortality (HR: 2.44; 95% CI: 1.08-5.51), and non-cardiovascular mortality (HR: 1.78; 95% CI: 0.82-3.84). A high risk of developing PAD was strongly linked to impaired preclinical systolic function and an increased likelihood for subsequent hospitalization for HF, all-cause mortality, CV mortality and non-CV mortality. There is a clear need for preventive strategies aimed at reducing hospitalizations for HF and mortality in this high-risk population.

Relation of early-stage renal insufficiency and cardiac structure and function in a large population of asymptomatic Asians: a cross-sectional cohort analysis

Background

Few studies have addressed early-stage kidney disease and preclinical cardiac structural and functional abnormalities from a large-scale Asian population. Further, the extent to which measures of myocardial function and whether these associations may vary by testing various formulas of renal insufficiency remains largely unexplored.

Objective

To explore the associations among renal function, proteinuria, and left ventricular (LV) structural and diastolic functional alterations.

Design

A cross-sectional, retrospective cohort study.

Setting

Registered data from a cardiovascular health screening program at MacKay Memorial Hospital from June 2009 to December 2012.

Participants

Asymptomatic individuals.

Measurements

Renal function was evaluated in terms of estimated glomerular filtration rate (eGFR) by both MDRD and CKD-EPI formulas and severity of proteinuria, which were further related to cardiac structure, diastolic function (including LV e' by tissue Doppler), and circulating N-terminal pro-brain natriuretic peptide (NT-proBNP) level.

Results

Among 4942 participants (65.8% men, mean age 49.4 ± 11.2 years), the mean CKD-EPI/MDRD eGFR was 90.6 ± 15.7 and 88.5 ± 16.9 ml/min/1.73m2, respectively. Lower eGFR, estimated either by the MDRD or CKD-EPI method, and higher proteinuria were significantly associated with lower LV e' and higher NT-proBNP (all p<0.05) even after adjusting for clinical covariates. In general, lower eGFR estimated by CKD-EPI and MDRD displayed similar impacts on worsening e' and NT-proBNP, rather than E/e', in multivariate models. Finally, lower LV e' or higher composite diastolic score, rather than E/e', demonstrated remarkable interaction with eGFR level estimated by either CKD-EPI or MDRD on circulating NT-proBNP level (p interaction <0.05).

Limitations

Proteinuria was estimated using a urine dipstick rather than more accurately by the urine protein-to-creatinine ratio. Also, pertaining drug history and clinical hard outcomes were lacking.

Conclusion

Both clinical estimate of renal insufficiency by eGFR or proteinuria, even in a relatively early clinical stage, were tightly linked to impaired cardiac diastolic relaxation and circulating NT-proBNP level. Elevation of NT-proBNP with worsening renal function may be influenced by impaired myocardial relaxation.

Both epicardial and peri-aortic adipose tissue blunt heart rate recovery beyond body fat mass

Background

Epicardial adipose tissue (EAT) as a marker of metabolic disorders has been shown to be closely associated with a variety of unfavorable cardiovascular events and cardiac arrhythmias. Data on regional-specific visceral adiposity outside the heart and its modulation on autonomic dysfunction, particularly heart rate recovery after exercise, remain obscure.

Methods

We studied 156 consecutive subjects (mean age: 49.3 ± 8.0 years) who underwent annual health surveys and completed treadmill tests. Multi-detector computed tomography-based visceral adiposity, including EAT and peri-aortic fat (PAF) tissue, was quantified using dedicated software (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA). We further correlated EAT and PAF with blood pressure and heart rate (HR) recovery information from an exercise treadmill test. Metabolic abnormalities were scored by anthropometrics in combination with biochemical data.

Results

Increased EAT and PAF were both associated with a smaller reduction in systolic blood pressure during the hyperventilation stage before exercise compared to supine status (β-coefficient (coef.): −0.19 and −0.23, respectively, both p < 0.05). Both visceral adipose tissue mediated an inverted relationship with heart rate recovery at 3 (EAT: β-coef.: −0.3; PAF: β-coef.: −0.36) and 6 min (EAT: β-coef.: −0.32; PAF: β-coef.: −0.34) after peak exercise, even after adjusting for baseline clinical variables and body fat composition (all p < 0.05).

Conclusion

Excessive visceral adiposity, whether proximal or distal to the heart, may modulate the autonomic response by lowering the rate of HR recovery from exercise after accounting for clinical metabolic index. Cardiac autonomic dysfunction may partly explain the increase in cardiovascular morbidity and mortality related to both visceral fats.

Association of Female Menopause With Atrioventricular Mechanics and Outcomes

Background

Despite known sex differences in cardiac structure and function, little is known about how menopause and estrogen associate with atrioventricular mechanics and outcomes.

Objective

To study how, sex differences, loss of estrogen in menopause and duration of menopause, relate to atrioventricular mechanics and outcomes.

Methods

Among 4051 asymptomatic adults (49.8 ± 10.8 years, 35%women), left ventricular (LV) and left atrial (LA) mechanics were assessed using speckle-tracking.

Results

Post-menopausal (vs. pre-menopausal) women had similar LV ejection fraction but reduced GLS, reduced PALS, increased LA stiffness, higher LV sphericity and LV torsion (all p &lt; 0.001). Multivariable analysis showed menopause to be associated with greater LV sphericity (0.02, 95%CI 0.01, 0.03), higher indexed LV mass (LVMi), lower mitral e’, lower LV GLS (0.37, 95%CI 0.04–0.70), higher LV torsion, larger LA volume, worse PALS (∼2.4-fold) and greater LA stiffness (0.028, 95%CI 0.01–0.05). Increasing years of menopause was associated with further reduction in GLS, markedly worse LA mechanics despite greater LV sphericity and higher torsion. Lower estradiol levels correlated with more impaired LV diastolic function, impaired LV GLS, greater LA stiffness, and increased LV sphericity and LV torsion (all p &lt; 0.05). Approximately 5.5% (37/669) of post-menopausal women incident HF over 2.9 years of follow-up. Greater LV sphericity [adjusted hazard ratio (aHR) 1.04, 95%CI 1.00–1.07], impaired GLS (aHR 0.87, 95%CI 0.78–0.97), reduced peak left atrial longitudinal strain (PALS, aHR 0.94, 95%CI 0.90–0.99) and higher LA stiffness (aHR 10.5, 95%CI 1.69–64.6) were independently associated with the primary outcome of HF hospitalizations in post-menopause. Both PALS &lt; 23% (aHR:1.32, 95%CI 1.01–3.49) and GLS &lt; 16% (aHR:5.80, 95%CI 1.79–18.8) remained prognostic for the incidence of HF in post-menopausal women in dichotomous analyses, even after adjusting for confounders. Results were consistent with composite outcomes of HF hospitalizations and 1-year all-cause mortality as well.

Conclusion

Menopause was associated with greater LV/LA remodeling and reduced LV longitudinal and LA function in women. The cardiac functional deficit with menopause and lower estradiol levels, along with their independent prognostic value post-menopause, may elucidate sex differences in heart failure further.

Association of Region-Specific Cardiac Adiposity With Dysglycemia and New-Onset Diabetes

Background Visceral adipose tissue is assumed to be an important indicator for insulin resistance and diabetes beyond overweight/obesity. We hypothesized that region-specific visceral adipose tissue may regulate differential biological effects for new-onset diabetes regardless of overall obesity. Methods and Results We quantified various visceral adipose tissue measures, including epicardial adipose tissue, paracardial adipose tissue, interatrial fat, periaortic fat, and thoracic aortic adipose tissue in 1039 consecutive asymptomatic participants who underwent multidetector computed tomography. We explored the associations of visceral adipose tissue with baseline dysglycemic indices and new-onset diabetes. Epicardial adipose tissue, paracardial adipose tissue, interatrial fat, periaortic fat, and thoracic aortic adipose tissue were differentially and independently associated with dysglycemic indices (fasting glucose, postprandial glucose, HbA1c, and homeostasis model assessment of insulin resistance) beyond anthropometric measures. The superimposition of interatrial fat and thoracic aortic adipose tissue on age, sex, body mass index, and baseline homeostasis model assessment of insulin resistance expanded the likelihood of baseline diabetes (from 67.2 to 86.0 and 64.4 to 70.8, P for ∆ ꭕ²: <0.001 and 0.011, respectively). Compared with the first tertile, the highest interatrial fat tertile showed a nearly doubled risk for new-onset diabetes (hazard ratio, 2.09 [95% CI, 1.38-3.15], P<0.001) after adjusting for Chinese Visceral Adiposity Index. Conclusions Region-specific visceral adiposity may not perform equally in discriminating baseline dysglycemia or diabetes, and showed differential predictive performance in new-onset diabetes. Our data suggested that interatrial fat may serve as a potential marker for new-onset diabetes.

Atrioventricular Longitudinal Mechanics Using Novel Speckle-Tracking Improved Risk Stratification Beyond Baseline Thyroid Hormone in Asymptomatic Subclinical Hypothyroidism

BACKGROUND

Hypothyroidism is reportedly associated with increased cardiovascular risk and heart failure. We aimed to elucidate the mechanistic influence of atrio-ventricular deformations and their prognostic utilizations in asymptomatic subclinical hypothyroidism (SCH).

METHODS

We assessed speckle-tracking of deformations among 4173 population-based asymptomatic individuals classified as euthyroid (0.25< thyroid-stimulating hormone [TSH] ≤4.0 μIU/mL, n=3799) or having mild (4< TSH ≤10.0 μIU/mL, n=349) or marked (TSH >10 μIU/mL, n=25) SCH. We further related deformational indices to outcomes of atrial fibrillation and heart failure.

RESULTS

Despite borderline differences in indexed left ventricular mass and left atrial volume (P=0.054 and 0.051), those classified as mild and marked SCH presented with modest but significant reductions of global longitudinal strain, and showed elevated E/tissue Doppler imaging (TDI)-e', markedly diminished peak atrial longitudinal strain and higher left atrial stiffness (all P<0.05) when compared with euthyroid subjects. A higher TSH level was independently associated with reduced TDI-s'/TDI-e', worse global atrio-ventricular strains (global longitudinal strain/peak atrial longitudinal strain), elevated E/TDI-e', and worsened left atrial strain rate components (all P<0.05). Over a median 5.6 years (interquartile range, 4.7-6.5 years) follow-up, myocardial deformations yielded independent risk prediction using Cox regression in models adjusted for baseline covariates, N-terminal pro-brain natriuretic peptide, E/e', and treatment effect. Incorporation of global atrio-ventricular strain (global longitudinal strain/peak atrial longitudinal strain) and strain rates further showed improved risk reclassification when added to the baseline TSH strata (classified as euthyroid and mild and marked SCH; all P<0.05). Cox regression models remained significant with improved risk reclassification beyond TSH-based strata by using slightly different deformational cutoffs after excluding marked SCH group.

CONCLUSIONS

Hypothyroidism, even when asymptomatic, may widely influence subclinical atrio-ventricular mechanical functions that may lead to higher heart failure and atrial fibrillation risk. We proposed the potential usefulness and prognostic utilization of myocardial strains in such population.

Variant Aldehyde Dehydrogenase 2 (ALDH2*2) as a Risk Factor for Mechanical LA Substrate Formation and Atrial Fibrillation with Modest Alcohol Consumption in Ethnic Asians

Aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism is a common genetic variant in Asians that is responsible for defective toxic aldehyde and lipid peroxidation metabolism after alcohol consumption. The extent to which low alcohol consumption may cause atrial substrates to trigger atrial fibrillation (AF) development in users with ALDH2 variants remains to be determined. We prospectively enrolled 249 ethnic Asians, including 56 non-drinkers and 193 habitual drinkers (135 (70%) as ALDH2 wild-type: GG, rs671; 58 (30%) as ALDH2 variants: G/A or A/A, rs671). Novel left atrial (LA) mechanical substrates with dynamic characteristics were assessed using a speckle-tracking algorithm and correlated to daily alcohol consumption and ALDH2 genotypes. Despite modest and comparable alcohol consumption by the habitual alcohol users (14.3 [8.3~28.6] and 12.3 [6.3~30.7] g/day for those without and with ALDH2 polymorphism, p = 0.31), there was a substantial and graded increase in the 4-HNE adduct and prolonged PR, and a reduction in novel LA mechanical parameters (including peak atrial longitudinal strain (PALS) and phasic strain rates (reservoir, conduit, and booster pump functions), p < 0.05), rather than an LA emptying fraction (LAEF) or LA volume index across non-drinkers, and in habitual drinkers without and with ALDH2 polymorphism (all p < 0.05). The presence of ALDH2 polymorphism worsened the association between increasing daily alcohol dose and LAEF, PALS, and phasic reservoir and booster functions (all P_interaction: <0.05). Binge drinking superimposed on regular alcohol use exclusively further worsened LA booster pump function compared to regular drinking without binge use (1.66 ± 0.57 vs. 1.97 ± 0.56 1/s, p = 0.001). Impaired LA booster function further independently helped to predict AF after consideration of the CHARGE-AF score (adjusted 1.68 (95% CI: 1.06–2.67), p = 0.028, per 1 z-score increment). Habitual modest alcohol consumption led to mechanical LA substrate formation in an ethnic Asian population, which was more pronounced in subjects harboring ALDH2 variants. Impaired LA booster functions may serve as a useful predictor of AF in such populations.

Prognostic superiority of global longitudinal strain beyond four-tiered ventricular hypertrophy in asymptomatic individuals

BACKGROUND

This study aims to explore the clinical correlates of myocardial deformations using speckle-tracking algorithm and to determine the prognostic utility of such measures in asymptomatic ethnic Chinese population.

METHODS

Global longitudinal (GLS), circumferential strain (GCS), and torsion were analyzed using featured tissue-tracking algorithm among 4049 symptom-free ethnic Chinese population. Hypertrophy (LVH) was classified into 4 tiers: indeterminate, dilated, thick and thick/dilated, by gender-stratified partition of end-diastolic volume index (EDVi) and LV mass/EDV0.67.

RESULTS

LVH (7.3%) showed substantially lower GLS (-20.3 ± 1.82% vs. -18.9 ± 2.08%) yet higher torsion (2.20 ± 0.90 vs. 2.39 ± 1.01, p < 0.001) than non-LVH participants. Those with thick LVH (n = 123) were more obese, had higher blood pressure and increased high-sensitivity C-reactive protein (hs-CRP); with dilated/thick LVH (n = 26) group demonstrating highest pro-brain natriuretic peptide (NT-proBNP) and worse GLS compared to indeterminate-/non-LVH groups. There were independent associations among larger EDVi, higher NT-proBNP and decreased torsion, and among greater LV mass/EDV0.67, worse GLS, greater GCS/torsion and hs-CRP. Over a median of 2.3 years (IQR: 1.2-4.8), the dilated, thick, and dilated/thick LVH categorizations were associated with higher risk of composite all-cause death and heart failure (HF) compared to non-LVH (adjusted hazard ratio [HR]: 3.65, 3.72, 6.01, respectively, all p < 0.05). Per 1% GLS reduction was independently associated with higher risk (adjusted HR: 1.31, p < 0.001) and improved risk prediction (p ≤ 0.001 by integrated discrimination improvement [IDI]: 3.5%, 95% CI: 1.5%-5.6%, and continuous net reclassification improvement [NRI]: 42.3%, 95% CI: 24.0%-60.6%) over LVH.

CONCLUSION

GLS improved risk stratification of four-tiered classification of LVH in asymptomatic ethnic Chinese.

Visceral adiposity index outperforms conventional anthropometric assessments as predictor of diabetes mellitus in elderly Chinese: a population-based study

Background

This study assessed the performance of visceral adiposity index and body shape index in predicting diabetes mellitus (DM) risk and compared their predictive ability to that of body mass index and waist circumference.

Methods

Among 8249 consecutive subjects who attended the Nationwide Health Check Up System for Senior Citizens (≥ 65 years) between 2008 and 2018, we examined the associations of several adiposity indices with DM risk and explored gender differences.

Results

Among all adiposity indicators, Chinese visceral adiposity index (CVAI) demonstrated the highest discriminatory ability for diabetes mellitus with area under receiver operating characteristic curves (AUC) of 0.65, 0.68, and 0.66 for men, women, and all participants, respectively, and optimal cut-offs set as 126.09 in men and 117.77 in women. Compared with body shape index (ABSI), both CVAI and VAI were strongly associated with baseline DM (adjusted OR: 4.85, 95% CI: 4.05–5.82 and 4.22, 95% CI: 3.53–5.05 for 4th vs 1st quartile groups by CVAI and VAI, P < 0.001), which was more pronounced in older adult women (P_interaction < 0.05). Over a median of 5.25 years (IQR: 3.07–6.44 years) follow-up, Cox regression models showed higher predictive ability of CVAI and VAI compared to ABSI. Further, both CVAI and VAI independently predicted new-onset DM (adjusted HR: 1.29, 95% CI: 1.22–1.37 and 1.16, 95% CI: 1.11–1.21 by CVAI and VAI) and composite endpoint of new DM and death among those without baseline DM.

Conclusions

Our population-based data demonstrated that Chinese visceral adiposity index may serve as a superior clinical indicator of diabetes when compared with conventional anthropometric indices among older adult Chinese, especially in women.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-021-00608-6.

Correction: Associations of obesity and malnutrition with cardiac remodeling and cardiovascular outcomes in Asian adults: A cohort study

[This corrects the article DOI: 10.1371/journal.pmed.1003661.].

Associations of obesity and malnutrition with cardiac remodeling and cardiovascular outcomes in Asian adults: A cohort study

BACKGROUND

Obesity, a known risk factor for cardiovascular disease and heart failure (HF), is associated with adverse cardiac remodeling in the general population. Little is known about how nutritional status modifies the relationship between obesity and outcomes. We aimed to investigate the association of obesity and nutritional status with clinical characteristics, echocardiographic changes, and clinical outcomes in the general community.

METHODS AND FINDINGS

We examined 5,300 consecutive asymptomatic Asian participants who were prospectively recruited in a cardiovascular health screening program (mean age 49.6 ± 11.4 years, 64.8% male) between June 2009 to December 2012. Clinical and echocardiographic characteristics were described in participants, stratified by combined subgroups of obesity and nutritional status. Obesity was indexed by body mass index (BMI) (low, ≤25 kg/m2 [lean]; high, >25 kg/m2 [obese]) (WHO-recommended Asian cutoffs). Nutritional status was defined primarily by serum albumin (SA) concentration (low, <45 g/L [malnourished]; high, ≥45 g/L [well-nourished]), and secondarily by the prognostic nutritional index (PNI) and Global Leadership Initiative on Malnutrition (GLIM) criteria. Cox proportional hazard models were used to examine a 1-year composite outcome of hospitalization for HF or all-cause mortality while adjusting for age, sex, and other clinical confounders. Our community-based cohort consisted of 2,096 (39.0%) lean-well-nourished (low BMI, high SA), 1,369 (25.8%) obese-well-nourished (high BMI, high SA), 1,154 (21.8%) lean-malnourished (low BMI, low SA), and 681 (12.8%) obese-malnourished (high BMI, low SA) individuals. Obese-malnourished participants were on average older (54.5 ± 11.4 years) and more often women (41%), with a higher mean waist circumference (91.7 ± 8.8 cm), the highest percentage of body fat (32%), and the highest prevalence of hypertension (32%), diabetes (12%), and history of cardiovascular disease (11%), compared to all other subgroups (all p < 0.001). N-terminal pro B-type natriuretic peptide (NT-proBNP) levels were substantially increased in the malnourished (versus well-nourished) groups, to a similar extent in lean (70.7 ± 177.3 versus 36.8 ± 40.4 pg/mL) and obese (73.1 ± 216.8 versus 33.2 ± 40.8 pg/mL) (p < 0.001 in both) participants. The obese-malnourished (high BMI, low SA) group also had greater left ventricular remodeling (left ventricular mass index, 44.2 ± 1.52 versus 33.8 ± 8.28 gm/m2; relative wall thickness 0.39 ± 0.05 versus 0.38 ± 0.06) and worse diastolic function (TDI-e' 7.97 ± 2.16 versus 9.87 ± 2.47 cm/s; E/e' 9.19 ± 3.01 versus 7.36 ± 2.31; left atrial volume index 19.5 ± 7.66 versus 14.9 ± 5.49 mL/m2) compared to the lean-well-nourished (low BMI, high SA) group, as well as all other subgroups (p < 0.001 for all). Over a median 3.6 years (interquartile range 2.5 to 4.8 years) of follow-up, the obese-malnourished group had the highest multivariable-adjusted risk of the composite outcome (hazard ratio [HR] 2.49, 95% CI 1.43 to 4.34, p = 0.001), followed by the lean-malnourished (HR 1.78, 95% CI 1.04 to 3.04, p = 0.034) and obese-well-nourished (HR 1.41, 95% CI 0.77 to 2.58, p = 0.27) groups (with lean-well-nourished group as reference). Results were similar when indexed by other anthropometric indices (waist circumference and body fat) and other measures of nutritional status (PNI and GLIM criteria). Potential selection bias and residual confounding were the main limitations of the study.

CONCLUSIONS

In our cohort study among asymptomatic community-based adults in Taiwan, we found that obese individuals with poor nutritional status have the highest comorbidity burden, the most adverse cardiac remodeling, and the least favorable composite outcome.

Sex, racial differences and healthy aging in normative reference ranges on diastolic function in Ethnic Asians: 2016 ASE guideline revisited

BACKGROUND

Diastolic dysfunction (DD) has shown to be a hallmark pathological intermediate in the development of heart failure with preserved ejection fraction (HFpEF). We aim to establish age- and sex-stratified normal reference values of diastolic indices and to explore racial-differences.

METHODS

We explored age- and sex-related structural/functional alterations from 6023 healthy ethnic Asians (47.1 ± 10.9 years, 61.3% men) according to 2016 American Society of Echocardiography (ASE) diastolic dysfunction (DD) criteria. Racial comparisons were made using data from London Life Sciences Prospective Population (LOLIPOP) study.

RESULTS

Age- and sex-based normative ranges (including mean, median, 10% and 90% lower and upper reference values) were extracted from our large healthy population. In fully adjusted models, advanced age was independently associated with cardiac structural remodeling and worsened diastolic parameters including larger indexed LA volume (LAVi), lower e', higher E/e', and higher TR velocity; all p < 0.001), which were more prominent in women (P interaction: <0.05). Broadly, markedly lower e', higher E/e' and smaller LAVi were observed in ethnic Asians compared to Whites. DD defined by 2016 ASE criteria, despite at low prevalence (0.42%) in current healthy population, increased drastically with advanced age and performed perfectly in excluding abnormal NT-proBNP (≥125 pg/mL) (Specificity: 99.8%, NPV: 97.6%).

CONCLUSION

This is to date the largest cohort exploring the normative reference values using guideline-centered diastolic parameters from healthy Asians, with aging played as central role in diastolic dysfunction. Our observed sex and ethnic differences in defining healthy diastolic cut-offs likely impact future clinical definition for DD in Asians.

Visceral Adiposity, Pro-Inflammatory Signaling and Vasculopathy in Metabolically Unhealthy Non-Obesity Phenotype

The debate regarding the actual cardiovascular burden in metabolically healthy obese or metabolically unhealthy non-obesity individuals is ongoing. Accumulating data have suggested a unique pathophysiological role of pro-inflammatory cytokines in mediating metabolic and cardiovascular disorders by dysregulated visceral adiposity. To compare the burden of visceral adiposity, the inflammatory marker high-sensitivity C-reactive protein (hs-CRP) and the prevalent atherosclerotic burden in metabolically healthy obese (MHO) or metabolically unhealthy (MU) populations, were compared to those of metabolically healthy non-obesity subjects (MHNO). Coronary artery calcification score (CACS) and visceral fat, including pericardial fat (PCF)/thoracic peri-aortic fat (TAT), were quantified in 2846 asymptomatic subjects using a CT dataset. A cross-sectional analysis comparing CACS, inflammatory marker hs-CRP, and visceral fat burden among four obesity phenotypes (MHNO, metabolically unhealthy non-obesity (MUNO), MHO, and metabolically unhealthy obese (MUO)) was performed. Both MUNO and MUO demonstrated significantly higher hs-CRP and greater CACS than MHNO/MHO (adjusted coefficient: 25.46, 95% confidence interval (CI): 5.29–45.63; 43.55, 95% CI: 23.38–63.73 for MUNO and MUO (MHNO as reference); both p < 0.05). Visceral fat (PCF/TAT) was an independent determinant of MU and was similarly higher in the MUNO/MHO groups than in the MHNO group, with the MUO group having the largest amount. PCF/TAT, obesity, and MU remained significantly associated with higher CACS even after adjustment, with larger PCF/TAT modified effects for MU and diabetes in CACS (both p_interaction < 0.05). MU tightly linked to excessive visceral adiposity was a strong and independent risk factor for coronary atherosclerosis even in lean individuals, which could be partially explained by its coalignment with pathological pro-inflammatory signaling.

Associations of region-specific visceral adiposity with subclinical atrial dysfunction and outcomes of heart failure

AIMS

Excessive visceral adiposity (VAT) plays an essential role in metabolic derangements with those close to heart further mediates myocardial homeostasis. The disparate biological links between region-specific VAT and cardiometabolic profiles as mediators influencing atrial kinetics remain unexplored.

METHODS AND RESULTS

Among 1326 asymptomatic individuals, region-specific VAT including peri-aortic root fat (PARF) and total pericardial fat (PCF) of cardiac region, together with thoracic peri-aortic adipose tissue (TAT), was assessed using multiple-detector computed tomography. VAT measures were related to functional left atrial (LA) metrics assessed by speckle-tracking algorithm and clinical outcomes of atrial fibrillation (AF) and heart failure (HF). Multivariate linear regression models incorporating body fat, metabolic syndrome, and E/TDI-e' consistently demonstrated independent associations of larger PARF/PCF with peak atrial longitudinal systolic strain (PALS) reduction, higher LA stiffness, and worsened strain rate components; instead, TAT was independently associated with cardiometabolic profiles. PARF rather than PCF or TAT conferred independent prognostic values for incident AF/HF by multivariate Cox regression (adjusted hazard ratio: 1.56, 95% confidence interval: 1.17-2.08, P = 0.002) during a median of 1790 days (interquartile range: 25th to 75th: 1440-1927 days) of follow-up, with subjects categorized into worst PALS and largest VAT tertiles demonstrating highest events (all log-rank P < 0.001). Mediation analysis showed that higher triglyceride and lower high-density lipoproteins may serve as intermediary factors for effects between VAT and LA functional metrics, with lesser role by glucose level.

CONCLUSIONS

Visceral adiposity surrounding atrial region was tightly associated with subclinical atrial dysfunction and incident AF or HF beyond metabolic factors. Instead, peri-aortic adiposity may mediate their toxic effects mainly through circulating cardiometabolic profiles.

Aortic Root Remodeling as an Indicator for Diastolic Dysfunction and Normative Ranges in Asians: Comparison and Validation with Multidetector Computed Tomography

Background: The aortic root diameter (AoD) has been shown to be a marker of cardiovascular risk and heart failure (HF). Data regarding the normal reference ranges in Asians and their correlates with diastolic dysfunction using contemporary guidelines remain largely unexplored. Methods: Among 5343 consecutive population-based asymptomatic Asians with echocardiography evaluations for aortic root diameter (without/with indexing, presented as AoD/AoDi) were related to cardiac structure/function and N-terminal pro-brain B-type natriuretic peptide (Nt-ProBNP), with 245 participants compared with multidetector computed tomography (MDCT)-based aortic root geometry. Results: Advanced age, hypertension, higher diastolic blood pressure, and lower body fat all contributed to greater AoD/AoDi. The highest correlation between echo-based aortic diameter and the MDCT-derived measures was found at the level of the aortic sinuses of Valsalva (r = 0.80, p < 0.001). Age- and sex-stratified normative ranges of AoD/AoDi were provided in 3646 healthy participants. Multivariate linear regressions showed that AoDi was associated with a higher NT-proBNP, more unfavorable left ventricular (LV) remodeling, worsened LV systolic annular velocity (TDI-s′), a higher probability of presenting with LV hypertrophy, and abnormal LV diastolic indices except tricuspid regurgitation velocity by contemporary diastolic dysfunction (DD) criteria (all p < 0.05). AoDi superimposed on key clinical variables significantly expanded C-statistic from 0.71 to 0.84 (p for ∆AUROC: < 0.001). These associations were broadly weaker for AoD. Conclusion: In our large asymptomatic Asian population, echocardiography-defined aortic root dilation was associated with aging and hypertension and were correlated modestly with computed tomography measures. A larger indexed aortic diameter appeared to be a useful indicator in identifying baseline abnormal diastolic dysfunction.

Associations of serum uric acid level and gout with cardiac structure, function and sex differences from large scale asymptomatic Asians

Hyperuricemia (HU) is a marker for heart failure. There are relatively few data in the Asian population regarding the effects of hyperuricemia and gouty disorders on cardiac remodeling and diastolic dysfunction (DD), an intermediate stage in the development of heart failure. We consecutively recruited asymptomatic Asian individuals to undergo cardiovascular surveys. We categorized them into Non-HU, HU, and Gout groups. We measured cardiac structure and indices for diastolic function, including tissue Doppler (TDI)-derived LV e’ and E/e’. Among 5525 participants, 1568 had HU and 347 had gout. The presence of gout and higher uric acid levels (SUA) (<4, 4–6, 6–8, 8–10, > = 10 mg/dL) were associated with greater LV wall thickness, greater LV mass/volumes, larger LA volume, lower LV e’ and higher E/e’. Higher SUA was associated with greater LV mass index (adjusted coefficient: 0.37), greater mass/volume ratio (adjusted coefficient: 0.01) and larger LA volume index (adjusted coefficient: 0.39, all p<0.05). Both HU and Gout groups were associated with lower LV e’ (coefficient: -0.086, -0.05), higher E/e’ (coefficient: 0.075, 0.35, all p <0.05), larger LA volume, and higher DD risk (adjusted ORs: 1.21 and 1.91 using Non-HU as reference, respectively, both p <0.05). SUA set at 7.0 mg/dL provided the optimal cut-off for identifying DD, with markedly lower e’ (HU: 8.94 vs 8.07, Gout: 7.94 vs 7.26 cm/sec) and higher LV E/e’ in HU/Gout women than in men (HU: 7.84 vs 9.79 cm/sec for men and women, respectively, all p <0.05). Hyperuricemia, even at a relatively low clinical cut-off, was associated with unfavorable remodeling and was tightly linked to diastolic dysfunction. The presence of gout likely aggravated these conditions. Women with hyperuricemia or gout had worse diastolic indices than men despite similar degrees of LV remodeling.

Carotid arterial mechanics as useful biomarker of extracellular matrix turnover and preserved ejection fraction heart failure

Aims

We aimed to investigate the functional alterations, diagnostic utilization, and prognostic implication of carotid arterial deformations in subjects with cardiovascular risk factors and heart failure (HF) with preserved ejection fraction (HFpEF).

Methods and results

Among 251 prospectively participants (mean age 66.0 ± 9.8 years, 65.7% female) in a single centre between December 2011 and September 2014, carotid artery deformations including circumferential strain (CCS)/strain rate and radial strain were analysed by two‐dimensional speckle tracking. We further related these carotid artery deformation indices to HF biomarkers and cardiac structure and function by echocardiography and explored their prognostic values. Significant reductions of CCS, circumferential strain rate, and circumferential radial strain were observed across control (n = 52), high risk (n = 147), and HFpEF (n = 52) (trend P ≤ 0.001). Aging, hypertension, HFpEF, and higher pulse rate showed independent associations with reduced CCS by stepwise multivariate regressions (all P < 0.05). Higher CCS was inversely associated with better cardiac remodelling and functional indices, and lower multiple HF biomarkers (all P ≤ 0.005). After adjustment, higher CCS was independently associated with better global ventricular longitudinal strain/early diastolic strain rate, lower matrix metalloproteinase‐2, and N‐terminal propeptide of procollagen type III levels (adjusted coef: −0.08 and −19.9, all P < 0.05). During a median follow‐up of 1406 days (interquartile range: 1342‑1720 days), CCS less than 3.28% as a cut‐off had markedly higher HF events [Harrell's C: 0.72, adjusted HR: 2.20 (95% confidence interval: 1.24, 3.16), P = 0.008]. CCS also showed significantly improved risk prediction for HF over global ventricular longitudinal strain (net reclassification index: 48%, P = 0.001; integrated discrimination improvement: 1.8%, P < 0.001).

Conclusions

Carotid artery deformations using two‐dimensional speckle‐tracking imaging showed novel mechanistic insights on functional arterial alterations reflecting coupled arterial‐ventricular pathophysiology. Utilization of such measure may further provide additive prognostic value to advanced myocardial functional assessment.

Circulating Monocyte Count as a Surrogate Marker for Ventricular-Arterial Remodeling and Incident Heart Failure with Preserved Ejection Fraction

Among 2085 asymptomatic subjects (age: 51.0 ± 10.7 years, 41.3% female) with data available on common carotid artery diameter (CCAD) and circulating total white blood cell (WBC) counts, higher circulating leukocytes positively correlated with higher high sensitivity C-reactive protein (hs-CRP). Higher WBC/segmented cells and monocyte counts were independently associated with greater relative wall thicknesses and larger CCADs, which in general were more pronounced in men and obese subjects (body mass index ≥ 25 kg/m²) (all P _interaction: < 0.05). Using multivariate adjusting models, only the monocyte count independently predicted the left ventricular mass index (LVMi) (ß-Coef: 0.06, p = 0.01). Higher circulating WBC, segmented, and monocyte counts and a greater CCAD were all independently associated with a higher risk of heart failure (HF)/all-cause death during a median of 12.1 years of follow-up in fully adjusted models, with individuals manifesting both higher CCADs and monocyte counts incurring the highest risk of HF/death (adjusted hazard ratio: 2.81, 95% CI: 1.57. −5.03, p < 0.001; P _interaction, 0.035; lower CCAD/lower monocyte as reference). We conclude that a higher monocyte count is associated with cardiac remodeling and carotid artery dilation. Both an elevated monocyte count and a larger CCAD may indicate a specific phenotype that confers the highest risk of HF, which likely signifies the role of circulating monocytes in the pathophysiology of heart failure with preserved ejection fraction (HFpEF).

Malnutrition in acute heart failure with preserved ejection fraction: clinical correlates and prognostic implications

Aims

This study aimed to evaluate the prognostic significance of nutritional status in post‐discharge Asians with heart failure with preserved ejection fraction (HFpEF).

Methods and results

We examined the prognostic implications of body mass index (BMI) and nutritional markers among consecutive patients hospitalized for HFpEF. Nutritional metrics were estimated by serum albumin (SA), prognostic nutritional index (PNI), Controlling Nutritional Status (CONUT) score, and geriatric nutritional risk index. Among 1120 patients (mean age: 77.2 ± 12.6 years, 39.4% men), mean SA levels, PNI, CONUT scores, and geriatric nutritional risk index were 3.3 ± 0.6 g/dL, 40.2 ± 8.7, 5.5 ± 2.1, and 95.9 ± 14.5, respectively. Lean body size, higher white blood cell counts and C‐reactive protein levels, anaemia, and lack of angiotensin blocker use were independently associated with malnutrition (defined by SA < 3.5 g/dL). Higher SA levels [hazard ratio (HR): 0.67 (95% confidence interval, CI: 0.53–0.85)], higher PNI [HR: 0.97 (95% CI: 0.95–0.99)], and higher geriatric nutritional risk index [HR: 0.98 (95% CI: 0.97–0.99)] (all P < 0.05) were all associated with longer survival, with higher CONUT score [HR: 1.08 (95% CI: 1.02–1.13)] exhibited higher mortality in Cox regression models and with higher SA levels/PNI but not BMI further contributing to the reduced rate of re‐hospitalization (both P < 0.05). Categorizing BMI (25 kg/m² as cut‐off) and nutritional status showed significantly higher mortality rates among patients with lower BMI/malnutrition than among those with BMI/better nutrition (SA level, PNI, and CONUT score, all P < 0.01). Restricted cubic spline regression revealed a marked survival benefit of better nutrition with increasing BMI (adjusted P_interaction for both SA level and PNI: <0.001; adjusted P_interaction for CONUT score: 0.046).

Conclusions

Malnutrition was frequently and strongly associated with systemic inflammation in Asian patients hospitalized for acute HFpEF. Our findings also indicate that nutrition may play a pivotal role in metabolic protection in this population.

Diagnostic accuracy of left atrial remodelling and natriuretic peptide levels for preclinical heart failure

AIMS

Left atrial (LA) remodelling is an important predictor of cardiovascular events of heart failure (HF) and atrial fibrillation. Data regarding diagnostic value of LA remodelling on diastolic dysfunction (DD) and preclinical HF remain largely unexplored.

METHODS AND RESULTS

We assessed LA dimension (LAD) in 8368 consecutive asymptomatic Asians (mean age: 49.7, 38.9% women) and related such measure to updated American Society of Echocardiography (ASE) DD criteria and newly revised N-terminal pro-brain natriuretic peptide (NT-proBNP) cut-off (≥125 pg/mL) and HF with preserved ejection fraction criteria incorporating NT-proBNP and echocardiography parameters by the European Society of Cardiology (ESC). LAD and indexed LAD (LADi) were both inversely correlated with myocardial relaxation e' and positively associated with indexed LA volume, left ventricular E/e', and tricuspid regurgitation velocity (all P < 0.001) and showed significantly graded increase across ASE-defined 'normal', 'inconclusive', and 'DD' categories (30.9, 34.4, and 36.5 mm; 16.7, 19.1, and 20.6 mm/m² , for LAD/LADi, both P for trend: <0.001, respectively). Substantial differences of LAD/LADi (31.3 vs. 33.6 mm/16.7 vs. 19.2 mm/m² , both P < 0.001) between ESC low and high HF probability using NT-proBNP cut-off were also observed. Multivariate linear and logistic models demonstrated that LAD set at 34 mm was independently associated with ASE-defined diastolic indices, DD existence, and elevated NT-proBNP (all P < 0.05). The use of LAD further yielded high diagnostic accuracy in DD (area under receiving operative characteristic curve: 0.77, 95% confidence interval [0.73, 0.80]; negative predictive value: 97.9%) and in ESC-recommended HF with preserved ejection fraction criteria (area under receiving operative characteristic curve: 0.70, 95% confidence interval [0.65, 0.75]; negative predictive value: 98.7%) with high predictive value in LA remodelling (>34 mL/m² ; positive predictive value: 96%) and well-discriminated ESC-recommended NT-proBNP (≥125 pg/mL, LAD: 37 mm) for HF.

CONCLUSIONS

Single utilization of atrial remodelling is highly useful for ruling out presence of DD and provides practical threshold for identifying preclinical HF based on most updated guidelines.

The relationship of renal function to segmental vascular stiffness, ankle-brachial index, and peripheral artery disease

The authors consecutively assessed various arterial pulse-wave velocity (PWV) indices and ankle-brachial index (ABI) by an automatic device (VP2000, OMRON Health Care Co. Ltd., Kyota, Japan) in outpatients with ≥ 1 cardiovascular risk. PAD was defined as ABI ≤ 0.9. Among 2309 outpatients (mean age 62.4 years), worse renal function was associated with higher brachial-ankle PWV, heart-carotid PWV, heart-femoral PWV (hf-PWV), and lower ABI (all P < .001). Multivariate regression models showed independent associations between lower eGFR, lower ABI (Coef: 0.42 & 0.41 for right and left), higher hf-PWV (Coef: -11.4 [95% CI: -15.4, -7.3]) and greater PAD risk (adjusted OR: 0.83 [95% CI: 0.76, 0.91], all P < .05). eGFR set at 77 mL/min/1.73m² was observed to be useful clinical cutoff (c-statistics: 0.67) for identifying PAD (P for ΔAUROC: .009; likelihood X² : 93.82 to 137.43, P < .001) when superimposed on clinical risks. This study suggested early renal insufficiency is tightly linked to region-specific vascular stiffness and PAD.

The association among MDCT-derived three-dimensional visceral adiposities on cardiac diastology and dyssynchrony in asymptomatic population

Background

Visceral adipose tissue, a biologically active fat depot, has been proposed as a reliable marker for visceral adiposity and metabolic abnormalities. Effects of such adiposity on LV diastolic function and dyssynchrony remained largely unknown.

Methods

We assessed pericardial fat (PCF) and thoracic peri-aortic fat (TPAF) by three-dimensional (3D) volume-vender multi-detector computed tomography (MDCT) (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA). Echo-derived diastolic parameters and tissue Doppler imaging (TDI) defined mitral annular systolic (S’), early diastolic (E’) velocities as well as LV filling (E/E’) were all obtained. Intra-ventricular systolic (Sys-D) and diastolic (Dias-D) dyssynchrony were assessed by TDI method.

Results

A total of 318 asymptomatic subjects (mean age: 53.5 years, 36.8 % female) were eligible in this study. Greater PCF and TPAF were both associated with unfavorable diastolic indices and higher diastolic dyssynchrony (all p < 0.05). These associations remained relatively unchanged in multi-variate models. PCF and TPAF set at 81.68 & 8.11 ml yielded the largest sensitivity and specificity (78.6 and 60 % for PCF, 75 and 66.6 % for TPAF, respectively) in predicting abnormally high LV diastolic dyssynchrony, which was defined as Dias-D≧55 ms.

Conclusion

Increasing visceral adiposity may be associated with adverse effects on myocardium, primarily featured by worse diastolic function and greater degree of dyssynchrony.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-015-0136-8) contains supplementary material, which is available to authorized users.

Abstract P009: Relationship Between Increased Systolic and Diastolic Pressure and Left Atrial Train Rate

Background: Left atrial (LA) strain rate analysis by two-dimensional speckle tracking can represent a new tool to evaluate LA function. Office blood pressure is the most powerful non-invasive index of arterial stiffness which can determine LA function.

We hypothesized that increased systolic and diastolic pressure were associated with increased left atrial strain.

Methods: We consecutively examined 2D speckle-tracking in an asymptomatic cohort, with cardiac geometry, LA volume, LA ejection fraction, LA strain rate analyzed. The LA speckle tracking echocardiography curves were obtained using R-wave onset of the electrocardiogram as a reference point. The LA strain rate (SRs, SRe and SRa) were analyzed by commercialized software (GE EchoPAC; GE Vingmed, Norway).

Results: A total of 4052 volunteers were divided into quintiles by systolic or diastolic blood pressure (systolic pressure cut point 110, 118, 126, 136mmHg; diastolic pressure cur=t point 68, 71, 80, 85mmHg). A trend toward the greater systolic or diastolic pressure, the higher LA diameter, LA volume and LA strain rate across 5 groups were observed (Table1 and Table 2, all trend p<0.001 except LA SRs).

Conclusion: Increased in systolic and diastolic pressure were independently associated with increased LA strain rate, LA diameter and LA volume in asymptomatic populations.

Cardiac mechanics and ventricular twist by three-dimensional strain analysis in relation to B-type natriuretic peptide as a clinical prognosticator for heart failure patients

Background

Three dimensional (3D) echocardiography-derived measurements of myocardial deformation and twist have recently advanced as novel clinical tools. However, with the exception of left ventricular ejection fraction and mass quantifications in hypertension and heart failure populations, the prognostic value of such imaging techniques remains largely unexplored.

Methods

We studied 200 subjects (mean age: 60.2±16 years, 54% female, female n = 107) with known hypertension (n = 51), diastolic heart failure (n = 61), or systolic heart failure (n = 30), recruited from heart failure outpatient clinics. Fifty-eight healthy volunteers were used as a control group. All participants underwent 3D-based myocardial deformation and twist analysis (Artida, Toshiba Medical Systems, Tokyo, Japan). We further investigated associations between these measures and brain natriuretic peptide levels and clinical outcomes.

Results

The global 3D strain measurements of the healthy, hypertension, diastolic heart failure, and systolic heart failure groups were 28.03%, 24.43%, 19.70%, and 11.95%, respectively (all p<0.001). Global twist measurements were estimated to be 9.49°, 9.77°, 8.32°, and 4.56°, respectively. We observed significant differences regarding 3D-derived longitudinal, radial, and global 3D strains between the different disease categories (p<0.05), even when age, gender, BMI and heart rate were matched. In addition, 3D-derived longitudinal, circumferential, and 3D strains were all highly correlated with brain natriuretic peptide levels (p<0.001). At a mean 567.7 days follow-up (25^th–75^th IQR: 197–909 days), poorer 3D-derived longitudinal, radial, and global 3D strain measurements remained independently associated with a higher risk of cardiovascular related death or hospitalization due to heart failure, after adjusting for age, gender, and left ventricular ejection fraction (all p<0.05).

Conclusions

3D-based strain analysis may be a feasible and useful diagnostic tool for discriminating the extent of myocardial dysfunction. Furthermore, it is able to provide a prognostic value beyond traditional echocardiographic parameters in terms of ejection fraction.

Independent effects of body fat and inflammatory markers on ventricular geometry, midwall function, and atrial remodeling

BACKGROUND

The effect of body fat distribution on left ventricular (LV) mass and geometry has been recently recognized. However, data regarding circulating inflammatory markers in relation to regional visceral fat deposits, which are metabolically active tissues that can impact cardiac structural remodeling, remain sparse.

HYPOTHESIS

We hypothesized that obesity has adverse effects on cardiac function and structure.

METHODS

We consecutively studied 1071 asymptomatic subjects (age 49.5 ± 10.5 years, 39.4% female) free from significant valvular disorders, chronic lung disease, or renal disease. Echocardiography-defined cardiac structures and LV geometries including LV mass, mass-to-volume ratio, and fractional shortening were all determined. Body fat composition (Tanita-305 Body-Fat Analyzer; Tanita Corp., Tokyo, Japan) was obtained and calculated. Multivariate regression models from various models were used to represent the independent association between body fat and echo-derived ventricular mass and geometries.

RESULTS

In multivariable analysis, increasing body fat was significantly related to increase in left atrial (LA) and LV diameter, posterior wall thickness, relative wall thickness (RWT), LV mass, mass-to-volume ratio, and decreased midwall fractional shortening with or without stress correction (all P < 0.001). When LV mass and severity of mitral regurgitation was further added, the independent association between increased body fat composition and larger LA diameter remained significant (β coefficient = 0.37, P < 0.001). Elevated high-sensitivity C-reactive protein (Hs-CRP) level was associated with larger LA diameter, increased RWT, and worsened midwall mechanics in the female gender (all interaction P < 0.05).

CONCLUSIONS

Accumulated body fat seemed to be related to worse ventricular midwall contractility and atrial remodeling, particularly in the female gender, with high systemic inflammation. These gender and Hs-CRP-specific modification effects may potentiate the pathological mechanisms involved in heart failure with preserved ejection fraction.

Beyond malignancy: the role of carbohydrate antigen 125 in heart failure

Carbohydrate antigen 125 (CA-125), traditionally a tumor marker for screening, diagnosis, and monitoring in ovarian malignancy, had recently been shown increasing evidence and more extensively recognized/explored as a novel surrogate of heart failure (HF). The exact mechanisms underlying the pathophysiologic link between elevated serum CA-125 concentration and HF may be multi-factorial, with both mechanical and inflammatory process including numerous potential cytokines involved. Accumulating data had consistently indicated its diagnostic and prognostic role in HF patients in various clinical settings, however, there is limited clinical information regarding the incremental value or head-to-head comparison of such marker to other well-established HF markers. In this brief review, we aimed to discuss the biosynthesis, and potential insights of underlying pathophysiologies associated with CA-125 secretion in the scenarios of cardiac structural/functional alterations and HF, and further explored its current usage and roles in several recent reports.

Remodeling of rabbit abdominal aorta and Cx43 gap junctions after stent placement: effect of balloon injury plus cholesterol-enriched diet

AIM

To examine the effect of stenting and cholesterol-enriched diet (CED) on vascular remodeling, including the expression of connexin43 (Cx43) gap junctions in smooth muscle cells (SMC).

METHODS

Rabbits abdominal aortae were either implanted stent made of 316 stainless steel (group 1) or denuded followed by stent placement 28 days later (groups 2 and 3). Animals were given normal chow except those of group 3, which were fed CED after the denudation. Eight weeks later, the development of neointima and the expression of connexin43 (Cx43) were examined. In parallel, human aortic SMC were grown on 316 stainless steel or treated with C-reactive protein (CRP) followed by analysis of Cx43.

RESULTS

The results showed that, serum CRP levels became transiently elevated after denudation and stent implantation. For the stented aortic segments, the dimensions of neointima were group 3 > group 2 > group 1 (P<0.05). In groups 1 and 2, Cx43 gap junctions are less in amount in neointima of the stented segment, compared to the unstented upstream neointima or medial layer (all P<0.01). In culture experiments, Cx43 in SMC grown on stent material was up-regulated in growth medium but down-regulated in differentiation medium, and CRP did not affect Cx43 expression.

CONCLUSION

Vascular remodeling post stent implantation varied according to the presence of balloon injury, CED, or both. Cx43 expression in SMC is altered after exposure to stent and the regulation depended on the milieu.

The incremental value of regional dyssynchrony in determining functional mitral regurgitation beyond left ventricular geometry after narrow QRS anterior myocardial infarction: a real time three-dimensional echocardiography study

BACKGROUND

Determinants of functional mitral regurgitation (FMR) severity after acute anterior myocardial infarction (MI) remained unclear. Our aim was to: (1) test whether LV dyssynchrony upon real time three-dimensional echocardiography (RT-3DE) is independently associated with FMR severity; and (2) to investigate the role of regional systolic dyssynchrony index (SDI) in identifying FMR severity.

METHODS

RT-3DE was successfully performed on 64 consecutive patients following acute anterior MI with a narrow QRS complex (<130 ms) and another 30 healthy volunteers. MR severity was assessed using vena contracta method. SDI was derived from the dispersion of the time to minimum regional volume for all 16 LV segments. Multiple linear regression analysis was used to identify the independent relationship between FMR and SDI with and without multivariate adjustment.

RESULTS

The mean LV ejection fraction was 49.6%± 11.9% in the MI group. All regional (except apical) and global SDIs were associated with regional LV remodeling and were significantly correlated with FMR even after multivariate adjustment, with midwall SDI being most strongly associated with MR severity (R(2) = 0.55, P < 0.001). Regional midwall SDI superimposed on LV global geometry and mitral leaflet deformation substantially expanded the area under curve in identifying FMR (AUC increased from 0.69 to 0.93, c-statistics: P = 0.041).

CONCLUSIONS

While both global and regional dyssynchrony following anterior MI were independently related to FMR severity, regional midwall dyssynchrony further added incremental value in predicting FMR severity beyond traditional parameters. This finding provides a new insight into the understanding of FMR after anterior MI and may further potentiate specific therapeutic approaches.

AGE-BSA down-regulates endothelial connexin43 gap junctions

Background

Advanced glycation end products generated in the circulation of diabetic patients were reported to affect the function of vascular wall. We examined the effects of advanced glycation end products-bovine serum albumin (AGE-BSA) on endothelial connexin43 (Cx43) expression and gap-junction communication.

Results

In human aortic endothelial cells (HAEC) treated with a series concentrations of AGE-BSA (0-500 μg/ml) for 24 and 48 hours, Cx43 transcript and Cx43 protein were reduced in a dose dependent manner. In addition, gap-junction communication was reduced. To clarify the mechanisms underlying the down-regulation, MAPKs pathways in HAEC were examined. Both a MEK1 inhibitor (PD98059) and a p38 MAPK inhibitor (SB203580) significantly reversed the reductions of Cx43 mRNA and protein induced by AGE-BSA. Consistently, phosphorylation of ERK and p38 MAPK was enhanced in response to exposure to AGE-BSA. However, all reversions of down-regulated Cx43 by inhibitors did not restore the functional gap-junction communication.

Conclusions

AGE-BSA down-regulated Cx43 expression in HAEC, mainly through reduced Cx43 transcription, and the process involved activation of ERK and p38 MAPK.

Multimodality evaluation of the viability of stem cells delivered into different zones of myocardial infarction

BACKGROUND

We tested the hypothesis that multimodality imaging of mouse embryonic stem cells (mESCs) provides accurate assessment of cellular location, viability, and restorative potential after transplantation into different zones of myocardial infarction.

METHODS AND RESULTS

Mice underwent left anterior descending artery ligation followed by transplantation of dual-labeled mESCs with superparamagnetic iron oxide and luciferase via direct injection into 3 different zones of myocardial infarction: intra-infarction, peri-infarction, and normal (remote). One day after transplantation, magnetic resonance imaging enabled assessment of the precise anatomic locations of mESCs. Bioluminescence imaging allowed longitudinal analysis of cell viability through detection of luciferase activity. Subsequent evaluation of myocardial regeneration and functional restoration was performed by echocardiography and pressure-volume loop analysis. Using 16-segment analysis, we demonstrated precise localization of dual-labeled mESCs. A strong correlation between histology and magnetic resonance imaging was established (r=0.962, P=0.002). Bioluminescent imaging data demonstrated that cell viability in the remote group was significantly higher than in other groups. Echocardiography and pressure-volume loop analysis revealed improved functional restoration in animals treated with mESCs, although myocardial regeneration was not observed.

CONCLUSIONS

Multimodality evaluation of mESC engraftment in the heterogeneous tissue of myocardial infarction is possible. Magnetic resonance imaging demonstrated accurate anatomic localization of dual-labeled mESCs. Bioluminescent imaging enabled assessment of variable viability of mESCs transplanted into the infarcted myocardium. Echocardiography and pressure-volume loop analysis validated the restorative potential of mESCs. Although mESCs transplanted into the remote zone demonstrated the highest viability, precise delivery of mESCs into the peri-infarction region might be equally critical in restoring the injured myocardium.

Trace metals in different species of mollusca, water and sediments from Taiwan coastal area

Since October 1994, a long-term program of Asia/Pacific Mussel Watch: Taiwan Regional Studies has been carried out. The results indicate that trace metal contents in mollusca varied among 30 different species and the environments (water and sediments) along the Taiwan coast. The orders of bioaccumulation of trace metals in mollusca were: Cu (over 200 microg/g), Thais clavigera > Isognomon legumen > Clibanarius rivescens > Crassostrea gigas; Zn (over 700 microg/g), Moruta granulata > C. gigas > Asiatica cypraea arabica > T. clavigera; Cd (over 5 microg/g), Trochus hanleyanus > Acanthopleura japonica > Nerita albicilla > Patella flexuosa; Pb (over 2 microg/g), P. flexuosa > C. gigas > T. hanleyanus > T. clavigera > C. gigas > Capiyulum mitella; Ni (over 10 microg/g), Meretrix lusoria > Philine sp. > Littoraria scabra > Tridacna squamosa > T. hanleyanus; Cr (over 30 microg/g), Littoraria undulata > T. hanleyanus > N. albicilla > Nerita chamaelor > M. granulata; As (over 20 microg/g), Perna viridis > L. scabra; and Sn (over 5 microg/g), P. viridis > L. undulata> C. mitella> C. gigas. Their seasonal and regional variations as well as their correlation are evaluated and discussed.

Organotins and imposex in the rock shell, Thais clavigera, from oyster mariculture areas in Taiwan

The amounts of organotin compounds such as butyltins [sigma BTs: tributyl- (TBT), dibutyl- (DBT), monobutyl- (MBT)] and phenyltins [sigma PhTs: triphenyl- (TPhT), diphenyl- (DPhT) and monophenyl- (MPhT)] in rock shells, Thais clavigera, from the northern (Shiangsan), central (Lukang) and southern (Chiku) Taiwan oyster mariculture areas varied with season and location. High values of sigma BTs (mainly TBT) and low values of sigma PhTs (mainly TPhT) were found during winter (January 1999) at Shiangsan, while high amounts of sigma PhTs (mainly TPhT) and low sigma BTs (mainly TBT) were found during summer (August 1998) at Lukang. The snails were also affected by imposex. Imposex at Shiangsan, Lukang and Chiku increased from 67.1, 59.3 and 36.7% in summer to 100, 100 and 80% in winter, respectively. Relative penis size indices similar trend at Chiku site. No male displayed rock shells were found at Shiangsan and Lukang in winter. Linear correlations between pseudopenis length versus TBT (r = 0.7655, P < 0.001), DBT (r = 0.4253, P < 0.05), MBT (r = 0.5865, P < 0.01) and TPhT (r = -0.6160, P < 0.01) were obtained significant. Among 200 samples, significant positive correlations between length (pseudopenis/shell) ratio of female versus TBT (r = 0.6944, P < 0.005) and sigma BTs (r = 0.6413, r < 0.01) were also observed. The weak correlations between length (pseudopenis/shell) ratio of female versus DBT (r = 0.3085) and MBT (r = 0.4240, P < 0.1) and TPhT (-0.4917, P < 0.05; negative correlation) could indicate that DBT, MBT and TPhT have little or no effect on the development of imposex in rock shells.

Mussel watch: a review of Cu and other metals in various marine organisms in Taiwan, 1991-98

This study presents the distribution of Cu, Zn, Pb, Cd, Hg and As in various marine organisms collected along the western coast of Taiwan from 1991 to 1998, and also evaluates the time variation of Cu in oysters before (1980-85) and after (1986-98) the "green oyster" incident. The results show that relatively high geometric mean (GM) concentrations of Cu, Zn, Pb, Cd, As and Hg were generally found in Crassostrea gigas (Cu=229 microg/g, Zn=783 microg/g), Gomphina aeguialtera (Pb=30.3 microg/g), Tegillarca granosa (Cd=2.85 microg/g), Thais clavigera (As=96.9 microg/g) and Parapenaeopsis cornuta (Hg=1.35 microg/g), respectively. Especially, maximum Cu and Zn concentrations (GM=229 and 783 microg/g, respectively) in oysters (C. gigas) from different culture areas were much higher than those of the other organisms by about 1.13-458 and 2.40-63.7 times, respectively. Similarly, rock-shells (Thais clavigera) had a high capacity for accumulating Cu (GM=202 microg/g) and Zn (GM=326 microg/g) under the same physico-chemical conditions. The highest GM Cu and Zn concentrations of 1108 (range from 113 to 2806) and 1567 (range from 303 to 3593) microg/g were obtained in oysters from the Hsiangshan coastal area, one of the most important oyster culture areas in Taiwan. However, the highest GM Cd and As concentrations of 6.82 and 19.3 microg/g were found in oysters from the Machu Islands. Mean Cu concentrations in the oysters from the Erhjin Chi estuary declined from 2194+/-212 microg/g in 1986-90 to 545 microg/g (GM) in 1991-96. In the Hsiganshan area, GM Cu concentrations of 909 microg/g (1991-96) and 1351 microg/g (1997-98) in oysters were significantly higher than those of 201 microg/g (1980-85) and 682 microg/g (1986-90). The gradually increasing levels of Cu and Zn in the oysters from the Hsiangshan area have been observed year by year.

Estimation of metal and organochlorine pesticide exposures and potential health threat by consumption of oysters in Taiwan

Pollutant concentrations detected in oysters from 12 different culture areas of Taiwan (especially for the Hsiangshan area and the Machu Islands) from 1991-98 were evaluated to investigate potential carcinogenic (inorganic As and organochlorine pesticides) and non-carcinogenic (Cu, Zn, Cd and inorganic As) risk to the public from ingestion of the oysters. The highest geometric mean (GM) Cu and Zn concentrations of 1108 (range 113-2806) and 1567 (range 303-3593) microg/g dry weight were obtained in oysters from the Hsiangshan coastal area. The maximum GM Cd and As concentrations of 6.82 and 19.3 microg/g dry weight were found in oysters from the Machu Islands area. The p,p'-DDE values range from not detectable in Penghu Islands' oysters to 164 ng/g dry weight in Machu Islands' oysters. The highest tDDT (sum of p,p'-DDE, p,p'-DDD and p,p'-DDT) concentrations of 337 and 340 ng/g dry weight were found in oysters from Kimmen and Machu Islands, respectively. A calculated target hazard quotient (THQ; daily intake/reference dose) of 11.4 (based on 139 g oysters/day) for Cu caused by consuming oysters from the Hsiangshan area is higher than that from other areas (range 0.124-5.95). The highest average Cu intake from Hsiangshan's oysters for individuals is 11.4 times (i.e. THQ=11.4) more than that of reference dose (40 microg/kg/day). However, the maximum THQ values for Cd and As caused by consuming oysters collected from the Machu Islands were 5.57 and 2.63 for Cd and As, respectively. Generally, the results of THQ showed that if only the maximally exposed individuals were considered, the value of 65.4% for oyster was higher than 1.0 in comparison with reference dose. All cancer risk estimates for inorganic As from consuming oysters were higher than 10(-6) (range from 128x10(-6) to 509x10(-6) for maximally exposed individuals and range from 17.1x10(-6) to 68.0x10(-6) for typically exposed individuals, respectively); that is the risk of the lower end of the range of acceptable risk. The highest risk estimate for inorganic As was 509x10(-6) for consumption of oysters by Machu Islands' residents. The lifetime cancer risks of 19.0x10(-6) for tDDT by consuming oysters from the Machu Islands was higher than those from the Penghu Islands (0.37x10(-6)). Therefore, the sum of lifetime cancer risks for tDDT and inorganic As had the highest risks (total risk=528x10(-6)) of consuming oysters from the Machu Islands. Furthermore, a 10(-6) upper limit on lifetime risk as the health protection standard would require maximum oyster consumption rates of approximately 0.26 g/day.

133Xenon ventilation scan as a functional assessment in bronchiectasis

BACKGROUND

Mucus impaction in the airways impairs ventilation and exercise tolerance in patients with bronchiectasis. Parameters for evaluating the ventilatory dynamic change have been limited by variable cofactors. We developed a tool to evaluate the changes directly on images of a ventilation scan.

MATERIALS AND METHODS

We used a 133Xenon ventilation washout scan to assess the time of half clearance (T1/2) of the regions of interest (ROIs) corrected by that of a control area (CA) as T1/2ROI/CA. We then compared the ventilation washout scan with high-resolution computer tomography (HRCT) scoring to assess the severity of bronchiectasis, as well as conducting 6-minute walking tests or spirometry for the evaluation of the clinical response to a 3-day course of chest physiotherapy. Nine patients with bronchiectasis and mucus hypersecretion were enrolled in this study.

RESULTS

The functional impairments by mucus impaction or air trapping were well documented in the ventilation washout scan, which not only provided an anatomical image but also dynamic profiles. The ratios of T1/2ROI/CA were significantly correlated to the corresponding scoring of HRCT (3.45 +/- 0.85 vs 7.50 +/- 1.51, r2 = 0.61, p = 0.023, n = 8). The improvement in T1/2ROI/CA (from 3.45 +/- 0.85 to 2.60 +/- 0.59, p = 0.022, n = 9) was paralleled by an increase in the 6-minute walking test (from 310.4 +/- 43.2 m to 352.4 +/- 45.1 m, p = 0.028, n = 7).

CONCLUSION

The 133Xenon scan may be used to evaluate the heterogeneity of ventilation abnormalities and the efficacy of clinical therapy directly in patients with bronchiectasis.

Estimation of target hazard quotients and potential health risks for metals by consumption of seafood in Taiwan

The purpose of this paper is to describe the impact of metal pollution on the main seafood and assess the potential health risk from consuming the contaminated seafood in Taiwan. The results of geometric mean (GM) metal concentrations in various seafood showed that the copper, zinc, and arsenic concentrations in oysters were significantly (p < 0.001) higher than those in the other seafood by about 1,057, 74.3, and 56.2 times, respectively. The green color found in the oysters was due to high GM copper and zinc concentrations of 909 (ranging from 113-2,805) and 1,293 (ranging from 303-3,593) microg/g dry wt, respectively. In addition, using a maximum consumption rate of 139 g/day of oysters for individuals, calculations yield target hazard quotients (daily intake/reference dose) of below 1 for cadmium and mercury and high values of 1.61, 9. 33, and 1.77 for inorganic arsenic, copper, and zinc in adults, respectively. The various lifetime cancer risks for inorganic arsenic (maximum exposed individuals risk ranging from 9.93 x 10(-6) to 3.11 x 10(-4)) might be caused by consuming different seafood in Taiwan. The highest risk estimate for inorganic arsenic was 5.10 x 10(-4) for consumption of oysters by Machu Islands residents. The long-term exposure of metals through consumption of oysters, especially for some high-risk groups, could be dangerous. Taking inorganic arsenic for example, a 10(-6) upper limit on lifetime risk as the health protection standard would require maximum oyster residue levels of approximately 0.0076-0.056 microg/g wet wt, for consumption rates of 139-18.6 g/d. In the light of known risks to public health, the government should issue an immediate warning to the public to refrain from eating all seafood harvested from the Taiwan coastal areas, especially the Hsiangshan area and the Machu Islands.

Relationship between copper speciation in sediments and bioaccumulation by marine bivalves of Taiwan

This paper evaluates the relationships between copper species in sediments and accumulation by the purple clam (Hiatula diphos) and venus clam (Gomphina aeguilatera) collected from the field and culture (aquaculture) ponds in the polluted coastal area of Lukang, Taiwan. Sediment was sampled along with the molluscs, including oysters (Crassostrea gigas), purple clams (Hiatula diphos), rock-shells (Thais clavigera), venus clams (Gomphina aeguilatera), and hard clams (Meretrix lusoria), from two unique environments of Lukang during the period from August 1993 to July 1994. The data indicate that the total copper concentrations in sediments from culture ponds (185 microg g(-1)) was higher than those of the field (44.0 microg g(-1)). Copper species in sediments were analyzed by a sequential leaching technique. Results show that concentrations of various copper species in the sediments are in the range of 1.14 +/- 0.59 to 13.2 +/- 22.4 microg g(-1) and 0.36 +/- 0.24 to 133 +/- 36.7 microg g(-1) for the two environments, respectively. Also the exchangeable copper in sediment from culture ponds was 15 times higher than that from the field. In addition, the sum of exchangeable and copper carbonates had the highest percentages of copper in both the pond sediment (86.6 %) and the field sediment (50.7 %). Maximum copper concentrations (309 +/- 35.1 microg g(-1)) in oysters were much higher than those in the other benthic organisms by about 4-127 times. Similarly, the data also showed that copper concentrations in Thais clavigera were 12-32 times higher than those in other benthic organisms. Copper concentrations in various benthic organisms differed significantly (p < 0.05) from that in Thais clavigera. This capacity makes Thais clavigera a potential candidate for monitoring copper in marine sediments. In terms of copper species, the best correlation was generally obtained between copper carbonates in sediments and copper concentrations in Hiatula diphos (r = 0.886*). A strong multiple regression correlation (p < 0.05, r2 = 0.7894) also indicates that the copper carbonates may dominate as the available form of copper to Hiatula diphos from various environments in the Lukang coastal area under natural physicochemical conditions.

Species of copper and zinc in sediments collected from the antarctic ocean and the Taiwan Erhjin Chi coastal area

The species of copper and zinc, such as bioexchangeable, skeletal, easily reducible (Fe and Mn oxides), moderately reducible (crystalline Mn oxide), organic combined with sulfides, and detritus with minerals, in mud and sand, separated from the surface Antarctic Ocean and the Taiwan Erhjin Chi coastal (including river and estuarine) sediments, have been analyzed by sequential leaching methods. Results show that in the Antarctic Ocean sediments, high concentrations of total copper (128 mg/kg) and zinc (458 mg/kg) were found in the high mud (99.09%) content samples compared with the low concentrations of total copper (83.8 mg/kg) and zinc (288 mg/kg) in low mud (51.69%) content samples. High concentrations of copper, zinc, manganese and iron are possibly due to the characteristics of manganese nodules, in which the species of copper and zinc are mainly contained in the crystalline Mn oxide phase. In the Taiwan Erhjin Chi coastal sediments, the total copper and zinc concentrations in mud and sand vary with season and location. High values were generally observed in the river sediments during the dry season, and low values were in the estuarine and coastal sediments during the heavy rainy season. High percentages of copper (as high as 49.4%) and zinc (as high as 76.7%) in mud and sand were in the bioexchangeable phase including the skeletal phase. This result might be correlated with the problems arising from human impact on copper and zinc as well as sewage pollution in Taiwan. In the organic combined phase, biogenic particulate matter related to higher primary productivity in the Antarctic Ocean is also discussed.

Effects of long-term Novacor artificial heart support on blood rheology

This study presents characteristics of hemorheology for six patients during long-term support (85-144 days) on a Novacor left ventricular assist device (LVAD) as a bridge-to-cardiac transplantation. Results indicate that a certain "baseline" rheology can be identified in patients whose support was uneventful. However, in the patients who had one or more neurologic episodes during support, these events were associated with altered hemorheology, including increases in plasma and relative blood viscosity, and red cell rigidity.

Alterations in erythrocyte rheology in patients with severe peripheral vascular disease: 1. Cell volume dependence of erythrocyte rigidity

The erythrocyte rigidity of patients suffering from severe peripheral vascular disease (PVD) was measured by a filtration method using 3 microns pore size filters. Filtration pressures for both PVD patients and normal subjects showed a cell volume dependency, and patient filtration pressures were normalized to cell volume to evaluate intrinsic, ie, nonvolume dependent, abnormalities in erythrocyte deformability. A significant (p less than 0.001) increase in cell rigidity was found in 44 of 54 PVD patients in comparison with volume-matched normal controls. No significant difference was found between patient mean corpusculer hemoglobin (MCH) and normal MCH at any given mean corpuscular volume (MCV), indicating that observed increases in erythrocyte rigidity are not attributable to changes in patient MCH. Therefore, the mechanism of increase in erythrocyte rigidity for PVD patients still needs further investigation into such parameters as levels of adenosine triphosphate,2,3-DPG, and membrane fluidity (calcium- and/or protein-binding membrane, cholesterol and phospholipid content of membrane, etc), as well as other aspects of erythrocyte physiology.

Interim use of Jarvik-7 and Novacor artificial heart: blood rheology and transient ischemic attacks (TIA's)

The rheological properties of blood were studied in patients supported by both the Jarvik-7 total artificial heart (TAH) and Novacor left ventricular assist device (LVAD) as a bridge to cardiac transplantation. Both groups of patients had abnormalities in blood rheology which differed according to the type of device implanted as well as on the clinical state of the patient. The rheology of individual patients correlated well with their clinical status and outcome, with incidences of TIA's and/or stroke being accompanied by marked increases in relative blood viscosity, erythrocyte rigidity, fibrinogen concentration and platelet aggregation in varying combination. Observed abnormalities in blood rheology were also crucial to thrombus formation on artificial heart valves as well. Our results show that the therapeutic management of rheological parameters should prove to be a unique and clinically rewarding approach to these patients.

Artificial heart. Hemorrheology and transient ischemic attacks

Hemorrheology was studied in patients undergoing artificial heart support as a bridge-to-cardiac transplantation. Abnormal hemorrheology was seen in two patients, one on a Jarvik-7 total artificial heart, and the other on a Novacor left ventricular assist device. Both of these patients suffered neurologic episodes. The rheology of these two patients coincided well with their clinical status, and was accompanied by marked increases in relative blood viscosity, erythrocyte rigidity, fibrinogen concentration, and platelet aggregation. Results show that improving hemorrheology may be a beneficial avenue to pursue in preventing or treating transient ischemic attacks or other complications in patients during support with mechanical devices.

Green oysters caused by copper pollution on the Taiwan coast

The first case of green oysters (Crassostrea gigas) broke out along the Charting mariculture area of south-western Taiwan in January 1986. The green color was found to be due to high copper content in the oyster tissue. Since then, a long-term survey around this area shows that total dissolved copper ranges from 4.99 to 23.6 microg/liter and particulate copper ranges from 1.09 to 5.51 microg/liter in sea-water. The green oysters collected from the Erhjin Chi estuary on 26 January, 1989 gave the highest copper content, 4401+/-79 ppm dry wt. Other green oyster cases were occasionally observed in the Hsiangsan and Anpin mariculture areas. Meanwhile, an experiment of copper accumulation in oysters was conducted at three stations (south-western Taiwan) for up to 90 days. Multiple regression analysis indicates that the food pathway may predominate in copper accumulation by green oysters. This bioaccumulation experiment shows that the total uptake of copper per oyster is an exponential function of exposure time for the first 2 weeks with an accumulation rate of 214 ppm Cu/day and then levels off. The average values of concentration factors for oysters (about 5 x 10(5)) were very close to steady-state values under the natural conditions at each station.

Characteristics of blood rheology in patients during Novacor left ventricular assist system support

Blood rheologic properties were studied in 11 patients on Novacor LVAS support (1-126 days) as a bridge to transplantation. Overall, these patients showed slight increases in mean blood viscosity and red cell rigidity. Their mean plasma fibrinogen was in the upper normal range. However, the degree of rheologic change observed, and the individual factors affected most, were unique to each patient and hemorheologic results correlated well with the patient's clinical status.