The New Normal: How Should We Assess Cardiac Chamber Sizes and Proportionality across the Full Spectrum of Body Sizes with Varying Degrees of Adiposity?

Obesity and Risk of Incident Left Ventricular Hypertrophy in Community-Dwelling Populations With Hypertension: An Observational Study

BACKGROUND

The aim of this study was to evaluate the association between obesity and risk of incident left ventricular hypertrophy (LVH) in community-dwelling populations with hypertension and investigate whether this association would be attenuated by a lower achieved systolic blood pressure (SBP).

METHODS AND RESULTS

We used the EMINCA (Echocardiographic Measurements in Normal Chinese Adults) criteria, which were derived from healthy Chinese populations to define LVH. A total of 2069 participants with hypertension and without LVH (obesity 20.4%) were included. The association between obesity and risk of incident LVH was evaluated using Cox proportional hazard models and stratified by achieved follow-up SBP levels (≥140, 130-139, and <130 mm Hg). These analyses were also assessed using the American Society of Echocardiography/European Association of Cardiovascular Imaging criteria, which were derived from European populations to define LVH. After a median follow-up of 2.90 years, the rates of incident LVH in the normal-weight, overweight, and obese groups were 13.5%, 20.3%, and 27.8%, respectively (P<0.001). In reference to normal weight, obesity was associated with increased risk of incident LVH (adjusted hazard ratio [aHR], 2.51 [95% CI, 1.91-3.29]), which was attenuated when achieved SBP was <130 mm Hg (aHR, 1.78 [95% CI, 0.99-3.19]). This association remained significant when achieved SBP was ≥140 mm Hg (aHR, 3.45 [95% CI, 2.13-5.58]) or at 130 to 139 mm Hg (aHR, 2.32 [95% CI, 1.23-4.36]). Differences in these findings were noted when LVH was defined by the American Society of Echocardiography/European Association of Cardiovascular Imaging criteria.

CONCLUSIONS

Obesity was associated with incident LVH and an SBP target <130 mm Hg might be needed to attenuate this risk in patients with hypertension and obesity.

Reference Values for Indexed Echocardiographic Chamber Sizes in Older Adults: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Normalization of echocardiographic chamber measurements for body surface area may result in misclassification of individuals with obesity or sarcopenia. Normalization for alternative measures of body size may be preferable, but there remains a dearth of information on their normative values and association with cardiovascular function metrics.

METHODS AND RESULTS

A total of 3032 individuals underwent comprehensive 2-dimensional echocardiography at Exam 6 in MESA (Multi-Ethnic Study of Atherosclerosis). In the subgroup of 608 individuals free of cardiopulmonary disease (69.5±7.0 years, 46% male, 48% White, 17% Chinese, 15% Black, 21% Hispanic), normative values were derived for left and right cardiac chamber measurements across a variety of ratiometric (body surface area, body mass index, height) and allometric (height1.6, height2.7) scaling parameters. Normative upper and lower reference values were provided for each scaling parameter stratified across age groups, sex, and race or ethnicity. Among scaling parameters, body surface area and height were associated with the least variability across race and ethnicity categories and height2.7 was associated with the least variability across sex categories.

CONCLUSIONS

In this diverse cohort of community-dwelling older adults, we provide normative values for common echocardiographic parameters across a variety of indexation methods.

Obesity in heart failure with preserved ejection fraction: Insights from the REDUCE LAP-HF II trial

AIMS

Obesity is causally related to the development of heart failure with preserved ejection fraction (HFpEF) but complicates the diagnosis and treatment of this disorder. We aimed to determine the relationship between severity of obesity and clinical, echocardiographic and haemodynamic parameters in a large cohort of patients with documented HFpEF.

METHODS AND RESULTS

The REDUCE LAP-HF II trial randomized 626 patients with ejection fraction ≥40% and exercise pulmonary capillary wedge pressure (PCWP) ≥25 mmHg to atrial shunt or sham procedure. We tested for associations between body mass index (BMI), clinical characteristics, cardiac structural and functional abnormalities, physical limitations, quality of life and outcomes with atrial shunt therapy. Overall, 60.9% of patients had BMI ≥30 kg/m2 . As the severity of obesity increased, symptoms (Kansas City Cardiomyopathy Questionnaire score) and 6-min walk distance worsened. More severe obesity was associated with lower natriuretic peptide levels despite more cardiac remodelling, higher cardiac filling pressures, and higher cardiac output. Lower cut points for E/e' were needed to identify elevated PCWP in more obese patients. Strain measurements in all four chambers were maintained as BMI increased. Pulmonary vascular resistance at rest and exercise decreased with higher BMI. Obesity was associated with more first and recurrent heart failure events. However, there was no significant interaction between obesity and treatment effects of the atrial shunt.

CONCLUSIONS

Increasing severity of obesity was associated with greater cardiac remodelling, higher right and left ventricular filling pressures, higher cardiac output and increased subsequent heart failure events. Despite significant obesity, many HFpEF patients have preserved right heart and pulmonary vascular function and thus, may be appropriate candidates for atrial shunt therapy.

Variations in indexation of left atrial volume across different races

Background

Left atrial volume (LAV) has prognostic value. Guidelines propose indexation to body surface area (BSA), however studies demonstrate this can overcorrect for body size. Limited studies investigate indexation across different ethnicities. We sought to evaluate the effect of ethnicity on indexation.

Methods

Using data from the World Alliance of Societies of Echocardiography (WASE) cohort, healthy subjects were classified by race as White, Black, Asian, or Other. Biplane LAV was indexed to traditional isometric measurements (BSA, height, weight, ideal body weight (IBW) and IBW derived BSA (IBSA)), as well as previously-derived allometric height exponents (2.7 and 1.72). Additionally, an allometric height exponent for our cohort was derived (linear regression of the logarithmic transformation of LAV = a(height)b) as 1.87. All indices were then assessed using Spearman correlation, with a good index retaining correlation of LAV/index to raw LAV (r∼1), while avoiding overcorrection by the index (r∼0).

Results

There were 1366 subjects (White: 524, Black: 149, Asian: 523, Other: 170; median age 44 years, 653 females (47.8%)). In the entire group, BSA, IBSA, height1.87 and height1.72 performed well with retaining correlation to raw LAV (r > 0.9 for all), and minimising overcorrection to body size (r < 0.1 for all). On race-specific analysis, BSA overcorrected for body size in the White population (r = 0.128). Height1.72 minimised overcorrection for body size in all populations (r ≤ 0.1 for all races).

Conclusion

Despite a cohort with normal BMI, there was still disparity in LAV indexation with BSA across races. Allometric height indexation, particularly using height1.72, is a possible solution, although further validation studies in BMI extremes are required.

Application of Allometric Methods for Indexation of Left Ventricular End-Diastolic Volume to Normal Echocardiographic Data and Assessing Gender and Racial Differences

BACKGROUND

Gender and racial differences in cardiac chamber size are vital to establish normal ranges of cardiac chamber size in healthy subjects. Many studies report either nonindexed raw measurements or measurements indexed to isometric body surface area (BSA) when establishing normal reference values. Other studies advocate allometric indexation for standardization of heart size. We compared several allometric methods on gender and racial differences in left ventricular end-diastolic volume (LVEDV) measured on three-dimensional echocardiography.

METHODS

Three-dimensional echocardiographic LVEDV data from the World Alliance Societies of Echocardiography normal values study were indexed to isometric BSA, BSA^1.5, BSA^1.8, isometric height, height^2.3, height^2.9, and estimated lean body mass. Gender, racial, national, and regional differences in indexed and nonindexed LVEDV were assessed using Cohen's d statistic or Cohen's f statistic, according to the number of groups being compared. Cohen's d < 0.20 and Cohen's f < 0.10 were regarded as very small relative magnitudes of difference.

RESULTS

Differences in LVEDV among White, Black, and Asian races were smallest when BSA^1.5 or BSA^1.8 was used for indexation, followed by estimated lean body mass. LVEDV/BSA^1.5 was nearly identical for men and women (very small, d = 0.05). However, both LVEDV/BSA^1.5 and LVEDV/BSA^1.8 still provided moderate relative magnitudes of difference (f = 0.22-0.37) among geographic regions. Specifically, among Asians, Indians had the smallest LVEDV/BSA^{1.5 (1.8)}. Brazilians had the smallest LVEDV/BSA^{1.5 (1.8)} among Whites.

CONCLUSIONS

Gender and racial differences in LVEDV became smaller when LVEDV was indexed to BSA^1.5 or BSA^1.8. However, differences in LVEDV among nations remain even after applying allometric scaling. This finding suggests that differences in body composition and/or hemodynamics are potentially more important determinants of heart size than race or gender.

Premature Death in Bodybuilders: What Do We Know?

Premature deaths in bodybuilders regularly make headlines and are cited as evidence that bodybuilding is a dangerous activity. A wealth of research has revealed elite athletes typically enjoy lower mortality rates than non-athletes, but research on bodybuilder lifespan is surprisingly limited. Anabolic androgenic steroid (AAS) use is commonly cited as a key contributor to morbidity and premature mortality in bodybuilders, but this area of research is highly nuanced and influenced by numerous confounders unique to bodybuilding. It is quite possible that bodybuilders are at elevated risk and that AAS use is the primary reason for this, but there remains much unknown in this realm. As global participation in bodybuilding increases, and healthcare providers play a more active role in monitoring bodybuilder health, there is a need to identify how numerous factors associated with bodybuilding ultimately influence short- and long-term health and mortality rate. In this Current Opinion, we discuss what is currently known about the bodybuilder lifespan, identify the nuances of the literature regarding bodybuilder health and AAS use, and provide recommendations for future research on this topic.

Echocardiographic measurements of the left heart chambers size in a large cohort of subjects: comparison of body surface area and height indexation to account for effects of obesity

BACKGROUND

The assessment of cardiac chamber size in the obese population is a challenging subject. Values usually indexed to body surface area (BSA) are smaller in obese subjects and prone to overcorrection. This study aimed to find reference thresholds to account for effects of obesity from a large cohort of patients and to evaluate the indexation by height as an alternative to BSA.

METHODS

The last 10-years records of our Echocardiography Unit were retrospectively analyzed and 14,007 subjects without known cardiac disease were included (45±15 years, 54% women, 20% obese). Measurements included left atrial diameter, area and volume (LAD, LAA and LAV), left ventricular (LV) end-diastolic (LVEDD) and end-systolic diameters (LVESD), aortic root diameter (ARD) and LV mass (LVM). Absolute, BSA and height indexed maximum thresholds (mean+1.96.SD) were calculated. An allometric indexation of the form variable/Height^β was tested. Correlation coefficients between indexed and absolute values were calculated to evaluate their proportional association (ideally r=1). Correlations between indexed values and body size represented residual associations to be minimized (ideally r=0).

RESULTS

The strongest association of echocardiographic measurements with body size was observed for BSA (r=0.36-0.63), whereas the isometric and allometric height models showed lower comparable values (r=0.28-0.48). Positive correlations with BMI were mostly observed for LA size (r≈0.36) and LVM (r≈0.36) measurements. Scaling exponents β for the allometric height indexation were 1.72 for LAV and 2.33 for LVM. Correlations between indexed and absolute values were higher for height than BSA (0.80-0.98 vs 0.44-0.92). Correlations between indexed values and height were closer to zero than for BSA, particularly using the allometric model. The overcorrection observed with increasing obesity class after BSA indexation was avoided after height indexation.

CONCLUSIONS

Unlike BSA, height indexing provided an adequate body size scaling of left heart chambers size avoiding overcorrection using allometric models in particular.