The Upcoming Epidemic of Heart Failure in South Asia

Currently, South Asia accounts for a quarter of the world population, yet it already claims ≈60% of the global burden of heart disease. Besides the epidemics of type 2 diabetes mellitus and coronary heart disease already faced by South Asian countries, recent studies suggest that South Asians may also be at an increased risk of heart failure (HF), and that it presents at earlier ages than in most other racial/ethnic groups. Although a frequently underrecognized threat, an eventual HF epidemic in the densely populated South Asian nations could have dramatic health, social and economic consequences, and urgent interventions are needed to flatten the curve of HF in South Asia. In this review, we discuss recent studies portraying these trends, and describe the mechanisms that may explain an increased risk of premature HF in South Asians compared with other groups, with a special focus on highly relevant features in South Asian populations including premature coronary heart disease, early type 2 diabetes mellitus, ubiquitous abdominal obesity, exposure to the world's highest levels of air pollution, highly prevalent pretransition forms of HF such as rheumatic heart disease, and underdevelopment of healthcare systems. Other rising lifestyle-related risk factors such as use of tobacco products, hypertension, and general obesity are also discussed. We evaluate the prognosis of HF in South Asian countries and the implications of an anticipated HF epidemic. Finally, we discuss proposed interventions aimed at curbing these adverse trends, management approaches that can improve the prognosis of prevalent HF in South Asian countries, and research gaps in this important field.

The effect of negative remodeling on fractional flow reserve after cardiac transplantation

BACKGROUND

Negative remodeling is a common occurrence early after cardiac transplantation. Its impact on the development of myocardial ischemia is not well documented. The aim of this study is to investigate the impact of negative remodeling on fractional flow reserve after cardiac transplantation.

METHODS

Thirty-four cardiac transplant recipients underwent intravascular ultrasound (IVUS) and fractional flow reserve (FFR) assessment soon after transplantation and one year later. Patients were divided into those with and without negative remodeling based on IVUS, and the impact on FFR was assessed. In the 19 patients with negative remodeling, there was no significant change in plaque volume (119.3±82.0 to 131.3±91.2mm³, p=0.21), but vessel volume (775.6±212.0 to 621.9±144.1mm³, p<0.0001) and lumen volume (656.3±169.1 to 490.7±132.0mm³, p<0.0001) decreased significantly and FFR likewise decreased significantly (0.88±0.06 to 0.84±0.07, p=0.04). In the 15 patients without negative remodeling, vessel volume did not change (711.7±217.6 to 745.7±198.5, p=0.28), but there was a significant increase in plaque volume (126.8±88.3 to 194.4±92.7, p<0.001) and a resultant significant decrease in FFR (0.89±0.05 to 0.85±0.05, p=0.01).

CONCLUSION

Negative remodeling itself, without any change in plaque volume can cause a significant decrease in fractional flow reserve after cardiac transplantation and appears to be another possible mechanism for myocardial ischemia.

Geographic Variations in Cardiovascular Disease Mortality Among Asian American Subgroups, 2003-2011

BACKGROUND

There are well-documented geographical differences in cardiovascular disease (CVD) mortality for non-Hispanic whites. However, it remains unknown whether similar geographical variation in CVD mortality exists for Asian American subgroups. This study aims to examine geographical differences in CVD mortality among Asian American subgroups living in the United States and whether they are consistent with geographical differences observed among non-Hispanic whites.

METHODS AND RESULTS

Using US death records from 2003 to 2011 (n=3 897 040 CVD deaths), age-adjusted CVD mortality rates per 100 000 population and age-adjusted mortality rate ratios were calculated for the 6 largest Asian American subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, and Vietnamese) and compared with non-Hispanic whites. There were consistently lower mortality rates for all Asian American subgroups compared with non-Hispanic whites across divisions for CVD mortality and ischemic heart disease mortality. However, cerebrovascular disease mortality demonstrated substantial geographical differences by Asian American subgroup. There were a number of regional divisions where certain Asian American subgroups (Filipino and Japanese men, Korean and Vietnamese men and women) possessed no mortality advantage compared with non-Hispanic whites. The most striking geographical variation was with Filipino men (age-adjusted mortality rate ratio=1.18; 95% CI, 1.14-1.24) and Japanese men (age-adjusted mortality rate ratio=1.05; 95% CI: 1.00-1.11) in the Pacific division who had significantly higher cerebrovascular mortality than non-Hispanic whites.

CONCLUSIONS

There was substantial geographical variation in Asian American subgroup mortality for cerebrovascular disease when compared with non-Hispanic whites. It deserves increased attention to prioritize prevention and treatment in the Pacific division where approximately 80% of Filipinos CVD deaths and 90% of Japanese CVD deaths occur in the United States.

Racial/ethnic differences in hypertension prevalence, treatment, and control for outpatients in northern California 2010-2012

BACKGROUND

Hypertension (HTN) is a known major cardiovascular disease risk factor, but prevalence, treatment, and control of HTN among rapidly growing minority groups such as Asian Americans and Hispanics are unknown largely due to either underrepresentation in epidemiologic studies or aggregation of Asian American subgroups.

METHODS

A three-year cross-section (2010-2012) of patients from a large ambulatory care setting in northern California was examined in the following subgroups: Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese, Mexicans, non-Hispanic Blacks (NHBs), and non-Hispanic Whites (NHWs). We defined HTN as two separate nonemergent office visit blood pressure measurements ≥140/90 mm Hg, physician diagnosis of HTN, or use of antihypertensive medications.

RESULTS

A total of 208,985 patients were included in the study. Age-adjusted HTN prevalence ranged from 30.0% in Chinese women to 59.9% in Filipino men. Most minority subgroups had lower or similar odds of having HTN compared with NHWs, except for Filipinos and NHBs whose odds were significantly higher after adjusting for patient demographic and clinical characteristics. Asian Americans and NHBs were more likely to be treated for HTN compared with NHWs. Achievement of blood pressure control was lower among Filipino women (odds ratio = 0.82, 99% confidence interval 0.70-0.96) and NHB men (odds ratio = 0.73, 99% confidence interval 0.58-0.91), compared with NHW women and men.

CONCLUSIONS

Substantial racial/ethnic variation in HTN prevalence, treatment, and control was found in our study population. Filipino and NHB women and men are at especially high risk for HTN and may have more difficulty in achieving adequate blood pressure control.

Leading Causes of Death among Asian American Subgroups (2003-2011)

BACKGROUND

Our current understanding of Asian American mortality patterns has been distorted by the historical aggregation of diverse Asian subgroups on death certificates, masking important differences in the leading causes of death across subgroups. In this analysis, we aim to fill an important knowledge gap in Asian American health by reporting leading causes of mortality by disaggregated Asian American subgroups.

METHODS AND FINDINGS

We examined national mortality records for the six largest Asian subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese) and non-Hispanic Whites (NHWs) from 2003-2011, and ranked the leading causes of death. We calculated all-cause and cause-specific age-adjusted rates, temporal trends with annual percent changes, and rate ratios by race/ethnicity and sex. Rankings revealed that as an aggregated group, cancer was the leading cause of death for Asian Americans. When disaggregated, there was notable heterogeneity. Among women, cancer was the leading cause of death for every group except Asian Indians. In men, cancer was the leading cause of death among Chinese, Korean, and Vietnamese men, while heart disease was the leading cause of death among Asian Indians, Filipino and Japanese men. The proportion of death due to heart disease for Asian Indian males was nearly double that of cancer (31% vs. 18%). Temporal trends showed increased mortality of cancer and diabetes in Asian Indians and Vietnamese; increased stroke mortality in Asian Indians; increased suicide mortality in Koreans; and increased mortality from Alzheimer's disease for all racial/ethnic groups from 2003-2011. All-cause rate ratios revealed that overall mortality is lower in Asian Americans compared to NHWs.

CONCLUSIONS

Our findings show heterogeneity in the leading causes of death among Asian American subgroups. Additional research should focus on culturally competent and cost-effective approaches to prevent and treat specific diseases among these growing diverse populations.

Cardiovascular disease mortality in Asian Americans

BACKGROUND

Asian Americans are a rapidly growing racial/ethnic group in the United States. Our current understanding of Asian-American cardiovascular disease mortality patterns is distorted by the aggregation of distinct subgroups.

OBJECTIVES

The purpose of the study was to examine heart disease and stroke mortality rates in Asian-American subgroups to determine racial/ethnic differences in cardiovascular disease mortality within the United States.

METHODS

We examined heart disease and stroke mortality rates for the 6 largest Asian-American subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, and Vietnamese) from 2003 to 2010. U.S. death records were used to identify race/ethnicity and cause of death by International Classification of Diseases-10th revision coding. Using both U.S. Census data and death record data, standardized mortality ratios (SMRs), relative SMRs (rSMRs), and proportional mortality ratios were calculated for each sex and ethnic group relative to non-Hispanic whites (NHWs).

RESULTS

In this study, 10,442,034 death records were examined. Whereas NHW men and women had the highest overall mortality rates, Asian Indian men and women and Filipino men had greater proportionate mortality burden from ischemic heart disease. The proportionate mortality burden of hypertensive heart disease and cerebrovascular disease, especially hemorrhagic stroke, was higher in every Asian-American subgroup compared with NHWs.

CONCLUSIONS

The heterogeneity in cardiovascular disease mortality patterns among diverse Asian-American subgroups calls attention to the need for more research to help direct more specific treatment and prevention efforts, in particular with hypertension and stroke, to reduce health disparities for this growing population.

Racial/ethnic differences in dyslipidemia patterns

BACKGROUND

No studies have comprehensively examined the prevalence of dyslipidemia, a major risk factor for cardiovascular disease, among diverse racial/ethnic minority groups. The primary aim of this study was to identify racial/ethnic differences in dyslipidemia among minorities including Asian Americans (Asian Indian, Chinese, Filipino, Japanese, Korean, or Vietnamese), Mexican Americans, and blacks compared with non-Hispanic whites.

METHODS AND RESULTS

Using a 3-year cross section (2008-2011), we identified 169 430 active primary care patients (35 years or older) from an outpatient healthcare organization in northern California. Age-standardized prevalence rates were calculated for 3 dyslipidemia subtypes: high triglycerides (fasting laboratory value ≥150 mg/dL), low levels of high-density lipoprotein cholesterol (fasting laboratory value <40 mg/dL [men] and <50 mg/dL [women]), and high levels of low-density lipoprotein cholesterol (fasting laboratory value ≥130 mg/dL or taking low-density lipoprotein-lowering agents). Odds ratios were calculated by multivariable logistic regression, with adjustment for patient characteristics (age, measured body mass index, smoking). Compared with non-Hispanic whites, every minority subgroup had an increased prevalence of high triglycerides except blacks. Most minority groups had an increased prevalence of low high-density lipoprotein cholesterol, except for Japanese and blacks. The prevalence of high low-density lipoprotein cholesterol was increased among Asian Indians, Filipinos, Japanese, and Vietnamese compared with non-Hispanic whites.

CONCLUSIONS

Minority groups, except for blacks, were more likely to have high triglyceride/low high-density lipoprotein cholesterol dyslipidemia. Further research is needed to determine how racial/ethnic differences in dyslipidemia affect racial/ethnic differences in cardiovascular disease rates.

Efficient adenylyl cyclase activation by a beta2-adrenoceptor-G(i)alpha2 fusion protein

The G-protein G(i)alpha can activate adenylyl cyclase (AC), but the relevance of this AC activation is unknown. We used receptor-G protein co-expression and receptor-G protein fusion proteins to investigate G(i)alpha(2) regulation of AC in Sf9 cells. G(i)alpha(2) was fused to the beta(2)-adrenoceptor (beta(2)AR), a preferentially G(s)-coupled receptor, or the formyl peptide receptor (FPR), a G(i)-coupled receptor. The FPR co-expressed with, or fused to, G(i)alpha(2), reduced AC activity. In contrast, the beta(2)AR fused to G(i)alpha(2) was a highly efficient AC activator, while the beta(2)AR co-expressed with G(i)alpha(2) was not. Agonist efficiently stimulated incorporation of [alpha-32P]GTP azidoanilide into beta(2)AR-G(i)alpha(2). We explain AC activation by beta(2)AR-G(i)alpha(2) by a model in which there is interaction of the beta(2)AR and AC, preventing tethered G(i)alpha(2) from interacting with the inhibitory G(i)alpha site of AC. The postulated beta(2)AR/AC interaction brings G(i)alpha(2) into close proximity of the G(s)alpha site of AC, enabling G(i)alpha(2) to activate AC.