Treatment of heart failure in African Americans--a call to action.

Advances in heart failure treatment have not necessarily translated into equity in improved outcomes for African Americans. Heart failure in African Americans is characterized by a higher prevalence, especially at younger ages; more-adverse course with more frequent hospitalizations; and higher mortality rates compared to the general population. Despite this distinct disease profile, African Americans are remarkably underrepresented in large heart failure trials. This paper reviews the unique course of heart failure in African Americans and discusses treatment in the context of clinical trial evidence. African Americans with heart failure may respond differently to some standard therapies compared to whites, but low levels of enrollment of AAs in large clinical trials preclude valid conclusions in certain cases. An important exception is the African American Heart Failure Trial (AHeFT), a well-designed, prospective, randomized, placebo-controlled, double-blind study, that added a combination of fixed-dose isosorbide dinitrate/hydralazine (ISDN/ HYD) to standard therapy and showed a 43% improvement in survival and a 33% reduction in first hospitalizations. Despite compelling evidence from AHeFT, post hoc secondary analyses, and recommendations from current practice guidelines, ISDN/HYD remains underutilized in African Americans with heart failure. In this paper, we put forth a call to action for racial equity in clinical research and treatment in African Americans with heart failure.

Erythrocytosis in a scleroderma patient.

A 40-year-old black male with scleroderma lung disease presented with blurry vision and headache. His presenting hemoglobin was 22.3 g/dL and his serum erythropoietin level was surprisingly low. Although nocturnal hypoxemia was evident, his daytime resting arterial oxygen saturation was normal. The patient's symptoms of hyperviscosity improved after phlebotomy, as his hemoglobin gradually decreased to 18.3 g/dL. Repeat serum erythropoietin levels were in normal and high ranges. Patients with chronic interstitial lung disease and erythrocytosis could have normoxemia at rest and a normal or low serum erythropoietin level at the peak of erythrocytosis. A repeat sampling of serum erythropoietin and monitoring of oxygen saturation during sleep and exertion may help in diagnosis. Physicians should prescribe continuous oxygen therapy for patients with chronic interstitial lung disease and erythrocytosis, even if diurnal resting hypoxemia is absent.

The metabolic syndrome: recognition and management.

The National Cholesterol Education Program defines the metabolic syndrome as three or more of five abnormalities: waist circumference of >40 in (102 cm) for men or >35 in (88 cm) for women, triglyceride level of > or =150 mg/dL, high-density lipoprotein cholesterol of <40 mg/dL in men or <50 mg/dL in women, blood pressure of > or =130 or > or =85 mm Hg, and fasting glucose of > or =110 mg/dL. It is related to insulin resistance, but the two terms are not synonymous. Both are associated strongly with obesity. The metabolic syndrome is important as an indicator of increased risk of cardiovascular disease (CVD) in patients with and without clinical CVD. The CVD risk of the metabolic syndrome is greater than that conferred by any single CVD risk factor. Since risk factors tend to cluster, if one component of the metabolic syndrome is present, one should assess for other risk factors. The metabolic syndrome is also predictive of new-onset type 2 diabetes. Early diagnosis provides justification for measures that can improve components of the syndrome and reduce CVD risk. The management strategy for metabolic syndrome focuses on overall CVD risk rather than single risk factors; effective therapy includes priority for weight reduction and increased physical activity. Pharmacotherapy is typically needed for control of high blood pressure, hypercoagulability, and increased levels of blood glucose and triglycerides.

Impact of sodium-glucose cotransporter 2 inhibitors on blood pressure.

SGLT2 inhibitors are glucose-lowering agents used to treat type 2 diabetes mellitus (T2DM). These agents target the kidney to promote urinary glucose excretion, resulting in improved blood glucose control. SGLT2-inhibitor therapy is also associated with weight loss and blood pressure (BP) lowering. Hypertension is a common comorbidity in patients with T2DM, and is associated with excess morbidity and mortality. This review summarizes data on the effect of SGLT2 inhibitors marketed in the US (namely canagliflozin, dapagliflozin, or empagliflozin) on BP in patients with T2DM. Boolean searches were conducted that included terms related to BP or hypertension with terms for SGLT2 inhibitors, canagliflozin, dapagliflozin, or empagliflozin using PubMed, Google, and Google Scholar. Data from numerous randomized controlled trials of SGLT2 inhibitors in patients with T2DM demonstrated clinically relevant reductions in both systolic and diastolic BP, assessed via seated office measurements and 24-hour ambulatory BP monitoring. Observed BP lowering was not associated with compensatory increases in heart rate. Circadian BP rhythm was also maintained. The mechanism of SGLT2 inhibitor-associated BP reduction is not fully understood, but is assumed to be related to osmotic diuresis and natriuresis. Other factors that may also contribute to BP reduction include SGLT2 inhibitor-associated decreases in body weight and reduced arterial stiffness. Local inhibition of the renin-angiotensin-aldosterone system secondary to increased delivery of sodium to the juxtaglomerular apparatus during SGLT2 inhibition has also been postulated. Although SGLT2 inhibitors are not indicated as BP-lowering agents, the modest decreases in systolic and diastolic BP observed with SGLT2 inhibitors may provide an extra clinical advantage for the majority of patients with T2DM, in addition to improving blood glucose control.

Hypertension in african americans aged 60 to 79 years: statement from the international society of hypertension in blacks.

A 2014 hypertension guideline raised goal systolic blood pressure (SBP) from <140 mm Hg to <150 mm Hg for adults 60 years and older without diabetes mellitus (DM) or chronic kidney disease (CKD). The authors aimed to define the status of hypertension in black adults 60 to 79 years from the National Health and Nutrition Examination Survey 2005-2012 and provide practical guidance. Black patients were more often aware and treated (P≤.005) for hypertension than whites and had higher rates of DM/CKD (P<.001), similar control to <140/<90 mm Hg with DM/CKD (P=.59), and lower control without DM/CKD (<140/<90 mm Hg and <150/<90 mm Hg, P≤.01). Limited awareness (<30%) and infrequent health care (>30% 0-1 health-care visits per year) occurred in untreated black and white hypertensive patients without DM/CKD and BP ≥140/<90 mm Hg. The literature suggests benefits of treated SBP <140 mm Hg in adults 60 to 79 years without DM/CKD. The International Society of Hypertension in Blacks recommends: (1) continuing efforts to achieve BP <140/<90 mm Hg in those with DM/CK, and (2) identifying hypertensive patients without DM/CKD and BP ≥140/<90 mm Hg and treat to an SBP <140 mm Hg in black adults 60-79 years.

Validation of measurements of ventilation-to-perfusion ratio inequality in the lung from expired gas.

The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (Va/Q) inequality in the lung. To further validate this estimate, we examined three measures of Va/Q inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions and after exposure to aerosolized methacholine. These measurements were then compared with arterial blood gases and with measurements of Va/Q inhomogeneity obtained using the multiple inert gas elimination technique. The slope of the instantaneous respiratory exchange ratio (R slope) vs. expired volume was poorly correlated with independent measures, probably because of the curvilinear nature of the relationship due to continuing gas exchange. When R was converted to the intrabreath Va/Q (iV/Q), the best index was the slope of iV/Q vs. volume over phase III (iV/Q slope). This was strongly correlated with independent measures, especially those relating to inhomogeneity of perfusion. The correlations for iV/Q slope and R slope considerably improved when only the first half of phase III was considered. We conclude that a useful noninvasive measurement of Va/Q inhomogeneity can be derived from the intrabreath respiratory exchange ratio.

The Metabolic Syndrome in African Americans: a review.

The Metabolic Syndrome represents a specific clustering of cardiovascular risk factors. One of several recently proposed definitions encompasses 3 or more of the following 5 abnormalities: waist circumference > 102 cm in men or > 88 cm in women, serum triglyceride level > or = 150 mg/dL, high-density lipoprotein cholesterol level < 40 mg/dL in men or < 50 mg/dL in women, blood pressure (BP) > or = 130/> or = 85 mm Hg and serum glucose > or = 110 mg/dL. The diagnosis of Metabolic Syndrome allows early recognition of an increased risk of cardiovascular disease. African Americans have the highest coronary heart disease mortality of any ethnic group in the United States. African-American women and Hispanic men and women have the highest prevalence of the Metabolic Syndrome. This phenomenon is attributable mainly to the disproportionate occurrence of elevated BP, obesity, and diabetes in African Americans, and the high prevalence of obesity and diabetes in Hispanics. Management of the Metabolic Syndrome consists primarily of modification or reversal of the root causes and direct therapy of the risk factors. The first strategy involves weight reduction and increased physical activity, both of which can improve all components of the syndrome. The second strategy often involves drug treatment of the individual risk factors to further improve BP, lipids, and glucose thereby decreasing the risk of cardiovascular disease. This comprehensive review is provided as part of the educational activities of the African-American Lipid and Cardiovascular Council (AALCC).

Effect of repetitive exercise testing on breathlessness in humans.

There are conflicting reports on the reproducibility of the visual analogue scale (VAS) and the modified Borg scale for the estimation of breathlessness during exercise. In an attempt to clarify the situation, two groups of healthy subjects undertook a progressive exercise test either daily (Group A) or weekly (Group B) on 10 separate occasions. Breathlessness was estimated every 1 min using the VAS. After 10 occasions, both Group A (P <0.05) and Group B ( P <0.01) showed a significant increase in the mean intercept of the breathlessness/ventilation (VAS/ V (I)) relationship. The increase was not progressive; using change point regression, reproducible values were found to occur after approximately the fifth occasion in both subject groups. As the slope of the VAS/ V (I) relationship was highly reproducible and did not change with repeat testing, it would appear that at least two mechanisms are involved in the generation of the sensation of breathlessness. A decrease in the exercise heart rate over the same time period was significantly correlated with changes in the VAS/ V (I) intercept in both groups (P <0.01 and P <0.005 respectively). The relationship is unlikely to be causal, but may be indicative of a common underlying mechanism. It is suggested that breathlessness scores are likely to decrease as a direct result of repetitive testing over, on average, the first five periods of assessment. On the basis of this study, it may be inferred that a physiological mechanism contributes to the modulation of breathlessness during repetitive exercise testing.