Prevalence of stroke in systolic heart failure.

BACKGROUND: Heart disease is a major independent risk factor for stroke, ranking third after age and hypertension. Heart failure (HF) patient constitutes an important subgroup of patients with stroke, because of their poor outcome and high rates of mortality and stroke recurrence. We examined the prevalence of stroke in patients with heart failure from 3 different geographic regions. METHODS AND RESULTS: We compared the prevalence of self-reported history of stroke in participants with systolic HF from 3 different geographic regions (Houma, LA; Miami, FL; and Tbilisi, Georgia, Eastern Europe). We examined the prevalence of stroke/adjusting for patient demographic and health characteristics. Stroke prevalence was reported by 79 (7.8%) of 1017 participants from Louisiana, 51 (9.2%) of 556 participants from Florida, and 5 (1.3%) of 383 participants from Georgia. After multivariable adjustment, the prevalence of stroke was significantly lower in Georgia compared to Florida and Louisiana sites. Patients on ß-blocker medication were 3.58 times (95% CI 1.96-6.55) more likely to report stroke compared to those without ß-blockers (×2 = 19.5, P ≤ .0001). There were significantly fewer participants on ß-blockers from Georgia (7%) compared to participants from Florida (87%) and Louisiana (94%; (×2 = 24.3, P<.001). CONCLUSIONS: Self-reported stroke prevalence in participants with HF was not consistent among the 3 sites. These differences in prevalence may in part be explained by the lower reported use of ß-blockers in the Georgia site. Longitudinal studies are needed to determine whether ß-blockers increase the risk of stroke in HF population.

Epidemiology and survival of the five stages of chronic kidney disease in a systolic heart failure population.

AIMS: The epidemiology of the five stages of chronic kidney disease (CKD) in systolic heart failure (HF) patients has predominantly been described in hospitalized White patients, with little known about the prevalence in outpatient Blacks and Hispanics. The purpose of this study was to compare the prevalence of the five stages of CKD by race, ethnicity (Whites, Blacks, and Hispanics), and gender in an outpatient systolic HF population and also to evaluate the impact of CKD on mortality. METHODS AND RESULTS: We conducted a prospective study of 1301 patients recruited from two hospital facilities in Louisiana and Florida, USA. All patients were enrolled in a systolic HF disease management programme (HFDMP), which enrolled patients with an ejection fraction of < or =40% by echocardiography. The estimated glomerular filtration rate was calculated using the abbreviated Modification of Diet in Renal Disease Study equation. Patients were classified into five stages of CKD according to the National Kidney Foundation classification system. A total of 338 patients (26%) were found to have CKD. Patients with CKD were older, more likely to be Hispanics, to have less education, New York Heart Association class III, elevated systolic blood pressure, and diabetes. There was no statistical difference in prevalence by gender. Survival was reduced in patients with CKD. CONCLUSION: The prevalence of CKD in an outpatient systolic HFDMP is high, with over one in four patients affected. CKD patients had significantly lower survival rates compared with patients without CKD.

Potassium in hypertension.

Potassium is the most important ion in the living cell, affecting almost every cellular function. Numerous clinical and epidemiologic studies support the knowledge that potassium is a fundamental factor in blood pressure regulation. The role of potassium in blood pressure regulation is reviewed in this article, focusing on its impact on the vascular vessel and the kidney, which are tissues strongly affected by potassium balance. The role of potassium on nitric oxide synthesis and superoxide formation is analyzed. Finally, the study of cell potassium as a marker for hypertension is discussed.

Erythrocyte sodium-lithium countertransport and blood pressure: a genome-wide linkage study.

Increased activity of erythrocyte sodium-lithium countertransport is associated with essential hypertension. Sodium-lithium countertransport is highly heritable, but no single gene product mediating the exchange or explaining the association of increased sodium-lithium countertransport activity and hypertension has been identified. We performed a linkage study by using erythrocyte sodium-lithium countertransport as a quantitative phenotype and genome-wide markers at an average resolution of approximately 10 cM to identify quantitative trait loci explaining sodium-lithium countertransport activity. A peak LOD score of 2.83 was detected on chromosome 15q at D15S642, a marker previously shown to be linked to blood pressure. Several genes mapped to this region are possible candidates for factors affecting erythrocyte sodium-lithium countertransport and/or blood pressure. Further studies confirming the presence of a quantitative trait locus in this region and evaluating these candidate genes may help explain the association of elevated sodium-lithium countertransport and hypertension.