Calcium-alkali syndrome in the modern era.

The ingestion of calcium, along with alkali, results in a well-described triad of hypercalcemia, metabolic alkalosis, and renal insufficiency. Over time, the epidemiology and root cause of the syndrome have shifted, such that the disorder, originally called the milk-alkali syndrome, is now better described as the calcium-alkali syndrome. The calcium-alkali syndrome is an important cause of morbidity that may be on the rise, an unintended consequence of shifts in calcium and vitamin D intake in segments of the population. We review the pathophysiology of the calcium-alkali syndrome.

Renal failure in patients with left ventricular assist devices.

Implantable left ventricular assist devices (LVADs) are increasingly being used as a bridge to transplantation or as destination therapy in patients with end stage heart failure refractory to conventional medical therapy. A significant number of these patients have associated renal dysfunction before LVAD implantation, which may improve after LVAD placement due to enhanced perfusion. Other patients develop AKI after implantation. LVAD recipients who develop AKI requiring renal replacement therapy in the hospital or who ultimately require long-term outpatient hemodialysis therapy present management challenges with respect to hemodynamics, volume, and dialysis access. This review discusses the mechanics of a continuous-flow LVAD (the HeartMate II), the effects of continuous blood flow on the kidney, renal outcomes of patients after LVAD implantation, dialysis modality selection, vascular access, hemodynamic monitoring during the dialytic procedure, and other issues relevant to caring for these patients.

Carotid plaque, carotid intima-media thickness, and coronary calcification equally discriminate prevalent cardiovascular disease in kidney disease.

BACKGROUND: Despite the significant morbidity and mortality attributable to cardiovascular disease (CVD), risk stratification remains an important challenge in the chronic kidney disease (CKD) population. We examined the discriminative ability of noninvasive measures of atherosclerosis, including carotid intima-media thickness (cIMT), carotid plaque, coronary artery calcification (CAC) and ascending and descending thoracic aorta calcification (TCAC), and Framingham risk score (FRS) to predict self-reported prevalent CVD. METHODS AND RESULTS: Participants were enrolled in the cIMT ancillary study of the Chronic Renal Insufficiency Cohort (CRIC) study and also had all of the above measures within an 18-month period. CVD was present in 21% of study participants. C-statistics were used to ascertain the discriminatory power of each measure of atherosclerosis. The study population (n = 220) was 64% male; 51% black and 45% white. The proportion of individuals with estimated glomerular filtration rate ≥60, 45-59, 30-44, and <30 ml/min/1.73 m(2) was 21, 41, 28, and 11%, respectively. In multivariable analyses adjusting for demographic factors, we failed to find a difference between CAC, carotid plaque, and cIMT as predictors of self-reported prevalent CVD (C-statistic 0.70, 95% CI: 0.62-0.78; C-statistic 0.68, 95% CI: 0.60-0.75, and C-statistic 0.64, CI: 0.56-0.72, respectively). CAC was statistically better than FRS. FRS was the weakest discriminator of self-reported prevalent CVD (C-statistic 0.58). CONCLUSIONS: There was a significant burden of atherosclerosis among individuals with CKD, ascertained by several different imaging modalities. We were unable to find a difference in the ability of CAC, carotid plaque, and cIMT to predict self-reported prevalent CVD.

Health literacy associated with blood pressure but not other cardiovascular disease risk factors among dialysis patients.

BACKGROUND: Limited health literacy is prevalent and has been linked to adverse patient outcomes. We examined the relationship between health literacy and cardiovascular disease (CVD) risk factors, including blood pressure (BP) parameters, lipids, waist-to-hip ratio (WHR), body mass index (BMI), and tobacco utilization among dialysis patients. METHODS: We conducted a cross-sectional study of 72 participants in a prospective cohort study of vascular calcification in newly initiated dialysis patients. Health literacy was assessed using the Short Test of Functional Health Literacy (S-TOFHLA) in Adults. The study population was dichotomized into those with and without adequate literacy. Linear and logistic regression analyses were used to predict continuous and dichotomous cardiovascular risk factor variables, respectively. RESULTS: Twenty-one percent had limited health literacy. Compared to limited health literacy, adequate health literacy was associated with lower BP parameters in multivariable analyses (systolic blood pressure (SBP): ß -16.8, s.e. 6.7, P = 0.01; diastolic blood pressure (DBP): ß -13.8, s.e. 4.1, P = 0.001; mean arterial pressure (MAP): ß -14.8, s.e. 4.6, P = 0.002). Health literacy was not a statistically significant predictor of low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, WHR, BMI, or tobacco utilization. CONCLUSIONS: Limited health literacy is common in individuals on dialysis. Individuals with adequate health literacy skills had DBP readings that were on average 13.8 mm Hg lower and MAP that was 14.8 mm Hg lower than those with inadequate health literacy. Prospective studies to elucidate if improvements in health literacy skills will lead to improvement in BP control are needed.

The impact of obstructive sleep apnea on chronic kidney disease.

Obstructive sleep apnea (OSA) is an important clinical problem in the chronic kidney disease (CKD) population. OSA is associated with hypoxemia and sleep fragmentation, which activates the sympathetic nervous system, the renin-angiotensin-aldosterone system, alters cardiovascular hemodynamics, and results in free radical generation. In turn, a variety of deleterious processes such as endothelial dysfunction, inflammation, platelet aggregation, atherosclerosis, and fibrosis are triggered, predisposing individuals to adverse cardiovascular events and likely renal damage. Independent of obesity, OSA is associated with glomerular hyperfiltration and may be an independent predictor of proteinuria, a risk factor for CKD progression. OSA is also associated with hypertension, another important risk factor for CKD progression, particularly proteinuric CKD. OSA may mediate renal damage via several mechanisms, and there is a need to better elucidate the impact of OSA on incident renal disease and CKD progression.

Metabolic syndrome and coronary artery calcification in renal transplant recipients.

BACKGROUND: Coronary artery calcification (CAC) and metabolic syndrome (MS) have been associated with increased cardiovascular risk. The study objective was to examine the association of MS with CAC presence and progression in renal transplant recipients. METHODS: We measured the CAC progression in asymptomatic recipients who had no prior history of coronary artery disease. RESULTS: MS was common (55.4%). Median CAC scores were 0, 33.1, 98, and 261.9 for patients with one, two, three, and four or more positive components of the MS, respectively. Severe CAC scores were more common in recipients with MS (P=0.04). Although recipients with MS had higher mean CAC scores at baseline and significant CAC progression (483 [590.6] vs. 619 [813.8], P=0.01), MS was not an independent predictor of annualized rate of CAC change in a multivariate model. CONCLUSION: Future studies to evaluate if MS treatment improves cardiovascular outcomes are imperative.