Aortic pulse pressure is associated with carotid IMT in chronic kidney disease: report from Chronic Renal Insufficiency Cohort.

BACKGROUND: Patients with chronic kidney disease (CKD) have a disproportionate risk of cardiovascular disease. This study was designed to assess the association between two noninvasive measures of cardiovascular risk, pulse wave analysis (PWA), and carotid intima-media thickness (IMT), in a cohort of CKD patients enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study. METHODS: Three hundred and sixty-seven subjects with CKD enrolled in the CRIC study at the University of Pennsylvania site (mean age 59.9 years, blood pressure 129/74 mm Hg, estimated glomerular filtration rate 48 ml/min/1.73 m2, IMT 0.8 mm) had both carotid IMT and PWA measurements. Carotid ultrasound was also used to determine the presence of plaque. PWA was used to determine augmentation index (AI), amplification ratio (AMPR), aortic pulse pressure (C_PP), and central aortic systolic pressure (C_SP). RESULTS: IMT was significantly associated with all PWA-derived measures. However, on multivariable linear regression analysis, only AMPR (regression coefficient -0.072, P = 0.006), C_PP (regression coefficient 0.0025, P < 0.001), and C_SP (regression coefficient 0.0017, P < 0.001) remained significantly associated with IMT. The prevalence of carotid plaque in the cohort was 59%. Of the PWA-derived measures, only C_PP was significantly associated with the presence of carotid plaque (P < 0.001). CONCLUSIONS: PWA-derived measures are associated with carotid IMT and plaque in the CKD. Of these measures, C_PP was most associated with carotid IMT and plaque.

Beta-blockers for hypertension: are they going out of style?

Although beta-blockers lower blood pressure in most patients, the outcomes of clinical hypertension trials of these drugs have been disappointing, and the value of beta-blockers in treating hypertensive patients who do not have compelling indications for them has been questioned. Until these drugs are proved beneficial, they should be used as antihypertensive therapy only in patients with compelling cardiac indications for them or as add-on agents in those with uncontrolled or resistant hypertension.

Blood pressure goals and arterial stiffness in chronic kidney disease.

The association of optimal blood pressure (BP) control and arterial stiffness was evaluated in 172 patients with chronic kidney disease. The authors compared the augmentation index (AIx) of patients who achieved a recommended BP goal (<130/80 mm Hg) with those who did not (> or = 130/80 mm Hg). The median age was 57 years, 60% were male, and 70% were Caucasian. One-third of patients had achieved a BP goal of <130/80 mm Hg. AIx was significantly lower in patients who achieved BP goal than in those who did not (median AIx, 19% vs 23%; P=.04). AIx remained significantly lower in patients who achieved the BP goal, after adjusting for age, sex, and height (mean effect on AIx, -3.3%; 95% confidence interval, -6.1% to -0.4%; P=.03). Achievement of BP goal of <130/80 mm Hg in chronic kidney disease patients is associated with significantly lower AIx and may reflect a reduction in overall arterial stiffness.

Resistant hypertension in the elderly.

Resistant hypertension is more prevalent in the elderly population. Current data clearly shows the benefit of blood pressure control in older individuals. It is important to first differentiate pseudoresistance from true resistant and institute appropriate therapy. In those patients with resistant hypertension without an identifiable cause, non invasive measurement of hemodynamic profile is an important option to achieve meet blood pressure goals.

Uric acid transport.

PURPOSE OF REVIEW: The goal of this article is to review the physiology and describe newly defined molecular mechanisms that are responsible for renal urate transport. RECENT FINDINGS: Four complementary DNAs have recently been cloned whose expressed proteins transport urate. Two of these proteins have been localized to the apical membrane of proximal tubular cells: one, a urate transporter/channel, a galectin, is an electrogenic transporter (an ion channel); the second is a urate-anion electroneutral exchanger, a member of the organic anion transporter family. The other urate transport proteins, organic anion transporters 1 and 3, are also members of the organic anion transporter family. These proteins have been localized to the basolateral membrane of proximal tubular cells: organic anion transporter 1 is an electroneutral organic anion exchanger; the mechanism of urate transport on organic anion transporter 3 remains to be determined. SUMMARY: The molecular definition and localization of four urate transport proteins provides a basis for developing a molecular model of the bi-directional transport of urate in renal proximal tubules. It seems likely that the urate-anion exchanger is responsible for luminal reabsorption while the urate transporter/channel permits secretion of urate from the cell into the lumen. Since organic anion transporters 1 and 3 reside in the basolateral membrane, one or both may be relevant in the reabsorptive flux of urate into the peritubular capillary as well as in the cellular uptake of urate from the peritubular space, the first step in the process of urate secretion. Knowledge of the molecular basis of urate transport should provide greater insights into states of altered transport as well as assist in development of drugs to modify urate flux.