Clinical associations of total kidney volume: the Framingham Heart Study.

BACKGROUND: Total kidney volume (TKV) is an imaging biomarker that may have diagnostic and prognostic utility. The relationships between kidney volume, renal function and cardiovascular disease (CVD) have not been characterized in a large community-dwelling population. This information is needed to advance the clinical application of TKV. METHODS: We measured TKV in 1852 Framingham Heart Study participants (mean age 64.1 ± 9.2 years, 53% women) using magnetic resonance imaging. A healthy sample was used to define reference values. The associations between TKV, renal function and CVD risk factors were determined using multivariable logistic regression analysis. RESULTS: Overall, mean TKV was 278 ± 54 cm3 for women and 365 ± 66 cm3 for men. Risk factors for high TKV (>90% healthy referent size) were body surface area (BSA), diabetes, smoking and albuminuria, while age, female and estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 were protective. Participants with high TKV had higher odds of diabetes [odds ratio (OR) 2.15, P < 0.001] and lower odds of eGFR <60 mL/min/1.73 m2 (OR 0.32, P = 0.007). Risk factors for low TKV (<10% healthy referent size) were age, female and eGFR <60 mL/min/1.73 m2, while BSA and diabetes were protective. Participants with low TKV had higher odds of eGFR <60 mL/min/1.73 m2 (OR 6.12, P < 0.001) and albuminuria (OR 1.56, P = 0.03). CONCLUSIONS: Low TKV is associated with markers of kidney damage including albuminuria and eGFR <60 mL/min/1.73 m2, while high TKV is associated with diabetes and decreased odds of eGFR <60 mL/min/1.73 m2. Prospective studies are needed to characterize the natural progression and clinical consequences of TKV.

Treatment of life-threatening hyperkalemia with peritoneal dialysis in the ED.

Severe hyperkalemia (serum potassium N 7.0 mmol/L) is an uncommon electrolyte abnormality in patients undergoing maintenance peritoneal dialysis (PD). Hemodialysis (HD) has been suggested as the definitive therapy for severe hyperkalemia in this population,although there is limited data regarding renal replacement options.We report a case of life-threatening hyperkalemia with electrocardiogram changes in a nonadherent PD patient who was successfully treated with standard medical therapy and manual exchanges initiated by emergency department (ED) personnel. The patient did not require HD. This case demonstrates the potential utility of PD as a treatment option for severe hyperkalemia in established dialysis patients when EDs are prepared to deliver exchanges. This report maybe particularly relevant due to the increasing prevalence rate of PD and for centers with limited HD access.

Renal artery calcium, cardiovascular risk factors, and indexes of renal function.

Vascular calcium is well studied in the coronary and peripheral arteries, although there are limited data focusing on calcium deposits specific to renal arteries. The associations among renal artery calcium (RAC), cardiovascular disease risk factors, and indexes of renal function are unknown. We examined 2,699 Framingham Heart Study participants who were part of a multidetector computed tomography substudy from 2008 to 2011. RAC was measured as a calcified plaque of >130 HU and an area of >3 contiguous pixels. Detectable RAC was defined as an Agatston score >0. Chronic kidney disease was defined as an estimated glomerular filtration rate of <60 ml/min/1.73 m(2). Microalbuminuria was defined as an albumin/creatinine ratio of ≥17 mg/g for men and ≥25 mg/g for women. Multivariable adjusted logistic regression models were used to evaluate the associations between RAC, cardiovascular disease risk factors, and renal function. The associations were secondarily adjusted for coronary artery calcium (CAC) that was used as a marker of nonrenal systemic vascular calcium. The prevalence of RAC was 28.2%; this was similar in women (28.8%) and men (27.5%). Patients with RAC had a higher odds of microalbuminuria (odds ratio [OR] 1.79, 95% confidence interval [CI] 1.22 to 2.61, p = 0.003), hypertension (OR 2.11, 95% CI 1.69 to 2.64, p <0.001), and diabetes (OR 1.60, 95% CI 1.14 to 2.24, p = 0.01) but not chronic kidney disease (OR 0.87, 95% CI 0.58 to 1.32). After adjustment for CAC, the association with microalbuminuria and hypertension persisted, but the association with diabetes became nonsignificant. In conclusion, RAC is common and independently associated with microalbuminuria and hypertension after adjustment for nonrenal vascular calcium. RAC may be uniquely associated with these markers of renal end-organ damage.