Brain natriuretic peptide in hemodialysis patients: predictive value for hemodynamic change during hemodialysis and cardiac function.

BACKGROUND: Though brain natriuretic peptide (BNP) is widely used as a clinical marker of cardiac function, there is considerable confusion in the interpretation of its value in hemodialysis (HD) patients whose BNPs are often elevated without cardiac diseases. The aim of the present study is to examine the predictive value of BNP for blood pressure (BP) fall during HD and cardiac function. METHODS: Subjects consisted of 205 (160 males, 45 females; age 66.5 +/- 10.5 years) consecutive uremic patients requiring maintenance HD who were admitted to our hospital during 2001-2004. One hundred and eleven cases had a history of ischemic heart disease. We measured BNP in all cases and collected clinical data including age, sex, duration of HD, blood examination and echocardiography. RESULTS: BNP of all 205 cases ranged from 6 to 16,097 pg/ml (median 831). During HD, the average BP change was -24.5 +/- 20.5 mm Hg, and 111 cases showed a systolic BP reduction >20 mm Hg. BNP did not predict the degree of BP fall. After adjusting confounding factors, the presence of ischemic heart disease, ultrafiltration rate, systolic BP before HD and serum sodium concentration showed a significant correlation with BP change (t = -2.84, -2.76, -4.68 and 2.90; p = 0.005, <0.01, <0.0001 and <0.005, respectively). In relation to echocardiographic indices, BNP >785 pg/ml could predict left ventricular dysfunction (fractional shortening of the left ventricle <30%, sensitivity 73%, specificity 65%). CONCLUSION: The level of BNP could not predict BP fall during HD. However, BNP is a good indicator of cardiac function even in uremic patients.

Reverse white-coat effect as an independent risk for microalbuminuria in treated hypertensive patients.

BACKGROUND: The influence of the converse phenomenon of white-coat hypertension called 'reverse white-coat hypertension' or 'masked hypertension' on hypertensive target organ damage has not been fully elucidated. The present study assessed the hypothesis that this phenomenon may specifically associate with microalbuminuria, a marker of early renal damage, in treated hypertension. METHODS: A total of 267 treated essential hypertensive patients (133 men and 134 women; mean age, 66 years) without renal insufficiency or macroalbuminuria were enrolled in this study. Patients were classified into three groups by the difference between office and day-time ambulatory systolic blood pressure (BP) levels; i.e. subjects with white-coat effect (W group: office--day-time systolic BP > or =20 mmHg, n = 48), with reverse white-coat effect (R group: office - day-time systolic BP < - 10 mmHg, n = 43) and without white-coat or reverse white-coat effect (N group: -10 mmHg < or = office--day-time systolic BP <20 mmHg, n = 176). The urinary albumin (U-Alb) level was measured as the albumin to creatinine excretion ratio in the urine. Microalbuminuria was defined as U-Alb of > or =30 and <300 mg/g Cr. RESULTS: R group had a well-controlled office BP (130/77 mmHg), but their day-time BP (148/87 mmHg) was elevated compared with the other two groups. The levels of U-Alb excretion in N group, W group and R group were 12.3 (8.4, 25.6), 16.0 (10.5, 31.7) and 24.3 (10.2, 79.7) mg/g Cr [median (interquartile range)], respectively. Both U-Alb level and prevalence of microalbuminuria were significantly greater in R group than in N group. Multivariate analyses revealed that the presence of reverse white-coat effect, but not white-coat effect, was a significant predictor for microalbuminuria, independent of various clinical variables including ambulatory BP levels (odds ratio 2.63 vs N group, P = 0.02). CONCLUSION: These findings suggest that the presence of reverse white-coat effect may be an independent risk for early renal damage in treated hypertensive patients.