ABSTRACT: B-type natriuretic peptide (BNP) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP) are biomarkers of cardiovascular disease that is common in patients with chronic kidney disease (CKD). Conflicting data on the influence of glomerular filtration rate (GFR) on BNP and NT-proBNP levels in CKD may stem from failure to account fully for the effects of coexistent cardiac disease, dysfunction, and volume overload.
Prospective head-to-head comparison of plasma BNP and NT-proBNP in ambulatory euvolemic CKD patients with normal LV ejection fraction and no manifest cardiac or vascular disease. GFR was estimated by the Modification of Diet in Renal Disease formula, BNP and NT-proBNP measured using Abbott AxSYM and Roche Elecsys assays, respectively, and cardiac morphology and function assessed by transthoracic echocardiography.
In 142 patients (42% female) of mean age 60 +/- 11 yr, mean left ventricular ejection fraction was 71% +/- 6%, GFR 38 +/- 14 ml/min per 1.73 m(2), and median BNP and NT-proBNP level 59 and 311 pg/ml, respectively. Multivariate predictors of NT-proBNP level were GFR, beta-blocker usage, LV mass index, and hemoglobin level. Plasma BNP was independently predicted by LV mass index and beta-blocker usage but not GFR. In the 74 patients without diastolic dysfunction, there was a significant rise in NT-proBNP but not BNP as GFR declined.
Unlike NT-proBNP, plasma BNP level is relatively independent of GFR. BNP may therefore be the more appropriate biomarker to screen for cardiac dysfunction in CKD.
Clinical Journal of the American Society of Nephrology 11/2008; 3(6):1644-51. · 5.23 Impact Factor
ABSTRACT: Left ventricular mass (LVM) is an independent risk factor for cardiovascular outcome. We aimed to define normal reference values of LVM/body surface area (BSA) in a multiethnic Southeast Asian population across ages, and define demographic parameters that predict LVM/BSA.
198 subjects (44% men, mean age 40 +/- 14 years, 82% Chinese, 13% Malay and 5% Indian) with no cardiovascular comorbidity and had normal echo images for age were included in the analysis. Echo LVM was calculated as: 1.04 x[(left ventricular internal diameter at end-diastole [LVIDd]+ interventricular septal thickness at end-diastole [IVSd]+ left ventricular posterior wall thickness at end-diastole [LVPWd])(3)- LVIDd(3)x 0.8]+ 0.6(1), indexed by BSA (LVM/BSA)* and expressed as g/m(2).
BSA and blood pressure (BP) were comparable between dichotomous age groups < or >or= 50 years within the same gender. Women aged >or= 50 years had larger IVSD, LVPWd, LVM and LVM/BSA compared to younger cohort. (p < 0.01 for all variables). The 95th percentile of LVM in men and women were 189 g and 148 g respectively; corresponding values for LVM/BSA were 106 and 96 g/m(2). These values are consistently smaller than published values from the West. Age (r = 0.27, P < 0.001), gender (r =-0.30, P < 0.001), and systolic BP (r = 0.25, P = 0.003) were significant univariate predictors of LVM/BSA.
We therefore propose a different cutoff value for the diagnosis of LV hypertrophy among Southeast Asians.
Echocardiography 10/2008; 25(8):805-11. · 1.24 Impact Factor
ABSTRACT: Intact left atrial booster pump function helps maintain cardiac compensation in patients with aortic valve stenosis (AS). Because late diastolic mitral annular (A') velocity reflects left atrial systolic function, we hypothesized that A' velocity correlates with plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) level and clinical outcome in AS.
We prospectively enrolled 53 consecutive patients (median age 74 years) with variable degrees of AS, in sinus rhythm, and left ventricular ejection fraction greater than 50%. Indices of valvular stenosis, left ventricular diastolic dysfunction, and mitral annular motion were correlated with plasma NT-proBNP and a composite clinical end point comprising cardiac death and symptom-driven aortic valve replacement.
Tissue Doppler echocardiographic parameters, including early diastolic (E') velocity and A' velocity and ratio of early diastolic transmitral (E) to E' velocity (E/E') at the annular septum correlated better with NT-proBNP levels than body surface area-indexed aortic valve area. Eighteen patients had the composite end point, which was univariately predicted by body surface area-indexed aortic valve area, NT-proBNP, and all tissue Doppler echocardiographic indices. This outcome was most strongly predicted by the combination of septal A' velocity and E/E' ratio in bivariate Cox modeling. Septal annular A' velocity less than 9.6 cm/s was associated with significantly reduced event-free survival (Kaplan Meier log rank = 27.3, P < .0001) and predicted the end point with a sensitivity, specificity, and accuracy of 94%, 80%, and 85%, respectively.
In patients with AS and normal ejection fraction, annular tissue Doppler echocardiographic indices may better reflect the physiologic consequences of afterload burden on the left ventricle than body surface area-indexed aortic valve area. Lower A' velocity is a predictor of cardiac death and need for valve surgery, suggesting an important role for compensatory left atrial booster pump function.
Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 05/2008; 21(5):475-81. · 2.98 Impact Factor
ABSTRACT: Little is known regarding the tissue Doppler characteristics and clinical significance of mitral annular motion during diastasis (L' wave).
In consecutive patients with left ventricular hypertrophy and normal ejection fraction, standard Doppler and Doppler tissue imaging were performed. Patients were followed up for heart failure (HF) hospitalization.
Of 177 patients, 53 (30%) had an L', detected most frequently at the lateral mitral annulus, whereas 35 (20%) had middiastolic transmitral flow (L wave), which almost invariably coexisted with the L'. The L' predicted increased left ventricular filling pressure with 74% sensitivity and 82% specificity, and increased risk of future HF (hazard ratio 3.9 [P = .030]), even after adjusting for baseline clinical differences (hazard ratio 6.5 [P = .024]). When associated with an L wave, HF risk increased further.
Middiastolic annular motion, detectable in almost a third of patients with left ventricular hypertrophy, may be an early marker of diastolic dysfunction and a prognostic marker for HF.
Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 03/2008; 21(2):165-70. · 2.98 Impact Factor
International Journal of Cardiology 03/2006; 107(1):123-5. · 7.08 Impact Factor