Heart failure with preserved ejection fraction is the most frequent but commonly overlooked phenotype in patients on chronic hemodialysis.

Introduction: Heart failure (HF) is a serious complication of end-stage kidney disease (ESKD). However, most data come from retrospective studies that included patients on chronic hemodialysis at the time of its initiation. These patients are frequently overhydrated, which significantly influences the echocardiogram findings. The primary aim of this study was to analyze the prevalence of heart failure and its phenotypes. The secondary aims were (1) to describe the potential of N-terminal pro-brain natriuretic peptide (NTproBNP) for HF diagnosis in ESKD patients on hemodialysis, (2) to analyze the frequency of abnormal left ventricular geometry, and (3) to describe the differences between various HF phenotypes in this population. Methods: We included all patients on chronic hemodialysis for at least 3 months from five hemodialysis units who were willing to participate, had no living kidney transplant donor, and had a life expectancy longer than 6 months at the time of inclusion. Detailed echocardiography together with hemodynamic calculations, dialysis arteriovenous fistula flow volume calculation, and basic lab analysis were performed in conditions of clinical stability. Excess of severe overhydration was excluded by clinical examination and by employing bioimpedance. Results: A total of 214 patients aged 66.4 ± 14.6 years were included. HF was diagnosed in 57% of them. Among patients with HF, HF with preserved ejection fraction (HFpEF) was, by far, the most common phenotype and occurred in 35%, while HF with reduced ejection fraction (HFrEF) occurred only in 7%, HF with mildly reduced ejection fraction (HFmrEF) in 7%, and high-output HF in 9%. Patients with HFpEF differed from patients with no HF significantly in the following: they were older (62 ± 14 vs. 70 ± 14, p = 0.002) and had a higher left ventricular mass index [96(36) vs. 108(45), p = 0.015], higher left atrial index [33(12) vs. 44(16), p < 0.0001], and higher estimated central venous pressure [5(4) vs. 6(8), p = 0.004] and pulmonary artery systolic pressure [31(9) vs. 40(23), p = 0.006] but slightly lower tricuspid annular plane systolic excursion (TAPSE): 22 ± 5 vs. 24 ± 5, p = 0.04. NTproBNP had low sensitivity and specificity for diagnosing HF or HFpEF: with the use of the cutoff value of 8,296 ng/L, the sensitivity of HF diagnosis was only 52% while the specificity was 79%. However, NTproBNP levels were significantly related to echocardiographic variables, most significantly to the indexed left atrial volume (R = 0.56, p < 10-5) and to the estimated systolic pulmonary arterial pressure (R = 0.50, p < 10-5). Conclusions: HFpEF was by far the most common heart failure phenotype in patients on chronic hemodialysis and was followed by high-output HF. Patients suffering from HFpEF were older and had not only typical echocardiographic changes but also higher hydration that mirrored increased filling pressures of both ventricles than in those of patients without HF.

Determinants of circulating matrix metalloproteinase-2 and pregnancy-associated plasma protein-A in patients with chronic kidney disease.

BACKGROUND: Matrix metalloproteinase-2 (MMP-2) and pregnancy-associated plasma protein-A (PAPP-A) have been implicated in chronic kidney disease (CKD) and cardiovascular disease (CVD). However, the serum determinants of MMP-2 and PAPP-A in CKD are unknown. The aim of the present study is to evaluate the clinical significance of MMP-2 and PAPP-A and their determinants in patients with CKD. METHODS: The studied group consisted of 203 subjects: 159 patients with chronic kidney disease stages 1 - 5 (CKD 1 - 5), and 44 healthy control subjects. MMP-2 levels were assessed immunochemically using ELISA (enzyme linked immunosorbent assay), PAPP-A levels were determined immunochemically with TRACE (time-resolved amplified cryptate emission), and routine biochemical parameters were measured using standard methods. RESULTS: Compared with healthy controls, CKD patients (3 - 5) had no significant changes in MMP-2 levels. MMP-2 levels (195 +/- 76 vs. 255 +/- 77 ng/mL, p < 0.0001) were significantly lower in CKD patients (1 - 2) and PAPP-A levels (12.1 +/- 8.5 vs. 9.3 +/- 2.2 mIU/L, p = 0.001) were significantly higher in CKD 4 compared to control subjects. Multivariate analysis revealed that PAPP-A (p < 0.0001), proteinuria (p = 0.002), alpha-2-macroglobulin (p = 0.01), and negatively albumin (p = 0.02) and haemoglobin (p = 0.0002), were independent correlates of MMP-2 after adjustment for age and glomerular filtration rate. Proteinuria (p = 0.02), creatinine (p < 0.0001), and negatively albumin (p = 0.01), were independent correlates of PAPP-A adjusted for age and glomerular filtration rate. CONCLUSIONS: The present study demonstrated that serum MMP-2 and PAPP-A were independent correlates of proteinuria, albumin, and other examined parameters. Our results suggest the possibility that circulating MMP-2 and PAPP-A be used as indicators for renal damage in CKD patients on conservative treatment.

Associations of serum levels of advanced glycation end products with nutrition markers and anemia in patients with chronic kidney disease.

BACKGROUND: Advanced glycation end product (AGE) levels are elevated in patients with decreased renal function and may contribute to the excessive cardiovascular disease in this population. However, their relation to nutrition, anemia, and micro inflammation is not well characterized. The aim of this study is to determine their relationship in patients with chronic kidney disease (CKD). METHODS: The studied group consisted of 203 subjects: 159 patients with CKD 1-5 and 44 healthy control subjects. AGE levels were assessed by spectrofluorimetry, and routine biochemical parameters were measured using standard methods. RESULTS: AGE levels were significantly increased in CKD patients compared with controls (3.9 ± 1.7 × 105 AU in CKD 1-5 patients vs. 3.2 ± 0.48 × 105 AU in controls, p < 0.0001). AGE levels increased from CKD 3. AGE levels were positively associated with age, albumin, prealbumin, and orosomucoid, and were negatively associated with hemoglobin and estimated glomerular filtration rate. In multiple regression analysis, after adjustment to age and glomerular filtration rate, AGE levels remained independently correlated with albumin and prealbumin and negatively correlated with hemoglobin. CONCLUSIONS: This study is the demonstration that nutrition markers, albumin and prealbumin, are the positive determinants and hemoglobin is the negative determinant of serum AGE levels in patients with CKD.

Changes in levels of matrix metalloproteinase-2 and -9, pregnancy-associated plasma protein-A in patients with various nephropathies.

BACKGROUND: Specific changes and imbalanced concentrations of matrix metalloproteinases (MMPs) and pregnancy-associated plasma protein-A (PAPP-A) may reflect the pathophysiology of various nephropathies (GN). We compared MMP-2, MMP-9 and PAPP-A levels in patients with GN, with those found in healthy controls. METHODS: We studied 45 controls and 128 patients with GN, defined by kidney biopsy: IgA nephropathy (IgAN, n=33), membranous glomerulonephritis (MN, n=23), minimal change nephrotic syndrome (MCNS, n=7), focal segmental glomerular sclerosis (FSGS, n=11), lupus nephritis (LN, n=22) and ANCA-associated glomerulonephritis (AAV, n=32). MMP-2 and MMP-9 levels were assessed using enzyme-linked immunosorbent assay; PAPP-A levels were determined with time-resolved amplified cryptate emission, and routine biochemical parameters were measured. RESULTS: Compared with controls, IgAN patients exhibited a significant decrease in levels of MMP-2 contrasted with increased MMP-9 and unchanged PAPP-A levels. LN patients exhibited a parallel decrease in MMP-2, MMP-9 and PAPP-A levels. In the MCNS/FSGS and AAV patients, MMP-2, MMP-9 and PAPP-A levels were unchanged. In MN patients, increased MMP-9 levels contrasted with unchanged MMP-2 and PAPP-A levels (all p<0.05). Both MMP-2 (r=-0.34, p<0.0001) and PAPP-A levels (r=-0.31, p<0.0001) were inversely correlated with estimated glomerular filtration rate in all GN groups. CONCLUSIONS: Serum levels of MMP-2, MMP-9 and PAPP-A significantly differed between various nephropathies. These findings suggest that MMPs and PAPP-A are involved in different underlying mechanisms in the regulation of glomerular and tubulointerstitial fibrosis and scarring in these renal diseases.