Alessandra Pola

Predictors of Renal and Patient Outcomes in Atheroembolic Renal Disease: A Prospective Study

Atheroembolic renal disease (AERD) is part of a multisystemic disease accompanied by high cardiovascular comorbidity and mortality. Interrelationships between traditional risk factors for atherosclerosis, vascular comorbidities, precipitating factors, and markers of clinical severity of the disease in determining outcome remain poorly understood. Patients with AERD presenting to a single center between 1996 and 2002 were followed-up with prospective collection of clinical and biochemical data. The major outcomes included end-stage renal disease (ESRD) and death. Ninety-five patients were identified (81 male). AERD was iatrogenic in 87%. Mean age was 71.4 yr. Twenty-three patients (24%) developed ESRD; 36 patients (37.9%) died. Cox regression analysis showed that significant independent predictors of ESRD were long-standing hypertension (hazard ratio [HR] = 1.1; P < 0.001) and preexisting chronic renal impairment (HR = 2.12; P = 0.02); use of statins was independently associated with decreased risk of ESRD (HR = 0.02; P = 0.003). Age (HR = 1.09; P = 0.009), diabetes (HR = 2.55; P = 0.034), and ESRD (HR = 2.21; P = 0.029) were independent risk factors for patient mortality; male gender was independently associated with decreased risk of death (HR = 0.27; P = 0.007). Cardiovascular comorbidities, precipitating factors, and clinical severity of AERD had no prognostic impact on renal and patient survival. It is concluded that AERD has a strong clinical impact on patient and renal survival. The study clearly shows the importance of preexisting chronic renal impairment in determining both renal and patient outcome, this latter being mediated by the development of ESRD. The protective effect of statins on the development of ESRD should be evaluated in a prospective study.

Direct Effect of the Correction of Acidosis on Plasma Parathyroid Hormone Concentrations, Calcium and Phosphate in Hemodialysis Patients: A Prospective Study

Background: Metabolic acidosis contributes to renal osteodystrophy and together with hyperphosphatemia, hypocalcemia and altered vitamin D metabolism may result in increased levels of intact parathyroid hormone (iPTH) and metastatic calcifications. However, the impact of the correction of metabolic acidosis on iPTH levels and calcium-phosphate metabolism is still controversial. Study Design: The effects of the correction of metabolic acidosis on serum concentrations of iPTH, calcium (Ca), phosphate (PO4) and alkaline phosphatase were prospectively studied. Twelve uremic patients on maintenance hemodialysis (HD) for 49 months (median; range 6–243 months) with serum bicarbonate levels ≤20 mmol/l were studied before and after 3 months of oral sodium bicarbonate supplementation. Predialysis serum bicarbonate, arterial pH, ionized calcium, plasma sodium, plasma potassium, serum creatinine, hemoglobin, Kt/V, postdialysis body weight, predialysis systolic and diastolic blood pressure were also evaluated before and after correction. Results: Serum bicarbonate levels and arterial pH increased respectively from 19.3 ± 0.6 to 24.4 ± 1.2 mmol/l (p < 0.0001) and 7.34 ± 0.03 to 7.40 ± 0.02 (p < 0.001). iPTH levels decreased significantly from 399 ± 475 to 305 ± 353 pg/ml (p = 0.026). No changes in total serum Ca, plasma PO4, serum akaline phosphatase, Kt/V, serum creatinine, hemoglobin, body weight, predialysis systolic and diastolic blood pressures were observed. iCa decreased significantly. Conclusions: Our study demonstrates that the correction of metabolic acidosis in chronic HD patients reduces iPTH concentrations in HD patients with secondary hyperparathyroidism possibly by a direct effect on iPTH secretion.

Effect of post-dilutional on-line haemodiafiltration on serum calcium, phosphate and parathyroid hormone concentrations in uraemic patients

BACKGROUND Strict control of serum calcium and phosphate concentrations is paramount to prevent secondary hyperparathyroidism in haemodialysis (HD) patients. Standard intermittent low-flux HD (Lf-HD) is not sufficient to reach this goal. The aim of this study was to evaluate the effect of on-line haemodiafiltration (Ol-HDF) on serum calcium (sCa), phosphate (sPO4) and parathyroid hormone (PTHint) concentrations. METHODS Of the 220 patients screened, 65 met the inclusion criteria for the study; 30 of whom agreed to participate in the study (Study group), the others were considered as the control group (Controls). Protocol for Study the group consisted of 6 months conventional Lf-HD (Period 1) and 6 months of post-dilutional Ol-HDF (Period 2). Controls continued their usual Lf-HD and were followed for 12 months. The main variables evaluated at the start and at the end of each period were sCa, sPO(4) and PTHint. RESULTS The switchover from Lf-HD to Ol-HDF resulted in a significant reduction of sPO4 (from 5.1 ± 1.0 to 4.0 ± 0.7; P < 0.0001) and PTHint concentrations (from 307 ± 167 to 194 ± 98; P < 0.0001), no significant changes were found in both sCa concentrations (from 9.1 ± 0.7 to 8.9 ± 0.6) and phosphate binder dose. Kt/Vurea increased significantly, and beta(2) microglobulin concentrations decreased significantly. In the Controls, no significant variations of the same variables were observed over time, except for a significant increase in sevelamer intake. CONCLUSION This study supports the idea that Ol-HDF could be better than Lf-HD in controlling mineral metabolism in HD patients.

Magnitude of end-dialysis overweight is associated with all-cause and cardiovascular mortality: a 3-year prospective study.

Background: We hypothesized that the difference between the prescribed end-dialysis body weight, defined end-dialysis over-weight (edOW; kg), and the body weight which is actually attained could impact survival in hemodialysis (HD) patients. The aim of this prospective observational study was to evaluate if edOW could influence survival in a cohort of prevalent HD patients, controlled for multiple dialysis and clinical risk factors and followed for 3 years. Methods: One hundred and eighty-two patients (117 men, age 65 ± 13 years) on regular HD treatment for at least 6 months [median 48 months (range: 6-366)] were followed from January 1, 2008 to December 31, 2010. Eighty-four patients (46%) did not achieve their prescribed dry body weight (dBW); their median edOW was 0.4 kg (range: 0.1-1.4). Ninety-eight died during observation, mainly from cardiovascular reasons (69%). Multivariate Cox regression analysis was utilized to evaluate the effect edOW, ultrafiltration rate (UFR), interdialytic weight gain (IDWG), age, sex, dialytic vintage, cardiovascular disease, antihypertensive therapy, diabetes, duration of HD, dBW, BMI, mean arterial blood pressure, Kt/V, and protein catabolic rate (PCRn) had on mortality. Results: Age (HR: 1.04; CI: 1.03-1.05; p <0.0001), IDWG (HR: 2.62; CI: 2.06-3.34; p < 0.01), UFR (HR: 1.13; CI: 1.09-1.16; p< 0.01), PCRn (HR: 0.02; CI: 0.01-0.04; p <0.001), and edOW (HR: 2.71; CI: 1.95-3.75; p < 0.02) were independently correlated to survival. The relative receiver operating characteristic curve identified a cutoff value of 0.3 kg for edOW in predicting death. Conclusions: High edOW is independently associated with an increased long-term risk of all-cause and cardiovascular mortality in HD patients. Better survival was observed in patients with edOW <0.3 kg. For patients with higher edOW, longer or more frequent dialysis sessions should be considered in order to prevent the deleterious consequences of excessive body fluid expansion.

Role of Dialysis Sodium Gradient on Intradialytic Hypertension: An Observational Study

Introduction: The causes of intradialytic hypertension (IDHyper) are not well understood and this condition can complicate the clinical management of hemodialysis (HD) patients. Aim: To evaluate the potential role of intradialytic sodium gradient (NaG) on blood pressure values and IDHyper during HD. Patients and Methods: 206 prevalent HD patients on 3 times weekly HD treatment for at least 6 months (dialytic vintage 6-240 months) followed at our institution were studied. Mean age was 68 ± 14 years, 129 were men. For 2 consecutive months (24 HD sessions) after the start of observation, the following variables were evaluated in predialysis after the long interdialysis interval: pre-HD plasma sodium (pNa, mmol/l) and potassium (pK, mmol/l) concentrations (mean value of 8 determinations), pre- and post-HD systolic (SBP, mm Hg) and diastolic (DBP, mm Hg) blood pressure, dry body weight (dBW, kg), interdialytic weight gain (IDWG, kg), ultrafiltration rate (UFR, ml/kg/h), dialysis dose (Kt/V), protein catabolic rate (PCRn, g/kg/day), hemoglobin (Hb, g/dl). SBP, DBP, IDWG, UFR are the mean values of the 24 HD sessions. 76% of patients were on antihypertensive therapy, 171 patients were on bicarbonate HD, and 35 on HDF. Dialysate Na concentration was set at 140 mmol/l in all patients. Duration of HD and the blood and dialysate flow rate were kept constant during observation. Statistical Analysis: Data are expressed as mean ± SD; linear and multiple regression analysis and t test for unpaired data were employed. Significant differences were defined as p < 0.05. Results: Pre-HD pNa was 138.1 ± 2.3 mmol/l, pK 5.0 ± 0.4 mmol/l, dBW 67 ± 14 kg, IDWG 2.9 ± 0.8 kg, UFR 11.2 ± 3.7 ml/kg/h, Kt/V 1.43 ± 0.18, PCRn 1.13 ± 0.17 g/kg/day, and Hb 11.2 ± 0.8 g/dl. Pre- and post-HD SBP values were 139 ± 13 and 134 ± 12 mm Hg (p < 0.0001); pre- and post-HD DBP did not change significantly. A dialysis Na gradient (NaG) (dialysate Na - pre-HD pNa) was calculated, as well as the delta of SBP (ΔSBP) (post-HD SBP - pre-HD SBP). IDHyper was defined as ΔSBP >0. A significant direct correlation was found between NaG and ΔSBP (p < 0.0001) and multiple regression analysis with ΔSBP as dependent variable confirmed the strong correlation with NaG (p < 0.00001). According to ΔSBP behavior, 171 patients (83%) had a decrease or no change in post-HD SBP (group 1; no IDHyper); 35 patients (17%) increased their post-HD SBP (group 2; IDHyper). NaG values were significantly greater in patients in group 2 (group 1: 1.5 ± 2.2 vs. group 2: 3.3 ± 2.5, p < 0.0001). Conclusions: This study shows that the intradialytic ΔSBP is independently and strongly associated with the dialytic NaG. The more positive the NaG (net intradialytic Na gain), the more positive the ΔSBP and IDHyper.