Valentina Pistolesi

Regional citrate anticoagulation in cardiac surgery patients at high risk of bleeding: a continuous veno-venous hemofiltration protocol with a low concentration citrate solution.

IntroductionRegional citrate anticoagulation (RCA) is a valid option in patients at high risk of bleeding who are undergoing continuous renal replacement therapy (CRRT). The aim of this study was to evaluate, in critically ill patients with severe acute kidney injury following cardiac surgery, the efficacy and safety of RCA-continuous veno-venous hemofiltration (CVVH) using a low concentration citrate solution.MethodsIn high bleeding-risk cardiac surgery patients, we adopted, as an alternative to heparin or no anticoagulation, RCA-CVVH using a 12 mmol/l citrate solution. For RCA-CVVH settings, we developed a mathematical model to roughly estimate citrate load and calcium loss. In order to minimize calcium chloride supplementation, a calcium-containing solution was used as post-dilution replacement fluid.Statistical analysis was performed using the Student t-test or analysis of variance (ANOVA) with post-hoc tests, Wilcoxon or Kruskal-Wallis tests for non-parametric analysis, and Kaplan-Meier survival analysis with Log Rank test.ResultsThirty-three patients (age 70.8 ± 9.5, Sequential Organ Failure Assessment (SOFA) score 13.9 ± 2.5) were switched to RCA-CVVH from no anticoagulation CRRT. Among them, 16 patients had been previously switched from heparin to no anticoagulation because of bleeding or heparin-related complications. RCA-CVVH filter life (49.8 ± 35.4 hours, median 41, 152 circuits) was significantly longer (P < 0.0001) when compared with heparin (30.6 ± 24.3 hours, median 22, 73 circuits) or no anticoagulation (25.7 ± 21.2 hours, median 20, 77 circuits). Target circuit and systemic Ca++ were easily maintained (0.37 ± 0.09 and 1.18 ± 0.13 mmol/l), while the persistence of a mild metabolic acidosis required bicarbonate supplementation (5.8 ± 5.9 mmol/hours) in 27 patients. The probability of circuit running at 24, 48, 72 hours was higher during RCA-CVVH (P < 0.0001), with a lower discrepancy between delivered and prescribed CRRT dose (P < 0.0001). RCA was associated with a lower transfusion rate (P < 0.02). Platelet count (P = 0.012) and antithrombin III activity (P = 0.004) increased throughout RCA-CVVH, reducing the need for supplementation.ConclusionsRCA safely prolonged filter life while decreasing CRRT downtime, transfusion rates and supplementation needs for antithrombin III and platelets. In cardiac surgery patients with severe multiple organ dysfunction syndrome, the adoption of a 12 mmol/l citrate solution may provide a suboptimal buffers supply, easily overwhelmed by bicarbonate supplementation.

Regional Citrate Anticoagulation for RRTs in Critically Ill Patients with AKI

Hemorrhagic complications have been reported in up to 30% of critically ill patients with AKI undergoing RRT with systemic anticoagulation. Because bleeding is associated with significantly increased mortality risk, strategies aimed at reducing hemorrhagic complications while maintaining extracorporeal circulation should be implemented. Among the alternatives to systemic anticoagulation, regional citrate anticoagulation has been shown to prolong circuit life while reducing the incidence of hemorrhagic complications and lowering transfusion needs. For these reasons, the recently published Kidney Disease Improving Global Outcomes Clinical Practice Guidelines for Acute Kidney Injury have recommended regional citrate anticoagulation as the preferred anticoagulation modality for continuous RRT in critically ill patients in whom it is not contraindicated. However, the use of regional citrate anticoagulation is still limited because of concerns related to the risk of metabolic complications, the complexity of the proposed protocols, and the need for customized solutions. The introduction of simplified anticoagulation protocols based on citrate and the development of dialysis monitors with integrated infusion systems and dedicated software could lead to the wider use of regional citrate anticoagulation in upcoming years.

Incidence of contrast-induced acute kidney injury associated with diagnostic or interventional coronary angiography

BACKGROUND Contrast-induced acute kidney injury (CI-AKI) represents an important cause of hospital-acquired AKI. The aim of this study was to evaluate the incidence of CI-AKI after coronary angiography (CA) or percutaneous coronary intervention (PCI) and the role of patient-/procedure-related risk factors. METHODS For 11 months, patients undergoing CA or PCI were prospectively evaluated for CI-AKI, and factors possibly affecting CI-AKI were analyzed. Statistical analysis was completed using Students t-test, chi-square or Fisher exact test, and multivariate logistic regression. RESULTS Among 585 consecutive patients, incidence of CI-AKI was 5.1% (n=30) and renal replacement therapy was required in 10% of those (n=3). Incidence of CI-AKI was higher in patients with anemia or chronic kidney disease (CKD) associated with diabetes. Basal hemoglobin was significantly lower in CI-AKI patients while Mehran score, contrast medium (CM) volume, contrast ratio (CM volume / maximum contrast dose) and ratio glomerular filtration rate (CM volume / GFR) were significantly higher. Multivariate analysis selected a higher contrast ratio as a factor independently associated with a higher risk of CI-AKI which otherwise appeared to be lower with increasing basal hemoglobin. CONCLUSIONS The incidence of CI-AKI after CA or PCI was higher in patients with CKD associated with diabetes. Lower levels of basal hemoglobin appeared to be related to a higher risk of CI-AKI, and contrast media volume, especially if exceeding the dose adjusted for renal function, was a strong modifiable risk factor for CI-AKI.

Cardiac, Inflammatory and Metabolic Parameters: Hemodialysis versus Peritoneal Dialysis

Introduction: Mortality in dialysis patients is higher than in the general population, and cardiovascular disease represents the leading cause of death. Hypertension and volume overload are important risk factors for the development of left ventricular hypertrophy (LVH) in hemodialysis (HD) and peritoneal dialysis (PD) patients. Other factors are mainly represented by hyperparathyroidism, vascular calcification, arterial stiffness and inflammation. The aim of this study was to compare blood pressure (BP) and metabolic parameters with cardiovascular changes [cardiothoracic ratio (CTR), aortic arch calcification (AAC) and LV mass index (LVMI)] between PD and HD patients. Materials and Methods: 45 patients (23 HD and 22 PD patients) were enrolled. BP measurements, echocardiography and chest X-ray were performed in each patient to determine the LVMI and to evaluate the CTR and AAC. Inflammatory indexes, intact parathyroid hormone (iPTH) and arterial blood gas analysis were also evaluated. Results: LVMI was higher in PD than HD patients (139 ± 19 vs. 104 ± 22; p = 0.04). In PD patients, a significant correlation between iPTH, C-reactive protein and the presence of LVH was observed (r = 0.70, p = 0.04; r = 0.70, p = 0.03, respectively). The CTR was increased in PD patients as compared to HD patients, while no significant differences in cardiac calcifications were determined. Conclusions: Our data indicate that HD patients present more effective BP control than PD patients. Adequate fluid and metabolic control are necessary to assess the adequacy of BP, which is strongly correlated with the increase in LVMI and with the increased CTR in dialysis patients. PD is a home therapy and allows a better quality of life, but PD patients may present a further increased cardiovascular risk if not adequately monitored.

Continuous veno-venous hemofiltration using a phosphate-containing replacement fluid in the setting of regional citrate anticoagulation

Purpose The need for prolonged anticoagulation and the occurrence of hypophosphatemia are well known drawbacks of continuous renal replacement therapies (CRRT). The aim was to evaluate the effects on acid-base status and serum phosphate of a regional citrate anticoagulation (RCA) protocol for continuous veno-venous hemofiltration (CVVH) combining the use of citrate with a phosphate-containing replacement fluid. Methods In a small cohort of heart surgery patients undergoing CRRT for acute kidney injury, we adopted an RCA-CVVH protocol based on a commercially available citrate solution (18 mmol/l) combined with a recently introduced phosphate-containing replacement fluid (HCO3− 30 mmol/l, phosphate 1.2), aimed at preventing phosphate depletion. Results In 10 high bleeding-risk patients, the RCA-CVVH protocol provided an adequate circuit lifetime (46.8 ± 30.3 h) despite the adoption of a low citrate dose and a higher than usual target circuit Ca2+ (≤0.5 mmol/l). Acid-base status was adequately maintained without the need for additional interventions on RCA-CVVH parameters and without indirect sign of citrate accumulation [(pH 7.43 (7.41-7.47), bicarbonate 24.4 mmol/l (23.2-25.6), BE 0 (-1.5 to 1.1), calcium ratio 1.97 (1.82-2.01); median (IQR)]. Serum phosphate was steadily maintained in a narrow range throughout RCA-CVVH days [1.1 mmol/l (0.9-1.4)]. A low amount of phosphorus supplementation (0.9 ± 2 g/day) was required in only 30% of patients. Conclusions Although needing further evaluation, the proposed RCA-CVVH protocol ensured a safe and effective RCA without electrolyte and/or acid-base derangements. CRRT-induced hypophosphatemia was prevented in most of the patients by the adoption of a phosphate-containing replacement solution, minimizing phosphate supplementation needs.

Regional citrate anticoagulation for renal replacement therapies in patients with acute kidney injury: a position statement of the Work Group “Renal Replacement Therapies in Critically Ill Patients” of the Italian Society of Nephrology

Patients with acute kidney injury (AKI) on renal replacement therapy (RRT) are at increased risk for bleeding but usually require anticoagulation of the extracorporeal circuit, a key prerequisite for delivery of an adequate RRT dose. To this end, many anti-hemostatic strategies have been proposed, unfractionated heparin—with all of its significant drawbacks and complications—being the most common method used so far. In this clinical context, regional citrate anticoagulation (RCA) could represent the most promising strategy, and it has been endorsed by recent guidelines on AKI. The aim of this position statement is to critically review the current evidence on RCA for the extracorporeal circuit of RRT in patients with AKI, in order to provide suggestions for its application in clinical practice. To this purpose, the most relevant clinical studies and recent guidelines on AKI with special regard to anti-hemostatic strategies for RRT circuit maintenance have been reviewed and commented. Experts from the Working Group “Renal Replacement Therapies in Critically Ill Patients” of the Italian Society of Nephrology have prepared this position paper, which discusses the basic principles, advantages and drawbacks of RCA based on the available safety and efficacy data. Advice is given on how to use and monitor RCA in the different RRT modalities, in order to avoid complications while maximizing the delivery of the prescribed RRT dose.

Diagnosis of Arterial Media Calcification in Chronic Kidney Disease

Purpose: Arterial media calcification (AMC) is often the only vascular calcification (VC) present in young patients with chronic renal failure and its presence is associated with higher mortality rates. Currently, X-ray imaging (as a standard approach) is able to show AMC in areas without diffuse overlapping arterial intimal calcification (AIC), but X-ray imaging only allows us to identify this lesion when the vessel is widely calcified. The aim of this study was to evaluate the possibility of using ultrasonography as opposed to X-rays to visualize AMC in patients with chronic renal failure. Patients and Methods: In this cross-sectional study, we examined 105 patients (chronic kidney disease stage IV: 19 patients, hemodialysis: 48 patients, renal transplant: 26 patients; mean age: 54 ± 14 years; 65 males and 40 females); B-mode ultrasonography was performed to detect AMC or AIC on the superficial femoral artery (SFA). As a control, plain radiography of the thigh was performed in all patients. Results: Upon ultrasonography investigation, 12 subjects were excluded due to diffuse VC on the SFA that did not permit a distinction between AMC and AIC. In the remaining 93 patients, AMC was detected on the SFA in 43 patients using ultrasonography and in 20 patients using the standard approach. The sensitivity and specificity of the standard approach for the detection of AMC on the SFA were 47 and 100%, respectively. The positive and negative predictive values of the standard approach were 1 and 0.68, respectively. Conclusion: Ultrasonography is able to detect AMC better than the X-ray approach, focusing on individuals at higher risk.

Correction: Interaction of healthcare staff’s attitude with barriers to physical activity in hemodialysis patients: A quantitative assessment

Background and aim of the study In hemodialysis patients, sedentarism is a potentially modifiable mortality risk factor. We explored whether healthcare staff’s attitude towards exercise interacts with patient-perceived barriers in modifying the level of physical activity in this population. Methods In this prospective, cross-sectional, multicenter study we recruited 608 adult patients and 330 members of the healthcare staff in 16 hemodialysis units in Italy. We assessed patient-perceived barriers to, and healthcare staff’s attitude towards, exercise by specific questionnaires. We fitted multilevel linear models to analyze the relationships of either barriers or staff’s attitude, and their interaction, with a measure of patient self-reported physical activity (the Human Activity Profile–Adjusted Activity Score [HAP-AAS]), adjusting for multiple confounders. We also employed latent class analysis to dichotomize patients into those endorsing or not endorsing barriers. Results Most barriers were negatively associated with the HAP-AAS (adjusted change attributable to a given barrier ranging between -5.1 [“Feeling too old”, 95% Confidence Interval: -9.4 to -0.8] and -15.6 [“Ulcers on legs and feet”, 95%CI: -24.8 to -6.5]. We found a significant interaction between staff’s attitude and barriers (adjusted P values ranging between 0.03 [“I do not believe that it is physician’s or nurse’s role providing advice on exercise to patients on dialysis”] and 0.001 [“I do not often ask patients about exercise”]). A beneficial effect of a proactive staff’s attitude was evident only in patients not endorsing barriers. Conclusions Barriers and non-proactive staff’s attitude reduce physical activity in hemodialysis patients. Patients not endorsing barriers benefit the most from a proactive staff’s attitude.

Preventing Continuous Renal Replacement Therapy-Induced Hypophosphatemia: An Extended Clinical Experience with a Phosphate-Containing Solution in the Setting of Regional Citrate Anticoagulation

Aims: To evaluate the efficacy and safety of a commercially available phosphate-containing solution for continuous renal replacement therapy (CRRT) in preventing CRRT-related hypophosphatemia. Methods: In heart surgery patients undergoing continuous veno-venous haemodiafiltration (CVVHDF) with regional citrate anticoagulation (RCA), we combined an 18 mmol/l citrate solution with a phosphate-containing (1.2 mmol/l) dialysate/replacement fluid evaluating the incidence of hypophosphatemia and the need for parenteral phosphorus supplementation. Results: In 75 patients on RCA-CVVHDF, the mean filter life was 53.9 ± 33.6 h. Regardless of baseline levels, phosphoremia was progressively corrected and maintained in a narrow normality range throughout RCA-CRRT days (after 72 h: 1.14 ± 0.25 mmol/l). Considering the whole CRRT period, 45 out of 975 (4.6%) serum phosphorus determinations met the criteria for mild (<0.81 mmol/l) or moderate (<0.61 mmol/l) hypophosphatemia; severe hypophosphatemia (<0.32 mmol/l) never occurred. After 72 h 88% of the patients were normophosphatemic, 9% hyperphosphatemic and 3% hypophosphatemic. Conclusions: RCA-CVVHDF with a phosphate-containing solution enabled the maintenance of phosphorus levels within normophosphatemic range in most of the patients, minimizing the occurrence of CRRT-related hypophosphatemia.

Neurological and Psychological Changes in Hemodialysis Patients Before and After the Treatment: Neuro-Psychological Changes in Hemodialysis Patients

Neurological, psychological, and cognitive disorders in chronic kidney disease may contribute to poor quality of life in these patients. The aim of this study was to assess the electroencephalographic, psychological, and cognitive changes before and after hemodialysis (HD) compared with healthy controls (HC). Sixteen HD patients and 15 HC were enrolled. Electroencephalogram (EEG), Minnesota multiphasic personality inventory (MMPI‐2) Satisfaction profile (SAT‐P), and Neuropsychological test Global z‐scores (NPZ5) were performed before (T0) and after (T1) HD treatment and in HC. Renal function, inflammatory markers and mineral metabolism indexes were also evaluated. Patients did not show significant differences before and after HD in the absolute and relative power of band of EEG, except in Theta/Alpha index (P < 0.001). At T1, HD patients showed significant differences in Beta, Delta and Theta band, in addition to Theta/alpha index, with respect to HC. Moreover, HD patients showed significant differences in specific MMPI‐2 clinical and content scales, SAT‐P domains and NPZ5 tests of memory and concentration with respect to HC. We also observed significant correlations between renal function, mineral metabolism, inflammatory markers and psychocognitive alterations. In our sample EEG abnormalities tend to reduce, but not significantly, after HD treatment and differences remain present with respect to HC. In HD patients cognitive and psychological alterations were associated with reduced quality of life and correlated with mineral metabolism and inflammation. Modification in EEG and in psychological and cognitive parameters should be assessed in a larger HD population to confirm our observation.