Michele Prencipe

Adsorption Dialysis: From Physical Principles to Clinical Applications

The uremic syndrome is characterized by the retention of various solutes that would normally be excreted by the kidneys. The substances that interact negatively with biologic functions are called uremic toxins. Over the past five decades, the membranes used for the treatment of chronic kidney disease have continuously evolved. The exposure of blood to any extracorporeal artificial surface results in the activation of several pathways within the body, including those involving coagulation and complement activation. One of the by-products of this generalized activation process is protein adsorption to the membrane surface, another phenomenon which can have a significant impact on solute removal. In fact, an array of studies showed that with increasing size of middle-sized proteins and other compounds, relatively more clearance is achieved by membrane adsorption compared with loss into the dialysate. A high adsorptive capacity, one of the main features of polymethylmethacrylate (PMMA) membranes, is very helpful and may both increase the total amount of solutes removed and remove different kinds of solutes. In this setting, a few studies have shown a variety of efficient clinical implications for adsorption hemodialysis, such as uremic pruritus, anemia, carpal tunnel syndrome and renal amyloidosis, immune dysfunction and improved response to vaccination. In addition, nutrition and survival were also improved using PMMA membranes.

Acute Kidney Injury in the Elderly: Epidemiology, Risk Factors and Outcomes

Structural and functional changes affecting the aging kidney predispose to an increased risk of Acute Kidney Injury (AKI) in the elderly, a condition which is becoming more and more relevant with the increase in life expectancy. The epidemiology of AKI in the elderly is not well assessed, because of the variable etiology, the coexistence of several comorbidities, the various clinical settings and geographical areas where the condition is managed, and the lack of uniform definition criteria. Currently, the use of the term AKI is suggested to mean any abrupt reduction in kidney function, while acute renal failure is just meant to indicate severe dysfunctions requiring renal replacement treatment. Comorbidities, common among elderly patients and several age-related conditions are risk factors for AKI. Moreover, also in elderly patients the presence of baseline proteinuria and reduced glomerular filtration rate are both powerful independent risk factors for AKI. Elderly patients with Chronic Kidney Disease (CKD) who develop AKI are at high risk for mortality, non-recovery from AKI and progression to more advanced stages of CKD and even to endstage renal disease. As a consequence, the challenge for nephrologists is to find strategies to either prevent AKI or prevent the transition from AKI to CKD.

Usefulness of US imaging in overhydrated nephropathic patients

Achievement of a normal hydration status is one of the major targets of hemodialysis. It is based on the estimation of “dry weight”, the term used to define normal body fluid content. The concept of dry weight in hemodialysis patients is clinically undisputed, but it is not always easy to achieve in this population. Assessment of hydration status by clinical evaluation is imprecise and often unreliable. Measurement of the inferior vena cava (IVC) diameter has been shown to reflect individual fluid status. The relationship between variation in IVC diameter before and after hemodialysis session and weight loss has been investigated. Ultrasound (US) measurement of the IVC diameter is considered a valid measure of the hydration status and is routinely used in hemodialysis patients. Moreover, a relationship between IVC diameter, respiratory activity and hydration status, evaluated by considering both plasma volume and central venous pressure, has been demonstrated. In conclusion, assessment of hydration status based on blood pressure and central venous pressure can be considered reliable only in patients without signs of heart failure.SommarioIl raggiungimento di un normale stato di idratazione è di fondamentale importanza nei pazienti in emodialisi e si basa sulla stima del “peso secco”, che indica il normale contenuto corporeo di fluidi. Il “peso secco” non è sempre facile da ottenere in questa popolazione di pazienti. La valutazione clinica dello stato di idratazione è spesso imprecisa e talvolta inaffidabile. Il diametro della vena cava inferiore (VCI) sembra riflettere lo stato di idratazione del paziente. La relazione tra la variazione del diametro della VCI prima e dopo la seduta emodialitica e la perdita di peso è già stata studiata. La misurazione ecografica del diametro della VCI è un valido strumento per la stima dello stato di idratazione ed è utilizzato quotidianamente nei pazienti in emodialisi. Inoltre, è stata dimostrata una relazione tra il diametro della VCI, l’attività respiratoria e lo stato di idratazione, considerando sia il volume plasmatico che la pressione venosa centrale. Concludendo, la valutazione dello stato di idratazione, basata sulla pressione arteriosa e sulla pressione venosa centrale, può essere considerata affidabile solo nei paziente senza scompenso cardiaco.

Increasing Incidence of Primary Aldosteronism in Patients Investigated for Resistant Hypertension: An Observational Study from a NephrologyUnit

Introduction: Primary Aldosteronism (PA) is a secondary form of hypertension characterized by an autonomous and inappropriately high production of aldosterone. Its prevalence is 5-12% and the two main subtypes are the Bilateral Adrenal Hyperplasia (BAH) and the Aldosterone-Producing Adenoma (APA). In this study, we report the results of an evalutation of some patients diagnosed with PA in a Nephrology Unit between 1987-2011. Patients and methods: As much as 54 patients were screened for PA by measuring Plasma Aldosterone Concentration (PAC) and Plasma Renin Activity (PRA), and by calculating the aldosterone/renin ratio (ARR). Confirmation tests were performed on 47 patients with PAC ≥ 15 ng/dL and ARR ≥ 40. Subtype diagnosing was possible through adrenal CT scan, scintigraphy and adrenal venous sampling. Results: As much as 31 patients were diagnosed with PA. In 17 of them, the concordance of CT, scintigraphy and AVS findings made it possible to determine the subtype diagnosis: BAH in 10 and APA in 7 patients. Conclusions: Our results confirm the increasing frequency of diagnosis of PA among patients investigated for resistant hypertension. Early detection of PA in nephrological settings is important because of the relationship between aldosterone and kidney function.

[PP.21.21] BLOOD PRESSURE CONTROL IN HYPERTENSIVE OUTPATIENTS: RESULTS OF A 18-MONTH RETROSPECTIVE STUDY

Objective: is one of the most important risk factors for coronary heart disease, congestive heart failure, stroke, renal insufficiency and cardiovascular mortality. Antihypertensive treatment lowers blood pressure (BP) levels and reduces cardiovascular risk. In developed countries, BP control is improving and approaching 70% of treated patients. Herewith we report the results of a retrospective study carried out on hypertensive outpatients. Design and method: A total of 1,245 consecutive outpatients were evaluated from January 1st, 2015 to June 30th, 2016. In agreement with the current guidelines, hypertension was defined as sitting BP levels equal or higher than 140/90 mmHg or use of antihypertensive drugs. Having excluded 126 patients who did not meet these criteria, 1,119 patients (631 females, 488 males; mean age: 59.87 ± 12.26 years) remained and constituted the eligible sample for the present analysis. In them, the following parameters were assessed: age, sex, body-mass index (BMI), waist circumference (WC), smoking status, BP levels both in the sitting and in the standing position, estimated glomerular filtration rate (eGFR), serum glucose, glycosylated haemoglobin, lipid profile, antihypertensive drugs prescribed. Patients whose sitting BP levels were equal or lower than 140/90 mmHg were considered as having achieved BP control. Results: Overall, 75.96% of hypertensive patients achieved BP control. Compared to patients whose BP was not controlled, those achieving the BP target were significantly younger (mean age: 59.44 ± 12.07 vs. 61.21 ± 12.78 years, p = 0.039) and showed a lower BMI (29.19 ± 6.07 vs. 30.80 ± 6.07 kg/m2, p < 0.001), a lower WC (99.58 ± 11.82 vs. 102.15 ± 16.66 cm, p = 0.033) and a higher eGFR (86.22 ± 19.60 vs. 83.37 ± 20.82 mL/min, p = 0.043). Moreover, they were prescribed fewer antihypertensive drugs (1.79 ± 0.87 vs. 2.13 ± 0.99, p < 0.0001). With regard to the main comorbidities, diabetes mellitus (DM) and chronic kidney disease (CKD) were less frequent among patients achieving than in those not achieving BP control (DM, 8.0% vs. 14.1%, p < 0.05; CKD, 5.3% vs. 7.8%, p = 0.18). Conclusions: Nearly 76% of our outpatients achieved BP control. This figure is higher than the objective of 70% of treated and controlled hypertensive patients set for 2015 in Europe.

[PP.06.10] BLOOD PRESSURE CONTROL IN HYPERTENSIVE PATIENTS ATTENDING AN AMBULATORY NEPHROLOGY UNIT

Objective: Hypertension is a major cardiovascular risk factor. Antihypertensive treatment can lower blood pressure (BP) levels and reduce the risk. In developed countries, the rate of BP control is improving and approaching the 70% of treated patients. Herewith we report the results of an observational study of hypertensive outpatients carried out by an ambulatory nephrology unit dedicated to hypertension. Design and method: A total of 740 consecutive patients attended our ambulatory nephrology unit dedicated to hypertension from 1 January to 31 December 2015. In agreement with the current guidelines, hypertension was defined as sitting BP levels equal or higher than 140/90 mmHg and/or use of antihypertensive drugs. Having excluded 87 patients who did not meet these criteria, 653 patients (mean age: 59.6 years; 367 females, 266 males) remained and constituted the eligible sample for the present analysis. In them, the following parameters were assessed: age, sex, body-mass index (BMI), waist circumference, BP levels both in the sitting and in the standing position, renal function, serum glucose, glycosylated haemoglobin, lipid profile, antihypertensive drugs prescribed. In addition, other investigations (electrocardiogram, echocardiogram and funduscopy) were performed in order to search for asymptomatic organ damage (OD). Patients that had sitting BP levels equal or lower than 140/90 mmHg were considered as having achieved BP control. Results: On the whole, 78.5% of our patients achieved BP control. Compared to patients whose BP was not controlled, those achieving the BP target were slightly younger (mean age: 59.33 vs 60.60 years) and showed a lower BMI (29.11 vs 31.08 kg/m2) and a higher glomerular filtration rate (86.23 vs 82.97 mL/min). Moreover, they were prescribed a lesser number of antihypertensive drugs (1.81 vs 2.11). No significant difference there was in comorbidities and OD, such diabetes mellitus, chronic kidney disease and left ventricular hypertrophy. Conclusions: Under proper treatment, more than 78% of our hypertensive patients achieved BP control. This figure is higher than the objective of 70% of treated and controlled hypertensive patients set for 2015 in Europe.

823 HYPERTENSION IN THE ELDERLY WITH SUNDRY COMORBIDITIES: A 30-MONTH OBSERVATIONAL STUDY BY A NEPHROLOGY AMBULATORY UNIT DEDICATED TO HYPERTENSION

Objective: The prevalence of hypertension increases with age and in the elderly is 60-80%. Herewith we report an observational study on an outpatient population carried out by a specialized unit of nephrology. Design and methods: The following parameters were recorded from a cohort of 405 consecutive hypertensive patients observed over a period of 30 months (October 2009 - March 2012): age, sex, number of visits, body-mass index, waist circumference, blood pressure (BP), glomerular filtration rate (GFR), lipid profile, comorbidities, antihypertensive drugs prescribed. Concordant with the current guidelines, patients that had a sitting BP ⩽140/90 mmHg and patients with chronic kidney disease (CKD) or diabetes mellitus (DM) that had a sitting BP ⩽130/80 mmHg, were considered as having achieved BP control. Results: 175 hypertensive patients (72 males/103 females, 43.2% of the cohort) were older than 65 years. The following comorbidities, graded as 1+ to 4+ were detected: ischemic/hypertrophic cardiopathy, dyslipidemia, CKD, DM, peripheral arteriopathy, metabolic syndrome, overweight, obesity. BP control was achieved by 63,6% of patients, but only by 43.4% of those with DM and 37.2% of those with CKD. Compared to patients whose BP was not controlled, those achieving BP target were slightly younger (mean age 73.1 vs. 75.4 years) and showed a higher GFR (68.4 vs. 61.5 mL/min); moreover, they were more strictly followed up (2.17 vs. 1.67 visit per patient). There was no significant difference in the number of antihypertensive drugs prescribed. Conclusions: Under proper monitoring and treatment, nearly 2/3 of our hypertensive elderly outpatients achieved BP control.

PREVALENCE AND CONTROL OF HYPERTENSION IN CHRONIC HEMODIALYSIS PATIENTS: RESULTS OF A SINGLE-CENTRE CLINICAL AUDIT: PP.8.215

Hypertension (HTN) is very common in chronic hemodialysis patients, with a prevalence of 72%, a very poor control and an annual mortality of 23%. We report the results of a clinical audit on prevalence and control of HTN in our hemodialysis patients. The following parameters in a cohort of 89 patients were assessed in one-month observational study, conducted in October 2010: blood pressure (BP) before the beginning (preHD BP) and after the end of the treatment (postHD BP), age, sex, comorbidity, serum hemoglobin (Hb) levels, plasma and dialysate sodium levels, interdialytic weight gain (IWG), serum parathyroid hormone (PTH) levels, prescription of erythropoiesis stimulating agents (ESA) and of antihypertensive drugs. In agreeement to the current guidelines, patients with preHD BP ≤140/90 mmHg and postHD BP ≤130/80 mmHg were considered normortensive. Forty-nine patients (55%) were found to be hypertensive. The following comorbidities, graded as 1+ to 3+, were detected: ischemic/hypertrophic cardiopathy, dyslipidemia, peripheral arteriopathy, diabetes mellitus. Only 14.3% of patients achieved both preHD and postHD BP targets. Compared to patients whose BP was not controlled, those achieving BP targets were younger, had lower dialysate sodium levels and showed a greater IWG. No significant difference there was in serum Hb levels, plasma sodium levels, serum PTH levels, prescription of antihypertensive drugs and ESA. Our data confirm the high prevalence of HTN and the unsatisfactory BP control in hemodialysis patients. A low-salt diet, probing for dry-weight and the antihypertensive medication may help to achieve the BP control.