PCSK9 inhibitors: effectiveness of treatment and changes in background lipid-lowering therapy in a real world Italian population. The AT-TARGET-IT study

Introduction

PCSK9 inhibitors (PCSK9i) significantly decrease LDL cholesterol (LDL-C), either as monotherapy or in addition to the maximally tolerated dose of statin and/or ezetimibe. Yet, few data are available on efficacy and background lipid-lowering therapy (LLT) adjustment in patients treated with PCSK9i in real-world observations.

Purpose

AT-TARGET-IT is an Italian multicenter registry involving 9 Italian centers, designed to assess efficacy, adherence, and persistence of PCSK9i, as well as prescribing doctors' behavior in patients with atherosclerotic cardiovascular disease (ASCVD) or familial hypercholesterolemia (FH). The aim of the present analysis was to assess efficacy and changes in background LLT therapy in patients on PCSK9i in a real-world single country observation.

Methods

From June through November 2021, we enrolled patients with PCSK9i first prescription from 6 months before inclusion through starting of PCSK9i use. Clinical and demographic characteristics, concomitant therapies, blood chemistry, were recorded at the time of first prescription and at the latest observation preceding inclusion in the study. Background therapy was assessed at baseline and during follow-up, evaluating treatment withdrawal, reduction of doses, or changes from statin-ezetimibe association to single drug therapy.

Results

We enrolled 798 patients (27% with FH) receiving either alirocumab or evolocumab and followed for a median time of 19.3 months. At the time of PCSK9i first prescription LDL-C was 147.6 mg/dl and reached 51.5 mg/dl at the time of latest observation (64% reduction), and 129 patients (16%) were not receiving any LLT, 669 patients received background LLT, of them 246 (31%) were taking ezetimibe alone and 423 (53%) were taking statins with or without ezetimibe. At the end of the observation period, 785 patients (98%) were still receiving PCSK9i and 550 (69%) did not change background LLT. Of 248 patients changing background LLT, 116 (47%) withdrew therapy, 132 (53%) changed dose or type of LLT. After stratification by achievement of LDL-C target according CV risk class, 483 patients achieved the target (60%). Target was achieved at the end of the observation period in 63% of patients taking triple therapy, 65% patients receiving PCSK9i plus statins, 62% of patients receiving PCSK9i plus ezetimibe and 55% receiving PCSK9i alone (Figure 1). No significant differences in terms of percentage of patients changing background LLT during PCSK9i treatment were found between patients at target for LDL-C and those not at target.

Conclusion

AT-TARGET-IT study shows that PCSK9i therapy is effective in reaching LDL-C target in the majority of patients, yet a sizable number of them (40%) remains undertreated. LLT background therapy is either reduced or withdrawn in 31% of patients, being responsible for not reaching target. Reasons for inappropriate LLT changes in patients receiving PCSK9i should be identified and removed to optimize lipid control.

Funding Acknowledgement

Type of funding sources: None.

P405 ALDOSTERONE AND INTERLEUKIN–6: IS IT A NEW ASSOCIATION IN COVID–19?

Introduction

Several pieces of evidence have confirmed the interleukin–6 (IL–6) activity in the cytokine storm induced by COVID–19 pneumonia. Furthermore, the correlation between serum IL–6 levels and plasma aldosterone has been widely ascertained in patients with primary aldosteronism (PA). Hence, the highest levels of aldosterone may increase IL–6 in COVID–19 patients with PA.

Case Presentation

We reported the clinical case of a 47–year–old woman with severe COVID–19 pneumonia complicated by Guillain–Barré Syndrome (GBS). At admission, the patient presented severe interstitial pneumonia complicated by hypoxemia and respiratory failure, which required mechanical ventilation. Blood tests revealed very high levels of IL–6 (serum IL–6: 402 pg / mL) and its soluble receptor (soluble IL–6 receptor> 1900 pg / mL). In addition, the patient was diagnosed with PA after accidental evidence of right adrenal adenoma, resistant arterial hypertension, severe hypokalemia, and elevated serum levels of aldosterone with a high aldosterone/renin ratio. Therefore, infusion therapy with spironolactone was administered with a rapid improvement of the clinical condition. Later she was diagnosed with acute motor and sensory axonal neuropathy and with the indication of motor rehabilitation.

Conclusions

The higher aldosterone levels in PA could be associated with more severe forms of COVID–19, stimulating the production of IL–6 and its pro–inflammatory effects. Hence, the association between IL–6 and aldosterone may have a synergistic effect in the development of more severe complications such as GBS. The highest aldosterone levels and activity could be also identified in patients with COVID–19 pneumonia and secondary aldosteronism. More studies are needed to evaluate spironolactone therapy in COVID–19.

C70 HIGH–SENSITIVE CARDIAC TROPONINS ELEVATION: NOT ONLY A CARDIAC DISEASE. ROLE OF HETEROPHILE ANTIBODIES

Introduction

High–sensitive troponins I and T (hs–TnI and hs–TnT) represents the main biomarkers of Acute Coronary Syndrome diagnosis when combined with ST–T segment changes at ECG and typical clinical presentation. Elevated serum values of cardiac troponins can also be found in several cardiac diseases such as myopericarditis, pulmonary embolism and heart failure, conversely also in non–cardiac diseases. Among them, the analytical interference due to heterophile antibodies (HA) represent a rare non–cardiac cause of troponins elevation.

Case Presentation

We report a case of a 20–year–old man admitted to our Cardiology department for palpitations and dyspnea, associated with persistently high levels of TnI–HS. He presented no cardiovascular risk factors. During hospitalization the patient was asymptomatic with persistent TnI–HS elevation (1051.4 pg/mL; r.n. 0–34 pg/mL) associated with no CK–MB values changes or typical rise and fall of myocardial damage biomarkers at lab test. Cardiac magnetic resonance excluded myopericarditis or cardiomyopathies in this patient, therefore HA capture test was performed using HA blocking tube reagents. The analytical interference due to HA has been identified with a post–test hs–TnI value of 16.9 pg/mL.

Conclusions

The analytical interference due to HA is a rare and underestimated cause of false–positive results in cardiac troponin essay, however it should be excluded mostly in young patients without cardiovascular risk factors. Persistent hs–TnI and hs–TnT elevation combined with the absence of typical rise and fall of cardiac troponins and with no CK–MB alterations should help the clinician to recognize this analytical phenomenon at the emergency department.

Comparison of neuropsychological profiles in children and adolescent with anorexia nervosa and avoidant/restrictive food intake disorder (ARFID)

Introduction

Anorexia Nervosa (AN) is an eating disorder characterized by low body weight, fear of gaining weight and distorted perception of body. Patients have rigidity, repetition of thoughts, alterations in decision-making skills and poor ability to provide new solutions. Avoidant/Restrictive Food Intake Disorder (ARFID) is a new eating disorder characterized by the absence of distress about body shape or fear of weight gain. Studies on neurocognitive aspects are few and no effective treatments are known.

Objectives

The aim of our study was to further investigate the executive functions’ domains in AN and ARFID children and adolescents, to provide possible distinct neurocognitive traits in these patients.

Methods

AN or ARFID patients (15 + 15; range 6-18 years), were assessed by neuropsychological tools, such as: Wechsler Intelligence Scale to measure I.Q. profile, NEPSY-II to explore attention and executive functions, Tower of London test to detect planning and problem solving abilities, the Bells Test to evaluate visual selective and focused attention, the Wisconsing Card Sorting Test (WCST) for assessment of flexibility and directing behaviors by achieving a goal and the Rey-Osterrieth complex figure test (ROCF) to assess visual-spatial abilities.

Results

Patients with ARFID presented impairments in several executive functions domains, with difficulties in the impulse inhibition, in the sustained attention and in visual-spatial skills. Finally, in their anamnesis a higher comorbidity with neurodevelopmental disorders such as specific learning disorder has been underlined.

Conclusions

The identification of specific deficit in neuropsychological profile of ARFID patients could be a rehabilitation target, together with standardized treatment.

Mentalization in developmental age’s eating disorders: Comparison between anorexia nervosa and avoidant/restrictive food intake disorder (ARFID)

Introduction

Anorexia Nervosa (AN) and Avoidant/Restrictive Food Intake Disorder (ARFID) are two primary restrictive eating disorders described in DSM-5, characterized both of them by insufficient food intake. This behavior In ARFID is not driven by weight and shape concerns that tipify AN. While there are several studies that highlight the presence of mentalizing difficulties in AN, there are still no data about mentalizing profile in ARFID.

Objectives

The aim of this study was to better characterize the mentalizing profile of AN and ARFID children and adolescent.

Methods

Two groups of AN or ARFID outpatients (15+15), aged 6 to 18 years, were assessed by Alexythimia Questionnaire for Children (AQC) and Toronto Alexythimia Scale-20 (TAS-20) to evaluate alexythimia; by Interpersonal Reactivity Index (IRI) and Basic Empathy Scale (BES) to assess empathy; by NEPSY-II social perception subtests to evaluate Theory of Mind and Emotion recognition. Exclusion criteria were the presence of intellectual disability, pervasive developmental disorders and binge eating behavior (eating disorder other than AN or ARFID).

Results

Preliminary results showed different mentalizing profiles between ARFID and AN patients, with differences in the score for affective empathy, lower in ARFID than in AN patients while the score for alexythimia traits resulted higher in AN population.

Conclusions

By our results, mentalization impairment appeared trans-diagnostic across several eating disorders. This first result should be further improved to better analyze this construct in order to develop effective clinical intervention to improve the subject’s affective regulation.

Disclosure

No significant relationships.

Plasma Volume Changes Induced by Sequential Ultrafiltration-Hemodialysis and Sequential Hemodialysis-Ultrafiltration

Isolated ultrafiltration (UF) has been shown to preserve plasma volume (PV) by means of a high plasma refilling rate, mediated by a rapid rise in oncotic pressure. This mechanism contributes to the good tolerance of sequential ultrafiltration-hemodialysis (SUH). This study compared PV changes induced by SUH and sequential hemodialysis-ultrafiltration (SHU). Seven dialysis patients underwent two sets of SUH and SHU, in which 2 h of UF (≃ 3L) respectively preceded or followed 2 h of no-weight-change hemodialysis (ISO HD). VEM (volume of extravascular mobilization), VEM/VUF (percent of plasma refilling rate) and ΔPV were calculated by mathematical formulas. Results showed: 1) a high VEM/VUF during the UF period, either before or after ISO HD: 80 and 77% respectively; 2) a significant increase in PV during ISO HD after UF, compared to ISO HD before UF: + 229 ml and + 43 ml, P < 0.05; 3) VEM/VUF significantly higher during SUH than during SHU: 87 and 80%, P < 0.01. In conclusion, the decrease in PV was lower in SUH than in SHU (11 vs. 19%, P < 0.001) because the plasma refilling persisted through the ISO HD period.

An innovative iterative thresholding algorithm for tumour segmentation and volumetric quantification on SPECT images: Monte Carlo-based methodology and validation

PURPOSE

Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging play an important role in the segmentation of functioning parts of organs or tumours, but an accurate and reproducible delineation is still a challenging task. In this work, an innovative iterative thresholding method for tumour segmentation has been proposed and implemented for a SPECT system. This method, which is based on experimental threshold-volume calibrations, implements also the recovery coefficients (RC) of the imaging system, so it has been called recovering iterative thresholding method (RIThM). The possibility to employ Monte Carlo (MC) simulations for system calibration was also investigated.

METHODS

The RIThM is an iterative algorithm coded using MATLAB: after an initial rough estimate of the volume of interest, the following calculations are repeated: (i) the corresponding source-to-background ratio (SBR) is measured and corrected by means of the RC curve; (ii) the threshold corresponding to the amended SBR value and the volume estimate is then found using threshold-volume data; (iii) new volume estimate is obtained by image thresholding. The process goes on until convergence. The RIThM was implemented for an Infinia Hawkeye 4 (GE Healthcare) SPECT/CT system, using a Jaszczak phantom and several test objects. Two MC codes were tested to simulate the calibration images: SIMIND and SimSet. For validation, test images consisting of hot spheres and some anatomical structures of the Zubal head phantom were simulated with SIMIND code. Additional test objects (flasks and vials) were also imaged experimentally. Finally, the RIThM was applied to evaluate three cases of brain metastases and two cases of high grade gliomas.

RESULTS

Comparing experimental thresholds and those obtained by MC simulations, a maximum difference of about 4% was found, within the errors (+/- 2% and +/- 5%, for volumes > or = 5 ml or < 5 ml, respectively). Also for the RC data, the comparison showed differences (up to 8%) within the assigned error (+/- 6%). ANOVA test demonstrated that the calibration results (in terms of thresholds or RCs at various volumes) obtained by MC simulations were indistinguishable from those obtained experimentally. The accuracy in volume determination for the simulated hot spheres was between -9% and 15% in the range 4-270 ml, whereas for volumes less than 4 ml (in the range 1-3 ml) the difference increased abruptly reaching values greater than 100%. For the Zubal head phantom, errors ranged between 9% and 18%. For the experimental test images, the accuracy level was within +/- 10%, for volumes in the range 20-110 ml. The preliminary test of application on patients evidenced the suitability of the method in a clinical setting.

CONCLUSIONS

The MC-guided delineation of tumor volume may reduce the acquisition time required for the experimental calibration. Analysis of images of several simulated and experimental test objects, Zubal head phantom and clinical cases demonstrated the robustness, suitability, accuracy, and speed of the proposed method. Nevertheless, studies concerning tumors of irregular shape and/or nonuniform distribution of the background activity are still in progress.

[Is intermittent peritoneal dialysis with icodextrin a valid option in the long-term treatment of refractory congestive heart failure?]

Refractory congestive heart failure (CHF) is affected by a very high morbidity and mortality. We report our experience in the long-term treatment of refractory CHF (NYHA class IV) by means of intermittent peritoneal dialysis (PD) with icodextrin (ICO) solutions in 4 male patients with a mean age of 71.5 + or - 5.6 (standard deviation) years and with a variable degree of chronic renal failure: 1 nocturnal exchange with ICO in 3 patients and 2 exchanges (ICO + isotonic dextrose solution) in 1 patient. The mean PD follow-up period was 24.3 + 15.6 months. After stabilization on PD, all patients had a statistically significant increase in daily diuresis (from 587.5 + or - 165.2 to 1700.0 + or - 141.4 mL, p < 0.003), a statistically significant decrease in body weight (11.3 + or - 3.4 kg, p < 0.007), and a statistically significant improvement in NYHA class (from 4.0 + or - 0.0 to 2.5 + or - 2.6, p < 0.01). Three patients had no hospitalizations due to cardiac illness in the PD follow-up period. No episodes of peritonitis occurred. Three patients died after 11, 13 and 43 months of PD treatment: 2 because of sudden death and 1 because of neoplastic cachexia. No death could be attributed to any complication related to PD treatment. Intermittent PD with ICO solutions can be proposed as a long-term treatment modality for refractory CHF. It allows an improvement in quality - if not quantity - of life. Randomized controlled trials are needed to confirm the evidence derived from case reports.

[Against CRRT: hybrid treatments are gaining ground]

Renal replacement therapies (RRT) are a key component of the therapeutic approach to acute kidney injury in the ICU. They are usually performed as intermittent hemodialysis (IHD) or continuous RRT (CRRT). Each of these therapies has its advantages and disadvantages. The so-called ''hybrid'' therapies have been gaining popularity in recent years. This kind of treatment, known as ''sustained low-efficiency dialysis'' or SLED, has most of the advantages of IHD and CRRT, without sharing their disadvantages and limitations.

[Management of central venous catheter: prevention of thrombosis and bacteremia]

The use of central venous catheters (CVC) as vascular access has increased considerably in recent years, especially because of the progressive aging and increasingly severe comorbidities of the dialysis population. The main factors limiting the long-term use of a hemodialysis catheter are thrombosis and infection. Thrombosis can be treated with thrombolytic agents and prevented effectively by means of anticoagulants. CVC infections represent the main cause of morbidity and mortality in these patients. This is the reason why systemic antibiotic therapy must be started very rapidly, based even on a simple clinical suspicion and in the absence of any confirmation of bacteremia. If antibiotic therapy fails, the CVC must be removed. The recent introduction of antibiotic lock therapy appears to be an effective means to prevent bacteremia. However, it must not be forgotten that the best way of preventing CVC-related bacteremia is by reinforcing all control procedures, with the active involvement of patients and staff.

[A particular case of hemodialysis with a single-pass batch system]

The GENIUS 90 Therapy System (GENIUS) (Fresenius Medical Care, Bad Homburg, Germany) is a mobile dialysis machine with a 90-liter, thermally insulated glass tank. Fresh dialysis fluid is prepared by mixing sterile ingredients (electrolytes and glucose) with preheated ultrapure water. Here we report the case of a 60-year-old hemodialysis patient who was hospitalized in our unit in November 2005 because of an ischemic stroke affecting the left temporal-parietal-occipital region of the brain. The persisting clinical features included right hemiplegia, motor aphasia, epilepsy and stage I coma. The patient started thrice-weekly GENIUS hemodialysis treatment (about 270 sessions to date) in his hospital room with no continuous nursing assistance. In conclusion, GENIUS is able to offer user-friendly, high-quality and adequate dialysis treatment.

[We should strive for optimal hemodialysis: treatment time is the key factor]

Nephrologists should strive for optimal hemodialysis. Convection, at least as it is conceived today, is far from optimal and the same is true of standard bicarbonate dialysis. A very recent paper by Eloot et al (Kidney Int 2008: 73: 765-70) clearly illustrates the way towards optimal hemodialysis by showing in a simple and intelligent manner the independent effect of the factor time on the adequacy of hemodialysis. Furthermore, it simplifies the conceptual scenario of dialysis adequacy and points to diffusion mechanisms as the key modality to remove uremic retention solutes. Thus, it is clear that we should strive for longer and/or more frequent dialysis sessions. Long nocturnal home hemodialysis every other night appears to be more appealing to patients than 5 to 7 dialysis sessions a week. The Italian Society of Nephrology should promote trials and the National Health Service should provide funds for these promising hemodialysis schedules.

[Occlusion of hemodialysis vascular accesses by means of endovascular procedures]

Correct management of complications is crucial to the long-term survival of vascular access for hemodialysis. The present work report our experience with endovascular procedures in the occlusion of complicated arteriovenous fistulas (AVFs) and grafts in patients with a high surgical risk. Among the endovascular procedures carried out between January 2003 and December 2006, all those regarding the occlusion of vascular accesses by means of embolization or exclusion were selected retrospectively. Embolization means the release into the circulation of material to occlude the vascular lumen; exclusion is obtained by means of covered stents, which, when placed in a blood vessel, exclude its ramifications. Seven procedures of endovascular occlusion of vascular accesses were performed in the study period. All patients were considered as having a high surgical risk or presented technical difficulties related to surgical intervention. Venous hypertension was the indication in 5 cases and grade III or IV steal syndrome was the indication in 2 cases. Six AVFs were treated: 2 distal radiocephalic, 1 brachiocephalic, 2 brachiobasilic, and 1 Gracz AVF; an antebrachial graft was also treated. Occlusion was obtained in 4 cases by means of embolization and in 3 cases by means of exclusion. The technical success was 100% with virtually no complications. Endovascular occlusion of vascular access represents an effective and safe procedure in selected cases, also when compared with the surgical approach. Furthermore, the different technical solutions available allow to adequately solve the problems linked to anatomical variability and to the sites of the vascular accesses.

[Management of arteriovenous fistula: anastomosis and more....]

The huge amount of human and economic resources necessary for a vascular access creation in haemodialysis strongly requires a very careful patient assessment and the choice of the most appropriate procedures, both aiming at improving quality of care and optimizing available resources. This review focuses on arteriovenous fistula (AVF) monitoring and surveillance, not only by following current guidelines, but also by exploring the most interesting data of the literature; attention is particularly focused on the haemodynamic aspects of AVF, which play a relevant role not only in himself. the natural history of vascular access, but also of the patient.

[Cardiac arrhythmias in patients with renal insufficiency treated with periodic hemodialysis]

Despite substantial progress in dialysis technology, cardiovascular disease remain the sole major cause of death in chronic dialysis patients. Nearly half of deaths on chronic maintenance hemodialysis are secondary to myocardial infarction, cardiac arrest, malignant arrhythmias and other cardiac causes. In fact, diabetes, anemia, hyperparathyroidism, and hypertension wide prevalence among chronic dialysis patients foster structural heart diseases. Moreover fluid overload and metabolic abnormalities such as metabolic acidosis, dyskalemia, dysmagnesemia lead to an increased risk of clinically significant ventricular arrhythmias and sudden cardiac death. During dialysis patients show a non-homogeneous repolarization through an increase in Q-T duration and Q-T dispersion. The dialysis-related sudden variation in extra-cellular potassium, calcium and pH levels may be contributing factors to the genesis of an electrical disequilibrium in myocardial cells. One of the potential therapeutic options is, in fact, adjusting the dialysis bath. The K profiling with non-constant K concentration in the dialysate, but with high concentration in the first hour of dialysis and progressive reduction until the end of the session, seems very promising in reducing the arrhythmic risk in cardiomyopathy patients.

[Intradialytic hypotension: The role of volemia]

Intradialytic hypotension (IDH) is one of the most serious complications in renal replacement therapy (RRT). The main cause of IDH is hypovolemia due to an imbalance between the amount of fluid removed and the refilling capacity of the intravascular compartment. IDH occurs when compensatory mechanisms for hypovolemia are overwhelmed by excessive fluid removal. As long as RRT is limited to only a few hours per week, IDH will continue to be a relevant problem. Research has focused mainly on enlarging the compensatory capacity for ultrafiltration-induced hypovolemia. This review critically discusses the technical approaches that have been recently introduced to the therapy with the promise of reducing hypovolemia-induced IDH.

Distinct forms of cholinergic modulation in parallel thalamic sensory pathways

Mammalian thalamus is a critical site where early perception of sensorimotor signals is dynamically regulated by acetylcholine in a behavioral state-dependent manner. In this study, we examined how synaptic transmission is modulated by acetylcholine in auditory thalamus where sensory relay neurons form parallel lemniscal and nonlemniscal pathways. The former mediates tonotopic relay of acoustic signals, whereas the latter is involved in detecting and transmitting auditory cues of behavioral relevance. We report here that activation of cholinergic muscarinic receptors had opposite membrane effects on these parallel synaptic pathways. In lemniscal neurons, muscarine induced a sustained membrane depolarization and tonic firing by closing a linear K(+) conductance. In contrast, in nonlemniscal neurons, muscarine evoked a membrane hyperpolarization by opening a voltage-independent K(+) conductance. Depending on the level of membrane hyperpolarization and the strength of local synaptic input, nonlemniscal neurons were either suppressed or selectively engaged in detecting and transmitting synchronized synaptic input by firing a high-frequency spike burst. Immunohistochemical and Western blotting experiments showed that nonlemniscal neurons predominantly expressed M2 muscarinic receptors, whereas lemniscal cells had a significantly higher level of M1 receptors. Our data indicate that cholinergic modulation in the thalamus is pathway-specific. Enhanced cholinergic tone during behavioral arousal or attention may render synaptic transmission in nonlemniscal thalamus highly sensitive to the context of local synaptic activities.

[An exceptionally severe hyperuricemia in acute renal failure caused by spontaneous tumor lysis syndrome (TLS)]

Acute tumor lysis syndrome (TLS) is a catastrophic complication of the treatment of certain neoplastic disorders. It most commonly occurs in association with hematologic malignancies and manifests a few hours to a few days after initiation of specific chemotherapy. Acute spontaneous TLS has been described in leukemia and lymphoma and in some patients with solid tumors prior to institution of therapy. The findings that may be seen in acute TLS include hyperphosphatemia, hypocalcemia, hyperuricemia, hyperkalemia, and acute oliguric or anuric renal failure due to uric acid precipitation within the tubules (acute uric acid nephropathy) and to calcium phosphate deposition in the renal parenchyma and vessels. We report here a case of acute spontaneous TLS (high grade B-cell lymphoma of the right colon) in which serum uric acid concentration attained exceptionally high levels (36.7 mg/dL). The patient underwent acute oliguric renal failure soon after right colectomy. He was treated by means of a large infusion of saline. The renal function recovered in such a rapid way that no dialysis treatment was required. In conclusion the present case report has two peculiarities: that of being one of the rare examples of spontaneous TLS, and that of showing an exceptionally severe hyperuricemia, probably the highest ever reported in the literature. The administration of a large volume of saline was able to ensure a complete recovery of renal function. Therefore, hydration with saline remains the keystone in the prevention and treatment of acute TLS.

[Sacrococcygeal pilonidal sinus disease. Treatment by "open" and "closed" technique: personal experience]

The Authors report their own experience concerning the treatment of the sacrococcigeal pilonidal sinus disease. Results obtained with the "open" and "closed" techniques were compared. Although results were similar in terms of complications and relapses, the closed technique is to be preferred, because it allows a more rapid return to working activities. In the light of the new trends of sanitary economy a modulated treatment of the disease is suggested.

Effect of acetate-free biofiltration on the anaemia of haemodialysis patients: a prospective cross-over study

BACKGROUND

The discussion about the pathogenesis of renal anaemia, whether it is primarily due to relative erythropoietin (Epo) deficiency or to uraemic inhibition of erythropoiesis, is still open. Although it has so far not been possible to identify or isolate a substance retained in uraemia with a suppressive action directed specifically against red-cell production, dialysis therapy can improve the effect of both residual endogenous Epo and exogenous rHuEpo. To what extent the mode and/or the dose of dialysis influence Epo efficacy is as yet poorly understood.

METHODS

This study was performed as a single-centre trial. The protocol included a run-in period of 4 months followed by a prospective cross-over study including 6 months each of acetate-free biofiltration (AFB) with a high-flux biocompatible membrane and standard bicarbonate dialysis (BD) with a low-flux cellulosic membrane in a random sequence. AFB is a haemodiafiltration technique based on a continuous post-dilution infusion of a sterile isotonic bicarbonate solution. At the start of the run-in period (and for the entire length of the study), rHuEpo administration was withdrawn; patients whose haemoglobin (Hb) levels dropped at a level <8.0 g/dl at one single monthly check, had to be withdrawn from the study. A blood sample was collected every month for the blood gas analysis and for the determination of blood urea nitrogen, serum creatinine, sodium, potassium, calcium, phosphorus, Hb, erythrocyte, reticulocyte, leukocyte and thrombocyte cell counts, mean globular volume and haematocrit. An equilibrated single pool Kt/V(urea)>1.2 was mandatory in both treatment modalities. Serum iron, total iron-binding capacity, and ferritin were checked every 3 months.

RESULTS

Twenty-three of 137 haemodialysis patients were considered eligible for the trial on the basis of the entry criteria. Of these, 15 volunteered and only 10 completed the study. No significant differences in the haematological indices, in the biochemical parameters assessing body iron stores, or in i.v. iron dosage was observed when comparing AFB with BD treatments. The equilibrated single pool Kt/V(urea) was always >1.2 and in no case was a significant difference observed when comparing AFB with BD treatments. Treatment time was significantly different between the two treatments (262+/-2 min in BD and 249+/-1 in AFB, P<0.0001). Neither pre- nor post-dialysis systolic and diastolic blood pressures, pre-dialysis serum bicarbonate and pH, pre-dialysis serum sodium, potassium, calcium, or phosphorus were significantly different when comparing the two treatment modalities. All 10 patients completed the 1-year follow-up without any major side-effects.

CONCLUSIONS

Our study did not show any improvement of anaemia when treating a highly selected patient group, in the absence of any Epo therapy, with AFB compared with standard BD. Even though these conclusions cannot be extended in toto to the entire dialysis population, in which there is a large proportion of Epo-treated patients with Hb levels around 11 g/dl, we may nevertheless conclude that when patients are well selected, adequately dialysed, and not iron- and/or vitamin-depleted, the effect of a haemodiafiltration technique with a high-flux biocompatible membrane is less than might be expected from the results of uncontrolled studies.

Anterior ischemic optic neuropathy and dialysis: role of hypotension and anemia

The pathogenesis of anterior ischemic optic neuropathy (AION) primarily involves interference with the posterior ciliary artery blood supply to the prelaminar optic nerve. Uremic patients often have coexisting pathology such as hypotension (decreased blood delivery), or hypertension, atherosclerosis (increased resistance to blood supply), and anemia (low blood oxygen carrying capacity), predisposing them to AION. We describe a 49-year-old patient on dialysis for many years. He had long-standing hypotension, worsened during each dialysis treatment. He awoke one morning at age 48 complaining of blurred vision in the left inferior field. Based on the clinical course, funduscopic and fluorangiographic examination and visual field defects, AION was diagnosed. Nine months after the loss of vision in the left eye, vision in the right eye became blurred and worsened over the next 24 hours. The diagnosis of AION in the right eye was made. At the last examination ten months later, the patient, still amaurotic, was given a very poor prognosis for further recovery of the visual defects. Surprisingly, very few cases of AION have been reported in chronic uremic patients on dialysis: to the best of our knowledge, only 12 including ours. Most of these cases share some features, including hypotension above all and anemia as common risk factors. Neither the type of dialysis treatment (hemo-, peritoneal dialysis) nor sex seem to have any influence on the occurrence of AION. Uremic children can be affected. What is striking in the three published pediatric cases is that they all had polycystic kidney disease. Treatment of AION in all 12 cases consisted of a combination of steroids, i.v. saline, blood transfusions and rhEpo. AION was more frequently bilateral and irreversible, ending in permanent amaurosis. In conclusion, this study aims to stress that most cases of AION occurring in chronic uremic patients on dialysis have some common features, including hypotension above all and anemia as common risk factors.