Publications by authors named "Elias Kyriakou"

25 Publications

  • Page 1 of 1

Seeking Strategies to Optimize Blood Utilization: The Preliminary Experience with Implementing a Patient Blood Management Program in a Greek Tertiary Hospital.

J Clin Med 2021 May 15;10(10). Epub 2021 May 15.

Laboratory of Haematology and Blood Bank Unit, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, 12462 Athens, Greece.

Objectives: Our aim was to assess blood utilization after implementation of a patient blood management (PBM) program in a Greek tertiary hospital.

Methods: An electronic transfusion request form and a prospective audit of transfusion practice were implemented. After the one-year implementation period, a retrospective review was performed to assess transfusion practice in medical patients.

Results: Pre-PBM, a total of 9478 RBC units were transfused (mean: 1.75 units per patient) compared with 9289 transfused units (mean: 1.57 units per patient) post-PBM. Regarding the post-PBM period, the mean hemoglobin (Hb) level of the 3099 medical patients without comorbidities transfused was 7.19 ± 0.79 gr/dL. Among them, 2065 (66.6%) had Hb levels >7.0 gr/dL, while 167 (5.3%) had Hb levels >8.0 gr/dL. In addition, 331 (25.3%) of the transfused patients with comorbidities had Hb >8.0 gr/dL. The Hb transfusion thresholds significantly differed across the clinics ( < 0.001), while 21.8% of all medical non-bleeding patients received more than one RBC unit transfusion.

Conclusion: A poor adherence with the restrictive transfusion threshold of 7.0 gr/dL was observed. The adoption of a less strict threshold might be a temporary step to allow physicians to become familiar with the program and be informed on the safety and advantages of the restrictive transfusion strategy.
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http://dx.doi.org/10.3390/jcm10102141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8157216PMC
May 2021

Platelets transfusion in Greece: Where, when, why? A national survey.

Asian J Transfus Sci 2020 Jul-Dec;14(2):158-166. Epub 2020 Dec 19.

Department of Blood Transfusion, General Hospital of Messologgi, Messologgi, Greece.

Background: Platelet transfusion is among the most useful therapeutic tools in modern clinical settings which mean that ensuring an adequate supply is of paramount importance.

Aim: The aim of our study was to record the use and wastage of platelet concentrates (PCs) in Greece, so as to come up with evidence-based interventions.

Methods: The study was conducted during May and June 2015. We evaluated the use of random-donor platelets (RDPs) and single-donor apheresis platelets (SDPs). We analyzed such parameters as hospital department and diagnosis, indication for transfusion, PCs' age at the time of transfusion, and wastage rate.

Results: We used data from 21 hospitals across the country. A total of 12,061 RDPs and 1189 SDPs were transfused, with an average of 4.84 (±2.72) and 1.12 (±2.73) units per episode, respectively. Most patients had been admitted to the internal medicine and hematology departments. The transfusions were mostly given prophylactically, usually in cases of acute leukemia, and mostly on the day before expiration. Wastage rate was 16.75% for RPDs and 2.70% for SDPs, primarily because of the expiration of the use-by date.

Conclusions: This is the first national survey regarding platelet transfusion in Greece. Since most patients were admitted in internal medicine and hematology departments, we recommend that the staff of the abovementioned departments should undergo training on contemporary transfusion guidelines. Platelet discard rate could further be lowered through the centralization of inventory management along with the extension of the lifetime of PCs by means of emerging technologies.
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http://dx.doi.org/10.4103/ajts.AJTS_72_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7983137PMC
December 2020

Current Practice in FFP Preparation and Use in Greece: A National Survey

Turk J Haematol 2021 02 22;38(1):22-32. Epub 2020 Nov 22.

General Hospital, Department of Blood Transfusion, Korinthos, Greece

Objective: Fresh frozen plasma (FFP) transfusion is widely used in modern clinical settings. Practices regarding its use vary due to lack of guidelines from randomized trials. The aim of this study was to assess both the current practices regarding FFP production, use, and wastage and the implementation of quality control (QC), female donor plasma production policies, and use of pharmaceutical hemostatic agents in Greece.

Materials And Methods: The study was conducted during February-April 2018. For the first part of the study, data including FFP transfusion indication, hospital department, diagnosis, FFP units/transfusion episode, ABO compatibility, blood donor’s sex, and reasons for discarding were collected. For the second part, questionnaire data were analyzed.

Results: According to data from 20 Greek hospitals, 12655 FFP units were transfused to 2700 patients during 5069 transfusion episodes in the studied period of time. Most patients were hospitalized in internal medicine, general surgery, and intensive care unit departments. Each patient received on average 4.69 units (2.5 units/episode). Transfusion requests were in accordance with international guidelines in 63.44% of cases and 99.04% of the units were given to ABO-identical patients. Main reasons for discarding included failure to meet quality requirements (30.06%), female donors (22.17%), and other causes (27.26%). Among 96.9% of all transfusion services across the country, 28.26% perform QC according to the directions of the European Directorate for the Quality of Medicines & Health Care and 68.83% discard plasma from female donors. Pharmaceutic hemostatic agents are used in 37.23% of the hospitals.

Conclusion: This is the first national survey regarding FFP production and transfusion in Greece. Staff of internal medicine, general surgery, and ICU departments, where most FFP-transfused patients are hospitalized, should be regularly involved in training on contemporary transfusion guidelines. Upcoming centralization of FFP production and inventory management could help in homogenizing practices regarding FFP use and improve product quality. Strengthening the use of pharmaceutic hemostatic agents could improve patients’ management.
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http://dx.doi.org/10.4274/tjh.galenos.2020.2020.0241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7927442PMC
February 2021

The haemostatic profile in critically ill COVID-19 patients receiving therapeutic anticoagulant therapy: An observational study.

Medicine (Baltimore) 2020 Nov;99(47):e23365

Second Department of Critical Care, "Attikon" University Hospital, National and Kapodistrian University of Athens, Medical School.

Hypercoagulability and thrombosis remain a challenge in severe coronavirus disease 2019 (COVID-19) infections. Our aim is to investigate the hemostatic profile of critically ill COVID-19 patients on therapeutic anticoagulant treatment.Forty one patients were enrolled into the study. We recruited 11 consecutive, COVID-19, patients who received therapeutic anticoagulant treatment on intensive care unit (ICU) admission. Disease severity indexes, biochemical, hematological and haemostatic parameters, endogenous thrombin potential (ETP), plasminogen activator inhibitor-1 (PAI-1) activity and extrinsically activated rotational thromboelastometry assay (EXTEM) were recorded on days 1, 3, 7. We also enrolled 9 ICU non-COVID-19, 21 non-ICU COVID-19 patients and 20 healthy blood donors as control populations.Critically ill COVID-19 patients demonstrated a more hypercoagulable and hypofibrinolytic profile related to those with COVID-19 mild illness, based on EXTEM amplitude at 10 min (A10), maximum clot firmness (MCF) and lysis index at 60 min (LI60) variables (p = 0.020, 0.046 and 0.001, respectively). Similarly, a more hypercoagulable state was detected in COVID-19 ICU patients related to non-COVID-19 ICU patients based on A10 and MCF parameters (p = 0.03 and 0.04, respectively). On the contrary, ETP and EXTEM (clotting time) CT values were similar between patients with severe and mild form of the COVID-19 infection, probably due to anticoagulant treatment given.Critically ill COVID-19 patients showed a hypercoagulable profile despite the therapeutic anticoagulant doses given. Due to the small sample size and the study design, the prognostic role of the hypercoagulability in this clinical setting remains unknown and further research is required in order to be assessed.
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http://dx.doi.org/10.1097/MD.0000000000023365DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7676559PMC
November 2020

The role of ROTEM variables based on clot elasticity and platelet component in predicting bleeding risk in thrombocytopenic critically ill neonates.

Eur J Haematol 2021 Feb 27;106(2):175-183. Epub 2020 Oct 27.

Laboratory of Haematology and Blood Bank Unit, "Attiko" Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.

Background: Our aim was to investigate the role of thromboelastometry (ROTEM) parameters, including maximum clot elasticity (MCE) and platelet component (PLTEM MCE and PLTEM MCF), in early prediction of bleeding events in thrombocytopenic critically ill neonates.

Material And Methods: This single-center, prospective cohort study included 110 consecutive thrombocytopenic neonates with sepsis, suspected sepsis, or hypoxia. On the first day of disease onset, ROTEM EXTEM and FIBTEM assays were performed and the neonatal bleeding assessment tool was used for the evaluation of bleeding events.

Results: Most EXTEM and FIBTEM ROTEM parameters significantly differed between neonates with (n = 77) and without bleeding events (n = 33). Neonates with bleeding events had significantly lower PLTEM MCE and PLTEM MCF values compared to those without bleeding events (P < .001). Platelet count was found to be strongly positively correlated with EXTEM A5 (Spearman's rho = 0.61, P < .001) and A10 (rho = 0.64, P < .001). EXTEM A10 demonstrated the best prognostic performance (AUC = 0.853) with an optimal cutoff value (≤37 mm) (sensitivity = 91%, specificity = 76%) for prediction of bleeding events in thrombocytopenic neonates.

Conclusions: EXTEM A5 and EXTEM A10 were found to be strong predictors of hemorrhage, compared to most ROTEM variables quantifying clot elasticity and platelet component in thrombocytopenic critically ill neonates.
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http://dx.doi.org/10.1111/ejh.13534DOI Listing
February 2021

Effects of electronic cigarette on platelet and vascular function after four months of use.

Food Chem Toxicol 2020 Jul 25;141:111389. Epub 2020 Apr 25.

Laboratory of Haematology & Blood Bank Unit, "Attikon" University Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.

We examined the effects of electronic cigarette on platelet and vascular function after 4 months of use compared to tobacco smoking. Forty smokers without cardiovascular disease were randomized to smoke either conventional cigarettes or an electronic cigarette (nicotine concentration of 12 mg/ml). At baseline and after four months, we measured a) platelet function by Platelet Function Analyzer PFA-100 and Light Transmission Aggregometry, b) pulse wave velocity, c) plasma malondialdehyde levels as oxidative stress index and d) the exhaled CO level. After 4 months, continuation of conventional cigarette smoking further impaired platelet function compared to vaping as assessed by PFA (mean increase 27.1 vs 11.6 s, p for interaction = 0.048) and by LTA (decline 24.1 vs 9.4%, p for interaction = 0.045). Conversely, compared to smoking, vaping resulted in greater reduction of exhaled CO (6.9 ppm vs 2.6, p for interaction < 0.001), improvement of PWV (decrease of 0.8 m/s vs increase of 0.8 m/s, p for interaction = 0.020) and reduction of MDA (reduction 0.13 vs increase 0.19 nmol/L, p for interaction = 0.035). Switching to electronic cigarette for 4 months has a neutral effect on platelet function while it reduces arterial stiffness and oxidative stress compared to tobacco smoking.
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http://dx.doi.org/10.1016/j.fct.2020.111389DOI Listing
July 2020

β-Amyloid and mitochondrial-derived peptide-c are additive predictors of adverse outcome to high-on-treatment platelet reactivity in type 2 diabetics with revascularized coronary artery disease.

J Thromb Thrombolysis 2020 Apr;49(3):365-376

Laboratory of Haematology & Blood Bank Unit, 'Attikon University Hospital', School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.

Background And Aims: Increased β-amyloid and decreased mitochondrial-derived peptide (MOTS-c), are reported in diabetes. We investigated their additive value to high on-clopidogrel platelet reactivity (HPR) for adverse outcome in type 2 diabetics after recent revascularization.

Patients And Methods: In 121 type II diabetics, treated with clopidogrel and aspirin, (93 males, mean age 67.2 years) we measured: (a) maximum platelet aggregation to adenosine diphosphate (ADP) by light transmission aggregometry (LTAmax), (b) malondialdehyde (MDA), as oxidative stress marker, (c) MOTS-c, (d) β-amyloid blood levels. Cardiac death and acute coronary syndromes (MACE) were recorded during 2 years of follow-up.

Results: Out of 121 patients, 32 showed HPR (LTAmax > 48%,). At baseline, HPR was associated with β-amyloid > 51 pg/ml (p = 0.006) after adjusting clinical variables, HbA1c, MOTS-c, MDA and medication. During follow-up, 22 patients suffered a MACE. HPR, β-amyloid > 51 pg/ml and MOTS-c < 167 ng/ml were predictors of MACE (relative risk 3.1, 3.5 and 3.8 respectively, p < 0.05) after adjusting for confounders and medication. There was significant interaction between HPR and β-amyloid or MOTS-c for the prediction of MACE (p < 0.05). Patients with HPR and β-amyloid > 51 mg/dl or HPR and MOTS-c concentration < 167 ng/ml had a fourfold higher risk for MACE than patients without these predictors (relative risk 4.694 and 4.447 respectively p < 0.01). The above results were confirmed in an external validation cohort of 90 patients with diabetes and CAD.

Conclusions: Increased β-amyloid or low MOTS-c are additive predictors to high on-clopidogrel platelet reactivity for adverse outcome in diabetics with CAD during 2-years follow-up. Clinical Trial Registration-URL: https://www.clinicaltrials.gov. Unique identifier: NCT04027712.
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http://dx.doi.org/10.1007/s11239-020-02060-4DOI Listing
April 2020

The prognostic value of multiple electrode aggregometry and light transmittance aggregometry in stable cardiovascular patients with type 2 diabetes mellitus.

Thromb Res 2019 08 4;180:47-54. Epub 2019 Jun 4.

Second Cardiology Department, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.

Aim: Limited data are available regarding the clinical relevance of platelet function measurements in stable patients with coronary artery disease (CAD). Our aim is to evaluate the agreement between multiple electrode aggregometry (MEA) and light transmittance aggregometry (LTA) in detecting clopidogrel low responders and their prognostic value in CAD patients with type 2 diabetes mellitus (T2DM) on dual platelet inhibition.

Methods: LTA and MEA were performed in 122 stable cardiovascular patients with T2DM. The upper quartile of patients according to maximum LTA (LTAmax) and MEA measurements were defined as clopidogrel low responders. Agreement between the two methods was evaluated by kappa statistics. We assessed the potential correlation between antiplatelet response and clinical outcome and the optimal cutoff value according to ROC analysis to predict the occurrence of major adverse cardiovascular events (MACE), during 1-year follow-up period.

Results: Cohen's kappa coefficients (0.214) indicated fair agreement (70.2%) between LTA and MEA. A total of 25 MACE occurred in 108 patients (23.1%). Patients with MACE had higher LTAmax than those without (57.1 ± 16.5 vs 49.3 ± 18.3, respectively, p = 0.023). MEA measurements were similar between patients with and without MACE (30.1 ± 15.4 vs 30.6 ± 20.8, respectively; p = 0.84). Multiple logistic regression showed LTAmax response as an independent predictor of death from cardiovascular causes (Odds Ratio, adjusted:0.2;0.05-0.81). ROC analysis indicated that LTAmax cutoff of 62.5% best predicted death (AUC = 0.67, sensitivity = 78%, specificity = 61.5%).

Conclusions: The assessment of platelet responsiveness remains highly test-specific. Our results support the prognostic role of LTA, but not MEA testing, for death risk evaluation in stable cardiovascular T2DM patients.
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http://dx.doi.org/10.1016/j.thromres.2019.06.001DOI Listing
August 2019

Thromboelastometry: studying hemostatic profile in small for gestational age neonates-a pilot observational study.

Eur J Pediatr 2019 Apr 1;178(4):551-557. Epub 2019 Feb 1.

Laboratory of Haematology and Blood Bank Unit, "Attiko" Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.

Scarce data exists about the hemostatic status of small for gestational age (SGA) neonates. We aimed at evaluating the hemostatic profile of SGA neonates, using thromboelastometry (TEM). This is an observational study performed in a Greek tertiary General Hospital during an 18-month period. Ninety-three neonates were included in the study: 48 appropriate for gestational age weight (AGA) neonates and 45 SGA neonates Extrinsically activated TEM (ex-TEM) parameters, such as clotting time, clot formation time, amplitude recorded at 5 and 10 min, a angle, maximum clot firmness, lysis index at 60 min, and also platelet count, were used for the evaluation of the hemostatic profile in all neonates. No statistically significant differences were noticed regarding all ex-TEM parameters between AGA and SGA neonates, while no event of hemorrhage or thrombosis was noticed in the study population.Conclusions: The coagulation system of SGA neonates seems to be fully functional, with no evident tendency toward coagulopathy or thrombosis, when compared with AGA neonates. TEM seems to provide a promising and valid assessment of coagulation and fibrinolysis systems and may be used as a valuable biomarker, in the future. Further studies, with large samples, are necessary to confirm our results. What is Known: • SGA neonates may present coagulation disorders mainly due to hepatic dysfunction, polycythemia, and thrombocytopenia owing to long-term intrauterine hypoxia. • In the literature, despite the statistically significant differences in laboratory results between SGA and AGA neonates, no clinical manifestations of significantly altered hemostasis were recorded. Data of TEM interpretation of hemostasis in SGA neonates are not available. What is New: • TEM seems to interpret coagulation mechanism of preterm and full-term SGA neonates and confirm previous relevant literature findings regarding hemostasis in these neonates.
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http://dx.doi.org/10.1007/s00431-019-03331-wDOI Listing
April 2019

Laboratory Assessment of the Anticoagulant Activity of Apixaban in Patients With Nonvalvular Atrial Fibrillation.

Clin Appl Thromb Hemost 2018 Dec 1;24(9_suppl):194S-201S. Epub 2018 Oct 1.

Laboratory of Haematology & Blood Bank Unit, "Attiko" University Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.

Our aim is to determine the most appropriate laboratory tests, besides anti-factor Xa (anti-FXa) chromogenic assays, to estimate the degree of anticoagulation with apixaban and compare it with that of rivaroxaban in real-world patients. Twenty patients with nonvalvular atrial fibrillation treated with apixaban 5 mg twice daily and 20 patients on rivaroxaban 20 mg once daily were studied. Conventional coagulation tests, thrombin generation assay (TGA), and thromboelastometry (nonactivated TEM [NATEM] assay) were performed in the 40 patients and 20 controls. The anti-FXa chromogenic assays were used to measure apixaban and rivaroxaban plasma levels. The NATEM measurements showed no significant difference between the 2 groups of patients. Concerning TGA, endogenous thrombin potential (ETP) was significantly decreased in patients on rivaroxaban as compared to those treated with apixaban ( < .003). A statistically significant, strong inverse correlation between apixaban plasma concentrations and ETP ( < .001) was observed. Apixaban significantly reduces ETP compared to controls, but to a lesser extent than rivaroxaban. Thrombin generation assay might provide additional information on apixaban exposure, which is required in order to individualize treatment especially for patients with a high bleeding risk. Our findings have to be further investigated in studies with larger sample sizes, in the entire range of apixaban exposure, with other direct oral anticoagulants, and in relation to clinical outcomes.
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http://dx.doi.org/10.1177/1076029618802364DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6714834PMC
December 2018

Platelet and coagulation disorders in newly diagnosed patients with pulmonary arterial hypertension.

Platelets 2019 26;30(5):646-651. Epub 2018 Jul 26.

d Laboratory of Hematology & Blood Bank Unit , University Hospital Attikon, School of Medicine, National and Kapodistrian University of Athens , Athens , Greece.

There is a complex and not fully elucidated association between pulmonary arterial hypertension (PAH) and coagulation disorders. The goal of this study was to evaluate platelet function, coagulation and fibrinolysis in PAH patients at diagnosis, before PAH-specific treatment initiation. We enrolled 20 healthy controls and 30 PAH patients (20 with connective tissue disease (CTD-PAH) and 10 idiopathic (iPAH)). None of the participants was on any antiplatelet or anticoagulation therapy. Blood samples from PAH patients were collected during the initial right heart catheterization. All subjects were assessed with platelet function analyzer-100 (PFA-100), epinephrine (Epi) and ADP-induced light transmission aggregometry (LTA), thromboelastometry (ROTEM) and endogenous thrombin potential (ETP). Our results showed that Epi and ADP-LTA values were significantly lower in newly diagnosed PAH patients compared to controls. Disaggregation was present in 73% of patients, a characteristic not seen in healthy individuals. In ROTEM assay, CT and CFT measurements were significantly higher and a angle lower compared to controls. ETP testing revealed significantly reduced outcomes in AUC, Cmax and Tmax. When CTD-PAH and iPAH patient groups were compared, iPAH ADP-LTA values were significantly decreased compared to CTD-PAH. In conclusion, newly diagnosed PAH patients presented with decreased platelet aggregation, clot propagation and thrombin generation, along with delayed initiation of the coagulation process. These hemostatic deficits could indicate an "exhaustion" of the coagulation process that could be caused by endothelial dysfunction and chronic activation of the procoagulant pathways. Further studies are warranted to confirm these laboratory findings and assess their potential clinical significance.
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http://dx.doi.org/10.1080/09537104.2018.1499890DOI Listing
November 2019

Comparison between Nageotte and flow cytometric counting of residual leucocytes in freshly prepared leucocyte-reduced red blood cell components.

Transfus Apher Sci 2018 Aug 7;57(4):544-548. Epub 2018 Jun 7.

Laboratory of Haematology & Blood Bank Unit, "Attikon" Hospital, School of Medicine, National and Kapodistrian University of Athens, 1 Rimini Str., 12462, Athens, Greece. Electronic address:

Background: Flow cytometry (FC) and Nageotte hemocytometry represent the most widely accepted methods for counting residual white blood cells (rWBCs) in leucocyte-reduced (LR) blood components. Our aim was to study the agreement between the two methods, under real working blood bank conditions.

Materials And Methods: 94 freshly produced LR red blood cell (RBC) units were tested for rWBC concentrations by FC and Nageotte. To assess the precision of each method, we calculated the intra-assay coefficients of variation (CV), and followed the Bland-Altman methodology to study the agreement between the two methods.

Results: CV was 18.5% and 26.2% for the Nageotte and the FC, respectively. However, the agreement between the duplicate observations, using the binary cut-off threshold of 1 × 10 WBCs per unit to define the results as "pass/fail", was 71.9% for the Nageotte and 93.3% for the FC. Linear regression analysis did not show any correlation (R-squared = 0.01, p = 0.35) between the two methods, while the Bland-Altman analysis for the measuring agreement showed a bias toward a higher Nageotte count of 0.77 × 10 leucocytes per unit (p < 0.001) with the 95% limits of agreement (d ± 2 sd) ranging from -0.40 × 10 to 1.94 × 10 leucocytes per unit.

Conclusion: The absence of agreement between Nageotte and FC method, with the differences within d ± 2 sd being of high clinical importance, suggests that the two methods cannot be used for clinical purposes interchangeably. The Nageotte seems unsuitable for quality control even with a pass-fail criterion, under real working blood bank conditions.
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http://dx.doi.org/10.1016/j.transci.2018.06.002DOI Listing
August 2018

Renal involvement in paroxysmal nocturnal hemoglobinuria: an update on clinical features, pathophysiology and treatment.

Hematology 2018 Sep 28;23(8):558-566. Epub 2018 Feb 28.

e Department of Transfusion Service and Clinical Hemostasis , 'Saint Savvas' Oncology Hospital , Athens , Greece.

Objectives: The present review summarizes the available knowledge regarding acute and chronic kidney dysfunction in patients with paroxysmal nocturnal hemoglobinuria (PNH) focusing on its clinical features, pathophysiology and treatment.

Methods: A thorough PubMed search was performed using as main keywords: 'paroxysmal nocturnal hemoglobinuria', 'acute kidney injury', 'chronic kidney disease' and 'eculizumab'.

Results: PNH's etiopathogenesis is based on acquired mutations that lead to the reduction or absence of CD55 and CD59 complement regulators, which are responsible for some of the disease's major clinical features, like intravascular hemolysis, cytopenias and thrombosis. PNH is often underdiagnosed, mainly due to its occasional mild manifestations and to its ability to mimic other severe clinical conditions. Various mechanisms have been proposed for the kidney damage attributed to the release of cell-free heme and free iron, including inflammatory response, oxidative stress, nitric oxide depletion, renal ischemia, membrane damage and apoptosis. Eculizumab, a terminal complement inhibitor, provides a safe and effective treatment option, especially when it is initiated early in the presence of kidney damage.

Discussion: Kidney injury is a poorly investigated clinical feature of PNH that affects a significant portion of patients. Increased awareness is needed by physicians to recognize the early signs and symptoms of acute and chronic renal insufficiency, so as to initiate the necessary therapy. It is also important to re-evaluation of PNH-specific treatments during the course of the disease.

Conclusion: Understanding the difficult but at the same time impressive mechanisms behind PNH remains a challenge for treating physicians.
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http://dx.doi.org/10.1080/10245332.2018.1444563DOI Listing
September 2018

Thromboelastometry for diagnosis of neonatal sepsis-associated coagulopathy: an observational study.

Eur J Pediatr 2018 Mar 18;177(3):355-362. Epub 2017 Dec 18.

Laboratory of Haematology and Blood Bank Unit, School of Medicine, "Attiko" University Hospital, National and Kapodistrian University of Athens, 1 Rimini Str, 12462, Athens, Greece.

Our aim was to evaluate the potential role of standard extrinsically activated thromboelastometry (EXTEM) assay in the early detection of neonatal sepsis. We studied 91 hospitalized neonates categorized in two groups: group A included 35 neonates with confirmed sepsis, while group B included 56 neonates with suspected sepsis; 274 healthy neonates served as controls. Whenever sepsis was suspected, EXTEM assay was performed, Score for Neonatal Acute Physiology Perinatal Extension (SNAPPE) and Tοllner score were calculated, and clinical findings and laboratory results were recorded. Septic neonates had significantly prolonged clotting time (CT) and clot formation time (CFT), and reduced maximum clot firmness (MCF), compared to neonates with suspected sepsis (p values 0.001, 0.001, and 0.009, respectively) or healthy neonates (p values 0.001, 0.001, and 0.021, respectively). EXTEM parameters (CT, CFT, MCF) demonstrated a more intense hypocoagulable profile in septic neonates with hemorrhagic diathesis than those without (p values 0.021, 0.007, and 0.033, respectively). In septic neonates, CFT was correlated with platelet count, SNAPPE, Tollner score, and day of full enteral feeding (p values 0.01, 0.02, 0.05, and 0.03, respectively).

Conclusions: A ROTEM hypocoagulable profile at admission seems promising for the early detection of sepsis in neonates while the degree of hypocoagulation may be associated with sepsis severity. What is Known: • The early phase of septicemia might be difficult to be recognized in neonates. In adult septic patients, the diagnostic and prognostic role of thromboelastometry (ROTEM) have been extensively investigated. • Limited data are available on the role of ROTEM as an indicator of early neonatal sepsis. What is New: • ROTEM measurements indicate an early appearance of hypocoagulability in neonatal sepsis, while the degree of hypocoagulation might be associated with severity of sepsis. • ROTEM could be a useful tool in the early detection of sepsis in neonates.
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http://dx.doi.org/10.1007/s00431-017-3072-zDOI Listing
March 2018

Quantitative and qualitative analysis of regulatory T cells in B cell chronic lymphocytic leukemia.

Leuk Res 2017 09 25;60:74-81. Epub 2017 Jul 25.

Second Dept. of Internal Medicine and Research Institute, Attikon University Hospital, 1 Rimini st., Haidari, Athens, 12462, Greece. Electronic address:

Accumulated data indicate a significant role of T cell dysfunction in the pathogenesis of chronic lymphocytic leukemia. In CLL, regulatory T cells are significantly higher and show lower apoptotic levels compared to healthy donors. We demonstrate that CLL derived CD4CD25CD127 and CD4CD25CD127 subpopulations share a common immunophenotypic profile with conventional Tregs and are associated with advanced stage disease. We further provide evidence that the increased number of Tregs contributes indirectly to the proliferation of the CLL clone, by suppressing the proliferation of Teffs which in turn suppress CLL cells. These data are further supported by our observations that CLL derived Tregs appear rather incapable of inducing apoptosis of both normal B cells and CLL cells, in contrast to normal Tregs, suggesting an immunoediting effect of CLL cells on Tregs which negatively affects the functionality of the latter and contributes to the failure of Tregs in CLL to efficiently eliminate the abnormal clone.
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http://dx.doi.org/10.1016/j.leukres.2017.07.004DOI Listing
September 2017

Red Blood Cell Transfusions in Greece: Results of a Survey of Red Blood Cell Use in 2013.

Turk J Haematol 2017 Mar 22;34(1):52-58. Epub 2016 Nov 22.

Aretaieio Hospital, Kapodistrian University of Athens Medical School, Department of Blood Transfusion, Athens, Greece Phone: +306944602629 E-mail:

Objective: Greece is ranked as the second highest consumer of blood components in Europe. For an effective transfusion system and in order to reduce variability of transfusion practice by implementing evidence-based transfusion guidelines it is necessary to study and monitor blood management strategies. Our study was conducted in order to evaluate the use of red blood cell units (RBC-U) in nationwide scale mapping parameters that contribute to their proper management in Greece.

Materials And Methods: The survey was conducted by the Working Committee of Transfusion Medicine&Apheresis of the Hellenic Society of Hematology from January to December 2013. The collected data included the number, ABO/D blood group, patients' department, and storage age of RBC-U transfused.

Results: The number of RBC-U evaluated was 103,702 (17.77%) out of 583,457 RBC-U transfused in Greece in 2013. RBC-U transfused by hospital department (mean percentage) was as follows: Surgery 29.34%, Internal Medicine 29.48%, Oncology/Hematology 14.65%, Thalassemia 8.87%, Intensive Care Unit 6.55%, Nephrology 1.78%, Obstetrics/Gynecology 1.46%, Neonatal&Pediatric 0.31%, Private Hospitals 8.57%. RBC-U distribution according to ABO/D blood group was: A: 39.02%, B: 12.41%, AB: 5.16%, O: 43.41%, D+: 87.99%, D-: 12.01%. The majority of RBC-U (62.46%) was transfused in the first 15 days of storage, 25.24% at 16 to 28 days, and 12.28% at 29-42 days.

Conclusion: Despite a high intercenter variability in RBC transfusions, surgical and internal medicine patients were the most common groups of patients transfused with an increasing rate for internal medicine patients. The majority of RBC-U were transfused within the first 15 days of storage, which is possibly the consequence of blood supply insufficiency leading to the direct use of fresh blood. Benchmarking transfusion activity may help to decrease the inappropriate use of blood products, reduce the cost of care, and optimize the use of the voluntary donor's gift.
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http://dx.doi.org/10.4274/tjh.2016.0188DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451689PMC
March 2017

Comparative Assessment of the Anticoagulant Activity of Rivaroxaban and Dabigatran in Patients With Nonvalvular Atrial Fibrillation: A Noninterventional Study.

Medicine (Baltimore) 2016 Apr;95(14):e3037

From the Laboratory of Haematology and Blood Bank Unit, "Attiko" Hospital(AET, EK, PD); Second Cardiology Department, "Attiko" Hospital(II, KK, IP, JL); Second Department of Critical Care Medicine, "Attiko" Hospital(PK, IT); Department of Microbiology (VK), School of Medicine, National and Kapodistrian University of Athens, Athens, Greece; and Humanitas Clinical and Research Center (SB), Rozzano, Milan, Italy.

There is a shortage of data in everyday clinical practice about the anticoagulant effects caused by the new oral anticoagulants (NOAs). Our aim was to estimate the intensity of anticoagulant activity induced by rivaroxaban 20 mg qd and dabigatran 110 mg bid among patients with nonvalvular atrial fibrillation (NV-AF).We studied 20 patients with NV-AF treated with dabigatran, and 20 patients treated with rivaroxaban. We performed conventional coagulation tests, thrombin generation (TG) test, thromboelastometry (ROTEM), and epinephrine-induced light transmission aggregometry (LTA) in all 40 patients and 20 controls. Hemoclot Thrombin Inhibitors (HTI) and Factor Xa Direct Inhibitor (DiXaI) assay were used to measure dabigatran and rivaroxaban plasma levels, respectively.Measurements of all assays estimating anticoagulant activity across the 2 patient groups were similar, except for aPTT. Patients on dabigatran exhibited statistically significantly prolonged aPTT values (P < 0.001). In LTA, patients on dabigatran also showed decreased aggregation compared to those on rivaroxaban (P = 0.045). Regarding the TG test, there was no association between endogenous thrombin potential (ETP) and rivaroxaban plasma levels (P = 0.33) as opposed to dabigatran levels (P < 0.001), but significant correlations were observed between rivaroxaban plasma concentrations and kinetic parameters of TG assay (Tlag, P = 0.045; Tmax, P = 0.016; and Cmax, P = 0.003).Based on ROTEM and TG assays, the anticoagulant effects induced by the 2 drugs given in the specific dose regimens in real-world patients were comparable. Only platelet aggregation was found to be more affected by dabigatran as compared to rivaroxaban.
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http://dx.doi.org/10.1097/MD.0000000000003037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4998746PMC
April 2016

Impact of dabigatran on platelet function and fibrinolysis.

J Neurol Sci 2015 Oct 23;357(1-2):204-8. Epub 2015 Jul 23.

Second Department of Neurology, "Attikon" University Hospital, School of Medicine, University of Athens, Athens, Greece; International Clinical Research Center, St. Anne's University Hospital in Brno, Brno, Czech Republic. Electronic address:

Background: We sought to evaluate the potential enhanced fibrinolytic and antiplatelet activity of dabigatran etexilate (DE) due to decreased thrombin levels in patients with stroke or transient ischemic attack and non-valvular atrial fibrillation (NVAF).

Methods: Consecutive patients with cerebrovascular diseases and NVAF that were treated with DE in a tertiary university hospital. Fibrinolysis and platelet function were assessed by thromboelastometry (ROTEM) and platelet function analyzer (PFA)-100, respectively, before and after treatment with DE. Conventional coagulation tests, endogenous thrombin potential (ETP) and hemoclot thrombin inhibitors (HTI), were also performed in order to detect any possible correlation between dabigatran plasma levels, its anticoagulant activity and the intensity of platelet dysfunction or fibrinolysis.

Results: A total of nineteen patients fulfilled our inclusion criteria (mean age 62.3±7.2years; 47% males; median CHADS2-score: 3; interquartile range: 2-4). DE treatment was associated with a significant reduction of the lysis index (LI60) at 60min (p=0.036), and prolongation of the PFA-100 CEPI closure time (p=0.024). After dabigatran treatment, abnormal PFA-100 results were obtained in two patients (11%, 95% CI: 2%-33%). DE levels (determined by HTI) were strongly inversely correlated (rho=-0.85; p<0.001) with the area under the curve (AUC) values in ETP assay. Νo association was found between HTI and PFA-100 CEPI CT (p=0.64), or LI60 measurements (p=0.60).

Conclusions: Our findings indicate that DE might affect platelet function and fibrinolysis and highlight the potential role of ETP as an alternative option in DE monitoring. The intensity and clinical relevance of DE antiplatelet and fibrinolytic effects require further investigation.
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http://dx.doi.org/10.1016/j.jns.2015.07.031DOI Listing
October 2015

Laboratory assessment of the anticoagulant activity of dabigatran.

Clin Appl Thromb Hemost 2015 Jul 18;21(5):434-45. Epub 2014 Dec 18.

Laboratory of Haematology & Blood Bank Unit, "Attiko" University Hospital, School of Medicine, University of Athens, Athens, Greece

Background: Our aim was to identify laboratory assays in order to assess the anticoagulant effects of dabigatran etexilate (DE).

Methods: Twenty patients with nonvalvular atrial fibrillation treated on DE (110 mg per os twice daily) and 20 on acenocoumarol were studied. Conventional coagulation tests, endogenous thrombin potential (ETP), thromboelastometry (ROTEM), epinephrine-induced light transmission aggregometry (LTA), and Hemoclot Thrombin Inhibitors (HTI) were performed in all patients.

Results: In ROTEM analysis, the lysis index at 60 minutes was significantly lower in patients receiving DE (P = .011). In LTA, patients on DE showed decreased aggregation compared to those on acenocoumarol, marginally insignificant (P = .068). Regarding ETP, acenocoumarol affected thrombin generation more than dabigatran (area under the curve [AUC], P < .001), while statistically significant associations were detected between dabigatran levels, as determined by the HTI assay, and almost all parameters of ETP assay (AUC, P < .001).

Conclusion: The role of ETP in estimating anticoagulant activity of dabigatran possibly requires further research.
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http://dx.doi.org/10.1177/1076029614564209DOI Listing
July 2015

Cost-effectiveness of leucoreduction for prevention of febrile non-haemolytic transfusion reactions.

Blood Transfus 2014 Apr;12(2):232-7

Blood Transfusion Centre, General Hospital of Nikaia, Athens, Greece.

Background: The cost-effectiveness of universal leucoreduction of blood components remains unclear. When using leucoreduced red blood cells, the decrease in the rate of febrile non-haemolytic transfusion reactions (FNHTR) is the only proven, meaningful clinical benefit, whose relationship to costs can be calculated relatively easily. The aim of this study was to evaluate the cost-effectiveness of leucoreduction in avoiding FNHTR.

Materials And Methods: Data were obtained from two large tertiary hospitals in Athens, Greece, over a 4-year period (2009-2012). The incidence of FNHTR in patients transfused with leucoreduced or non-leucodepleted red blood cells, the additional cost of leucoreduction and the cost to treat the FNHTR were estimated. The incremental cost-effectiveness ratio (ICER), which is the ratio of the change in costs to the incremental benefits of leucoreduction, was calculated.

Results: In total, 86,032 red blood cell units were transfused. Of these, 53,409 were leucodepleted and 32,623 were non-leucoreduced. Among patients transfused with leucodepleted units, 25 cases (0.047%) met the criteria for having a FNHTR, while in patients treated with non-leucoreduced components, 134 FNHTR were observed (0.411%). The ICER of leucoreduction was € 6,916 (i.e., the cost to prevent one case of FNHTR).

Conclusions: Leucoreduction does not have a favourable cost-effectiveness ratio in relation to the occurrence of FNHTR. However, many factors, which could not be easily and accurately assessed, influence the long-term costs of transfusion. It is imperative to undertake a series of large, meticulously designed clinical studies across the entire spectrum of blood transfusion settings, to investigate most of the parameters involved.
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http://dx.doi.org/10.2450/2014.0263-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4039706PMC
April 2014

Impact of the proton pump inhibitors and CYP2C19*2 polymorphism on platelet response to clopidogrel as assessed by four platelet function assays.

Thromb Res 2013 Aug 2;132(2):e105-11. Epub 2013 Jul 2.

Laboratory of Haematology and Blood Bank Unit, "Attiko" University Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens - Greece. Electronic address:

Background: Previous studies suggested a possible negative interference of proton pump inhibitors (PPIs) on clopidogrel's antiplatelet effect because of the competitive inhibition of the CYP 2C19 isoenzyme. Moreover, carriers of the loss-of-function allele of CYP2C19 polymorphism (CYP2C19*2) display significantly lower responses to clopidogrel. In this study, we investigated the association between CYP2C19*2 genotype, PPI intake and clopidogrel resistance in patients with coronary artery disease (CAD) and their effect on clinical outcome.

Methods: We recruited 95 patients with CAD receiving chronic clopidogrel therapy in combination with aspirin. Platelet reactivity was simultaneously assessed by INNOVANCE PFA-100 P2Y, ADP-induced light transmission aggregometry (LTA), flow-cytometric vasodilator-stimulated phosphoprotein (VASP)-phosphorylation assay and multiple electrode aggregometry (Multiplate). Cardiovascular outcomes were recorded during 1-year follow-up period.

Results: Only platelet reactivity assessed by measuring platelet phosphorylated-VASP demonstrated a significant higher platelet reactivity in carriers of CYP2C19*2 (p=0.023). The other methods displayed higher - but not statistically significant - platelet reactivity in patients carrying the CYP2C19*2 variant as compared with non-carriers. Patients on PPIs demonstrated almost similar suppression of platelet reactivity in comparison with those not treated with PPIs by all platelet function assays. In logistic regression analysis none of the platelet function assays measurements were related with clinical outcomes. Similarly neither CYP2C19*2 genetic variant nor PPI treatment were associated with adverse clinical events.

Conclusions: PPI co-administration did not influence clopidogrel's antiplatelet effect on laboratory testing by all platelet function assays used. On the contrary, patients carrying CYP2C19*2 genotype had significantly higher residual platelet reactivity as estimated by VASP-phosphorylation assay.
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http://dx.doi.org/10.1016/j.thromres.2013.06.015DOI Listing
August 2013

Fondaparinux for the treatment of acute heparin-induced thrombocytopenia: a single-center experience.

Clin Appl Thromb Hemost 2010 Dec 13;16(6):663-7. Epub 2009 Oct 13.

Transfusion Medicine Department, KAT General Hospital, Athens, Greece.

Heparin-induced thrombocytopenia (HIT) is a life-threatening immune response to heparin that is associated with a high risk of thromboembolic complications. The syndrome is caused by antibodies that are reactive against complexes of platelet factor 4/heparin (PF4/H). For patients with HIT, the discontinuation of heparin alone is not sufficient and the diagnosis necessitates the administration of an alternative anticoagulant. Fondaparinux is a synthetic pentasaccharide that binds to antithrombin and potentiates inhibition of factor Xa. Data have shown that fondaparinux is structurally too short to induce an antibody response and could be a useful agent to treat HIT. In our hospital, we retrospectively analyzed the use of fondaparinux in the treatment of 24 patients with acute HIT during unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) administration and compared the results to a similar population of 20 patients who were treated with lepirudin. The treated patients had a complete platelet count recovery, and none experienced a new thromboembolic complication or major bleeding. The development of limb gangrene (2 patients who received lepirudin and 1 who received fondaparinux) likely resulted from a delay in diagnosis and treatment initiation. Our data suggest that fondaparinux may be considered a safe and an effective alternative treatment in HIT complicated with or without thrombosis.
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http://dx.doi.org/10.1177/1076029609347900DOI Listing
December 2010

Prognostic value of serum free light chain ratio at diagnosis in multiple myeloma.

Br J Haematol 2007 May;137(3):240-3

Department of Haematology, National and Kapodistrian University of Athens, Laikon General Hospital, Athens, Greece.

The prognostic value of baseline serum free light chain ratio (sFLCR) was investigated in 94 multiple myeloma (MM) patients. sFLCR was calculated as kappa/lambda or lambda/kappa, depending on the patients' dominating monoclonal light chain. Median baseline sFLCR was 3.57 in kappa-MM patients, 45.09 in lambda-MM. 'High' sFLCR (> or = the observed median value for kappa- and lambda-MM respectively) correlated with elevated serum creatinine and lactate dehydrogenase, extensive marrow infiltration and light chain type MM. The 5-year disease-specific survival was 82% and 30% in patients with sFLCR lower than and equal or greater than the median, respectively (P = 0.0001). sFLCR was an independent prognostic factor.
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http://dx.doi.org/10.1111/j.1365-2141.2007.06561.xDOI Listing
May 2007

Serial determination of FLT3 mutations in myelodysplastic syndrome patients at diagnosis, follow up or acute myeloid leukaemia transformation: incidence and their prognostic significance.

Br J Haematol 2006 Aug 20;134(3):302-6. Epub 2006 Jun 20.

First Department of Propaedeutic Medicine, Laikon Hospital, University of Athens, Athens, Greece.

The incidence of FLT3 mutations (internal tandem duplication and Asp835) was investigated in bone marrow samples from 97 patients with myelodysplastic syndrome [(MDS); excluding cases with refractory anaemia with excess blasts in transformation] at the time of diagnosis and several time points thereafter. Three patients had FLT3 mutations at presentation. Forty-two patients progressed to acute myeloid leukaemia (AML), including the three patients with FLT3 mutations at MDS diagnosis. Three additional patients acquired FLT3 mutations and progressed to AML in 1 month. FLT3 mutations seem to be a critical additional genetic event that transforms a minority of MDS patients to AML.
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http://dx.doi.org/10.1111/j.1365-2141.2006.06171.xDOI Listing
August 2006

Reduced CD43 expression on the neutrophils of MDS patients correlates with an activated phenotype of these cells.

Int J Hematol 2001 Jun;73(4):483-491

Department of Hematology, Venizelion Hospital of Herakleion, Crete, Greece.

CD43 (also known as leukosialin and sialophorin) is a surface sialoglycoprotein expressed at high levels on most leukocytes implicated in adhesion, antiadhesion, and activation/proliferation mechanisms. We studied the expression of this molecule on the leukocytes of patients with myelodysplastic syndromes (MDSs) in an effort to detect acquired deficiencies of this molecule. We used immunofluorescence flow cytometry in analyzing whole blood and isolated neutrophils from 49 MDS patients, 33 men and 16 women aged 33 to 85 years (median, 75 years), and 18 healthy individuals aged 35 to 80 years (median, 72 years). According to French-American-British classification criteria, 13 patients had refractory anemia, 18 had refractory anemia with ringed sideroblasts, 9 had refractory anemia with excess of blasts, 4 had refractory anemia with excess of blasts in transformation to acute leukemia, and 5 had chronic myelomonocytic leukemia. We found decreased expression of CD43 on the neutrophils of these patients, and we correlated this finding with the activation status of these cells as it is defined by their phenotypes. We studied the expression of CD11b, CD18, CD35, CD67, CD69, CD44, and CD53 molecules known to be changed in the activated form of neutrophils. CD43 expression correlated positively with CD53 and CD44 expression and negatively with CD11b, CD18, CD35, CD67, and CD69 expression. Additionally, increased levels of soluble vascular cell adhesion molecules were detected in these patients, suggesting endothelial cell activation. In conclusion, we believe that the decreased expression of CD43 on the neutrophils of MDS patients is associated with activation of these cells and is probably due to cleavage of the molecule from the cell surface and that the same mechanism is possibly responsible for the parallel down-regulation of CD44 and CD53.
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http://dx.doi.org/10.1007/BF02994011DOI Listing
June 2001
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