Platelet Reactivity and Response to Aspirin and Clopidogrel in Patients with Platelet Count Disorders.

BACKGROUND: Platelet reactivity and response to antiplatelet drugs, acetylsalicylic acid (ASA) and clopidogrel, in patients with thrombocytopenia and thrombocythemia can have a potentially important effect on the outcome. The effectiveness and safety of antiplatelet drugs in such patients has not been well examined. Measuring the effect of ASA and clopidogrel on platelets could help guide the therapy. Nevertheless, platelet response to antiplatelet drugs is not routinely measured in platelet count disorders and relevant evidence is scarce. AIMS: The study aimed to measure platelet reactivity and response to ASA and clopidogrel in patients with platelet count disorders. MATERIALS AND METHODS: This was a cross-sectional study of consecutive patients hospitalized in cardiology and hematology departments in the years 2018-2019. The study included patients with thrombocytopenia (PLT < 150 G/L) and thrombocythemia (PLT > 450 G/L) on ASA or dual antiplatelet therapy (DAPT; ASA plus clopidogrel). Controls included patients on antiplatelet drugs with normal platelet count. Platelet reactivity was measured in whole blood (Multiplate aggregometer, Roche, Switzerland) using arachidonic acid (AA), adenosine-5'-diphosphate (ADP), and thrombin receptor agonist peptide-6 (TRAP) as agonists. Platelet aggregation was expressed in arbitrary units (AU). AA-induced aggregation was used as a measure of response to ASA with a cut-off above 30 AU showing high on-treatment platelet reactivity to ASA (HTPR-A). ADP-induced aggregation measured response to clopidogrel with a cut-off above 48 AU for high on-treatment platelet reactivity to clopidogrel (HTPR-C). TRAP-induced aggregation measured baseline platelet reactivity not affected by oral antiplatelet drugs. RESULTS: The study included 174 patients. There were 64 patients with thrombocytopenia, 30 patients with chronic thrombocythemia, and 80 controls. All patients were on 75 mg of ASA and 32% of them additionally on 75 mg of clopidogrel due to a history of recent coronary artery angioplasty. AA- and ADP-induced aggregation was comparable between thrombocytopenic patients and controls (median (IQR) 19 (7-28) vs. 23 (15-38) for AA AU and 32 (16-44) vs. 50 (32-71) for ADP AU, respectively), while it was significantly higher in thrombocythemic patients (median (IQR) 80 (79-118) for AA AU and 124 (89-139) for ADP AU). TRAP-induced aggregation showed significantly lowest aggregation in thrombocytopenic (median (IQR) 41 (34-60) for TRAP AU) and highest in thrombocythemic patients (median (IQR) 137 (120-180) for TRAP AU). HTPR-A was frequent in thrombocythemic patients in comparison with thrombocytopenic patients and controls (60% vs. 4% vs. 15%, respectively; p < 0.0002). HTPR-C was highly common in thrombocythemic patients and least common in thrombocytopenic ones in comparison with controls (80% vs. 8% vs. 40%, respectively; p < 0.001). CONCLUSION: Chronic thrombocytopenia does not significantly affect platelet reactivity and response to ASA and clopidogrel in comparison with controls. Thrombocytosis significantly increases platelet reactivity and attenuates response to both ASA and clopidogrel.

Hematological malignancies in Polish population: what are the predictors of outcome in patients admitted to Intensive Care Unit?

INTRODUCTION: Patients with hematological malignancies (HM) require intensive chemotherapy with curative intent, especially in case of AML that results in more frequent admissions to Intensive Care Units (ICU). Due to our knowledge, this study is the first multicenter retrospective analysis in Polish population. METHODS: A total of 200 patients with HM hospitalized in 4 Polish hematological centers. Data concerning clinical indices and outcomes during admission and ICU stay were collected retrospectively. RESULTS: The most common hematological malignancy was acute leukemia (55%). The main cause of ICU admission was respiratory failure (88.5%), often accompanied by sepsis (58.5%) and acute renal failure (51.5%). In patients with hematological malignancies, the following factors were associated with ICU mortality: prolonged ICU stay (odd ratio [OR] = 6.98, 95% confidence interval [CI]: 1.38-35.33, χ2 = 5.61, p = 0.02), the presence of acute respiratory failure (odd ratio [OR] = 5.35, 95% confidence interval [CI]: 1.01-28.46, χ2 = 3.93, p = 0.04), and the need for renal replacement therapy (odd ratio [OR] = 8.75, 95% confidence interval [CI]: 1.23-62.11, χ2 = 4.78, p = 0.03). There were following associations with in-hospital mortality in patients with hematological malignancies: prolonged ICU stay (odd ratio [OR] = 10.12, 95% confidence interval [CI]: 1.85-55.37, χ2 = 7.21, p = 0.008), the presence of acute respiratory failure (odd ratio [OR] =5.24, 95% confidence interval [CI]: 1.36-20.16, χ2 = 5.87, p = 0.02), the need for catecholamine support (odd ratio [OR] =3.43, 95% confidence interval [CI]: 1.06-11.05, χ2 = 4.32, p = 0.04), and renal replacement therapy (odd ratio [OR] =5.55, 95% confidence interval [CI]: 1.14-26.92, χ2 = 4.59, p = 0.03). CONCLUSIONS: We have demonstrated that ICU and in-hospital mortalities among patients with hematological malignancies are still poor, but easier access to the intensive care unit and close cooperation between hematologists and intensivists may improve outcomes. We have found that acute failure of key organs (acute respiratory failure, end-stage renal failure requires renal replacement therapy) and length of ICU stay (but probably no comorbidities and illness severity) may have impact on mortality (both ICU and in-hospital).

Platelet polyphosphate level is elevated in patients with chronic primary thrombocytopenia: A preliminary study.

BACKGROUND: Platelets are key players in hemostasis. These blood cells contain different types of granules. Recently, there has been a growing interest in the role of inorganic polyphosphate (polyP) structures stored in dense granules of platelets and secreted during platelet activation. OBJECTIVES: To measure platelet polyP levels in patients with thrombocytopenia and thrombocythemia, and to examine the relationship of this indicator with platelet aggregation. MATERIAL AND METHODS: The study included 36 patients with hematological disorders (26 with primary chronic thrombocytopenia and 10 with essential thrombocythemia (ET)) and 40 healthy subjects. Platelet reactivity was measured using whole blood impedance aggregometry. The polyP levels were isolated from lysed platelets, which were obtained from citrated platelet-rich plasma. The procedure included inactivating endogenous phosphatases, removing phosphate units derived from DNA and proteins, and finally hydrolyzing them into monophosphate units. A colorimetric assay using malachite green and ammonium molybdate was performed in order to quantify polyP levels. RESULTS: The polyP concentrations were significantly higher in the patients with thrombocytopenia than in the patients with thrombocythemia or the controls. The polyP level was not correlated with the level of aggregation. CONCLUSIONS: The higher polyP levels observed in the patients with low platelet counts may indicate the existence of a compensatory mechanism that prevents excessive bleeding in such patients. Our study provides evidence of an essential role of polyP in platelet function and the coagulation process.

Secondary plasma cell leukemia: a multicenter retrospective study of 101 patients.

This multicenter retrospective study included 101 patients (median age 62 years) with secondary plasma cell leukemia (sPCL). The median time from initial multiple myeloma diagnosis to sPCL was 31 months. Fifty-five out of 72 patients (75%) who received any therapy were treated with immunomodulators (IMiDs) and/or proteasome inhibitors (PIs), and 14/72 (19%) underwent salvage autologous stem cell transplantation (ASCT). The overall response rate in patients who received ASCT or PI (either alone or in combination) was higher than in those who did not (93% vs. 36% and 60% vs. 30%, respectively). The median overall survival (OS) in patients who received therapy was 4.2 months (95% CI: 1.3; 8.0) with a 1-year OS of 19%. Platelet count ≤100 × 109/L at sPCL diagnosis was the only independent predictor of a poorer OS in treated patients (HR = 3.98, p = .0001). These findings suggest that patients with sPCL may benefit from salvage ASCT- and PI-based regimens.

Induction therapy alters plasma fibrin clot properties in multiple myeloma patients: association with thromboembolic complications.

Induction therapy in patients with multiple myeloma increases the risk of thromboembolism. We have recently shown that multiple myeloma patients tend to form denser fibrin clots displaying poor lysability. We investigated the effect of induction therapy on fibrin clot properties in multiple myeloma patients. Ex-vivo plasma fibrin clot permeability, turbidity, susceptibility to lysis, thrombin generation, factor VIII and fibrinolytic proteins were compared in 48 multiple myeloma patients prior to and following 3 months of induction therapy, mainly with cyclophosphamide-thalidomide-dexamethasone regimen. Patients on thromboprophylaxis with aspirin or heparins were eligible. A 3-month induction therapy resulted in improved clot properties, that is higher clot permeability, compaction, shorter lag phase and higher final turbidity, along with shorter clot lysis time and higher rate of D-dimer release from fibrin clots than the baseline values. The therapy also resulted in lower thrombin generation, antiplasmin and thrombin-activatable fibrinolysis inhibitor (TAFI), but elevated factor VIII. Progressive disease was associated with lower posttreatment clot permeability and lysability. Despite thromboprophylaxis, two patients developed ischemic stroke and 10 had venous thromboembolism. They were characterized by pretreatment lower clot permeability, prolonged clot lysis time, longer lag phase, higher peak thrombin generation, TAFI and plasminogen activator inhibitor -1. Formation of denser plasma fibrin clots with reduced lysability and increased thrombin generation at baseline could predispose to thrombotic complications during induction treatment in multiple myeloma patients. We observed improved fibrin clot properties and thrombin generation in multiple myeloma patients except those with progressive disease.

Analysis of free serum light chains in patients suffering from multiple myeloma complicated by light-chain amyloidosis.

BACKGROUND: AL amyloidosis is an acquired systemic disease in which a pathologic amorphous substance produced as a result of abnormal protein metabolism is deposited in the extracellular space of various tissues. OBJECTIVES: The aim of the study was to investigate the relationship between the kappa and lambda serum free light chains (sFLCs) and the development of AL amyloidosis in patients suffering from multiple myeloma (MM). MATERIAL AND METHODS: The investigations included 70 MM patients, 40 females and 30 males, aged 28-83 years. In 37 persons, MM was had been diagnosed recently; 33 patients had been undergoing treatment. Amyloidosis was diagnosed in 18 patients (25.7%), including nine females, nine males; six had newly diagnosed disease. Fifteen patients developed kidney failure. The control group consisted of 10 healthy donors. The concentration of sFLC ls were determined using the immunonephelometric method and expressed in mg/L. RESULTS: In 18 MM patients with amyloidosis the concentration of κ sFLCs ranged from 0.3 to 4780 (x = 854.5, SD = 1289), and was significantly higher (p = 0.039) than in the group without amyloidosis, where the range was from 0.3 to 426.0 (x = 68.9, SD = 98.1). The highest concentration of κ sFLCs was observed in the group of five patients with amyloidosis and renal failure. The concentration of λ sFLCs in patients with amyloidosis ranged from 0.5 to 41600 (x = 3035.7, SD = 9735) and was higher than in MM patients without amyloidosis, where it ranged from 0.5 to 834.0 (x = 79.3, SD = 193). In amyloidosis patients, the concentration of λ sFLCs was significantly higher (p = 0.05) in cases of renal failure as compared with the patients with normal renal function. CONCLUSIONS: The concentration of sFLCs is a strong indicator of amyloidosis development in MM patients.

The occurrence of Al amyloidosis (light-chain amyloidosis) in patients with multiple myeloma in Lower Silesia Region, Poland.

BACKGROUND: The incidence of amyloidosis is difficult to determine because the disease is often undiagnosed or diagnosed incorrectly. In Polish studies, there are no statistics and analyses of the factors that may influence the development of amyloidosis in patients with multiple myeloma. OBJECTIVES: The goal of this study was to estimate the incidence of AL amyloidosis in MM patients in Lower Silesia region. MATERIAL AND METHODS: 70 patients treated at the Department of Hematology, Provincial Hospital in Legnica and the Department of Hematology, Blood Neoplasm and Bone Marrow Transplantation, Medical University in Wroclaw were enrolled in the survey. 37 patients were newly diagnosed, 33 had been treated for 2-34 months. The basis for the diagnosis of amyloidosis was the presence of green colored amyloid deposits in the polarized light microscope in the adipose tissue (received from abdominal fold and stained with Congo red). RESULTS: Amyloidosis was diagnosed in 18 (25.7%) patients with MM, 9/9 F /M, aged 47-83 years. 6 (33%) pts with amyloidosis had newly diagnosed MM, in 12 (67%) progression of the disease was diagnosed. Amyloidosis occurred significantly more often (p = 0.048) in already treated patients. The odds ratio (OR) was 2.95. Amyloidosis occurred most frequently in patients with IgG myeloma (67%), (OR = 1.98), was more often found in patients with kappa light chain versus lambda, respectively 67% and 33%. The probability of amyloidosis in patients with clinical stage III was 1.5 times higher (p = 0.05) than in other stages (OR = 1.5), in persons with renal dysfunction was twice as high (OR = 2.4) compared to the renal competence group (p = 0.05). CONCLUSIONS: AL amyloidosis in the course of MM occurs in Lower Silesia region with a comparable rate to other regions of the world. It is significantly more often diagnosed in patients with relapsed or refractory disease, in persons with clinical stage III and with renal failure.