Circulating Erythrocyte Microparticles and the Biochemical Extent of Myocardial Injury in ST Elevation Myocardial Infarction.

OBJECTIVES: Red blood cell microparticles (RBCm) have potential adverse vascular effects and they have been shown to be elevated in ST elevation myocardial infarction (STEMI). The purpose of this study is to investigate their relationship with biochemical infarct size. METHODS: RBCm were quantified with flow cytometry in blood drawn from 60 STEMI patients after a primary angioplasty. The creatine kinase-myocardial brain fraction (CK-MB) was measured at predefined time points and the area under the curve (AUC) was calculated. RESULTS: RBCm count was correlated with CK-MB AUC (Spearman's ρ = 0.83, p < 0.001). The CK-MB AUC values per RBCm quartile (lower to upper) were: 3,351 (2,452-3,608), 5,005 (4,450-5,424), 5,903 (4,862-10,594), and 8,406 (6,848-12,782) ng × h/ml, respectively. From lower to upper quartiles, the maximal troponin I values were: 42.2 (23.3-49.3), 49.6 (28.8-54.1), 59.2 (41.4-77.3), and 69.1 (48.0-77.5) ng/ml (p = 0.005). In multivariable analysis, RBCm remained a significant predictor of CK-MB AUC (standardized ß = 0.63, adjusted p = 0.001). CONCLUSIONS: Erythrocyte microparticles appear to be related to the total myocardial damage biomarker output. The exact pathophysiologic routes, if any, for this interaction remain to be identified. However, these results suggest that erythrocytes may be a - thus far virtually ignored - player in the pathogenesis of ischemic injury.

Evaluation of automated capillary complete blood counts for routine clinical decision making in a large cohort of hematological patients, using Mindray BC-3000 Plus Auto and Sysmex XE-5000 hematology analyzers.

INTRODUCTION: Venous blood (VB) sampling for complete blood count (CBC) via venipuncture is the basic method for the daily evaluation of hematological patients. However, several issues during this process, such as venipuncture difficulty and repetitive attempts, may cause pain, phlebitis, hematomas, inadequate sampling, and patient discomfort. Capillary blood (CB) sampling could be an alternative and less painful solution for the patient. The purpose of this study was the comparative evaluation of basic CBC parameters, as counted from venous and capillary blood samples. METHODS: During the period 06/2016-06/2019 in which the study was conducted, 1634 automated counts of VB or CB were performed, derived from 425 hematological hospitalized patients. Bland-Altman plots were performed to show the agreement of VB and CB counts of common hematological parameters (Hb, Hct, WBC, absolute neutrophil count-[ANC], RBC, Plt, MCV, MCH), using two different hematology analyzers (Mindray BC-3000 Plus Auto and Sysmex XE-5000). Clinical significance of CB sampling was assessed by applying specific clinically significant cutoffs for Hb, ANC, and Plt. RESULTS: All measured parameters revealed a significant correlation (r > .9) between CB and VB samples, irrelatively of the hematology analyzer used. CB measurements of Hb, ANC, and Plt, at different clinically important cutoff levels, showed excellent sensitivity (87%-100%), specificity (95%-100%), positive predictive value, and negative predictive value (87%-100% and 90%-100%, respectively). CONCLUSION: Capillary blood and VB counts in hematological patients were equivalent for most basic hematological parameters. Hb, ANC, and Plt CB counts revealed clinically significant performance, indicating that they can reliably substitute VB sampling in the day work.

"Bone marrow aspirate automated counts on hematology analyzers: formulating a scoring system based on hematology parameters, to discriminate reactive versus myelodysplastic syndrome-related bone marrows".

INTRODUCTION: Diagnosis of myelodysplastic syndromes (MDS) is usually challenging. In this context, we have attempted to employ data derived from automated analysis of bone marrow (BM) samples as an ancillary tool for the discrimination between reactive marrow and MDS. METHODS: A total of 101 BM anticoagulated samples referred for flow cytometry (FCM) analysis on the clinical suspicion of MDS had been previously counted in a Mindray BC-6800 hematology analyzer (testing set). Among them, 22/101 randomly selected BM samples (comparison set) had been also simultaneously counted by an Advia 2120 and a CELL-DYN Sapphire hematology analyzer. Selected parameters obtained by Mindray BC-6800 were retrospectively evaluated with ROC and regression analysis in an attempt to formulate a discriminative scoring system (SS) for MDS. This system was further evaluated in the comparison set. RESULTS: The diagnosis of MDS was established in 37/101 patients assessed ("MDS" group). Three patients were diagnosed with myelodysplastic/myeloproliferative neoplasm (MDS/MPN), while 61 revealed a "reactive" bone marrow ("RBM" group). Statistical analysis revealed significant differences in Hb, RDW-CV%, NRBC%, and RET% values between the "MDS" and the "RBM" group. Specific cutoff values were then indicated and employed for the formulation of a SS of high sensitivity (86.84%) and specificity (86.89%). The encouraging performance characteristics of the proposed SS were also confirmed in the BM comparison set. CONCLUSION: Automated BM counts on hematology analyzers contributed to the formulation of a SS for the screening discrimination between reactive and MDS BM fluids, which seems to be applicable and informative, regardless of the analyzer used.

Red blood cell and platelet microparticles in myocardial infarction patients treated with primary angioplasty.

BACKGROUND: Red blood cell and platelet microparticles (RBCm and PLTm, respectively) have drawn research attention as to their potential prothrombotic and vasoconstrictive effects in experimental settings. However, the relevance of circulating microparticles in clinical settings is largely undetermined. METHODS: Circulating microparticles were quantified with a flow cytometric method in blood samples from consecutive STEMI patients after primary PCI. A matched cohort of healthy volunteers was used to derive reference values for comparison. STEMI patients were followed for 6 months for a composite clinical endpoint. RESULTS: Fifty-one STEMI patients (age 59.8 ± 8.8 years) and 50 controls (age 56.2 ± 9.2 years; p=0.155) were enrolled. RBCm concentration was 18,198 ± 6062/µl in the reference cohort versus 33,740 ± 21,169/µl in STEMI patients (p<0.001). RBCm count was not correlated to total RBCs (standardized beta 0.018; p=0.861). PLTm did not differ between groups (17,529 ± 16,292/µl in STEMI patients versus 14,372 ± 6211/µl in controls; p=0.203). RBCm c-statistic was 0.832 (95% confidence interval 0.720 to 0.944), while PLTm prognostic value was not statistically significant (c-statistic 0.614, 95% confidence interval 0.444 to 0.784). In the multivariate analysis, RBCm concentration was independently associated with the occurrence of the clinical endpoint, after adjustment for age, ejection fraction, serum creatinine and presence of diabetes (adjusted p=0.034). CONCLUSIONS: The present study demonstrates for the first time that erythrocyte microparticles are elevated in patients with STEMI treated with primary PCI, with levels approximately double those measured in a reference population of healthy volunteers, and their concentrations appear to be positively associated with adverse clinical events.