Mean platelet volume as a diagnostic marker for cardiovascular disease: drawbacks of preanalytical conditions and measuring techniques

Platelet indices and angiogenesis markers in hypertensive disorders of pregnancy

INTRODUCTION

Activated platelets exert a key role in the pathogenesis of preeclampsia (PE). There is evidence of distinctive patterns of platelet indices in PE in comparison to healthy pregnancies, therefore these indices can be potential tools for PE detection, risk stratification, and management. Considering the vascular aspects of its pathophysiology, PE is characterized by the increased levels of soluble FMS-like tyrosine kinase-1 (sFlt-1) an antiangiogenic factor, and reduced placental growth factor (PlGF), a proangiogenic factor. This study aimed to assess the platelet indices in hypertensive disorders of pregnancy (HDP) and its correlation with angiogenesis-related biomarkers.

METHODS

The groups for the study were: control (n = 114); gestational hypertension; (n = 112), and PE (n = 42). The platelet indices included were platelet counts (PLT-I and PLT-F), mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT), platelet large cell ratio (P-LCR), and immature platelet fraction (IPF# and IPF%). Serum levels of sFlt-1 and PlGF were assessed.

RESULTS

PLT-I, PLT-F, and PCT% were lower in PE, while MPV, PDW, P-LCR, IPF%, and IPF# were increased. The parameter MPV presented the best performance for the discrimination of PE. There was a moderate positive correlation between sFlt-1 levels and MPV, PDW, and P-LCR.

CONCLUSION

Platelet indices can be potentially applied as additional tools for the diagnosis and management of HDP. Activated platelets may act as an extra source of sFlt-1 in PE.

Platelet aggregates detected using quantitative phase imaging associate with COVID-19 severity

BACKGROUND

The clinical spectrum of acute SARS-CoV-2 infection ranges from an asymptomatic to life-threatening disease. Considering the broad spectrum of severity, reliable biomarkers are required for early risk stratification and prediction of clinical outcomes. Despite numerous efforts, no COVID-19-specific biomarker has been established to guide further diagnostic or even therapeutic approaches, most likely due to insufficient validation, methodical complexity, or economic factors. COVID-19-associated coagulopathy is a hallmark of the disease and is mainly attributed to dysregulated immunothrombosis. This process describes an intricate interplay of platelets, innate immune cells, the coagulation cascade, and the vascular endothelium leading to both micro- and macrothrombotic complications. In this context, increased levels of immunothrombotic components, including platelet and platelet-leukocyte aggregates, have been described and linked to COVID-19 severity.

METHODS

Here, we describe a label-free quantitative phase imaging approach, allowing the identification of cell-aggregates and their components at single-cell resolution within 30 min, which prospectively qualifies the method as point-of-care (POC) testing.

RESULTS

We find a significant association between the severity of COVID-19 and the amount of platelet and platelet-leukocyte aggregates. Additionally, we observe a linkage between severity, aggregate composition, and size distribution of platelets in aggregates.

CONCLUSIONS

This study presents a POC-compatible method for rapid quantitative analysis of blood cell aggregates in patients with COVID-19.

Effects of extracorporeal circulation with different time on platelet count after cardiac surgery: a retrospective study based on medical records

Our objective was to observe the effects of extracorporeal circulation (ECC) with different time on platelet count in patients undergoing cardiac surgery. A total of 427 patients who underwent elective cardiac surgery under ECC in affiliated hospital of north Sichuan medical college from January 1, 2018 to July 31, 2021 were divided into three groups according to ECC time. We concluded that thrombocytopenia was common after ECC, maximum drop of the platelet counts after ECC was usually seen on the second day after ECC, and platelet counts started to recover on the fifth day after ECC. With the extension of ECC time, the drop in platelet counts is more pronounced, the volume of perioperative blood loss and blood products transfusion are more, and the recovery level and speed of platelet counts is lower.

Effect of Deviated Nasal Septum on Mean Platelet Volume: A Prospective Study

Nasal obstruction due to Deviated Nasal Septum (DNS) is a commonly encountered condition by the Otorhinolaryngologist. This leads to chronic hypoxia which in turn leads to stimulation of platelets. This change can be assessed by estimation of the Mean Platelet Volume (MPV) which is a commonly available investigation while ordering a haemogram. As there is a lot of conflicting data about the relationship between DNS and MPV, this study was undertaken to evaluate if there is a relationship between these two parameters. A 1-year observational study was done and after adhering to the inclusion and exclusion criteria, there were 50 cases of deviated nasal septum and 50 controls who attended the ENT Out-Patient Department of a tertiary care hospital who were evaluated. Blood was drawn and the Mean Platelet Volume was estimated. It was found that there was no statistical significance between the cases and controls. Contradictory to other studies done in literature, our study did not find any correlation. This could be due to the type of septal deviation cases that were part of our study. Hence, multicentric studies with larger samples need to be studied in order to establish sound conclusions.

Platelet index on admission as a predictor of bacteremia in acute cholangitis: a 7-year retrospective observational study

Bacteremia frequently occurs in patients with acute cholangitis, which could increase the risk of mortality. This single-center retrospective observational study was conducted from July 2013 to July 2020 to evaluate the predictive value of platelet index for bacteremia at admission for acute cholecystitis. A total of 285 patients with acute cholangitis were divided into bacteremia group and non-bacteremia group. The incidence of bacteremia in acute cholangitis was 48.42%. The bacteremia group had more grade III patients, higher 30d mortality rate [17(12.32%) vs 8(5.44%), p = .040] and higher incidence of thrombocytopenia [76(55.07%) vs 35(23.81%), p < .001]. Platelet counts and plateletcrit were significantly lower in the bacteremia group [84.5(60, 180) vs 162(102,225) ×10⁹/L and 0.10(0.07, 0.21)% vs 0.18(0.12, 0.25) %, both p < .001]. ROC analysis indicated a high predictive value of platelet count and plateletcrit for bacteremia in patients with acute cholangitis and the area under the ROC curve (AUC) were 0.649 and 0.655, respectively. These results support the value of platelet count and plateletcrit in early prediction of bacteremia at admission for acute cholangitis.

Feasibility of a mean platelet volume standard: an international council for standardization in hematology (ICSH) inter-laboratory study

We have evaluated a commercial-fixed porcine platelet preparation (with and without added fixed human red blood cells (RBC)) for the potential standardization of mean platelet volume (MPV) measurements. The standards (Biotechne) were distributed internationally to 19 laboratories including all major hematology instrument manufacturers and academic/pathology laboratories. Overall, the standards demonstrated excellent stability up to 1 month within both MPV values and platelet counts when stored at 4°C. The presence of RBC significantly increased the platelet count and MPV values compared to platelets alone. However, as expected, there were differences in MPV values between different instruments and manufacturers. MPV values were also significantly higher in the whole blood standard compared to the platelet standard in the majority of instruments except with some instruments, where MPV values were significantly higher in the platelet only preparation. To further investigate this phenomenon, two different Platelet MPV preparations (with low and high MPV) in combination with 3 different RBC MCV preparations (with low, normal or high MCVs) were tested to try and further elucidate how RBC populations may impact upon platelet analysis (count, MPV, and PDW) using a single impedance analyzer. Both MPV and MCV values showed good stability over the course of the study for up to 50 days. As expected, the RBC preparation with the lowest MCV had the greatest impact on the MPV. However, this was not observed with an increase in MCV of the RBC or by a larger MPV of the platelet population. To further understand how different gating strategies may also influence results, we investigated the effect of either fixed or floating gate strategies upon MPV raw data from patient samples in a single impedance analyzer. Overall, it was clear that floating and fixed gate strategies also significantly impact upon MPV values. In conclusion, we have demonstrated the potential of an MPV standard with good stability characteristics for calibrating and comparing full blood counters that use different analysis principles, gating and MPV calculations. This may facilitate future instrument calibration and harmonization of results between different technologies.

Mean Platelet Volume: A Possible Predictor for Patients with Decompensated Chronic Heart Failure

Purpose

Despite all medical efforts and discoveries, heart failure (HF) remains one of the most important and common public health problems, with high mortality and hospitalization rates, due to decompensation of HF. In the present study, we aimed to identify a predictive factor through which we can evaluate the risk of readmission and mortality in the first year, given the initial admission of a patient with decompensated heart failure.

Patients and Methods

The parameter we have investigated is the mean platelet volume (MPV). Studies have shown that there is a significant correlation between the value of MPV and the risk of cardiovascular disease (CVD) and cardiovascular (CV) death. In this study, we enrolled 130 patients hospitalized for decompensated chronic HF (NYHA class IV HF or acute pulmonary edema) and analyzed whether there is a relationship between the value of the MPV at admission and 6-month rehospitalization, and 1-year mortality, respectively.

Results

The statistical analysis revealed significantly different values (p = 0.041) for MPV at admission between the group of patients without decompensated chronic HF compared to the group of patients with decompensated chronic HF (8.74 fl vs 9.08 fl). Also, the results of our study revealed that patients with decompensated chronic heart failure who were readmitted at 6 months and died at 1 year, respectively, had a higher MPV at admission (>9 fl), compared to those without the above-mentioned events, with a statistical significance.

Conclusion

A higher MPV at admission can be considered in our study as an independent predictor for rehospitalization and 1-year mortality of patients with decompensated chronic HF.

The role of platelet parameters for the diagnosis of preeclampsia among pregnant women attending at the University of Gondar Comprehensive Specialized Hospital antenatal care unit, Gondar, Ethiopia

Background

Preeclampsia (PE) is a pregnancy‐related illness characterized by high blood pressure (BP) and proteinuria after the 20th gestational week (GW). Platelet (PLT) parameter changes are the common hematological abnormalities observed in PE patients. The main aim of this study was to assess the role of PLT parameters for PE diagnosis among pregnant women.

Methods

A comparative cross‐sectional study was conducted at the University of Gondar Specialized Hospital. A total of 126 pregnant women (63 normotensive [NT] and 63 PE) were recruited using a convenient sampling method. Three milliliter blood was collected from each participant, and PLT parameters were determined using Sysmex XS‐500i analyzer. An independent t‐test supplemented with receiver‐operating characteristics (ROC) were used for comparisons and diagnostic value of PLT parameters between the study groups.

Results

Platelet count (PC) was significantly lower in the PE group compared to that in the NT group, whereas mean platelet volume (MPV), platelet large cell ratio (P‐LCR), and platelet distribution width (PDW) were significantly higher in PE. MPV had the largest area under the curve (AUC) [0.91: 95% CI; 0.85–0.96] followed by PC [0.79: 95% CI; 0.72–0.87]. MPV can differentiate PE patients from NT pregnant women at cut‐off value ≥12.10 fl (84.1% sensitivity and 87.3% specificity) while PC can indicate PE at a cut‐off value ≤176.5 × 10⁹/L (65.1% sensitivity and 87.3% specificity).

Conclusion

A decreased PC and an increased MPV, P‐LCR, and PDW can be used as a simple, cost‐effective, quick, and reliable method of PE screening. Of them, MPV is the best indicator of PE.

Criteria and potential predictors of severity in patients with COVID-19

Background

The challenge in treating severe COVID-19 in the absence of targeted medication is enforcing physicians to search carefully for clinical predictors of severity.

Aim

To define the profile of patients at risk of severe COVID-19 and to assess for certain predictors.

Methods

Confirmed COVID-19 cases were classified into the following: group A: mild/moderate cases and group B: severe/critical cases according to the selected criteria. History, radiological assessment, complete blood count, lactate dehydrogenase (LDH), myocardial enzymes, serum ferritin, and D dimer were assessed. Patients were followed for the need of ICU and mechanical ventilation. Duration till conversion, length of stay, and mortality were recorded.

Results

A total of 202 patients were analyzed. Group B had higher age (53.2 ± 12.6 vs 40.3 ± 10.3, P < 0.001), more prevalence of DM (60.61% vs 16.57% P < 0.001), hypertension (51.52% vs 20.12%, P < 0.001), ischemic heart (27.27% vs 3.55%, P < 0.001), bronchial asthma (36.36% vs 3.55%, P < 0.001), COPD (9.09% vs 1.18%, P = 0.03), higher mean platelet volume (MPV) (12.76 ± 7.13 vs 10.51 ± 7.78 (fL), P < 0.001), higher serum ferritin (954 ± 138 vs 447 ± 166 ng/ml, P < 0.001), higher LDH (604 ± 220 vs 384 ± 183 U/L, P-value < 0.001), higher creatine phosphokinase (24.27 ± 5.82 vs 16.4 ± 4.87 IU/L, P < 0.001), and higher mortality (30.3% vs 0.6%, P < 0.001). Multivariate regression of predictors of severity identified three predictors; age, MPV, serum ferritin, and IHD.

Conclusions

The current study places of interest the characteristic host-related features of severe COVID-19 and draws attention to potential predictors.

Potential inflammatory biomarkers for tinnitus in platelets and leukocytes: a critical scoping review and meta-analysis

OBJECTIVE

To explore the association between platelets or leukocytes and tinnitus.

DESIGN

A meta-analysis and scoping review examining the association between tinnitus and platelets and leukocytes. All 11 studies included were critically appraised using the Joanna Briggs Institute (JBI) checklist (2017a). A random effects model was used to pool the results of the studies examining mean platelet volume (MPV) and tinnitus.

STUDY SAMPLE

1935 studies were identified in the initial search, 11 of which were included in the scoping review. 6 of the 11 studies had their MPV values pooled in the meta-analysis.

RESULTS

Pooled results of 818 subjects from 6 studies indicated that MPV was significantly higher in those with tinnitus compared to a comparison group without tinnitus. The overall mean difference was 0.43 fL with a 95% confidence interval (CI) from 0.31 to 0.55 and a p value of < 0.0001 which was statistically significant. MPV is the only haematological parameter which is reliably associated with tinnitus.

CONCLUSIONS

MPV could be a useful biomarker for tinnitus. Further studies should aim to standardise methodology with more rigorous exclusion criteria to reproduce and define this association. NLR, PLR, WBC count, RDW and PDW do not show a reliable association with tinnitus.

Association between central non-dipping pattern and platelet morphology in adults with type 1 diabetes without cardiovascular disease: a cross-sectional study

The non-dipping pattern is nighttime systolic blood pressure (SBP) fall of less than 10%. Several studies showed that the non-dipping pattern, increased mean platelet volume (MPV), and platelet distribution width (PDW) are associated with elevated cardiovascular risk. Hypertensives with the non-dipping pattern have higher MPV than the dippers but this relationship was never investigated among people with type 1 diabetes mellitus (T1DM). This study aimed to investigate the association between the central dipping pattern and platelet morphology in T1DM subjects. We measured the central and brachial blood pressure with a validated non-invasive brachial oscillometric device—Arteriograph 24—during twenty-four-hour analysis in T1DM subjects without diagnosed hypertension. The group was divided based on the central dipping pattern for the dippers and the non-dippers. From a total of 62 subjects (32 males) aged 30.1 (25.7–37) years with T1DM duration 15.0 (9.0–20) years, 36 were non-dippers. The non-dipper group had significantly higher MPV (MPV (10.8 [10.3–11.5] vs 10.4 [10.0–10.7] fl; p = 0.041) and PDW (13.2 [11.7–14.9] vs 12.3 [11.7–12.8] fl; p = 0.029) than dipper group. Multivariable logistic regression revealed that MPV (OR 3.74; 95% CI 1.48–9.45; p = 0.005) and PDW (OR 1.91; 95% CI 1.22–3.00; p = 0.005) were positively associated with central non-dipping pattern adjusting for age, sex, smoking status, daily insulin intake, and height. MPV and PDW are positively associated with the central non-dipping pattern among people with T1DM.

Platelets parameters in septic shock: clinical usefulness and prognostic value

: Septic shock is a common cause of admission in the ICUs. Despite tremendous improvement in the management modalities, mortality remains high. Early diagnosis and prompt resuscitation are required to improve prognosis. Therefore, identifying a biomarker that could reveal the sepsis at its earlier stage is of paramount importance. In this regards, platelet parameters, such as mean platelet volume, immature platelet fraction and platelet-derived microparticles have been investigated as possible sepsis biomarkers. In fact, haemostasis disturbances are one of the hallmark of septic shock where platelets play a pivotal role in orchestrating the inflammatory response of the host. Moreover, these parameters could have a prognostic value as the severity of the multiorgan dysfunction is correlated with the inflammatory reaction.

Role of Platelet Indices as a Potential Marker for Malaria Severity

Purpose

Platelet parameter alteration such as platelet count and platelet indices are more common than in other blood cell lines due to diverse causative pathophysiological mechanisms in severe malaria infection. In malaria patients, no more studies evaluated platelet indices in relation to disease severity and prognosis. Therefore, this review assessed the current scientific knowledge on the potential role of platelet indices for the diagnostic marker of severe malaria infection.

Results

Hence, after reviewing recent literatures, elevation of mean platelet volume and platelet distribution width in addition to decreased plateletcrit and platelet counts is the known potential risk factor associated with warning signs of severe malaria. Thus, thrombocytopenia < 150 × 109/L, MPV ≥ 9.05 fL, and PDW ≥ 14.550% as well as significantly higher P-LCR and decrease in PCT are shown significant sensitivity and specificity as they are used as diagnostic and prognostic values in severe malaria infection.

Conclusion

Platelet indices are useful predictors of malaria severity. Immature platelet fraction (IPF%) is raised in the case of severe malaria, and it was significantly more useful than MPV. Advanced research will further investigate the platelet index abnormality associated with specific age and gender among specific malaria species.

Platelet Activity and Its Correlation with Inflammation and Cell Count Readings in Chronic Heart Failure Patients with Reduced Ejection Fraction

Background and objectives: There has been an increasing interest in the role of inflammation in thrombosis complications in chronic heart failure (HF) patients. The incidence of thrombosis in HF has been shown to be the highest in patients classified as NYHA IV (New York Heart association). It is stated that inflammation is regulated by platelet-induced activation of blood leukocytes. We aimed to compare the platelet and cell count readings in chronic HF with reduced ejection fraction (HFrEF) patients according to NYHA functional class and to evaluate the correlation between those readings. Materials and methods: A total of 185 patients were examined. The results of heart echoscopy (TEE) testing; fibrinogen, N-terminal pro b-type natriuretic peptide (NT-proBNP), C reactive protein (CRP), and cortisol concentrations; complete blood counts; and a 6 min walking test were assessed and platelet aggregation was determined. Results: Mean platelet volume (MPV) increased with deterioration of a patient’s state (p < 0.005). Lymphocyte count and percentage were the lowest in the NYHA IV group (p < 0.005). Neutrophil and monocyte percentage and count were the highest (p < 0.045) in the NYHA IV group. Adenosine diphosphate (ADP)- and ADR-induced platelet aggregation was higher in the NYHA III group compared to NYHA II and I groups (p < 0.023). NYHA functional class correlated with mean platelet volume (MPV) (r = 0.311, p = 0.0001), lymphocyte count (r = −0.186, p = 0.026), monocyte count (p = 0.172, p = 0.041), and percentage (r = 0.212, p = 0.011). CRP concentration correlated with NT-proBNP (r = 0.203, p = 0.005). MPV correlated with fibrinogen concentration (r = 0.244, p = 0.004). Conclusions: (1) MPV could be considered as an additional reading reflecting a patient’s condition, however the use of MPV to identify patients at risk of hypercoagulable state should be evaluated in more extensive studies; (2) increased neutrophil and monocyte counts could indicate a higher inflammatory state in chronic HFrEF.

Dynamic Change in Mean Platelet Volume and Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

Background: The mean platelet volume (MPV) has been shown to predict short-term outcomes in patients who have experienced aneurysmal subarachnoid hemorrhage (aSAH). The purpose of this study was to explore the temporal variation of MPV in patients with aSAH and its relationship to the development of delayed cerebral ischemia (DCI).

Methods: Data from 197 consecutive aSAH patients who were treated at our institution between January 2017 and December 2019 were collected and analyzed. Blood samples to assess MPV were obtained at 1–3, 3–5, 5–7, and 7–9 d after the initial hemorrhage. Univariate and multivariate analyses were performed to investigate whether MPV was an independent predictor of DCI and the receiver operating characteristic (ROC) curve and area under the curve (AUC) were determined.

Results: The MPV values in patients with DCI were significantly higher compared to those without DCI at 1–3, 3–5, 5–7, and 7–9 d after hemorrhage (P < 0.001). The trend for MPV in patients with DCI was increased at first and then decreased. The transition from increases to decreases occurred at 3–5 d after hemorrhage. The optimal cutoff value for MPV to accurately predict DCI was 10.35 fL at 3–5 d after aSAH in our cohort. Furthermore, the MPV observed at 3–5 d was an independent risk factor for DCI [odds ratio (OR) = 4.508, 95% confidence interval (CI): 2.665–7.626, P < 0.001].

Conclusions: MPV is a dynamic variable that occurs during aSAH, and a high MPV at 3–5 days after hemorrhage is associated with the development of DCI.

Immature Platelets and Risk of Cardiovascular Events among Patients with Ischemic Heart Disease: A Systematic Review

BACKGROUND

 Immature platelets are larger and may be more thrombogenic than mature platelets. This systematic review included studies on the association between mean platelet volume (MPV), immature platelet count (IPC), and immature platelet fraction (IPF) and the risk of major cardiovascular events (MACEs) in patients with acute coronary syndrome (ACS) or stable coronary artery disease (CAD).

METHODS

 The literature search included studies in PubMed, Embase, Web of Science, and Cochrane Library. The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Effect estimates that included multivariate adjusted odds ratios, relative risks, or hazard ratios were extracted.

RESULTS

 Forty-two studies were identified. High MPV was positively associated with MACE in 20 of 26 studies of patients with ACS, four of five studies in patients with stable CAD, and in all six studies comprising a combined population with ACS and stable CAD. Using continuous models of MPV in patients with ACS, effect estimates varied from 0.90 (95% confidence interval [CI]: 0.95-1.03) to 1.66 (95% CI: 1.32-2.09). The strength of these associations was broadly similar among patients with stable CAD and in combined populations. Five studies investigated IPC or IPF as exposures and all reported positive associations with MACE among patients with ACS, stable CAD, or in combined populations.

CONCLUSION

 This review demonstrated clear evidence for positive associations between measures of immature platelets and subsequent risk of MACE in acute and stable ischemic heart disease patients.

Mean platelet volume/platelet count ratio predicts severe pneumonia of COVID-19

Background

Although platelet mean volume/platelet count ratio (MPR) is considered to be a crucial marker of inflammatory and infectious diseases, the relationship between MPR and novel coronavirus infectious disease 2019 (COVID‐19) remains unclear.

Methods

In this retrospective study, 85 patients with confirmed COVID‐19 were enrolled and divided into low and high MPR group. Data from repeated measures were compared by the generalized estimating equations. Cox regression analyses were performed to assess the impact of MPR on the incidence of severe pneumonia (SP), with inverse probability of treatment weighting (IPTW) used to reduce confounding bias. The primary outcome is the incidence of SP of COVID‐19.

Results

During follow‐up, 17 (20.0%) patients were developed to SP. Compared with mild patients, patients with SP developed showed a higher MPR level at baseline, day 1, day 2, and day 3 after admission (P = .005, P = .015, P = .009, and P = .032, respectively). Kaplan‐Meier method showed a higher incidence of SP in the high MPR group than the low MPR group (log‐rank test = 10.66, P = .001). After adjustment, high MPR was associated with an elevated incidence of SP (HR, 5.841, 95% CI, 1.566‐21.791, P = .009). The IPTW method also suggested that MPR was a significant factor related to the incidence of SP (HR, 8.337, 95% CI, 4.045‐17.182, P < .001).

Conclusion

High MPR level is an independent risk factor for severe pneumonia in patients with COVID‐19.

Letter to the Editor: Mean Platelet Volume to Platelet Count Value May Not Be a Prognostic Marker in Patients with Crimean-Congo Hemorrhagic Fever

To the Editor, We read with great interest the retrospective article of Tekin and Engin that investigated the prognostic significance of the ratio of mean platelet volume (MPV) to platelet count ratio (MPVPCR) in patients with Crimean-Congo hemorrhagic fever (CCHF). The authors found that MPVPCR was significantly lower in survivors than in non-survivors, and there-fore they suggested that this ratio could be used as a mortality marker. We think there are other factors that might have affected the results of this study.

Platelet indices in patients with chronic inflammatory arthritis: a systematic review and meta-analysis

Correlation between platelet indices and chronic inflammatory arthritis (CIA) remains a moot point today. This meta-analysis aimed to evaluate whether platelet (PLT) count, mean platelet volume (MPV) and platelet distribution width (PDW) associated with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA). A systematic literature search was performed in PubMed, EMBASE, and Web of Science up to August 2019. Pooled standardized mean differences (SMD) and 95% confidence interval (CI) were calculated using a random-effect model. As a result, 34 studies were included, encompassing 17 on RA, 12 on AS, 3 on PsA and 2 on both RA and AS. In these studies, PLT count was significantly higher in RA (SMD = 0.55, 95% CI = 0.36-0.73, P < .001), AS (SMD = 0.53, 95% CI = 0.36-0.70, P < .001) and PsA patients (SMD = 1.29, 95% CI = 0.82-1.77, P < .001) than that in healthy subjects, while MPV and PDW presented nonsignificant differences in these intergroup comparisons (P > .05), and similar results were observed in subgroup analyses. The meta-regression analysis demonstrated that there were strong positive correlations between erythrocyte sedimentation rate and PLT count, and weak correlation trend between the disease activity score and PLT count in both RA and AS subjects without statistically significant difference. The sensitivity analysis indicated that these results were not unduly influenced by any single study. In conclusion, this meta-analysis demonstrated that PLT count was elevated in CIA patients and could be suitable for evaluating the disease activity, whereas MPV and PDW were independent of CIA.

Influence of different methods and anticoagulants on platelet parameter measurement

Platelets are the smallest and perhaps the most versatile components of human blood. Besides their role in coagulation and the maintenance of vascular integrity, they are involved in many physiological processes, ranging from immune response and leukocyte recruitment to the production of antimicrobial peptides and immune-suppressive factors like TGF-β. These versatile abilities make platelets interesting for researchers from different disciplines. However, beside profound investigation into platelets’ physiological role, there is a need for correct, standardized and thus reproducible quantification of platelet parameters. Mean platelet volume (MPV) is a widespread prognostic marker for several conditions, such as, acute coronary syndrome, chronic kidney disease and liver cirrhosis. Platelet activation is regarded as a marker for inflammatory processes, for example in autoimmune diseases such as type-1 diabetes, systemic lupus erythematosus and rheumatoid arthritis. The monitoring of platelet function is relevant for patients receiving antiplatelet medication. Platelet parameter measurement is affected by the choice of in vitro anticoagulant, the measurement technology and the time delay after sampling. This review focuses on the pre-analytical variability that arises as a result of the use of different in vitro anticoagulants and analyzer technologies when determining platelet parameters, since, even approximately 180 years after the discovery of platelets, there is still no standardized procedure.

Novel Approaches to Fine-Tune Therapeutic Targeting of Platelets in Atherosclerosis: A Critical Appraisal

The pathogenesis of atherosclerotic vascular disease is driven by a multitude of risk factors intertwining metabolic and inflammatory pathways. Increasing knowledge about platelet biology sheds light on how platelets take part in these processes from early to later stages of plaque development. Recent insights from experimental studies and mouse models substantiate platelets as initiators and amplifiers in atherogenic leukocyte recruitment. These studies are complemented by results from genetics studies shedding light on novel molecular mechanisms which provide an interesting prospect as novel targets. For instance, experimental studies provide further details how platelet-decorated von Willebrand factor tethered to activated endothelial cells plays a role in atherogenic monocyte recruitment. Novel aspects of platelets as atherogenic inductors of neutrophil extracellular traps and particularities in signaling pathways such as cyclic guanosine monophosphate and the inhibitory adaptor molecule SHB23/LNK associating platelets with atherogenesis are shared. In summary, it was our intention to balance insights from recent experimental data that support a plausible role for platelets in atherogenesis against a paucity of clinical evidence needed to validate this concept in humans.

Effects of Time-Interval since Blood Draw and of Anticoagulation on Platelet Testing (Count, Indices and Impedance Aggregometry): A Systematic Study with Blood from Healthy Volunteers

Platelet count, indices (mean volume, young-immature platelet fraction) and aggregation are widely used laboratory parameters to investigate primary hemostasis. We performed a systematic, thorough evaluation of the influence of the time-interval since blood draw from 20 healthy individuals and of the anticoagulation of collected blood on such parameters. Blood was anticoagulated with citrate, K₂-ethylenediaminetetraacetic acid (EDTA) and hirudin and analyzed 5, 30, 60, 120 and 180 min after blood draw. Multiple electrode aggregometry (MEA) was performed with either hirudin (half-diluted with NaCl) or citrate samples (half-diluted with NaCl or CaCl₂ 3 mM). Platelet count and indices (Sysmex XN-20) were rather stable over time with EDTA blood. MEA results were lower with citrate blood than with hirudin blood; supplementation with calcium was partially compensatory. MEA results were also lower when performed less than 30 or more than 120 min after blood draw. Platelet clumping, quantitatively estimated with microscope examination of blood smears, was more important in hirudin blood than citrate or EDTA blood and could explain some of the differences observed between preanalytical variables. The results stress once more the importance of preanalytical variables in hemostasis laboratory testing. Decision thresholds based on those tests are only applicable within specific preanalytical conditions.

Platelet Measurements and Type 2 Diabetes: Investigations in Two Population-Based Cohorts

Type 2 diabetes is a major risk factor for cardiovascular disease. Given the contribution of platelets to atherothrombosis—which in turn is a major contributor to cardiac events, there may be cause to consider platelet function in management of diabetes. Despite the large body of research concerning the role of platelets in cardiovascular complications of type 2 diabetes, evidence from population-based studies of platelet aggregation in diabetes is limited. Mean Platelet Volume (MPV), a cell trait partially associated with markers of platelet activity, is more commonly available. We investigated the association of metabolic syndrome and diabetes with platelet aggregation to three physiological agonists, ADP, collagen, and epinephrine, in the Framingham Heart Study Offspring cohort. We further examined the relationship between MPV measured with Beckman Coulter LH750 instruments and self-reported diabetes as well as MPV and diabetes medication in the UK BioBank cohort, performing the largest such analysis to date. Increased platelet aggregation associated with prevalent diabetes was observed for low concentration epinephrine (0.1 μM) alone and only in analyses of participants stratified either by male sex and/or having metabolic syndrome. Other agonists and concentrations were not significant for prevalent diabetes, or in opposite direction to the main hypothesis (i.e., they showed lower platelet aggregation associated with diabetes). After a median of 18.1 years follow-up, no platelet aggregation trait was associated with increased risk of diabetes (n = 344 cases). As expected, increased MPV was significantly associated with diabetes (β = 0.0976; P = 8.62 × 10⁻³³). Interestingly, sex-stratified analyses indicated the association of MPV with diabetes is markedly stronger in males (β = 0.1232; P = 1.00 × 10⁻³¹) than females (β = 0.0514; P = 7.37 × 10⁻⁵). Among diabetes medications increased MPV was associated with Insulin (β = 0.1341; P = 1.38 × 10⁻¹¹) and decreased MPV with both Metformin (β = 0.0763; P = 1.99 × 10⁻⁶) as well as the sulphonylureas (β = 0.0559; P = 0.0034). Each drug showed the same direction of effect in both sexes, however, the association with MPV was nearly twice as great or more in women compared to men. In conclusion, platelet function as measured by aggregation to ADP, collagen, or epinephrine does not appear to be consistently associated with diabetes, however, MPV is robustly associated suggesting future work may focus on how MPV segments pre-diabetics and diabetics for risk prediction.

Multicenter evaluation of analytical performances of platelet counts and platelet parameters: Carryover, precision, and stability

INTRODUCTION

The correctness of the results of automated platelet analysis is still highly debated. The aim of this multicenter study, conducted according to international guidelines, was to verify the analytical performance of nine different types of hematology analyzers (HAs) in the automated platelet analysis.

METHODS

Four hundred eighty-six peripheral blood samples (PB), collected in K₃ EDTA tubes, were analyzed by ABX Pentra, ADVIA2120i, BC-6800, BC-6800 Plus, Cell-DYN Sapphire, DxH800, XE-2100, XE-5000, XN-20 with PLT-F App. Within-run imprecision and between-run imprecision were carried out using PB and material control, respectively. The carryover, low limit of quantification (LoQ), and the PB stability were evaluated.

RESULTS

The carryover was absent for all HAs. The LoQ of PLT ranged between 2.0 (Cell-Dyn Sapphire) and 25.0 × 10⁹ /L (ADVIA 2120i), while immature platelet fraction (IPF) ranged between 1.0 (XN-20) and 12.0 × 10⁹ /L (XE-5000). The imprecision (%CV) increases as the platelet count decreases. No HAs showed desirable CV_APS for PLT counts less than 50.0 × 10⁹ /L, with the exception of Cell-DYN Sapphire (CV 3.0% with PLT-O mean value of 26.7 × 10⁹ /L), XN-20 (CV 2.4% with PLT-F mean value of 21.5 × 10⁹ /L), and BC-6800 Plus (CV 1.9% with PLT-O mean value of 26.5 × 10⁹ /L). The sample stability ranged between under two hours for MPV by ADVIA2120i and 8 hours for other PLT parameters and HAs.

CONCLUSION

The findings of this study may provide useful information regarding carryover, precision, and stability of platelet counts and parameters, especially in thrombocytopenic samples. Moreover, the stability of sample for platelet analysis is conditioned by the HA and by temperature and storage time.

Is Migraine an MPV-Related Disease? An Observational Study of Polish Neurological Patients

Many studies have found correlations between abnormal MPV and clinical reactivity in a variety of diseases. In the present paper, we sought MPV-related neurological diseases that are less frequently reported in the literature. The electronic medical records of 852 neurological patients with mean platelet volume (MPV) measurements (F = 45%, age = 55.7 ± 18.7, 8–104) were searched after the patients had received a diagnosis of a neurological disease (new and old episodes) according to the nine classes of the International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10). A set of consecutive statistical methods (i.e., cluster analysis, segmented regression, linear correlation, propensity score matching, and mixed effects Poisson regression) were used to establish a link between MPV and neurological disease. A statistically significant (p < 0.05) relationship with MPV was found only in pain syndrome patients, with seven out of eight clinically diagnosed migraine episodes. With all other ICD-10 classes of neurological diseases, the effect of MPV was found to be nonsignificant (p > 0.05). MPV may implicate a clinical relationship with pain syndrome and migraine episodes. More complex statistics could help analyse data and find new correlations.

High plateletcrit is associated with early loss of patency after open and endovascular interventions for chronic limb ischemia

OBJECTIVE

Plateletcrit (PCT) reflects the total platelet mass in blood and can be calculated from a complete blood count. We examined the effect of PCT on outcomes of endovascular and open interventions for chronic limb ischemia.

METHODS

Patients who underwent revascularization for chronic limb ischemia (Rutherford categories 3-6) between June 2001 and December 2014 were retrospectively identified. PCT on admission was recorded. Patients and limbs were divided into tertiles of low (0.046-0.211), medium (0.212-0.271), and high (0.272-0.842) PCT. Patency, limb salvage, major adverse limb events, major adverse cardiac events, and survival rates were calculated using Kaplan-Meier analysis and compared with log-rank test. Cox regression analysis was used for multivariate analysis.

RESULTS

A total of 1431 limbs (1210 patients) were identified and divided into low PCT (477 limbs in 407 patients), medium PCT (477 limbs in 407 patients), and high PCT (477 limbs in 396 patients) groups. The patients in the high tertile were 2 years older that the patients in the other two tertiles (P = .009). Five-year primary patency was 65% ± 3% in the low-PCT group compared with 55% ± 3% and 51% ± 3% in the medium and high PCT groups, respectively (P = .004). Five-year secondary patency was 81% ± 2% in the low PCT group compared with 82% ± 2% and 72% ± 3% in the medium and high PCT groups, respectively (P = .02). Five-year limb salvage rate was 86% ± 2% in the low PCT group compared with 79% ± 3% and 74% ± 3% in the medium PCT and high PCT groups, respectively (P = .004). Multivariate regression analysis showed that low PCT was independently associated with primary patency after endovascular interventions (hazard ratio, 0.67 [0.47-0.95]; P = .02) but not after open interventions (hazard ratio, 0.72 [0.43-1.21]; P = .21).

CONCLUSIONS

High PCT is associated with poor patency and limb salvage rates after interventions for lower extremity chronic limb ischemia. Multivariate regression analysis confirmed association of low PCT with improved primary patency after endovascular interventions but not after open interventions. High PCT may be a marker of increased platelet reactivity and could be used to identify patients at high risk for early thrombosis and failure after interventions.

High mean platelet volume to platelet count ratio as a predictor on poor outcomes after CABG

OBJECTIVES

To determine the effect of mean platelet volume (MPV) to platelet count (PC) ratio on postoperative poor outcomes, early mortality and long-term survival rate in patients undergoing CABG.

METHODS

Between February 2016 and September 2018, all patients undergoing CABG in our department were retrospectively reviewed. A total of 213 consecutive patients were included in the study.

RESULTS

Mean age was 61.5 ± 9.7 years and mean follow-up of all patients was 1.4 ± 0.5 years. All patients were divided into two groups as high and low MPV/PC ratio in terms of 3.825 of cut-off point. 72 patients had a high MPV/PC ratio, whereas, 141 patients had low MPV/PC ratio. The rates of reoperation for early vein-graft occlusion, low cardiac output syndrome and respiratory complication were significantly higher in group 1 (p = 0.03, 0.04 and 0.01). The mean hospital length of stay was higher in group 1 (p = 0.03). MPV/PC ratio for reoperation for early vein-graft occlusion; MPV and ejection fraction for low cardiac output syndrome; hyperlipidemia, chronic renal failure history and MPV/PC ratio for sepsis; male gender, CRF history and CPB time for atrial fibrillation; age, congestive heart failure history, myocardial infarction history and CPB time for the early mortality were found to be independent predictors. Peripheral arterial diseases, USAP and MPV/PC ratio were found to be independent predictors for the late mortality.

CONCLUSIONS

A high MPV/PC ratio is associated with early vein-graft occlusion and poor postoperative outcomes in the early period after CABG. Furthermore, it has a negative effect on late survival.

Predictive Value of Mean Platelet Volume/Platelet Count for Prognosis in Acute Myocardial Infarction

Increased mean platelet volume (MPV) has been associated with adverse clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI). We aim to assess whether MPV/platelet count (MPV/PC) ratio is a useful marker to predict long-term prognosis in patients with STEMI undergoing PCI. Moreover, the prognostic accuracy of MPV/PC ratio is compared with MPV. 962 consecutive patients with STEMI treated with P-PCI were considered. According to the admission MPV/PC values, the population was divided into two groups: high MPV/PC group (n = 320, MPV/PC ≥ 0.055) and low MPV/PC group (n = 642, MPV/PC < 0.055). Multivariate analysis showed that high MPV/PC was an independent predictor of major adverse cardiovascular event (MACE; hazard ratio [HR]: 1.121, 95% confidence interval [CI]: 1.056-1.190, P < 0.01), all-cause mortality (HR: 1.109, 95% CI: 1.016-1.209, P = 0.020), cardiac mortality (HR: 1.141, 95% CI: 1.038-1.253, P = 0.006), nonfatal myocardial reinfarction (HR: 1.148, 95% CI: 1.044-1.262, P = 0.004), and unplanned repeat revascularization (HR: 1.073, 95% CI: 1.007-1.144, P = 0.030), respectively. MPV/PC ratio has good accuracy for predicting MACE (the area under the receiver-operating characteristic curve: 0.764), and the cut-off value was 0.054 with a sensitivity of 0.813 and a specificity of 0.662. The discriminatory performance of MPV/PC ratio was better than MPV for predicting MACE (MPV/PC ratio versus MPV: z = 2.285, P = 0.022), in patients with STEMI undergoing P-PCI. MPV/PC ratio is able to but better than MPV to predict long-term adverse outcomes in patients with STEMI undergoing P-PCI.

Routine haemostasis testing before transplanted kidney biopsy: a cohort study

Kidney biopsy can result in bleeding complications. Prebiopsy testing using bleeding time (BT) is controversial. New whole blood haemostasis tests, such as platelet function analyser-100 (PFA-100) and multiple electrode aggregometry (MEA), might perform better. We postulated that PFA-100 would be suitable to replace BT prebiopsy. In 154 patients, transplanted kidney biopsies were performed after measurement of bleeding time, PFA-100, MEA and mean platelet volume (MPV). Bleeding outcome (haemoglobin (Hb) drop, haematuria (±bladder catheterization), ultrasound finding of a bleeding, need for (non)surgical intervention and/or transfusion) after the biopsy was correlated to each test. Male-female ratio was 2:1. 50% had a surveillance biopsy at either three or 12 months. Around 17% (had) used acetylsalicylic acid (ASA) prebiopsy. Of 17 bleeding events, one subject needed a transfusion. Most bleeding events were Hb reductions over 1 mmol/l and all resolved uneventful. BT, PFA-100, MEA and MPV did not predict a bleeding outcome; prior ASA use however could (odds ratio 3.19; 95%-CI 1.06 to 9.61). Diagnostic performance data and Bland-Altman analysis showed that BT could not be substituted by PFA-100. ASA use was the best determinant of bleeding after kidney biopsy. Routine haemostasis testing prebiopsy has no added value.

Mean Platelet Volume and Immature Platelet Fraction in Autoimmune Disorders

Mean platelet volume (MPV), measured using automated blood analysers, has been appraised as a potential biomarker in cardiovascular disease, diabetes mellitus, and cancer. The test, a useful tool in differentiation of thrombocytopenic states, has now been carried out for autoimmune disorders, but data are yet scarce. Controversial results have been obtained in systemic and organ-specific autoimmune disorders. Another test, the immature platelet fraction (IPF) reflects the amount of young, reticulated platelets. IPF is calculated by automated hematology analysis or flow cytometry, and it is usually high in patients with rapid platelet destruction. For both MPV and IPF, standardization of cutoff is a major need. In this review, we focus the current applicability of MPV and IPF as biomarkers in patients with autoimmune diseases.

The genetics of platelet count and volume in humans

The last decade has witnessed an explosion in the depth, variety, and amount of human genetic data that can be generated. This revolution in technical and analytical capacities has enabled the genetic investigation of human traits and disease in thousands to now millions of participants. Investigators have taken advantage of these advancements to gain insight into platelet biology and the platelet's role in human disease. To do so, large human genetics studies have examined the association of genetic variation with two quantitative traits measured in many population and patient based cohorts: platelet count (PLT) and mean platelet volume (MPV). This article will review the many human genetic strategies-ranging from genome-wide association study (GWAS), Exomechip, whole exome sequencing (WES), to whole genome sequencing (WGS)-employed to identify genes and variants that contribute to platelet traits. Additionally, we will discuss how these investigations have examined and interpreted the functional implications of these newly identified genetic factors and whether they also impart risk to human disease. The depth and size of genetic, phenotypic, and other -omic data are primed to continue their growth in the coming years and provide unprecedented opportunities to gain critical insights into platelet biology and how platelets contribute to disease.