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

Measurement of Platelet Counts and Volume Using Magnesium Sulfate as an Anticoagulant: Comparison of Impedance and Light-Scatter Technology

OBJECTIVES

Magnesium sulfate (MgSO 4 ) was recently reported as an alternative in vitro anticoagulant in pseudo-thrombocytopenia. Its suitability as an anticoagulant for the determination of reliable platelet parameters is the subject of this study.

METHODS

Platelet count and mean platelet volume were measured in blood samples anticoagulated with EDTA and MgSO 4 and compared. The platelet parameters were determined by impedance (XE 5000 [Sysmex, Norderstedt, Germany]; DxH 800 [Beckman-Coulter, Krefeld, Germany]) and laser light-scatter technology (Advia 120 [Siemens Healthcare Diagnostics, Eschborn, Germany]).

RESULTS

MgSO 4 anticoagulation underestimated platelet counts compared with EDTA. Mean platelet volume (MPV) in magnesium-anticoagulated blood was lower when measured by impedance but higher when light-scatter technology was used. Storage of the differently anticoagulated blood led to differently lower platelet counts after 24 hours, independent of the anticoagulant. In EDTA blood, the mean platelet volume increased moderately when measured by impedance but markedly when measured by laser light scatter. In MgSO 4 -anticoagulated blood, the MPV increase was negligible.

CONCLUSIONS

Impedance technology and magnesium anticoagulation might be advantageous for standardizing MPV measurements, although the mean platelet count is slightly underestimated by both technologies.

Mean platelet volume and mortality risk in a national incident hemodialysis cohort

BACKGROUND

Higher mean platelet volume (MPV) is an indicator of larger, reactive platelets, and has been associated with a higher risk of thrombosis and cardiovascular events in the general population. Hemodialysis patients have a higher risk for cardiovascular death and predisposition to platelet dysfunction (thrombosis and bleeding diathesis), but the relationship between MPV and mortality in this population is unknown.

METHODS

Among a 5-year cohort (1/2007-12/2011) of 149,118 incident hemodialysis patients from a large national dialysis organization, we examined the association between MPV and all-cause mortality. In primary analyses, we granularly analyzed MPV across five categories: 7.2-7.5, >7.5-9.5, >9.5-11.5, >11.5-13.5, and >13.5-15.0fL. In secondary analyses, we examined MPV categorized as low, normal, and high based on thresholds in the general population: 7.2-7.5, >7.5-11.5, and >11.5fL, respectively. Associations between baseline and time-dependent MPV with mortality were estimated using traditional and time-dependent Cox models in order to determine long-term and short-term exposure-mortality associations, respectively, using three adjustment levels: unadjusted, case-mix, and case-mix+laboratory models.

RESULTS

In primary analyses, higher baseline and time-dependent MPV levels were associated with incrementally higher death risk in case-mix+laboratory analyses (reference: >9.5-11.5fL). In secondary analyses, high baseline and time-dependent MPV levels were associated with higher mortality, whereas low MPV was associated with lower death risk across all multivariable models (reference: normal MPV).

CONCLUSIONS

Hemodialysis patients with higher MPV have heightened mortality risk. Further studies are needed to determine the pathophysiologic basis for the higher risk, and if modification of MPV ameliorates mortality in this population.

Usefulness of mean platelet volume as a marker for clinical outcomes after out-of-hospital cardiac arrest: a retrospective cohort study

Essentials It is unknown whether mean platelet volume (MPV) estimates outcomes after cardiac arrest (CA). We investigated whether MPV was associated with 30-day neurologic outcome and mortality after CA. Elevated MPV at admission was associated with poor neurological outcomes and mortality at 30 days. Identifying levels of MPV is helpful for estimating disease severity among resuscitated patients.

SUMMARY

Background Whole-body ischemia followed by reperfusion during cardiac arrest and after return of spontaneous circulation (ROSC) triggers systemic sterile inflammatory responses, inducing a sepsis-like state during post-cardiac arrest syndrome. Activated platelets are enlarged, and contain vasoactive and prothrombic factors that aggravate systemic inflammation and endothelial dysfunction. Objectives To investigate whether mean platelet volume (MPV) is useful as a marker for early mortality and neurologic outcomes in patients who achieve ROSC after out-of-hospital cardiac arrest (OHCA). Methods OHCA records from the Emergency Department Cardiac Arrest Registry were retrospectively analyzed. Patients who survived for > 24 h after ROSC were included. We evaluated mortality and cerebral performance category scores after 30 days. Results We analyzed records from 184 patients with OHCA. Increased 30-day mortality among patients who achieved ROSC after OHCA was associated with MPV at admission (hazard ratio [HR] 1.36; 95% confidence interval [CI] 1.06-1.75). An elevated MPV at admission was also associated with poor neurologic outcomes (HR 1.28; 95% CI 1.06-1.55). Conclusions An elevated MPV was independently associated with increased 30-day mortality, with the highest discriminative value being obtained upon admission after OHCA. An elevated MPV on admission was associated with poor neurologic outcomes. High MPVs are helpful for estimating 30-day mortality and neurologic outcomes among patients who achieve ROSC after OHCA.

No associations exist between mean platelet volume or platelet distribution width and thyroid function in Chinese

Mean platelet volume (MPV) and platelet distribution width (PDW) are morphometric indices of size distribution and variability of platelet. We aimed to explore the associations between MPV or PDW and thyroid function in a large Chinese cohort.This was a cross-sectional study with a recruitment of 13,622 self-reported healthy Chinese (8424 males, 5198 females). Clinical data of the participants comprised of anthropometric measurements, hepatic function, renal function, serum levels of lipid, glucose, C-reactive protein, erythrocyte sedimentation rate, platelet, MPV, PDW, and thyroid hormones. Database was sorted by sex, and the associations between MPV or PDW and thyroid function were analyzed by quartiles of MPV or PDW. Levels of MPV and PDW were compared in different thyroid function subgroups by 1-way analysis of variance and independent sample's t test. Receiver-operating characteristic (ROC) curve was adopted to determine diagnostic values of MPV and PDW for thyroid dysfunction. Crude and adjusted odds ratios of MPV and PDW for thyroid dysfunction with 95% confidence intervals were analyzed by binary logistic regression models.MPV, PDW, and thyroid stimulation hormone were significantly higher in females than in males. Females showed significantly higher incidence of hypothyroidism and hyperthyroidism than males. However, there were no significant differences of MPV and PDW among different thyroid function subgroups in both sexes, and no obvious correlations were revealed between MPV or PDW and thyroid function. From ROC analysis, we demonstrated no diagnostic values of MPV and PDW for thyroid dysfunction. From binary logistic regression models, no risks of different MPV and PDW quartiles were identified for thyroid dysfunction in both sexes.We could not show any association between MPV or PDW and thyroid function. Prospective studies with better defined risk groups should be performed in the future for further verification and validation.

Magnesium Sulfate as an Alternative In Vitro Anticoagulant for the Measurement of Platelet Parameters?

OBJECTIVES

There are conflicting reports on the reliable measurement of platelet count and mean platelet volume (MPV) using EDTA or citrate. The anticoagulant properties of magnesium sulfate (MgSO4) are known from the literature. The aim of this study was to evaluate MgSO4 as an in vitro anticoagulant for platelet count, MPV, platelet distribution width, and platelet activation.

METHODS

Whole blood from volunteers was anticoagulated by EDTA, citrate, or MgSO4 Platelets were counted by the XE 5000 (Sysmex, Norderstedt, Germany) impedance and fluorescence optical technique.

RESULTS

The mean impedance platelet counts were 227.7, 197.0, and 201.1 × 10(9)/L in EDTA-, citrate-, or MgSO4-anticoagulated blood, respectively. The counts were 4.7% higher (EDTA) after 3 hours of storage but 4% lower in citrate-anticoagulated blood. The counts in magnesium samples remained stable. The MPV was 10.4 fL (EDTA), 9.5 fL (citrate), and 9.3 fL (MgSO4). EDTA samples showed cell swelling within the first 3 hours. This was lower in citrate and only marginal in magnesium samples. High activation of platelets was observed only in EDTA samples.

CONCLUSIONS

Magnesium anticoagulation might be advantageous for more reliable MPV measurements. Although platelet count is underestimated when the impedance method is used, the platelet count reveals similar results when measured by the fluorescent optical method.

The association between mean platelet volume and spontaneous echocardiographic contrast or left atrial thrombus in patients with mitral stenosis

Objective:

Although the role of platelet activation has been debated in patients with mitral stenosis (MS) and spontaneous echocardiographic contrast (SEC), data on differences in mean platelet volume (MPV) according to the presence of SEC/left atrial thrombus and the rhythm status are lacking. In this study, MPV was analyzed in patients with MS according to the presence of SEC/left atrial thrombus.

Methods:

Between January 2005 and March 2014, 188 symptomatic patients having moderate or severe MS (mean age, 45.0±11.7 years; female, 81.4%) with favorable valve morphology for percutaneous mitral balloon valvuloplasty (PMBV) and underwent a transesophageal echocardiogram to assess the eligibility for PMBV were retrospectively enrolled in the study. The relation between MPV and echocardiographic thromboembolic risk factors were evaluated. Independent predictors of SEC/left atrial thrombus presence were determined by multiple logistic regression analyses.

Results:

Among all patients, MPV did not differ according to the rhythm status or the presence of SEC/left atrial thrombus (p>0.05). Also, MPV did not vary according to the gender and presence of prior stroke in both atrial fibrillation and sinus rhythm groups (p>0.05). In correlation analysis, MPV did not show any significant correlation with the echocardiographic thrombus predictors (p>0.05).

Conclusion:

Using MPV with echocardiographic and clinical thrombus risk determinants for predicting individual thromboembolism risk in MS is debatable according to our results.

Platelet volume is associated with the Framingham risk score for cardiovascular disease in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Background:

Platelet volume indices (PVI), an easy and inexpensive surrogate measure of platelet function, have been associated with cardiovascular diseases (CVD) and their risk factors. However, results are conflicting because of the lack of standardized procedures. The purpose of this study is to investigate the relationship of PVI with the Framingham risk score (FRS).

Methods:

Baseline data (2008–2010) of 3115 participants enrolled in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) were used. PVI measurements were strictly controlled. The cohort was distributed according to risk factors and the general FRS was estimated. Multiple linear regression analysis was used to estimate the association between PVI and FRS.

Results:

Mean platelet volume (MPV), platelet distribution width (PDW) and platelet large cell ratio (P-LCR) independently correlated (p≤0.01) with FRS after adjustment for confounding variables. One unit increase in MPV, PDW, or P-LCR increased the FRS by 0.59%, 0.40%, and 0.08%, respectively. Diabetics had higher (p≤0.004) MPV, PDW, and P-LCR, and hypertensive individuals had higher (p≤0.045) PDW and P-LCR.

Conclusions:

Increased PVI was independently correlated with higher CVD risk based on the FRS, diabetes, and systolic hypertension. Prospective follow up of this cohort is warranted to confirm that PVI is associated with the development of CVD.

Mean Platelet Volume as a Surrogate Marker for Platelet Activation in Patients With Idiopathic Pulmonary Fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is associated with a prothrombotic state.

AIM

To study mean platelet volume (MPV) and Platelet Distribution Width (PDW) as markers of platelet activation and their potential association with lung function in patients with recently diagnosed IPF.

MATERIALS AND METHODS

This study included 56 patients with IPF (age 64.9±7.4 years) and 79 controls (age 64.2 ± 5.9 years).

RESULTS

An inverse relation was demonstrated between platelet count and MPV in the control group but not among patients with IPF. Platelet count was significantly lower in patients with IPF compared with controls (230 ± 60 vs 256 ± 75 × 10(3)/μL, P = .038). Conversely, MPV was higher in patients versus controls (10.3 ± 1.2 vs 9.8 ± 1.2 fl, P = .024), while there was no difference between the groups in PDW. Respiratory function was, as expected, significantly impaired in patients with IPF versus controls in terms of forced expiratory volume in first second (FEV1; 67.2 ± 23.1 vs 102.6 ± 15.9% of predicted value, P < .001), forced vital capacity (FVC; 65.3 ± 21 vs 95.2 ± 16.1% of predicted value, P < .001), FEV1/FVC (83.1 ± 15 vs 87.5 ± 6.4%, P = .041) and partial pressure of oxygen in arterial blood (PaO2; 67.1 ± 10.3 vs 81.5 ± 15.2 mm Hg, P < .001). No significant correlation was seen between MPV and FVC (r = -.1497, P = .275), MPV and lung diffusion capacity for carbon monoxide (r = .035, P = .798) and total lung capacity (r = .032, P = .820).

CONCLUSIONS

Patients with IPF exhibit higher MPV values and lower platelet count. Further studies are needed to assess the clinical implications of these findings.

Renal artery stenosis and mean platelet volume

Objective:

Increased mean platelet volume (MPV) has been reported in various atherosclerotic diseases. The aim of our study was to investigate the relationship between the atherosclerotic renal artery stenosis (ARAS) and various hematological parameters including MPV.

Methods:

This study was performed with a retrospective review of the angiographic images of patients who underwent renal angiography at Bülent Ecevit University catheter laboratory between January 2004 and December 2009. The patients were trichotomized into three groups based on the presence and severity of renal artery stenosis (RAS). Group 1 included patients with a critical RAS (33 patients; 18 female (F), 15 male (M); mean age 61.6±11.5 years), group 2 consisted of patients with non-critical RAS (26 patients; 15 F, 11 M; mean age 58.1±11.3 years), and group 3 was composed of patients without RAS (69 patients; 38 F, 31 M; mean age 53.5±11.9 years). Demographic data, complete blood count, and biochemical parameters were compared between the groups.

Results:

Comparison of the hematological parameters revealed that MPV and platelet distribution width were significantly higher in group 1 than in group 2 and 3 (8.96±0.99 fL versus 8.35±0.76 fL, 8.31±0.79 fL, respectively; p=0.001; 16.53±0.58% versus 16.19±0.56%, 16.29±0.53%, respectively; p=0.04).

Conclusion:

MPV levels are higher in patients with ARAS. Considering both the effect of platelets on atherosclerosis and their close association with other risk factors, MPV level may be an important factor in pathogenesis of ARAS.

Relationship between mean platelet volume and retinopathy of prematurity

PURPOSE

We aimed to investigate the association between mean platelet volume (MPV) and the occurrence of type 1 retinopathy of prematurity (ROP).

MATERIALS AND METHODS

This was a retrospective case-control study. Cases with ROP required laser surgery; controls developed no ROP or stage 1 ROP. Most recent peripheral blood platelet indices before laser (case) and matched age (control) were abstracted. Student's t-test and multivariate logistic regression analysis were used.

RESULTS

A significant difference was found in MPV values between infants with ROP and control groups (10.76 ± 1.27 fl, 10.04 ± 0.91 fl, p = 0.0001). No significant differences were found in the mean platelet counts or MPV/Platelet counts between the two groups (p = 0.4151, p = 0.1460, respectively). There was a 1.94-fold increase in the risk of retinopathy of prematurity (OR:1.94; p = 0.005) as the MPV value increased.

CONCLUSIONS

Elevated MPV is associated with the occurrence of type 1 ROP. A hypothesis is presented concerning the role of platelets as sequester and deliverer angiogenesis regulators during the neovascularization phase of ROP.

Is mean platelet volume really a severity marker for obstructive sleep apnea syndrome without comorbidities?

Obstructive sleep apnea syndrome (OSAS) is a common disorder that can lead to significant cardiovascular complications. Several studies have reported increased platelet activation and aggregation in patients with OSAS. In this study we aimed to show a correlation between mean platelet volume (MPV) and severity of OSAS in patients with OSAS without any overt cardiac disease or diabetes. The polysomnography recordings of 556 consecutive patients admitted to the sleep laboratory between January 2012 and July 2012 were retrospectively evaluated. The relationship between polysomnographic parameters and biochemical parameters was assessed. Polysomnographic results of 200 patients (154 males [77%]; mean age, 44.5 ± 11.4 years) were included. No correlation was observed between MPV and the average oxygen saturation index, the minimum desaturation index, or the oxygen desaturation index in the study population as well as in severe OSAS group (AHI > 30). The only correlation was found between MPV and AHI in the severe OSAS group (P = 0.010). MPV was not correlated with OSAS severity in patients without any overt cardiac disease or diabetes. These findings raise doubts about the suggestion that MPV might be a marker for OSAS severity, as recommended in earlier studies. Thus, further prospective data are needed.

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

In E.N.T clinical practice, patients with nasal obstruction due to deviated nasal septum is a common presentation. Nasal airway obstruction is a common cause of upper airway obstruction further leading to obstructive and hypoxic manifestations. Mean platelet volume (MPV) levels increase in hypoxic conditions. MPV is one of the platelet activation index which reflects the platelet production rate. Present prospective study conducted in the department of Otorhinolaryngology and Head and Neck surgery, Gandhi Medical College and Hamidia Hospital, Bhopal, on 63 patients with the clinical evidence of DNS and 63 healthy age matched subjects as control group, aimed to evaluate the relationship between MPV levels and nasal obstruction due to deviated nasal septum (DNS). The diagnosis of patients with DNS was based on anterior rhinoscopy and endoscopic nasal examination. Blood samples were collected before surgical correction. In present study, the authors found that there is preponderance of DNS in the age group of 25-45 years being the most active age group, males having the higher incidence. Majority of cases of DNS being left sided and of obstructed type. MPV were significantly higher in patients with DNS than the control group. Among the cases MPV being higher in females and in the impacted type of DNS. Present study reemphasized the concept that MPV is increased in chronic nasal obstruction due to DNS and this increase is in accordance with the severity of DNS.

Oxidative Stress and Spontaneous Reperfusion of Infarct-Related Artery in Patients With ST-Segment Elevation Myocardial Infarction

In the pathogenesis of atherosclerosis, oxidative stress plays a major role in plaque instability, rupture, and erosion, which subsequently leads to thrombus formation and causes total infarct-related artery (IRA) occlusion. We investigated the relationship between spontaneous reperfusion (SR) of IRA and oxidative stress in patients with anterior ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention. A total of 341 consecutive patients with anterior STEMI were prospectively included in the present study. Patients were divided into 2 groups according to their thrombolysis in myocardial infarction (TIMI) flow grade: SR group (66 patients, TIMI flow 3) and non-SR group (275 patients, TIMI flow 0-2). On multivariate logistic regression analysis, oxidative stress index (β = 0.868, 95% confidence interval [CI] = 0.806-0.934, P < .001), neutrophil to lymphocyte ratio, uric acid, mean platelet volume, Killip 2 to 4 class, and initial SYNTAX score were independently associated with SR. Oxidative stress as well as inflammation may play a pivotal role in the pathogenesis of SR in patients with STEMI.