Diagnostic performance of mean platelet volume for patients with acute coronary syndrome visiting an emergency department with acute chest pain: the Chinese scenario

Mean platelet volume and coronary artery disease

PURPOSE OF REVIEW

To critically review the literature describing links between mean platelet volume (MPV) and cardiovascular disease (CVD). We will focus on coronary artery disease (CAD). The MPV is measured routinely as part of a routine blood count.

RECENT FINDINGS

There is accumulating evidence showing that the MPV may predict CVD, as well as outcomes in patients with CAD. There is also evidence linking MPV and comorbidities (e.g. diabetes mellitus and impaired glycaemic control) that are expected in patients with CAD. The effect on MPV of drugs commonly used to treat CAD has not been clarified, but there is some evidence that they may exert a beneficial effect on the MPV. More specifically, the MPV may predict the effect of antiplatelet drugs (e.g. clopidogrel). There is also evidence relating MPV to stroke, atrial fibrillation, coronary artery ectasia and periprocedural outcomes after percutaneous coronary intervention (PCI).

SUMMARY

Measuring the MPV may prove useful in CVD risk assessment in patients with established CAD or at risk of developing CAD. Overall, there is evidence pointing to the role of MPV as a contributor rather than simple marker of CVD.

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.

Clinical utility of mean platelet volume and immature platelet fraction in acute coronary syndrome

Background

Platelets play an important role in the pathogenesis of acute coronary syndrome (ACS). Patients with ACS have an increased mean platelet volume (MPV) and immature platelet fraction (IPF) resulting in elevation of thrombotic ability. In this study, we evaluated the diagnostic performance of MPV and IPF in identifying suspected ACS patients at emergency department. Moreover, we investigated the correlation between MPV or IPF with initial troponin I (TnI), one of the current ACS biomarkers.

Methods

This was a single-center study recruiting suspected ACS patients who had acute chest pain at the emergency department. Whole blood samples were obtained from all participants and MPV and IPF were measured by Sysmex XE-5000 hematology analyzer within 20 min of blood sampling. The diagnostic values of MPV and IPF in identifying ACS were analyzed retrospectively.

Result

In this study, 63 in 104 suspected ACS patients were diagnosed as ACS (65.3%). MPV and IPF were higher in ACS patients compared to non-ACS patients (MPV: 10.7 ± 0.80 fL vs 10.0 ± 0.64 fL, p < 0.001; IPF: 3.7 ± 2.64% vs 3.1 ± 2.69%, p = 0.030). MPV and IPF were similar in unstable angina and acute myocardial infarction patients. We showed that elevation of MPV could be an independent predictive factor of ACS (odds ratio: 5.038). At the optimal cut-off value of 10.55 fL (AUC 95% CI: 0.637–0.836), the diagnostic performance of MPV in predicting ACS had an area under a receiver operating characteristic curve (AUC) of 0.736 with sensitivity and specificity of 54.2% and 82.8%, respectively. Patients with both of initial TnI and MPV higher than the established cut-off value had increased incidence (3.792 fold) for ACS development compared to patients with TnI below the cut-off value. Furthermore, diagnosing ACS with both MPV and initial TnI increased the positive predictive value from 84.2% to 86.7%. No correlation was observed between MPV or IPF and the mortality rate of ACS patients (MPV: 3.8% vs 11.1%, p = 0.300; IPF: 12.0% vs 37.5%, p = 0.054).

Conclusion

Here we show that ACS patients have higher MPV and IPF compared to non-ACS patients. We further demonstrate that MPV can be utilized as an independent predictor for early diagnosis of low-risk ACS patients who have acute chest pain.

Effect of preanalytical and analytical variables on the clinical utility of mean platelet volume

BACKGROUND

The study endpoint was to analyze the effect of preanalytical (time, temperature, anticoagulant) and analytical (imprecision, correlation between volume and platelet concentration) variables on mean platelet volume (MPV). A further aim was to calculate in an adult population the reference intervals using the Sysmex XE-5000 analyzer. A critical evaluation was also made of the clinical utility of these parameters.

METHODS

Analyses of the above values were performed in duplicate in 170 healthy adults of both sexes: (1) within 30 min from collection, and (2) after 4 h. To evaluate stability over time, the value of the platelet parameters of 20 subjects were determined, a re-analysis being performed for a period of up to 24 h on samples maintained at room temperature and 4°C using either K2-EDTA or Na-citrate as anticoagulants.

RESULTS

The stability over time of MPV closely depends on the anticoagulant used, storage temperature and time interval between venipuncture and analysis. An inverse, non-linear correlation between MPV and platelet count was also found.

CONCLUSIONS

In view of their effect on MPV and other related indices, the preanalytical and analytical variables make them, little more than experimental.

Derivation and validation of a cardiovascular risk score for prediction of major acute cardiovascular events in non-alcoholic fatty liver disease; the importance of an elevated mean platelet volume

BACKGROUND

Atherosclerotic cardiovascular disease is a key cause of morbidity in non-alcoholic fatty liver disease (NAFLD) but appropriate means to predict major acute cardiovascular events (MACE) are lacking.

AIM

To design a bespoke cardiovascular risk score in NAFLD.

METHODS

A retrospective derivation (2008-2016, 356 patients) and a prospective validation (2016- 2017, 111 patients) NAFLD cohort study was performed. Clinical and biochemical data were recorded at enrolment and mean platelet volume (MPV), Qrisk2 and Framingham scores were recorded one year prior to MACE (Cardiovascular death, acute coronary syndrome, stroke and transient ischaemic attack).

RESULTS

The derivation and validation cohorts were well-matched, with MACE prevalence 12.6% and 12%, respectively. On univariate analysis, age, diabetes, advanced fibrosis, collagen proportionate area >5%, MPV and liver stiffness were associated with MACE. After multivariate analysis, age, diabetes and MPV remained independently predictive of MACE. The "NAFLD CV-risk score" was generated using binary logistic regression: 0.06*(Age) + 0.963*(MPV) + 0.26*(DM¹ ) - 16.44; ¹ Diabetes mellitus: 1: present; 2: absent. (AUROC 0.84). A cut-off of -3.98 gave a sensitivity 97%, specificity 27%, PPV 16%, and NPV 99%. An MPV alone of >10.05 gave a sensitivity 97%, specificity 59%, PPV 24% and NPV 97% (AUROC 0.83). Validation cohort AUROCs were comparable at 0.77 (NAFLD CV-risk) and 0.72 (MPV). In the full cohort, the NAFLD CV-risk score and MPV outperformed both Qrisk2 and Framingham scores.

CONCLUSIONS

The NAFLD CV risk score and MPV accurately predict 1-year risk of MACE, thereby allowing better identification of patients that require optimisation of their cardiovascular risk profile.

The nonalcoholic fatty liver disease (NAFLD) fibrosis score, cardiovascular risk stratification and a strategy for secondary prevention with ezetimibe

OBJECTIVE

The nonalcoholic fatty liver disease fibrosis score (NFS) is comprised of unique metabolic risk indicators that may accurately predict residual cardiovascular (CV) risk in patients with established coronary disease and metabolic dysfunction.

METHODS

We applied the NFS prospectively to 14,819 post-ACS patients randomized to ezetimibe/simvastatin (E/S) or placebo/simvastatin (P/S), in the IMPROVE-IT trial, using validated NFS cutoffs. The primary endpoint included CV death, myocardial infarction, unstable angina, revascularization or stroke. Outcomes were compared between NFS categories and treatment arms using frequency of events, KM rates and adjusted Cox proportional hazard models. The ability of the NFS to predict recurrent CV events was independently validated in 5395 placebo-treated patients enrolled in the SOLID-TIMI 52 trial.

RESULTS

Among 14,819 patients enrolled in IMPROVE-IT, 14.2% (N = 2106) were high-risk (NFS > 0.67). The high-risk group had a 30% increased risk of recurrent major CV events, compared to the low-risk NFS group (HR 1.30 [1.19-1.43]; p < 0.001). Among high-risk patients, ezetimibe/simvastatin conferred a 3.7% absolute reduction in risk of recurrent CV events, compared to placebo/simvastatin (HR 0.85 [0.74-0.98]), translating to a number-needed-to-treat of 27. Similar benefit was not found in the low-risk group (HR ezetimibe/simvastatin vs. placebo/simvastatin, 1.01 [0.91-1.12]; p-interaction = 0.053). The relationship between NFS category and recurrent CV events was independently validated in patients enrolled in SOLID-TIMI 52 (HR for NFS > 0.67 vs. NFS < -1.455 = 1.55 [1.32-1.81]; p < 0.001).

CONCLUSION

Stratification of cardiovascular risk by NFS identifies an independent population of patients who are at highest risk of recurrent events, and most likely to benefit from dual lipid-lowering therapy. Clinical trials.gov: NCT00202878.

Diagnostic value of mean Platelet Volume for Chinese Patient with Acute Coronary Syndrome Presenting to an Emergency Department in Hong Kong

Objective

To determine the diagnostic value of mean platelet volume in local Chinese with acute coronary syndrome who attended emergency department in Hong Kong.

Design

cross sectional study.

Setting

emergency department of a local hospital.

Methods

Data of adult Chinese patients presented to a local emergency department (ED) with chest pain were retrieved from 1st October 2010 to 31st October 2010. Blood test for mean platelet volume (MPV) was drawn, and its relationship with development of acute coronary syndrome (ACS) was studied.

Results

429 patients were enrolled and 77 (17.9%) of them were diagnosed to have ACS. Non-statistically significant trend of elevated MPV was observed in ACS group vs non ACS group (8.0±1.12 fL vs. 7.8±1.03 fL, p=0.06). Subgroup analysis was performed on patients presented within 4 hours of onset of chest pain. Both MPV and adjusted MPV were higher in ACS group (p<0.03, and p<0.01 respectively). Cut-off 6.97 fL of adjusted MPV has the best performance, with 90.91% sensitivity and 22.86% specificity.

Conclusions

Adjusted-MPV is higher in ACS within 4 hour of presentation, but the discriminating power is not adequate. Further study is needed to validate the cut-off level and its clinical applicability.

Clinical use of Serial Mean Platelet Volume Measurement for Diagnosis of Non-ST Segment Elevation Myocardial Infarction in Patients Visiting Emergency Department with Acute Chest Pain

Objective

We aim to demonstrate diagnostic accuracy of serial MPV measuring and to assess its correlation with cardiac troponin I (cTnI) levels.

Design

Cross-sectional study.

Methods

Consecutive patients presenting to emergency department with new onset chest pain started in the last four hours without electrocardiographic ST segment and T wave changes, pathological q waves were included in study. Complete blood count and cTnI levels were studied on admission and six hours after presentation. Patients with cTnI levels higher than 0.06 ng/ml were diagnosed as non-ST elevation myocardial infarction (NSTEMI) and other patients were matched as the control group.

Results

NSTEMI group had significantly higher levels of MPV on admission and at the sixth hour. The increase in MPV was corraleted with elevation of cTnI levels. At six hours follow up, the increase in MPV levels predicted myocardial ischaemia (corrected r2=0.36; p=0.001) in linear regression analysis. The corresponding area under the receiver operating characteristic curve (ROC) for admission MPV, sixth hour MPV and increase in MPV levels in predicting myocardial ischaemia in patients with increased cTnI were 0.652, 0.727 and 0.896 respectively. If MPV threshold was selected as ≥0.10 fL during follow up, myocardial ischaemia was predicted with a sensitivity of 75% and specificity of 88%.

Conclusions

Elevation of MPV levels in patients with acute chest pain may be an indicator of myocardial ischaemia. Serial MPV measurement can be used to complement serial cTnI measurements to diagnose NSTEMI.

Platelet Count and Mean Platelet Volume at the Time of and After Acute Myocardial Infarction

Platelet count has been shown to be lower and mean platelet volume (MPV) to be higher in acute myocardial infarction (MI). However, it is not known whether these changes persist post-MI or if these measures are able to distinguish between acute thrombotic and non-thrombotic MI. Platelet count and MPV were measured in 80 subjects with acute MI (thrombotic and non-thrombotic) and stable coronary artery disease (CAD) at cardiac catheterization (acute phase) and at >3-month follow-up (quiescent phase). Subjects were stratified using stringent clinical, biochemical, histological, and angiographic criteria. Outcome measures were compared between groups by analysis of variance. Forty-seven subjects met criteria for acute MI with clearly defined thrombotic (n = 22) and non-thrombotic (n = 12) subsets. Fourteen subjects met criteria for stable CAD. No significant difference was observed in platelet count between subjects with acute MI and stable CAD at the acute or quiescent phase. MPV was higher in acute MI (9.18 ± 1.21) compared to stable CAD (8.13 ± 0.66; P = 0.003) at the acute phase but not at the quiescent phase (8.48 ± 0.58 vs 8.94 ± 1.42; P = 0.19). No difference in platelet count or MPV was detected between thrombotic and non-thrombotic subsets at acute or quiescent phases. The power to detect differences in these measures between thrombotic and non-thrombotic subsets was 58%. Higher MPV at the time of acute MI is not observed by 3 months post-MI (quiescent phase). Platelet count and MPV do not differ in subjects with thrombotic versus non-thrombotic MI. Further investigation is warranted to evaluate the utility of these measures in the diagnosis of acute MI.

Diagnostic Value of Mean Platelet Volume Combined With Troponin I for Acute Coronary Syndrome

OBJECTIVE

To explore diagnostic performance of mean platelet volume (MPV) for acute myocardial infarction (AMI) of patients with acute coronary syndrome (ACS).

METHODS

We compared MPV and other indicators of 1,524 patients with ACS. Among them, 880 patients were diagnosed with AMI, 344 were diagnosed with unstable angina pectoris and 350 were the control group.

RESULTS

The level of MPV in ACS group was significantly higher than the control group (9.5 ± 1.34fL versus 7.9 ± 1.03fL, P < 0.001). Additionally, MPV of AMI group was higher than unstable angina pectoris (9.4 ± 1.30fL versus 9.2 ± 1.42fL, P < 0.001). Increased MPV could be identified as an early independent predictor of AMI (odds ratio = 1.957, 95% CI: 1.389-2.758, P < 0.001). The area under the receiver operating characteristic curves curve for MPV combined with troponin I (TnI) was 0.816, the sensitivity (68.81%) and the specificity (97.98%) at the best cut-off value were higher than using MPV or TnI alone respectively.

CONCLUSIONS

MPV has been shown as an independent risk factor for early onset of AMI and can be applied to assist AMI diagnosis of ACS patients. Additionally, measuring MPV in conjunction with TnI levels can improve the diagnostic performance of TnI with higher sensitivity and specificity.

The Prognostic Impact of In-Hospital Change in Mean Platelet Volume in Patients With Non-ST-Segment Elevation Myocardial Infarction

It is unclear whether changes in mean platelet volume (MPV) are associated with total mortality in acute coronary syndromes. We investigated whether the change in MPV predicts total mortality in patients with non-ST-segment elevation myocardial infarction (NSTEMI). We retrospectively analyzed 419 consecutive patients (19 patients were excluded). The remaining patients were categorized as survivors (n = 351) or nonsurvivors (n = 49). Measurements of MPV were performed at admission and after 24 hours. The difference between the 2 measurements was considered as the MPV change (ΔMPV). The end point of the study was total mortality at 1-year follow-up. During the follow-up, there were 49 deaths (12.2%). Admission MPV was comparable in the 2 groups. However, both MPV (9.6 ± 1.4 fL vs 9.2 ± 1.0 fL, P = .044) and ΔMPV (0.40 [0.10-0.70] fL vs 0.70 [0.40-1.20] fL, P < .001) at the first 24 hours were higher in nonsurvivors than survivors. In multivariate analysis, ΔMPV was an independent predictor of total mortality (odds ratio: 1.84, 95% confidence interval: 1.28-2.65, P = .001). An early increase in MPV after admission was independently associated with total mortality in patients with NSTEMI. Such patients may need more effective antiplatelet therapy.

Diagnostic importance of admission platelet volume indices in patients with acute chest pain suggesting acute coronary syndrome

OBJECTIVE

Acute coronary syndrome (ACS) is a challenging issue in cardiovascular medicine. Given platelet role in atherothrombosis, we sought to determine whether platelet indices can be used as diagnostic tests for patients who suffered from an acute chest discomfort.

METHODS

We prospectively enrolled 862 patients with an acute chest pain and 184 healthy matched controls. They were divided into four groups: 184 controls, 249 of non-ACS, 421 of unstable angina (UA), and 192 of myocardial infarction (MI) cases. Blood samples were collected at admission to the emergency department for routine hematologic tests.

RESULTS

The mean platelet volume (MPV), platelet distribution width (PDW), and platelet large cell ratio (P-LCR) were significantly greater in patients with MI compared with those of non-ACS or control subjects. Negative and significant correlations existed between MPV, PDW, and P-LCR values and platelet count (P < 0.001). Receiver operating characteristic (ROC) curves showed that the MPV, PDW, and P-LCR with cut-off values of 9.15 fL, 11.35 fL, and 20.25% and with area under the curves of 0.563, 0.557, and 0.560, respectively, detected MI patients among those who had chest discomfort. The sensitivities and specificities were found to be 72% and 40%, 73% and 37%, and 68% and 44% for MPV, PDW, and P-LCR, respectively.

CONCLUSION

An elevated admission MPV, PDW, and P-LCR may be of benefit to detect chest pain resulting in MI from that of non-cardiac one, and also for risk stratification of patients who suffered from an acute chest discomfort.

Time-related changes in determinants of antiplatelet effect of clopidogrel in patients after myocardial infarction

Substantial variability of antiplatelet action is an important limitation of clopidogrel. The aim of this study was to evaluate time-related changes in determinants of clopidogrel responsiveness in patients after myocardial infarction. The study population comprised 191 consecutive patients treated with primary percutaneous coronary intervention for acute myocardial infarction. Follow-up visits were scheduled at 3, 6 and 9 months after discharge. ADP-induced platelet aggregation was tested with Multiplate Analyzer. Patients with ADP-PA>46.8U were defined as clopidogrel non-responders. The prevalence of clopidogrel non-responsiveness was highest during hospitalization and at 9 month follow-up visit, while it was lowest at 3 and 6 months after myocardial infarction (P=0.004). According to multivariate analysis, platelet count, mean platelet volume, concentration of hsCRP and leukocyte count influenced ADP-induced platelet aggregation in multiple assessment points. BMI, concentrations of hemoglobin, glycated hemoglobin, and BNP, hematocrit, adherence to medication, and patient׳s age were found to be independent predictors of high on-treatment ADP-induced platelet aggregation only at a single follow-up visit. Determinants of clopidogrel responsiveness in patients after myocardial infarction change within the long-term therapy. During hospitalization and early after discharge only biological factors affect ADP-induced platelet aggregation, while non-adherence to antiplatelet therapy may be a significant factor in determining clopidogrel non-responsiveness during late follow-up visits.

Increased Platelet Distribution Width Is Associated With Severity of Coronary Artery Disease in Patients With Acute Coronary Syndrome

Platelet activation plays a pivotal role in acute coronary syndrome (ACS). We investigated the relationship between platelet distribution width (PDW) and severity of coronary artery disease (CAD) in patients with ACS. A total of 502 patients with ACS were enrolled. High (n = 151) and low PDW (n = 351) groups were defined as patients having values in the third tertile (>17%) and lower 2 tertiles (≤17%). There were significantly higher Gensini score (44 [10-168] vs. 36 [2-132], P < .001), and neutrophil-lymphocyte ratio (3.1 [0.8-12.4] vs. .2.5 [0.3-13], P = .012) and baseline platelet counts were significantly lower (220 [61-623] vs. 233 [79-644] 10(3)/mm3, P = .022) in the high PDW group. The variables PDW >17%, diabetes mellitus, and myocardial infarction were found to be associated with high Gensini score (odds ratio [OR]: 1.91, 95% confidence interval [CI]: 1.27-2.88, P = .002; OR: 2.85, 95% CI: 1.91-4.25, P < .001; OR: 2.67, 95% CI:1.74-4.1, P < .001, respectively). An increased PDW (>17%) is associated with severity of CAD in patients with ACS.

Increased platelet distribution width is associated with ST-segment elevation myocardial infarction and thrombolysis failure

We investigated 2 hypotheses: (1) a relationship between platelet indices and stable coronary artery disease (CAD) and acute ST-segment elevation myocardial infarction (STEMI) and (2) a relationship between platelet indices on admission and thrombolysis outcomes in patients with STEMI. A total of 260 patients were enrolled. The white blood cell (WBC) and platelet distribution width (PDW) were found to be increased in patients with STEMI (P for both < .001). White blood cell and PDW were independent predictors of acute STEMI. Mean platelet volume (MPV) and PDW were significantly higher in the thrombolysis failure group than in the thrombolysis success group (9.9 ± 1.8 vs 9.2 ± 1.5 fL, P = .021 and 17.7 ± 1.0 vs 16.4 ± 2.1 fL, P < .001, respectively). Mean platelet volume and PDW were independent predictors of thrombolysis failure. Patients with acute STEMI had higher PDW than did patients with stable CAD. In addition, higher PDW and MPV seem to correlate with thrombolysis failure in patients with STEMI.

Mean platelet volume in patients with ischemic heart disease: meta-analysis of diagnostic studies

It is now widely acknowledged that larger platelets are biologically more active and express a greater prothrombotic potential, but there is no definitive evidence on the diagnostic accuracy role of mean platelet volume (MPV) in patients with ischemic heart disease. We performed an electronic search for articles that have assessed the diagnostic accuracy of MPV in patients admitted at the emergency department with a suspected diagnosis of ischemic heart disease, including articles in which the exact number of true-positive, false-positive, false-negative and true-negative test results could be either directly or indirectly extracted. Heterogeneity was assessed by I(2) test. The cumulative estimates and 95% confidence interval (95% CI) of sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), area under the receiver operator characteristic (ROC) curve (AUC) and diagnostic odds ratio (DOR) were calculated using a random effect model. Three studies were finally included in our analysis (mean quality score, 10.8) totaling 3577 participants (566 cases and 3011 controls). The between-study variation was high (I(2), 96.2%; P < 0.001). The pooled estimates were 0.820 (95% CI 0.786-0.851) for sensitivity, 0.461 (95% CI 0.443-0.479) for specificity, 0.932 (95% CI 0.918-0.944) for NPV and 0.222 (95% CI 0.205-0.241) for PPV and 0.652 (95% CI 0.596-0.707) for AUC. The DOR was 3.9 (95% CI 2.3-6.5), with 0.52 diagnostic accuracy. The outcome of this meta-analysis suggests that MPV does not meet the requirements for efficient triage of patients in emergency department when used as stand-alone test, whereas its combination with high-sensitive troponin immunoassays merits further investigations.

Is there a link between mean platelet volume and thrombotic events in antiphospholipid syndrome?

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the production of antiphospholipid antibodies (aPL) that promote vascular thrombosis and pregnancy loss. APS can occur in the absence of underlying or associated disease (primary APS) or in combination with other diseases (secondary APS). Mean platelet volume (MPV) is largely regarded as a useful surrogate marker of platelet activation. We aimed to investigate if there is a relationship between MPV and thrombotic events in APS. The study consisted of 22 patients and 22 healthy controls. Group 1 is defined as all the patients in the first day of thrombotic event. Group 2 is defined as the same patient population three months after the thrombotic event. The erythrocyte sedimentation rate, C-reactive protein, white blood cell count, platelet count, and MPV levels were retrospectively recorded from patient files. Statistical analyses showed that MPV was significantly higher in group 1 than group 2 (p < 0.0001) and healthy controls (p < 0.05). However, there was no difference between group 2 and healthy controls (p = 0.888). WBC, hemoglobin and other platelet indices such as platelet distribution width and platecrit did not differ in groups. In conclusion, MPV was increased at initial thrombotic event of APS, and then it was normalized three months later by therapeutic interventions. To our knowledge, this is the first study demonstrating a correlation between MPV and thrombotic events in APS.

The causal role of megakaryocyte–platelet hyperactivity in acute coronary syndromes

Platelets are causally involved in coronary artery obstruction in acute coronary syndromes (ACS). This cell type is unique to mammals and its production, which is unlike that of any other mammalian cell, involves polyploid nuclear change in the mother cell (megakaryocyte) and the production of anucleate cells with a log Gaussian distribution of volume. Platelets vary more in cellular volume than any other circulating blood element in mammals. Larger platelets are denser, contain more secretory granules, and are more reactive than their smaller counterparts. A causal relationship between the presence of large, dense, reactive platelets in the circulation and ACS is supported by many clinical studies. Furthermore, the results of two large, prospective, epidemiological studies have demonstrated that mean platelet volume was the strongest independent predictor of outcome in patients with acute myocardial infarction. Notably, evidence indicates that an increase in mean platelet volume in the pathogenesis of ACS can potentially overwhelm current therapeutics. The control system for the physiological and pathophysiological production of large platelets should, therefore, be researched. An understanding of this system might give rise to new therapeutics that could control platelet reactivity and thereby comprehensively prevent ACS.

Mean platelet volume and other platelet volume indices in patients with stable coronary artery disease and acute myocardial infarction: A case control study

Background:

Coronary artery disease is mainly caused by atherosclerosis and its complications. Platelets and their activity have an important role in initiation of atherosclerotic lesions and coronary thrombus formation. Larger platelets are enzymatically and metabolically more active and have a higher potential thrombotic ability as compared with smaller platelets.

Aims:

To study the changes in platelet volume indices and platelet count in acute myocardial infarction, stable coronary artery disease and compare them with controls to assess their usefulness in predicting coronary events.

Materials and Methods:

This was a comparative study of 128 subjects; 39 patients with acute myocardial infarction (AMI), 24 patients with stable coronary artery disease (SCAD) and 65 controls. Venous sample were drawn from AMI subjects on admission (within 4 hours of chest pain) and collected in standardized EDTA sample tubes. Platelet count and volume indices were assayed within 30 minutes of blood collection, using Sysmex KX21-N autoanalyzer. Venous samples were also drawn from SCAD on who were admitted for angiography and subject attending routine checkups.

Results:

The mean platelet volume was significantly higher in patients with AMI (9.65 ± 0.96) as compared to SCAD (9.37 ± 0.88) and controls (9.21 ± 0.58). The best cut-off values for MPV when predicting AMI and SCAD in patients were 9.25 fl (sensitivity 56.4%; specificity 45.9%) and 9.15 fl (sensitivity 54.2%; specificity 42.23%), respectively.

Conclusions:

Measurements of MPV may be of some benefit in detecting those patients at higher risk for an AMI and CAD.

Are platelet volume indices of clinical use? A multidisciplinary review

Platelet size correlates with platelet activity and can be assessed by platelet volume indices (PVI). The PVI, mean platelet volume (MPV), is universally available with routine blood counts by automated hemograms and therefore is an attractive index to study in clinical scenarios. PVI are useful in assessing the etiology of thrombocytopenia. In addition, a normal platelet distribution width in the setting of thrombocytosis is highly suggestive of a reactive etiology. Higher MPV is also associated with the presence of cardiovascular risk factors, chest pain due to acute coronary syndrome, and adverse outcome after acute coronary syndrome. Results from studies evaluating MPV in patients with peripheral artery disease, unprovoked deep vein thrombosis, and pulmonary embolism further advocate a potential role for MPV in identifying patients at high risk of thrombosis. Nevertheless, most of these data come from retrospective studies some of which have small study populations and confounding factors influencing platelet volume. Moreover, the cut-off values derived from these retrospective studies have not been validated prospectively. Despite the potential for clinical utility evident from these studies, the above-mentioned flaws together with technical problems in measuring MPV currently limit its clinical usefulness. Our review provides a perspective on PVI's potential clinical use.