Characteristics of platelet count and size and diagnostic accuracy of mean platelet volume in patients with venous thromboembolism. A systematic review and meta-analysis

Baseline platelet count and long-term clinical outcomes in patients with acute venous thromboembolism: a prospective cohort study

An abnormal platelet count (PC) is common in acute venous thromboembolism (VTE) but its relationship with clinical outcomes remains ill-defined. We aimed to explore the association between baseline PC and the long-term risk of clinically relevant outcomes in a prospective cohort of 991 patients with acute VTE. We classified patients into four PC groups: very low (< 100 G/l), low (≥ 100 to < 150 G/l), normal (≥ 150 G/l to ≤ 450 G/l), and high (> 450 G/l). The primary outcome was major bleeding (MB), secondary outcomes were recurrent VTE and overall mortality. We examined the association between PC and clinical outcomes, adjusting for confounders, competing risk for mortality, and periods of anticoagulation. After a median follow-up of 30 months, 132 (13%) of patients experienced MB, 122 (12%) had recurrent VTE, and 206 (21%) died. Compared to patients with a normal PC, patients with a very low PC had a sub-distribution hazard ratio (SHR) for MB of 1.23 (95% confidence interval [CI] 0.52-2.91) and those with a high PC a SHR of 1.87 (95%CI 0.82-4.29). Patients with a low PC had a twofold increased VTE recurrence risk (SHR 2.05, 95%CI 1.28-3.28). Patients with low and very low PC had a hazard ratio for mortality of 1.43 (95%CI 0.99-2.08) and of 1.55 (95%CI 0.80-2.99), respectively. Our findings do not suggest a consistent relationship between baseline PC and long-term clinical outcomes in patients with VTE.

An Atypical Presentation of a Saddle Embolism in the Setting of Malignancy

A 52-year-old male presented to the emergency room with acute abdominal pain. Imaging determined acute appendicitis, with an incidental finding of a renal mass. The biopsy was positive for renal cell carcinoma, and the patient underwent simultaneous appendectomy and nephrectomy. Postoperatively, the patient developed hypoxia at night with exertion, requiring oxygen supplementation. The remainder of his vital signs were stable. Due to renal function, a ventilation/perfusion (V/Q) scan was conducted, which showed a high probability of pulmonary embolism (PE). Follow-up computed tomography angiography of the chest showed a massive saddle embolism. Interventional radiology performed an uncomplicated thrombectomy, oxygen saturations improved, and the patient was discharged on apixaban.

Evaluation of systemic immune-inflammation index in acute deep vein thrombosis: A propensity-matched

OBJECTIVE

Deep vein thrombosis (DVT) progressing to pulmonary embolism is an important cause of mortality and morbidity worldwide. At present, color Doppler ultrasound is the most effective examination method for the diagnosis of DVT. The systemic immune-inflammation index (SII) has been introduced as a new indicator of comprehensive systemic immune thrombosis and inflammatory status in the body. We believe that the SII might be more specific and sensitive than the neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR). In the present study, we aimed to evaluate the predictive potential of the SII, NLR, and PLR in the diagnosis of DVT.

METHODS

The data of patients aged >18 years who were diagnosed with acute DVT in our hospital between June 2017 and June 2021 were retrospectively reviewed. During the study period, the data of 155 patients with acute DVT and 179 healthy control patients without DVT were included in the study. A propensity score analysis (1:1) was performed to eliminate differences between the two groups, and 63 patients from each group were included in the present study.

RESULTS

When the complete blood count parameters were examined between the patients with acute DVT and the control group, the hemoglobin, hematocrit, lymphocyte count, and platelet distribution width were lower in the DVT group. In contrast, the white blood cell count, neutrophil count, platelet count, NLR, PLR, SII, and mean platelet volume were higher in the DVT group. The changes in hemoglobin (P = .001), hematocrit (P = .001), white blood cell count (P = .001), neutrophil count (P = .001), lymphocyte count (P = .001), platelet count (P = .001), NLR (P=.001), PLR (P = .001), SII (P = .001), and mean platelet volume (P = .031) were significant on statistical analysis. However, the changes in the platelet distribution width were not significant (P = .794). The area under the curve for the NLR and PLR was 0.797 (95% confidence interval [CI], 0.747-0.848; P < .001) and 0.788 (95% CI, 0.737-0.840; P = .01), respectively. The sensitivity and specificity for an NLR >3.00 was 71.0% and 68.7%, respectively. The sensitivity and specificity for a PLR >142.66 was 70.3% and 68.5%, respectively. The area under the curve for SII was 0.861 (95% CI, 0.820-0.902; P < .001), with a sensitivity of 78.1% and specificity of 73.1% for an SII >755.54.

CONCLUSIONS

The SII can be used as an auxiliary diagnostic test for patients with venous thrombosis. This parameter is superior to the NLR and PLR with high sensitivity and specificity for patients with venous thrombosis.

Identification of Pulmonary Hypertension Animal Models Using a New Evolutionary Machine Learning Framework Based on Blood Routine Indicators

Pulmonary Hypertension (PH) is a global health problem that affects about 1% of the global population. Animal models of PH play a vital role in unraveling the pathophysiological mechanisms of the disease. The present study proposes a Kernel Extreme Learning Machine (KELM) model based on an improved Whale Optimization Algorithm (WOA) for predicting PH mouse models. The experimental results showed that the selected blood indicators, including Haemoglobin (HGB), Hematocrit (HCT), Mean, Platelet Volume (MPV), Platelet distribution width (PDW), and Platelet-Large Cell Ratio (P-LCR), were essential for identifying PH mouse models using the feature selection method proposed in this paper. Remarkably, the method achieved 100.0% accuracy and 100.0% specificity in classification, demonstrating that our method has great potential to be used for evaluating and identifying mouse PH models.

Joint effect of multiple prothrombotic genotypes and mean platelet volume on the risk of incident venous thromboembolism

BACKGROUND

A high mean platelet volume (MPV), a marker of increased platelet reactivity, is a risk factor for venous thromboembolism (VTE). Whether established prothrombotic single nucleotide polymorphisms (SNPs) further increase the VTE risk in subjects with high MPV because of biological interaction remains unknown.

AIM

To investigate the joint effect of high MPV and prothrombotic genotypes, comprising a 5-SNP genetic risk score (GRS), on the risk of VTE in a population-based case-cohort.

METHODS

Incident VTE cases (n=653) and a subcohort (n=1774) were derived from the Tromsø Study (1994-2012). DNA was genotyped for rs8176719 (ABO), rs6025 (F5), rs1799963 (F2), rs2036914 (F11) and rs2066865 (FGG). Hazard ratios (HRs) for VTE with 95% confidence intervals (CIs) were estimated according to predefined MPV-strata (<8.5, 8.5-9.5, ≥9.5fL) and number of risk alleles for each individual SNP and the GRS (0-1, 2-3, ≥4 risk alleles) in models adjusted for age, sex, body mass index and platelet count.

RESULTS

The combination of high MPV and risk alleles, either as individual SNPs or the GRS, had an additive effect on VTE risk. Compared with subjects with MPV <8.5fL and 0-1 risk allele, those with high MPV (≥9.5fL) and ≥4 risk alleles had HRs of 2.80 (95%CI 1.77-4.43) for overall VTE and 4.60 (95%CI 2.20-9.60) for unprovoked events, respectively, but there was no supra-additive effect on risk estimates.

CONCLUSION

The combination of high MPV and prothrombotic genotypes had an additive effect on VTE risk, suggesting there is no biological interaction between these risk factors in the pathogenesis of VTE.

Complete Blood Count-Derived Inflammation Indices and Retinal Vein Occlusion: A Case-Control Study

Introduction

This study evaluated complete blood count-derived inflammation indices in patients with retinal vein occlusion (RVO).

Methods

Participants in this case–control study were 54 patients with RVO and 54 age- and sex-matched control subjects. All participants underwent a thorough ophthalmic examination, as well as blood sample testing for complete blood count. Comparison of all parameters derived from complete blood count as well as calculation of specific indices was performed between patients with RVO and controls.

Results

Patients with RVO presented significantly higher white blood cell count (p = 0.033), neutrophil count (p = 0.003), neutrophil-to-lymphocyte ratio (NLR, p = 0.002), red cell distribution width (RDW, p = 0.009), mean platelet volume (MPV, p = 0.023), and systemic immune-inflammatory index (SII, p = 0.007) compared to controls. Receiver operator characteristic curve (ROC) analysis showed that NLR was superior to other inflammatory indices, having the greatest area under the curve. The optimal cutoff value for NLR to predict RVO was 2.29 with 46.2% sensitivity and 77.8% specificity.

Conclusion

Patients with RVO presented increased NLR, RDW, MPV, and SII, providing evidence that inflammation plays an important role in the pathogenesis of RVO. Complete blood cell count-derived indices can be easily calculated and may serve as an easy, simple, and cost-effective tool to evaluate the degree of systemic inflammation in patients with RVO, so as to potentially guide treatment.

Low Mean Platelet Volume is Associated with Deep Vein Thrombosis in Older Patients with Hip Fracture

This study aimed to explore the association between mean platelet volume (MPV) and preoperative deep vein thrombosis (DVT) in older patients with hip fracture. A total of 352 consecutive older patients with hip fracture were included from January 2014 to December 2020. MPV values were measured on admission, and color Doppler ultrasonography was performed for DVT screening before the planned surgery. The receiver operating characteristic (ROC) curve was used to establish the optimal cut-off value for the prediction of DVT. Univariate and multivariate logistic regression analysis were used to examine the association between factors and DVT. The overall prevalence of preoperative DVT was 15.1%, and patients with DVT had a lower value of MPV than non-DVT patients (11.6 ± 1.2 fL vs 12.3 ± 1.4 fL, P < .01). The cut-off point according to the ROC curve for MPV was 13.3 fL, and multivariate logistic regression analysis showed that MPV level < 13.3 fL was significantly associated with an increased risk of DVT (OR = 4.857, 95% CI: 1.091-21.617, P = .038), and with every 1.0 fL decrease in MPV, the risk increased by 27.7% (OR = 1.277, 95% CI: 1.001-1.629, P = .047). Our findings indicate that a low MPV level is associated with DVT in older patients with hip fracture. As MPV is a simple indicator that can be calculated from the blood routine test, it may be a potential biomarker of DVT with the combination of other tests, further studies are needed to confirm these results.

Diagnostic and Prognostic Value of Immune/Inflammation Biomarkers for Venous Thromboembolism: Is It Reliable for Clinical Practice?

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), has been an important cause of sudden in-hospital death. Studies have shown that the immune/inflammatory response plays an important role in the pathogenesis of vascular disease, with representative markers in the blood including the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR), systemic immune/inflammatory index (SII), etc. However, there is a variety of immune/inflammatory indicators. Moreover, most previous studies have been single-center investigations involving one or two indicators, with varying nature of cases, number of cases and study objectives, thereby making it difficult to reach consensus conclusions with good clinical guidelines. This article reviews the clinical value of immunoinflammatory indicators for VTE based on previous studies, including the diagnostic and prognostic capabilities. In conclusion, NLR provides promising predictive capability for the onset and prognosis of VTE and deserves extensive application in clinical practice. PLR also has certain diagnostic and prognostic value, but further studies are warranted to identify its reliability and stability. Monocytes, eosinophils and platelet-related indicators show some clinical association with VTE, although the predictive capabilities are mediocre. SII is of promising potential value for VTE and deserves further investigations. This review will provide new clues and valuable clinical guidance for the diagnosis and therapy of VTE.

Association between mean platelet volume and pulmonary embolism: a systematic review and meta-analysis

Platelet activation plays an important role in the progression of pulmonary embolism (PE). Mean platelet volume (MPV) can serve as a marker of platelet activity in patients with PE. Many studies have reported different results regarding the relationship. Therefore, we aimed to perform a systematic review and meta-analysis to evaluate the relationship between MPV and PE. Two reviewers independently searched relevant articles in databases from inception to April 21, 2021 and identified all studies on MPV and PE as the outcomes of interest. Further, we selected studies meeting the criteria and extracted the data. Of the 2505 publications identified, we included 18 studies after screening. Results showed MPV was significantly higher in patients with PE (0.83 fL, 95% CI: 0.38-1.28, P<0.001) than in controls. The mean difference in MPV between those who died and survivors of PE was 1.23 fL (95% CI: 0.96-1.51, P<0.001). Hence, an increased MPV is associated with PE. MPV could be a useful tool to predict the occurrence and death risk of PE together with other risk factors.

ASSOCIATION BETWEEN PLATELET INDICES AND RETINAL VEIN OCCLUSION: A Systematic Review and Meta-Analysis

PURPOSE

Platelet count, mean platelet volume, platelet distribution width, and plateletcrit are standard indices of platelet activation that have been studied in retinal vein occlusion (RVO) and its subtypes: branch retinal vein occlusion and central retinal vein occlusion. This systematic review and meta-analysis aimed to assess the association between these platelet parameters and RVO.

METHODS

We searched for studies investigating the association between these platelet indices and RVO in multiple online databases from inception to August 2020. Mean differences and the associated confidence intervals were obtained and calculated for each included study and pooled using random-effects inverse variance modeling. Meta-regression was used to explore interstudy and intrastudy heterogeneity.

RESULTS

Thousand three hundred and twenty-five unique studies were screened, from which 24 studies encompassing 2,718 patients were included. Mean platelet volume and platelet distribution width were significantly elevated in RVO, with pooled mean differences of 0.45 fL (95% CI 0.24-0.66, P < 0.0001) and 1.43% (95% CI 0.57-2.29, P = 0.0011), respectively. Platelet count and plateletcrit were not significantly associated with RVO. Mean platelet volume was also independently elevated in branch retinal vein occlusion and central retinal vein occlusion.

CONCLUSION

Mean platelet volume and platelet distribution width are significantly elevated in RVO. Further research is required to explore the independence and potential prognostic significance of these associations.

Diagnostic Role of Mean-Platelet Volume in Acute Pulmonary Embolism: A Meta-analysis and Systematic Review

Background:

Acute pulmonary embolism (PE) is the third most fatal cardiovascular disease. PE is frequently misdiagnosed due to its clinical presentation’s heterogeneity and the inexistence of biomarkers for its immediate diagnosis. Mean platelet volume (MPV) has shown a potential role as a biomarker in acute PE. In this analysis, we aimed to systematically compare the MPV in patients with and without definite diagnosis of PE, in emergency departments.

Methods:

Embase, PubMed and Medline were searched for relevant publications, in English. The main inclusion criteria were studies which compared MPV in patients with acute PEA versus a control group.

Results:

Thirteen studies consisting of a total number of 2428 participants were included. Of the participants included, 1316 were patients with confirmed acute PE, and 1112 were assigned to the control group. MPV was significantly higher in patients with acute PE than in controls (RR: 0.84, 95% CI: 0.76 – 0.92; P < .00001). There was a significant heterogeneity in the data.

Conclusions:

This analysis showed higher MPV to be associated with acute PE immediate diagnosis. These data show promise for the use of MPV as a readily available biomarker for the diagnosis of acute PE at the emergency department.

Effects of oral contraceptives on thyroid function and vice versa

BACKGROUND

Thyroid gland dysfunction represents an epidemiologically relevant disease in the female gender, where treatment with oral contraceptives (OCs) is frequently prescribed. Although OCs are able to impact the thyroid gland function, scanty data have been released on this matter so far.

AIM

The aim of this article was to review how hormonal OCs, including estrogen- or progesterone-only containing medications, interact with the hepatic production of thyroid-binding globulin (TBG) and, consequently, their effects on serum levels of thyroxine (T4) and triiodothyronine (T3). We also reviewed the effect of Levo-T4 (LT4) administration in women taking OCs and how they influence the thyroid function in both euthyroid women and in those receiving LT4.

REVIEW

The estrogenic component of the pills is capable of increasing various liver proteins, such as TBG, sex hormone-binding protein (SHBG) and coagulation factors. On the other hand, the role of progestogens is to modulate estrogen-dependent effects mainly through their anti-androgenic action. In fact, a reduction in the effects of androgens is useful to keep the thromboembolic and cardiovascular risks low, whereas OCs increase it especially in women with subclinical hypothyroidism or in those treated with LT4. Accordingly, subclinical hypothyroidism is known to be associated with a higher mean platelet volume than normal and this increases cardiovascular risk due to platelet hyperactivity caused by incomplete thrombocytopoietic maturation.

Large and small platelets-(When) do they differ?

Platelets are most important in providing cellular hemostasis but also take part in inflammation and immune processes. Increased platelet size has been regarded as a feature describing a young and more reactive subpopulation until studies were published which questioned this concept. Moreover, changes of platelet size given by the mean platelet volume (MPV) were described for immune thrombocytopenia, cardiovascular disease, atherosclerosis, venous thromboembolism, chronic lung disease, sepsis, cancer-associated thrombosis, autoimmune disorders, and others. This review summarizes the literature on what is known about platelets with different size and describes controversies of studies with large and small platelets putting a focus on their thrombogenicity, age, and on the association of MPV with the mentioned diseases.

Mean platelet volume in arterial and venous thrombotic disorders

The mean platelet volume (MPV) is an easy, rapid and inexpensive laboratory parameter which basically mirrors platelet size. Due to the essential role of platelets in hemostasis, many studies have assessed the MPV value in patients with arterial and venous thrombotic disorders. These have then been summarized in some interesting meta-analyses and recent studies that will be discussed in this narrative review. Taken together, the currently available evidence suggests that the MPV may be substantially increased in concomitance with acute episodes of coronary artery disease, venous thromboembolism, portal vein thrombosis, stroke, erectile dysfunction and preeclampsia. In many of these conditions, an increased MPV value may also be associated with unfavorable outcomes. Despite these convincing findings, some important technical issues should be considered for improving the clinical usefulness of this measure. These essentially include anticoagulant, timing of sample collection, the sample storage conditions, the influence of the analytical techniques, the approaches used for its calculation, the accurate definition of reference ranges and diagnostic cut-offs, as well as the current lack of standardization, which makes data obtained with different techniques/analyzers poorly comparable. Provided that the impact of these variables can be abated or minimized, the MPV can gain a valuable role in the laboratory workout of many arterial and venous thrombotic disorders.

Effect of platelet inhibitors on thrombus burden in patients with acute pulmonary embolism

Venous thromboembolism (VTE) whether provoked or not can be life-threatening due to an acute increase in load on the right ventricle (RV) from obstruction of the pulmonary artery (PA). Treatment for and prevention of VTE involves anti-thrombotic agents; more specifically, medications targeting the anticoagulation cascade. In spite of the widespread acceptance of anticoagulants in the treatment of VTE, there appears to be an ongoing belief that platelet reactivity contributes to thrombus burden in patients with acute pulmonary embolism (PE). This investigation of 398 patients presenting with acute PE evaluated whether anti-platelet medication use, which consisted mostly of aspirin therapy, at the time of presentation, affects PA thrombus burden, RV load, or short-term patient outcomes. We conclude that platelets may have been erroneously incriminated as direct thrombotic mediators in patients with acute PE since aspirin neither decreased PA thrombus burden, nor did aspirin improve short-term mortality following acute PE.

Platelet count and mean volume in acute stroke: a systematic review and meta-analysis

Changes of mean platelet volume (MPV) and platelet count (PC) could be a marker or a predictor of acute stroke (AS). We conducted a systematic review and meta-analysis of the published literature on the reporting of MPV and PC in AS. Studies were included in accordance with Patient Population or Problem, Intervention, Comparison, Outcomes, and Setting framework. The PRISMA strategy was used to report findings. Risk of bias was assessed with the Newcastle-Ottawa Scale. We included 34 eligible articles retrieved from the literature. PC was significantly lower in AS patients [standardized mean difference (SMD) = - 0.30, (95% CI: - 0.49 to - 0.11), N = 2492, P = .002] compared with controls (N = 3615). The MPV was significantly higher [SMD = 0.52 (95% CI: 0.28-0.76), N = 2739, P < .001] compared with controls (N = 3810). Subgroup analyses showed significantly lower PC in both ischemic stroke (Difference SMD = -0.18, 95% CI: -0.35-0.01) and hemorrhagic stroke (-0.94, -1.62 to -0.25), but only samples by citrate anticoagulant showed significantly lower result for patients compared to controls (-0.36, -0.68 to -0.04). Ischemic stroke patients had higher MPV (0.57, 0.31-0.83), and samples by Ethylenediaminetetraacetic acid (EDTA) anticoagulant showed significantly higher result for patients compared to controls (0.86, 0.55-1.17). PC and MPV appeared to be significantly different between patients with AS and control populations. MPV was significantly higher in ischemic stroke and PC was significantly lower in both ischemic and hemorrhagic strokes. These characteristics might be related to AS and associated with it. It is advisable to pay attention to elapsed time between phlebotomy and hematology analysis, anticoagulant and hemocytometer types in AS.

SYSTEMATIC REVIEW REGISTRATION

This meta-analysis is registered on the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD42017067864 (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=67864).