A study of correlation between Platelet Volume Indices (PVI) in patients of Dyslipidemia in tertiary care hospital

Background: The dyslipidemia is a risk factors for cardiovascular disease. Ischemic heart disease is the leading cause of death world wide. Platelet volume reflects platelet reactivity and has been suggested as an independent risk factor for ischemic events in cardiovascular disease. We have shown preliminary results on production of larger platelets by Mean Platelets Volume (MPV) and Platelets Distribution Width (PDW) determination in a group of patients with lipid profile abnormalities. Materials & Method: The study was performed in patients coming to GMERS Medical College, Junagadh from June 2016 to December 2017. Blood sample was collected in plain tube for lipid profile analysis, EDTA vaccutainer for haematological analysis. PVI were obtained by using Horriba 5 part auto mated cell counter & Lipid profile parameters by fully automated analyzer Roche’s COBAS INTEGRA 400plus. Results: our study comprising of 500 patient’s samples and 50 control samples, In patient’s group high levels of total cholesterol correlates more with high value of PDW than with MPV. Conclusion: PVI like MPV and PDW are strongly associated with dyslipidemia. The estimation of these PVI can be considered as an early, economical and rapid procedure for identification of complication sin hyper lipidemic patients.


Introduction
The dyslipidemia is a risk factors for cardiovascular disease (CVD) and diabetes. These factors include elevated triglyceride levels, low high-density lipoprotein levels, elevated cholesterol and obesity [1]. Non communicable diseases which include Diabetes mellitus and cardiovascular disease are world's biggest killer diseases, estimated to cause 3.5 millions death each year. Eighty percent of them are found in the low and middle income countries.
The WHO has developed an action plan for implementation of global strategies in prevention and control of non communicable diseases. Ischemic heart disease is the leading cause of death world wide. Platelets have definite role in causing its pathogenesis and its complications. A variety of data indicate patients with dyslipidemia have a high risk of developing cardiovascular morbidity and mortality [2,3]. Platelets play an important role in the pathogenesis of thrombosis and atherosclerosis. Activated platelets interact with endothelium and other inflammatory cells by the action of different molecules present on the platelet surface and/or stored in platelets granules, as P-selectin [4]. Platelet volume reflects platelet reactivity [5] and has been suggested as an independent risk factor for ischemic events in cardiovascular disease [6]. Large platelets are metabolically and enzymatically more active than small platelets and produce more thromboxane A2 [7,8]. Individuals with dyslipidemia have more tendencies to form atherosclerosis plaques with a consequent increasing consumption of platelets. We have shown preliminary results on production of larger platelets by MPV and PDW determination in a group of patients with lipid profile abnormalities [9].
The objective of the study was to study platelet parameters in the spectrum of dyslipidemia. Sample was taken after 10-12 hours fasting so triglyceride level doesn't get affected. All patients' and controls' samples were processed within 2 hours of sample collection. All haematological parameter were processsed using Horriba 5 part auto mated cell counter.

Materials and methods
Automated cell counters, have made the plate let count (PC) and the plate let volume indices (PVI)-mean platelet volume (MPV), platelet distribution width (PDW) routinely available in most clinical laboratories.
Proper quality measures like internal (IQC) and external quality (EQAS) were done through out the study. All Biochemistry parameters have been analyzed using fully automated analyzer Roche's COBAS INTEGRA 400 plus. And HDL-C, Total Cholesterol and Triglycerides were measured by enzymatic methods.
The obtained parameters were evaluated using descriptive statistical analysis.
Statistical analyses were performed using the IBM SPSS (statistical Package for the Social Sciences v 20.0) and Microsoft Office Excel 2007 software. The p value <0.05 was taken as significant.  Pre-sent study was a humble attempt to study the changes in platelet volume indices in cases of dyslipidemia.

Observations & Results
Studies have shown that platelet count and size might be gender and age dependent [10]. Hence wehave conducted this case control study with both age and sex matched controls to avoid any such bias in our results.
The collection of samples was done in EDTA bulbs and the samples were run between 2-6 hours after vene puncture to avoid bias due to swelling of platelets in EDTA [11].
We found that all three PVI -MPV, PDW were significantly higher (p-value <0.05) in the study group than the controls, i.e. hyper-lipidemic patients had significantly higher MPV, PDW than the normolipidemic patients.
The association of increased MPV, PDW, P-LCR, and platelet count with diseases related to endothelial dysfunction such as metabolic syndrome, diabetes, coronary artery disease (CAD), and malignancy has been shown in many studies [12,13,14,15]. PDW is a measure of plate let anisocytosis with higher value indicating reactive platelet population [16].
A practical and reliable index of platelet activation has been tested, as measurements of plate let number and size, the tendency to form aggregates and the concentration of released substances stored inplatelet granules [17]. A larger MPV is an indicator of in vivo platelet activation and it is increased in vascular diseases as myocardial and cerebral infarction [18].
We know that larger platelets are considered to be metabolically, enzymatically and functionally more active than the smaller platelets. They contain more dense granules and hence are more potent and thrombogenic and this might be a cause for hyperlipidemia being a pre-thrombotic state. This study is correlated well with other study Khemka et al [19] and Desai KN [20].
Patel DS et al [21] have performed study of 44 patients of dyslipidemia & metabolic syndrome. Results shows that, MPV and PDW were significantly high in patients having metabolic syndrome and dyslipidemia in case group compared to control group. The correlation between variables were significant in both groups (p<0.0005). these results are correlated well with our study.
Hyperlipidemic patients who have larger platelets are more likely to have an associated disease condition and the platelet volume indices may form a basis for the prediction of these diseases in hyperlipidemic patients.
An attempt was also made to correlate these platelet volume indices with the severity of hyperlipidemia. Because larger platelets are more reactive, they can contribute to an increased risk for cardiovascular diseases as a complication of metabolic syndrome. So, estimation of these PVI can be considered as an early, economical and rapid procedure for identification of complications in hyper lipidemic patients.
Also, further studies will elucidate the reactivity of the larger platelets and the utility of the new parameter in assessing qualitative abnormalities in platelets.
We conclude that high MPV and PDW can be considered as biomarkers for early detection of impending diabeteic complications like micro vascular complications.
So these are very cost effective revolutionary markers for early detections of such complications in developing countries at low cost.
Funding: Nil, Conflict of interest: None initiated Permission from IRB: Yes