ABC | Volume 112, Nº6, June 2019

Original Article Ding et al The clinical significance of platelet parameters such as MPV Arq Bras Cardiol. 2019; 112(6):715-719 Among these subjects, 38 were males and 12 were females, and their mean age was 60.9 ± 6.9 years. None of the abovementioned patients had severe liver or kidney disease, malignant tumors, idiopathic thrombocytopenia, or thrombocytopenia caused by other primary diseases. Sample collection In the early morning, 2 mL of elbow vein blood was withdrawn from each of these subjects under a fasting state, without receiving any hemostasis, coagulation and anticoagulation drugs. The collected blood was placed in EDTA-K2 anticoagulant tubes. Detection method Platelet count (PLT), plateletcrit (PCT), MPV, platelet distribution width (PDW), white blood cell (WBC) and neutrophil (NEU) counts were determined using an STKS automated hematology analyzer (Beckman Courter). Statistical analysis Statistical analysis was performed using the GraphPad Prism 5 software. Measurement data were presented as mean± standard deviation (x ± SD). Comparison of the means in multiple samples was performed using unpaired t-test. p < 0.05 was considered statistically significant. The prediction value of platelet parameters and the total leukocyte count for AMI and SCAD were evaluated using the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC). Correlations between parameters were analyzed using Pearson’s correlation statistical method. Results Results of the four platelet parameters and the total WBC count in AMI patients, SCAD patients and normal healthy subjects (Table 1). As shown in Table 1, compared with the control group, the MPV levels were significantly higher (p < 0.01), while the PLT and the PDWwere significantly lower (p<0.05) in the AMI and SCAD groups. Moreover, compared to the control group, the WBC and NEU levels were also significantly higher (p < 0.01) in the AMI group, but there was no significant difference in the SCAD group. However, the PCT levels had no significant difference between the patient groups and the control group. Evaluation of the diagnostic efficacy of each index by the diagnostic test As shown in Figure 1, in the AMI group, the AUC of PLT (95% CI) was 0.6474 (0.5206-0.7742) and the p-value compared with controls was < 0.05, which shows that the differences were statistically significant. The AUC of MPV (95%Cl) was 0.9032 (0.8232-0.9832) and the p-value compared with controls was < 0.01, which revealed that the differences were statistically significant. Furthermore, the AUC of PDW (95% CI) was 0.6529 (0.5239-0.7819) and the p-value compared with controls was < 0.05; the AUC of PCT (95% CI) was 0.5687 (0.4364-0.701) and the p-value compared with controls was < 0.05, and the AUC of WBC (95% CI) was 0.9190 (0.8475‑0.9906) and the p-value compared with controls was < 0.01. Finally, the AUC of NEU (95% CI) was 0.9310 (0.8678‑0.9942) and the p-value compared with controls was < 0.01. These differences were all statistically significant. These results imply that the diagnostic value of PLT, MPV, WBC and NEU was significantly higher in the AMI group. As shown in Figure 2, in the SCAD group, the AUC of PLT (95% CI) was 0.6176 (0.4907-0.7445) and the p-value compared with controls was > 0.05. The AUC of PDW (95% CI) was 0.6818 (0.5554-0.8081) and the p-value compared with controls was < 0.01, with the differences being statistically significant. The AUC of PDW (95% CI) was 0.5609 (0.4268‑0.6949) and the p-value compared with controls was >0.05, whereas the AUC of PCT (95% CI) was 0.5332(0.3994-0.6671) and the p-value compared with controls was > 0.05, and the AUC of WBC (95% CI) was 0.5635 (0.4368-0.6903) and the p-value compared with controls was > 0.05. Finally, the AUC of NEU (95% CI) was 0.5447 (0.4138-0.6756) and the p-value compared with controls was > 0.05. These results imply that the diagnostic value of MPV was significantly higher in the SCAD group. Correlation analysis of MPV with PLT, PCT and PDW in patients with myocardial infarction Pearson’s correlation coefficient between MPV and PLT was 0.3817; Pearson’s correlation coefficient between MPV and PCT was 0.1103. Pearson’s correlation coefficient between MPV and PDW was 0.0726. It indicates that the MPV and PLT in patients with myocardial infarction have a strong correlation. Table 1 – Platelet parameters and total number of white blood cells and neutrophils in the AMI, SCAD and the control groups Parameters AMI (n = 31) SCAD (n = 34) control group (n = 50) PLT (x 10 9 ) 185.84 ± 61.26 193.62 ± 47.1 206.28 ± 36.17 MPV (fL) 10.42 ± 1.26 9.16 ± 1.28 8.42 ± 0.72 PCT (%) 0.1777 ± 0.0464 0.1709 ± 0.0393 0.1693 ± 0.0287 PDW (%) 16.2 ± 0.65 16.0 ± 1.37 16.5 ± 0.32 WBC (x 10 9 /L) 10.60 ± 2.53 6.61 ± 1.54 6.37 ± 1.25 NEU (x 10 9 /L) 8.34 ± 2.66 3.99 ± 1.25 3.79 ± 0.93 Compared with the control group, the MPV levels were significantly higher (p < 0.01), while the PLT and the PDW were significantly lower (p < 0.05) in the AMI and SCAD groups. Besides, compared to the control group, the WBC and NEU levels were also significantly higher (p < 0.01) in theAMI group, but there was no significant difference in the SCAD group. However, the PCT levels showed no significant difference between the patient groups and the control group. 716