In our study, we assessed the association between MPV and PC with the development and prognosis of BAD-stroke, finding that MPV and PC were closely related to the prognosis of BAD-stroke. Patients with a higher MPV and PC were more prone to developing END, which occurred in 66% of patients in the poor prognosis group, indicating that there is a strong association between END and poor prognosis in BAD-stroke.
To our knowledge, there are few analyses of the effect of MPV on stroke subtypes in previous studies, and our study, for the first time, investigated the predictive value of MPV and PC for prognosis in BAD-stroke patients. MPV was found to be associated with poor prognosis of BAD-stroke, and a higher MPV had a negative relationship with 3-month outcomes of BAD-stroke patients. The ROC analysis results showed that an MPV ≥ 12.35 had a sensitivity of 74% in predicting poor prognosis, and the specificity was 84.9%. Previous studies have demonstrated that MPV was associated with poor prognosis in patients with acute cerebral infarction [6; 9; 10; 11], which was consistent with our findings. There are currently few studies on the relationship between PC and stroke prognosis. In 2019, a subgroup analysis of the China National Stroke Registry (CNSR) II that included 16,842 stroke participants found that PC within the normal range may be a qualified predictor for long-term recurrent stroke, mortality, and poor functional outcome in ischaemic stroke or transient ischaemic attack (TIA) patients [14]. Ye et al. [13] showed that patients with cerebral infarction with a PC of 126–225×109/L had the lowest mRS scores between three months and one year after onset. Several studies have previously shown an independent association between PC and cardiovascular mortality or adverse short-term outcomes in AMI patients [15; 16; 17; 20]. However, a study on the prognostic role of MPV and PC in ischaemic and haemorrhagic stroke suggested that PC may be a predictor of the prognosis of haemorrhagic stroke but not ischaemic stroke [9]. In addition, Du et al. [12] revealed that neither MPV nor PC has a significant relationship with the prognosis of haemorrhagic and ischaemic stroke. However, Du et al’s. [12] study defined poor outcomes as mRS scores ≥ 4 at 30 days after discharge, while our study and other studies defined poor outcomes as mRS scores > 2 at 90 days after discharge. In addition, MPV and PC were transformed into categorical variables in Du et al.’s [12] study. However, in our study, MPV and PC were assessed as continuous variables, which could be useful and more reliable in determining the relationship between the prognosis of stroke and platelet parameters. In addition, higher initial NIHSS scores on admission served as risk factors for prognosis in our study, which was similar to Wan and Ma’s [10] study. Higher initial NIHSS scores are suggested to indicate more severe paralysis, so they have a negative correlation with the prognosis of BAD stroke.
Clinically, BAD primarily manifests as END dominated by progressive motor deficiency, and the incidence of END in our study was 24.5%. Patients who experience END often have more severe paralysis. Our study showed that the proportion of patients with END in the poor prognosis group was 66% (33 of 50), which suggested that the presence of END has a close negative correlation with the prognosis of BAD-stroke (Table 4). Therefore, preventing the occurrence of END can greatly improve the prognosis of patients. The infarct size, infarct location and NIHSS score on admission have been shown to be significantly associated with END in previous studies [21; 22; 23; 24; 25]. Our study found that the MPV and PC values in the END group were significantly higher than those in the non-END group, and we demonstrated that elevated MPV and PC are independent risk factors for END in BAD (Table 4). In the PubMed database, only one article concentrated on the relationship between platelets and END in BAD. Oji et al. [26]retrospectively investigated 64 patients with BAD (17 in the END group and 47 in the non-END group) and found that the MPV on admission was significantly greater in the END group than in the non-END group (P < 0.05). Multivariate logistic regression analysis was not performed because of the relatively small number of patients in Oji et al.’s study[26], and our study compensates for this shortcoming. A previous study (n = 1468) reported that the combination of PC and plasma D-dimer in cerebral infarction may have more significant prognostic value for END (OR, 3.622; 95% CI, 1.732–7.573) than plasma D-dimer alone [27]. Thus, the combination of high MPV and PC values may be an independent biomarker for END in BAD. Clinicians should be alert to the occurrence of END in BAD patients, as this leads to poor prognosis. In addition, creatinine values were found to be associated with END in our study (P = 0.030).
Platelets play an important role in the process of thrombus formation and atherogenesis [28]. The pathological basis of BAD is the blockage of perforating arteries by atherosclerotic plaques [1]. Therefore, the number and function of platelets greatly affect the occurrence and development of cerebral infarction [12]. When atherosclerosis occurs, the vessel wall is damaged, which increases the area in contact with platelets, making the vessel wall more prone to thrombosis. An increased MPV leads to more thromboxane A2, the expression of more glycoprotein receptors, such as IIIa and IIb receptors, and stronger chemotaxis, adhesion, and aggregation functions. In addition, a larger MPV can promote the release more active factors, which exacerbate endothelial cell damage and inflammation, thereby promoting the progression of atherosclerosis and thrombosis [28]. We speculate that, due to the abovementioned mechanism, platelets with a larger MPV and a higher PC can cause local thrombus prolongation and repeated embolization of small blood vessels, which lead to END and poor prognosis in BAD patients.
The strengths of our research are as follows: (1) Little is known about the effects of MPV or PC on stroke subtype, and our study explored the relationship between platelet parameters (MPV and PC) and prognosis in BAD stroke for the first time. There are also several limitations to our study. First, it was a single-centre retrospective study with a modest sample size, and patients may have had a certain recall bias for functional recovery after 3 months. Second, we did not investigate the compliance of patients taking secondary prevention drugs for cerebral infarction and rehabilitation treatment after discharge, which would have an impact on the patient's 3-month functional prognosis. Third, platelet count was collected only at admission, with no record of changes in platelet values during disease. Although platelet indexes are relatively stable [29; 30], research has reported a paradoxical increase in MPV after initiation of antiplatelet therapy [31].