Stroke is a major cause of death and long-term cognitive impairment in China [20]. Timely treatment is critical to the prognosis of stroke patients, which reduces mortality and improves neurological prognosis [21]. Efficient pre-hospital assessment is essential for EMS to differentiate between hemorrhagic and ischemic stroke [22]. Traditionally, ischemic and hemorrhagic stroke had the common risk factors. However, the risk factors for identifying the different subtypes of stroke are unclear.
This study established a practical and convenient tool based on the FAST score and combined with age, systolic blood pressure, hypertension, and vomiting to predict the risk of hemorrhagic stroke in patients with suspected stroke symptoms for EMS staff. All independent predictors were acquired in clinical practice easily and inexpensively out-of-hospital. This nomogram has proven clinical utility and is useful for risk decision-making in patients with hemorrhagic stroke during pre-hospital first aid.
We found that age was an important independent factor to distinguish hemorrhagic stroke from ischemic stroke. The incidence of stroke among young adults has increased in the past two decades [23]. The patients with hemorrhagic stroke were younger than ischemic stroke [24, 25]. One study of 1,880 non-fatal stroke patients in Japan found that the mean age was 74.1 years for ischemic stroke, and 68.2 years for hemorrhagic stroke [26]. Further, a recent study also confirmed that the median age of patients was 74 (66–82) years for ischemic stroke, 70 (59–79) years for intracerebral hemorrhage, and 64 (53–75) years for subarachnoid hemorrhage among the 183,080 stroke patients [27]. Thus, younger patients who suspected stroke may have an increased risk of hemorrhagic stroke prehospital, which was associated with the poorer blood pressure control and an increased proportion of subarachnoid hemorrhage [28].
At present, hypertension has been recognized as the most important risk factor affecting the occurrence of stroke [29, 30]. This may be related to cerebral vascular remodeling caused by the decrease in the diameter of the cerebrovascular lumen and the increase in the thickness of the vascular wall when hypertension occurs [31]. The elevated blood pressure that occurred in the hyperacute phase of stroke was often associated with sympathetic overactivity [32, 33]. Rawshani et al’s study found that systolic blood pressure was a risk factor that affected cerebrovascular accidents [34]. Importantly, Katsanos confirmed that the lower the systolic blood pressure, the lower risk of hemorrhagic stroke happened, which was consistent with our results [35]. Therefore, we should pay more attention to uncontrolled systolic blood pressure in hypertensive patients, which induced the increased risk of hemorrhagic stroke [36]. Furthermore, we should focus on individual blood pressure treatment goals to reduce the risk of hemorrhagic stroke in hypertensive patients.
The FAST score is a traditional tool for identifying strokes with large vessel occlusion [37]. For patients suspected of acute stroke, questions including facial drooping, arm weakness, and slurred speech should be evaluated according to the FAST score [38, 39]. It was worth noting that stroke was the leading cause of adult-acquired disability [40]. In our study, we found that a higher incidence of slurred speech and arm weakness was observed in hemorrhagic stroke patients. Slurred speech was a manifestation of progressive central nervous system damage [41], always manifested as dysarthria, and was caused by weak, slow, or uncoordinated muscle control [42–44]. The appearance of arm weakness might be related to the regulation of hand function by the corticoreticulospinal tract [45]. Therefore, slurred speech and arm weakness played the important roles in the diagnosis of stroke, especially in hemorrhagic stroke.
Intracranial pressure could be increased after ischemic or hemorrhagic stroke [46, 47]. The typical clinical manifestations of elevated intracranial pressure were headache, vomiting, and even loss of consciousness [48]. Especially in hemorrhagic stroke, blood could extravasate into surrounding brain tissue due to blood vessel ruptures [49]. Our study also demonstrated that vomiting was an important clinical manifestation to distinguish hemorrhagic stroke. More importantly, in contrast to other symptoms, vomiting was a typical symptom that can be assessed even in patients with unconsciousness [50]. In addition, vomiting was the most common manifestation in children with hemorrhagic stroke [51], and it was rarely presented in children with ischemic stroke [52].
Our study has several limitations. First, it was a retrospective single-center study, in which potential selection bias and recall bias were inevitable. Second, this study was not external validation because of the smaller sample size, and multicenter studies should be conducted future. Furthermore, other stroke-related risk factors, such as alcohol consumption, smoking, and exercise habits were not included in our research, which were important factors affecting stroke and may have influenced our results.