Acute ischemic stroke (AIS) is the leading cause of disability and mortality, posing a severe threat to human well-being (1). Research on the Chinese population reveals that, in 2020, there were 15.5 million cases of ischemic stroke among adults >40 years, with a prevalence rate of approximately 2.3/100 people (2). Over 30% of AIS cases result from large vessel occlusion (LVO) (3). LVO causes ischemia and hypoperfusion in the affected area, and timely restoration of perfusion to the ischemic area can maintain brain cell activity. Thrombolysis treatment by intravenous recombinant tissue plasminogen activator is accessible within a 4.5 h window from the onset of symptoms. However, it is not always feasible owing to missed time windows or contraindications. In recent years, mechanical thrombectomy (MT) development has provided new treatment options for patients with AIS. MT treatment is safe and effective for patients with anterior circulation AIS (AC-AIS), extending the treatment time to 6–24 h (4).

Compared with AC-AIS, posterior circulation AIS (PC-AIS) occurs in the vertebrobasilar system-supplied area, resulting in a worse prognosis (5). The early symptoms of PC-AIS are mild and unspecific, making identification challenging. Therefore, patients with PC-AIS have a lower rate of benefit from intravenous thrombolysis than those with anterior circulation AIS, with only 1/6 of patients benefiting from this treatment (6). It indicates that MT is an important treatment for patients with PC-AIS. However, the outcome of MT treatment in PC-AIS remains controversial, with significant differences observed in four randomized controlled trials (RCTs). In the BEST and BASIC studies, no significant difference was observed in prognostic outcomes between the MT and drug therapy alone groups.

In contrast, the BAOCHE and ATTENTION studies indicated a more favorable prognosis for patients who underwent MT treatment (7–10). Most patients with PC-AIS can achieve revascularization after MT treatment; however, only 38% experience a good prognosis (11). Therefore, exploring the factors influencing prognosis can help clinicians identify patients at high risk of poor prognosis and provide more timely interventions. There are fewer studies on the factors influencing the prognosis of PC-AIS patients undergoing MT treatment. A meta-analysis revealed that hypertension and diabetes were associated with poor prognosis (12). Gao et al.’s study identified baseline National Institutes of Health Stroke Scale (NIHSS) score, posterior circulation acute stroke prognosis early computed tomography (PC-ASPECT) score, and modified thrombolysis in cerebral infarction (mTICI) classification as independent risk factors affecting patients’ prognosis (13).

Notably, no study investigates the impact of post-operative medical management on the risk of patients’ prognosis, and predictive models for poor prognosis and sICH are yet to be constructed. This study addresses these gaps by investigating factors affecting the prognosis and sICH of patients with PC-AIS undergoing MT and constructs a nomogram applicable to clinical practice. We aimed to guide targeted clinical interventions to improve the management of patients with PC-AIS and enhance their post-treatment prognosis.

Recently, MT has been used to treat AIS with increasing success. Despite its demonstrated superiority over drug treatment alone for patients with PC-AIS (14), the prognosis for most patients with PC-AIS remains poor, with a mortality rate of >30% and only 38% showing good prognosis (11). Our results showed that baseline NIHSS score, SBP CV, peak SBP, and HbA1c were identified as the independent risk factors for the prognosis of patients with PC-AIS. Atrial fibrillation, peak SBP, and peak DBP were independent risk factors for sICH. The nomograms were constructed to predict the prognosis and sICH of patients. These nomograms have good discrimination calibration and can be used as a valid tool in clinical practice.

The early recognition of PC-AIS is difficult, but the progression is rapid. One important indicator of stroke severity is the NIHSS score in patients. In patients with AC-AIS, the risk of poor prognosis after revascularization increases progressively as the NIHSS score rises (15, 16). However, few studies have investigated the effects of MT on patients with PC-AIS. Notably, the ENDOSTROKE study revealed that a low NIHSS score was an independent predictor of patient prognosis after 90 days of basilar artery occlusion (BAO) (17). Another study of 117 patients with BAO demonstrated that the baseline NIHSS score predicted mortality in patients who achieved successful revascularization (18). This study’s baseline NIHSS score was an independent risk factor for poor prognosis in patients with PC-AIS undergoing MT. As the NIHSS score increases by one point, the risk of poor prognosis increases by 0.102-fold. This finding highlights the importance of the NIHSS score as a prognostic assessment for patients with PC-AIS. Despite the greater risk of poor prognosis post-MT in patients with high NIHSS scores, there is still a chance of reperfusion of ischemic brain tissue and recovery of neurological function compared with drug therapy alone. A meta-analysis revealed that MT treatment was more beneficial than drug therapy alone for patients with NIHSS scores >20 (19). Patients with high NIHSS scores should not be excluded from MT treatment.

The focus of current research into MT treatment in patients with PC-AIS has primarily been on its safety and efficacy. However, post-operative patient management has received little attention. AIS is often associated with hypertension, and elevated BP variability is associated with greater mortality and disability following a stroke (20). Our study identified SBP CV as an independent risk factor for poor prognosis in PC-AIS with MT. In patients with AC-AIS, similar results were observed, where higher systolic blood pressure variability was a predictor of poor prognosis after MT and was associated with higher mortality (21, 22). This may be attributed to impaired cerebral autoregulation following AIS. Cerebral autoregulation maintains stable cerebral blood flow in the presence of fluctuations in systemic BP (23). This ability can protect the brain from the negative effects of blood pressure variations. When cerebral autoregulation is impaired, higher blood pressure variability can worsen ischemic and reperfusion injury, which can lead to complications such as hemorrhagic infarction and cerebral edema (24). These complications can ultimately lead to poor clinical outcomes. Therefore, maintaining a stable BP post-MT treatment is crucial in improving patient prognosis.

Elevated blood pressure increases the risk of reperfusion injury (25). Higher systemic arterial BP was associated with poor prognosis and a high risk of hemorrhage in patients with AC-AIS with MT treatment (26–28). In our study, peak SBP was an independent risk factor for poor prognosis and sICH, and peak DBP was an independent risk factor for sICH. The results of the ENCHANTED study revealed that intensive antihypertensive lowering to 140 mmHg did not enhance the prognosis of patients (29). This may be because rapid antihypertensive lowering increases the risk of hypoperfusion. Additionally, even with successful revascularization, some patients may still require higher BP levels to maintain normal perfusion. The current guidelines recommend maintaining SBP at 180 mmHg for 24 h post-MT (30), while the BEST study suggests that patients with AC-AIS with peak SBP exceeding 154.5 mmHg may have an increased risk of poor prognosis. However, there are no studies on post-operative BP management goals for patients with PC-AIS. In our study, we observed that the peak SBP of 161.5 mmHg was observed to best distinguish the prognostic outcome of patients. When the peak SBP exceeded this level, patients were at an increased risk of poor prognosis. Additionally, patients with a peak SBP >167.5 mmHg or peak DBP >92.5 mmHg have a higher likelihood of experiencing ICH within 24 h post-MT. Therefore, the management of SBP and DBP should be taken seriously in patients with AIS post-MT to reduce the risk of poor prognosis and sICH and to improve the quality of life of patients.

Additionally, our study results show that HbA1c is an independent risk factor for poor prognosis post-MT, and AF is an independent risk factor for sICH. HbA1c levels reflect the average blood sugar level over the past 2–3 months. Elevated HbA1c levels, indicating suboptimal long-term glucose management, emerge as a modifiable factor that warrants attention in the pre- and post-operative phases. Poor BG control can worsen ischemic injury through various mechanisms, such as disrupting the blood–brain barrier, increasing oxidative stress, exacerbating the thrombo-inflammatory cascade, and impairing fibrinolysis (31, 32). Ultimately, this leads to an expansion of infarct size and cerebral hemorrhage (33). Therefore, it is crucial to control blood glucose levels to improve patient prognosis.

Additionally, the independence of AF as a risk factor underscores the importance of vigilant monitoring and tailored interventions for individuals with this cardiac arrhythmia. Previous studies have identified that atrial fibrillation is an independent risk factor for hemorrhagic transformation in patients with AIS treated with intravenous thrombolysis or MT (34, 35), aligning with our findings.

However, the limitations to our study are as follows: (1) the small sample size of this study may influence the results; (2) as the patients in our study had high NIHSS scores, our findings may not apply to those with mild PC-AIS. Therefore, a larger multicenter study is required to confirm the results of the present study.

Our study aimed to identify factors influencing the prognosis of patients with posterior circulation AIS. Our results highlighted that the baseline NIHSS score, peak SBP, SBP CV, and HbA1c were independent factors affecting prognosis. AF, peak SBP, and peak DBP were associated with the risk of sICH. Furthermore, nomograms were developed to predict the prognosis and sICH for patients with PC-AIS. The models demonstrated good discrimination, calibration, and clinical applicability.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving humans were approved by the Ethics Committee of the First Hospital of Shanxi Medical University. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

JiL: Data curation, Formal analysis, Methodology, Software, Validation, Visualization, Writing – original draft. JZ: Conceptualization, Funding acquisition, Methodology, Supervision, Writing – review & editing. CL: Formal analysis, Funding acquisition, Supervision, Validation, Writing – review & editing. JuL: Data curation, Methodology, Resources, Software, Writing – review & editing. XW: Data curation, Project administration, Resources, Validation, Writing – review & editing. SW: Conceptualization, Data curation, Funding acquisition, Investigation, Project administration, Resources, Supervision, Writing – review & editing.