Predictors of hemorrhagic transformation after acute ischemic stroke based on the experts' opinion

Synergistic insights: the integrated role of CT/CTP and clinical parameters in hemorrhagic transformation prediction

BACKGROUND

Acute ischemic stroke presents significant challenges in healthcare, notably due to the risk and poor prognosis associated with hemorrhagic transformation (HT). Currently, there is a notable gap in the early clinical stage for a valid and reliable predictive model for HT.

METHODS

This single-center retrospective study analyzed data from 224 patients with acute ischemic stroke due to large vessel occlusion. We collected comprehensive clinical data, CT, and CTP parameters. A predictive model for HT was developed, incorporating clinical indicators alongside imaging data, and its efficacy was evaluated using decision curve analysis and calibration curves. In addition, we have also built a free browser-based online calculator based on this model for HT prediction.

RESULTS

The study identified atrial fibrillation and hypertension as significant risk factors for HT. Patients with HT showed more extensive initial ischemic damage and a smaller ischemic penumbra. Our novel predictive model, integrating clinical indicators with CT and CTP parameters, demonstrated superior predictive value compared to models based solely on clinical indicators.

CONCLUSIONS

The research highlighted the intricate interplay of clinical and imaging parameters in HT post-thrombectomy. It established a multifaceted predictive model, enhancing the understanding and management of acute ischemic stroke. Future studies should focus on validating this model in broader cohorts, further investigating the causal relationships, and exploring the nuanced effects of these parameters on patient outcomes post-stroke.

Hemorrhagic Transformation in Noncardioembolic Acute Ischemic Stroke: MRI Analysis From PACIFIC-STROKE

BACKGROUND

In the phase 2 PACIFIC-STROKE trial (Proper Dosing and Safety of the Oral FXIa Inhibitor BAY 2433334 in Patients Following Acute Noncardioembolic Stroke), asundexian, an oral factor XIa inhibitor, did not increase the risk of hemorrhagic transformation (HT). In this secondary analysis, we aimed to investigate the frequency, types, and risk factors of HT on brain magnetic resonance imaging (MRI).

METHODS

This was a secondary analysis of the PACIFIC-STROKE trial. Patients with mild-to-moderate acute noncardioembolic ischemic stroke were randomly assigned to asundexian or placebo plus guideline-based antiplatelet therapy. Brain MRIs were required at baseline (≤120 hours after stroke onset) and at 26 weeks or end-of-study. HT was defined using the Heidelberg classification and classified as early HT (identified on baseline MRI) or late HT (new HT by 26 weeks) based on iron-sensitive sequences. Multivariable logistic regression models were used to test factors that are associated with early HT and late HT, respectively.

RESULTS

Of 1745 patients with adequate baseline brain MRI (mean age, 67 years; mean National Institutes of Health Stroke Scale score, 2.8), early HT at baseline was detected in 497 (28.4%). Most were hemorrhagic infarctions (hemorrhagic infarction type 1: 15.2%; HI2: 12.7%) while a few were parenchymal hematomas (parenchymal hematoma type 1: 0.4%; parenchymal hematoma type 2: 0.2%). Early HT was more frequent with longer symptom onset-to-MRI interval. Male sex, diabetes, higher National Institutes of Health Stroke Scale large (>15 mm) infarct size, cortical involvement by infarct, higher number of acute infarcts, presence of chronic brain infarct, cerebral microbleed, and chronic cortical superficial siderosis were independently associated with early HT in the multivariable logistic regression model. Of 1507 with follow-up MRI, HT was seen in 642 (42.6%) overall, including 361 patients (23.9%) with late HT (new HT: 306; increased grade of baseline HT: 55). Higher National Institutes of Health Stroke Scale, large infarct size, cortical involvement of infarct, and higher number of acute infarcts predicted late HT.

CONCLUSIONS

About 28% of patients with noncardioembolic stroke had early HT, and 24% had late HT detectable by MRI. Given the high frequency of HT on MRI, more research is needed on how it influences treatment decisions and outcomes.

Predictive Factors for Hemorrhagic Transformation in Acute Ischemic Stroke in the REAL-World Clinical Practice

BACKGROUND

Few data exists on predictive factors of hemorrhagic transformation (HT) in real-world acute ischemic stroke patients. The aims of this study were: (i) to identify predictive variables of HT (ii) to develop a score for predicting HT.

METHODS

We retrospectively analyzed the clinical, radiographic, and laboratory data of patients with acute ischemic stroke consecutively admitted to our Stroke Unit along two years. Patients with HT were compared with those without HT. A multivariate logistic regression analysis was performed to identify independent predictors of HT on CT scan at 24 hours to develop a practical score.

RESULTS

The study population consisted of 564 patients with mean age 77.5±11.8 years. Fifty-two patients (9.2%) showed HT on brain CT at 24 hours (4.9% symptomatic). NIHSS score ≥8 at Stroke Unit admission (3 points), cardioembolic etiology (2 points), acute revascularization by systemic thrombolysis and/or mechanical thrombectomy (1 point), history of previous TIA/stroke (1 point), and major vessel occlusion (1 point) were found independent risk factors of HT and were included in the score (Hemorrhagic Transformation Empoli score (HTE)). The predictive power of HTE score was good with an AUC of 0.785 (95% CI: 0.749-0.818). Compared with 5 HT predictive scores proposed in the literature (THRIVE, SPAN-100, MSS, GRASPS, SITS-SIC), the HTE score significantly better predicted HT.

CONCLUSIONS

NIHSS score ≥8 at Stroke Unit admission, cardioembolism, urgent revascularization, previous TIA/stroke, and major vessel occlusion were independent predictors of HT. The HTE score has a good predictive power for HT. Prospective studies are warranted.

Association between serum calcium and hemorrhagic transformation in ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Hemorrhagic transformation (HT) is a common complication of ischemic stroke. A growing number of studies have found that serum calcium levels are lower in HT groups than in control groups. However, the relationship between serum calcium and HT remains controversial. We performed a meta-analysis to assess the relationship between serum calcium levels and HT.

METHODS AND RESULTS

Electronic databases were searched for studies on serum calcium and HT from inception to November 6, 2021. Ten studies included in present meta-analysis with a total of 3212 participants. Due to the high heterogeneity (I² = 81%), we chose the random effects model. The results showed that the serum calcium level in the HT group was significantly lower than that in the control group (pooled mean difference, -0.05; 95% confidence interval (CI), (-0.09, -0.02); P = 0.001). Whether thrombolytic or not the results were applied (pooled mean difference, -0.07; 95% CI, (-0.13, -0.01); P = 0.02 and pooled mean difference, -0.03; 95% CI, (-0.06, -0.01); P = 0.007).

CONCLUSIONS

Serum calcium was related to HT and may be one of the risk factors for HT.

Analysis of Factors Associated with Hemorrhagic Transformation in Acute Cerebellar Infarction

OBJECTIVES

Hemorrhagic transformation (HT) is a frequent and severe complication of ischemic stroke. This study aimed to evaluate the factors associated with the occurrence of HT in patients with acute cerebellar infarction.

MATERIALS AND METHODS

A total of 190 patients, 141 male (74.2%) and 49 female (25.8%) with mean age 61.84 ± 12.16 years, who were admitted within 72 h of acute cerebellar infarction onset from January 2017 to March 2021 were retrospectively recruited. The multivariate logistic regression analysis was used to evaluate the independent influent factors for HT and receiver-operating characteristic (ROC) curve was applied to calculate the predictive value of those factors for HT in patients with acute cerebellar infarction.

RESULTS

37 out of 190 recruited patients (19.47%) had HT within 14 days after acute cerebellar infarction onset. The incidence rates of HT occurring within 3 days, 3-7 days and 7-14 days were 13.5%, 40.5% and 45.9%, respectively. Results of the multivariable logistic regression analysis indicated that atrial fibrillation (AF) (OR 6.196, 95% CI 1.357-28.302, P = 0.019), infarct diameter (OR 5.813, 95% CI 2.932-11.526, P < 0.001), white matter hyperintensity (WMH) (OR 2.44, 95% CI 1.134-5.252, P = 0.023) were independent risk factors for HT in acute cerebellar infarction, while lymphocyte count (OR 0.319, 95% CI 0.142-0.716, P = 0.006) showed an independently protective effect.

CONCLUSIONS

Infarct diameter, AF and WMH are independent risk factors for HT in patients with acute cerebellar infarction, while the lymphocyte count is a protective factor.

Lower uric acid level may be associated with hemorrhagic transformation after intravenous thrombolysis

BACKGROUND

Previous studies have shown that uric acid (UA) is a powerful water-soluble antioxidant and free radical scavenger for humans. However, the relationship between serum uric acid (SUA) and hemorrhagic transformation (HT) is still controversial. To address this challenge, we aimed to explore the association between serum UA and HT in patients with acute ischemic stroke (AIS) after intravenous thrombolysis (IVT).

METHODS

A retrospective analysis was conducted in patients with anterior circulation AIS who underwent IVT at Affiliated Hospital of Qingdao University from 2016 to 2021. HT was evaluated by CT or MRI within 7 days after admission. Baseline demographic, clinical, and laboratory data were compared between the HT and non-HT groups, and between different types of HT groups which were documented according to the European Cooperative Acute Stroke Study III Classification (ECASS III).

RESULTS

A total of 727 AIS patients were enrolled, including 112 patients who experienced HT (HT group) and 615 patients who did not experience HT (non-HT group). Patients with HT had significantly lower UA levels compared to those without HT (253.65 ± 97.75 vs 315.97 ± 96.42, p < 0.001); however, there was no significant difference for UA levels in different types of HT (p = 0.907). After adjusting confounders, patients in the fourth UA quartile showed a significant decrease in HT compared with those in the first quartile (OR 0.266, 95% CI 0.107-0.661, p = 0.006). The best cutoff value was identified as 218.5 μmol/L after analysis.

CONCLUSIONS

These findings suggest that low levels of UA may be associated with HT after IVT.

Prediction of Hemorrhagic Transformation after Ischemic Stroke Using Machine Learning

Hemorrhagic transformation (HT) is one of the leading causes of a poor prognostic marker after acute ischemic stroke (AIS). We compared the performances of the several machine learning (ML) algorithms to predict HT after AIS using only structured data. A total of 2028 patients with AIS, who were admitted within seven days of symptoms onset, were included in this analysis. HT was defined based on the criteria of the European Co-operative Acute Stroke Study-II trial. The whole dataset was randomly divided into a training and a test dataset with a 7:3 ratio. Binary logistic regression, support vector machine, extreme gradient boosting, and artificial neural network (ANN) algorithms were used to assess the performance of predicting the HT occurrence after AIS. Five-fold cross validation and a grid search technique were used to optimize the hyperparameters of each ML model, which had its performance measured by the area under the receiver operating characteristic (AUROC) curve. Among the included AIS patients, the mean age and number of male subjects were 69.6 years and 1183 (58.3%), respectively. HT was observed in 318 subjects (15.7%). There were no significant differences in corresponding variables between the training and test dataset. Among all the ML algorithms, the ANN algorithm showed the best performance in terms of predicting the occurrence of HT in our dataset (0.844). Feature scaling including standardization and normalization, and the resampling strategy showed no additional improvement of the ANN's performance. The ANN-based prediction of HT after AIS showed better performance than the conventional ML algorithms. Deep learning may be used to predict important outcomes for structured data-based prediction.

Predictors of post-traumatic complication of mild brain injury in anticoagulated patients: DOACs are safer than VKAs

Although mild traumatic brain injury (MTBI) in people on oral anticoagulant treatment (OAT) is a frequent challenge for Emergency Department (ED), strong guidelines recommendations are lacking. In the attempt to assess the safety profile of direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs), we have recruited 473 patients with a MTBI on OAT (43.6% males; age 81.8 ± 8.7 years), admitted to the Pisa's University Hospital ED (Jan 2016-Oct 2018). All patients underwent a head CT scan with those with no sign of acute bleedings remaining under clinical observation for the ensuing 24 h. Fifty patients (10.6%, 95% CI: 8.1-13.7%) had immediate intracranial hemorrhage (ICH), with a prevalence of patient-important outcomes due to immediate ICH of 1.1% (95% CI 0.4-2.4%); 3 patients died (0.6%, 95% CI 0.2-1.8) and 2 required neurosurgical intervention. Immediate ICHs were more frequent in VKA-treated than in DOAC-treated patients (15.9 vs. 6.4%. RR 2.5. 95%CI 1.4-4.4. p < 0.05). Multivariate analysis identified that post-traumatic amnesia, evidence of trauma above clavicles, high blood glucose, high blood pressure (BP) at arrival, and low prothrombin activity were predictors of immediate ICH. The prevalence of delayed ICH was 1.0% (95%CI 0.4-2.5%) without differences between DOACs and VKAs. Despite ICH being a frequent complication of MTBI in patients on OAT, immediate and delayed patient-important outcomes are rare. DOACs have a better safety profile than VKAs. Simple clinical parameters such as blood pressure at arrival or blood glucose might provide useful predictors of immediate ICH.Trial registration number: 11924_CIPRIANO. Local ethics committee approval number 33096.

Hemostasis functions are associated with hemorrhagic transformation in non-atrial fibrillation patients: a case-control study

Background

Hemorrhagic transformation (HT) is a serious neurological complication of acute ischemic stroke (AIS) after revascularization. The majority of AIS patients do not have atrial fibrillation (AF) which could also develop into HT. In this study, we aimed to explore whether hemostasis parameters are risk factors of HT in non-AF patients.

Methods

We consecutively enrolled 285 AIS patients with HT. Meanwhile, age- and sex-matched 285 AIS patients without HT were included. The diagnosis of HT was determined by brain CT or MRI during hospitalization. All patients were divided into two subgroups based on the presence of AF and explore the differences between the two subgroups. Blood samples were obtained within 24 h of admission, and all patients were evenly classified into three tertiles according to platelet counts (PLT) levels.

Results

In this study, we found the first PLT tertile (OR = 3.509, 95%CI = 1.268–9.711, P = 0.016) was independently associated with HT in non-AF patients, taking the third tertile as a reference. Meanwhile, we also found mean platelet volume (MPV) (OR = 0.605, 95%CI = 0.455–0.805, P = 0.001) and fibrinogen (FIB) (OR = 1.928, 95%CI = 1.346–2.760, P < 0.001) were significantly associated with HT in non-AF patients. But in AF patients, hemostasis parameters showed no significant difference. Meanwhile, we found the MPV (OR = 1.314, 95%CI = 1.032–1.675, P = 0.027) and FIB (OR = 1.298, 95%CI = 1.047–1.610, P = 0.018) were significantly associated with long-term outcomes in non-AF HT patients.

Conclusions

Low PLT, low MPV, and high FIB levels were independently associated with HT in non-AF patients. Additionally, MPV and FIB levels were significantly associated with unfavorable long-term outcomes in non-AF HT patients. Our study showed that hemostasis functions at admission may be beneficial for clinicians to recognize patients with a high risk of HT at an early stage and improve unfavorable long-term outcomes in non-AF patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02065-3.