External Validation of Multiple Intravenous Thrombolysis Prediction Models

Research Article

Austin J Clin Neurol. 2022; 9(2): 1160.

External Validation of Multiple Intravenous Thrombolysis Prediction Models

Yinglei-Li1,3, Lingyun-Xi4, Litao-Li1,2*, Tao-Qie3, Bing-Dai3, Shichao-Liu3, Feifei-Yu3

1Department of Hebei Medical University, Shijiazhuang, China

2Department of Neurology, Hebei General Hospital,Shijiiazhuang, China

3Department of Emergency Medicine, Baoding FirstCentral Hospital, Baoding, China

4Department of Laboratory Medicine, Chinese People’s Liberation Army 82nd Army Group Hospital, Baoding, China

*Corresponding author: Litao-LiDepartment of Neurology, Hebei General Hospital, Shijiiazhuang, China, 050000

Received: November 12, 2022; Accepted: December 19, 2022; Published: December 25, 2022

Abstract

Background and Purpose: ASPECTS, ASTRAL, DRAGON, THRIVE-c and START are predictive models that have been gradually developed in recent years to predict functional outcome after acute stroke in patients treated with intravenous thrombolysis, respectively. We aimed to externally validate these scores to assess their predictive performance in this advanced stroke center in China.

Methods: We examined the clinical data of 835 patients with AIS who were admitted to the emergency department for intravenous thrombolysis at the Advanced Stroke Center, First Central Hospital, Baoding, China, between January 2016 and May 2022, and scored the patients using the five scales. The 3-month modified Rankin Scale scores were observed for each score point, and patients with scores 3 to 6 were defined as having a poor prognosis and compared with the proportions predicted based on risk scores. The ROC curve was used to analyze the predictive value of each score for poor prognosis at 3 months.

Results: Finally, 728 patients were included, and 318 (43.68%) had a poor prognosis. roc curve analysis, the five scores corresponded to C values of 0.851, 0.825, 0.854, 0.809, and 0819 in the overall patients, respectively, and in the pre-circulation 0.853, 0.813, 0.833, 0.804, 0.807, and 0.848, 0.862, 0.909, 0.811, 0.857 in the posterior cycle, respectively (all P> 0.05).

Conclusions: The five scores predicted the 3-month adverse prognostic risk in AIS patients undergoing intravenous thrombolysis in both anterior circulation and posterior circulation lesions, but the DRAGON score had the highest predictive diagnostic value in the posterior circulation.

Keywords: Intravenous Thrombolysis Anterior Circulation and Posterior Circulation Lesions Prognosis Registries Roc Curve Stroke.

Introduction

The annual incidence of ischemic stroke accounts for 14 million, which is about 70-80% of stroke. It is the second leading cause of death worldwide after ischemic heart disease and has a very high disability rate, making it one of the major diseases that seriously threaten human life, health and quality of life [1-3]. In the acute symptoms of ischemic stroke, That is, timely application of tissue-type plasminogen activator intravenous thrombolysis within the time window is the only approved and effective pharmacological treatment and timely intravenous thrombolysis significantly improves the prognosis of patients with acute ischemic stroke [4]. However, A significant proportion of patients, even when treated with intravenous thrombolysis even, they did not fully benefit, and still had complications, left neurological disability, and even bleeding and death [5]. Urgent thrombolysis and beneficial treatment may lead to awesome complications; Entangled in the risk of thrombolysis, itmay delay revascularizationd, resulting in the worsening of the disease itself [6-7]. Therefore, Early prognostic assessment of patients with AIS within the time window of intravenous thrombolytic therapy is very helpful, thus reducing the time delays in patient management [8] and preventing more serious complications.

In recent years, there are many studies on predictive models of scoring systems for prognosis of intravenous thrombolysis in patients with AIS [9-16]. The model [17] can predict the long-term prognosis of AIS patients early and accurately, which not only helps Doctors to diagnose and treat, but also can convey prognosis expectations to patients. However, most of the current prediction models have some limitations, for examples, many variables, difficult to obtain, cumbersome calculation, which have not been widely used in modern clinical practice. The establishment and validation [18] of prediction models are usually based on one or several specific cohorts. Small amount of verification in different geographical regions or ethnic groups is the main reasons limiting the application of these models in clinical. So, for the existing prediction model, it is very important to verify its prediction ability and the clinical influence in different areas [19].

Currently found, the ASPECTS, ASTRAL, DRAGON, THRIVE-c, and START models all use simple and easy to obtain available predictors in different ways, but they have the ability to predict clinical application. For the ASPECTS score, not only can the dichotomy of 0 to 7 and 8-10 be used, but also the trichotomous zones of 0-4, 5-7, 8-10 can be used [20-22]. DRAGON [10,23] was consisted of arterial CT high-density signs/early infarct signs, pre-stroke MRS score, age, baseline blood glucose, onset to time of administration OTT and baseline NIHSS score, with a total score of 10, calculated using multivariate logistic regression analysis, including imaging information [23]. ASTRAL [11] it does not require emergency imaging information and consists of six readily available clinical parameters: age, NIHSS score, time from onset to admission DNT, visual field range, blood glucose and level of consciousness [24-25] using multivariate logistic regression analysis. The original THRIVE score [12] was a categorical variable consisting of baseline NIHSS score, age, and chronic disease score (including hypertension, diabetes, and a trial fibrillation) with a total score of 9. And later, so as to predict the prognosis of every individual, the team modified this scoring system by converting the original variables (NIHSS score and age), which were transformed into a dichotomous calculation, the THRIVE-c score [26-27], into a continuous variable. The START [13,28] model were calculated as continuous variables for NIHSS score, age, MRS score (modified Rankin Scales) before this stroke and OTT time (onset-to-treatment time,). All these five models have been validated nationally and internationally as to predict the probability of adverse prognosis at 3 months in patients undergoing intravenous thrombolysis [22-28]. Although the respective variables vary, there is still a small of evidence regarding their respective clinical usefulness and the corresponding comparative validation. The intent of this study was to evaluate the prognostic predictive function of these five models in patients with AIS undergoing intravenous thrombolysis by independent external validation and comparison using patient data from our stroke center.

Research Materials and Methods

The design of this study was all in accordance with the guidelines established in the Declaration of Helsinki. And was approved by the ethics committee of Baoding first central hospital (ethics approval number: 2022-063). This study is a retrospective analysis, including patients with stroke who received intravenous thrombolytic therapy with alteplase in the national high-end stroke center of the first Central Hospital of Baoding city from January 1, 2016 to May 31, 2022.

Inclusion Criteria

(1) Age ≥18 years.

(2) Indication for intravenous thrombolysis.

(3) Obtain informed consent from patient and family and sign.

Exclusion Criteria

(1) Patients receiving further endovascular treatment.

(2) Patients with a final diagnosis of stroke-like disease.

(3) Patients with missing data on predictor variables for ASPECTS, ASTRAL, DRAGON, THRIVE-c and START models.

(4) Patients who were missed during the 3-month follow-up.

The responsible physician decided whether to thrombolyze the patient intravenously by referring to the international guidelines [4-5] at the early time for AIS patients. Patients receiving intravenous thrombolytic therapy were given written informed consent by themselves or their immediate family members. The dose of alteplase treatment was divided into a standard dose (0.9 mg/kg) or a low dose (0.6 mg/kg), and the maximum dose administered was 90 mg.

Research Methods

We retrospectively counted and analyzed the data of AIS patients in the thrombolysis database of the First Central Hospital of Baoding, which was continuously collected. Data collection personnel have been trained in relevant professions. We collected baseline characteristics, vascular risk factors, current and previous stroke severity, clinical examination and experimental examination results, information on current treatment, and so on.

Vascular risk factors include hypertension, coronary artery disease, diabetes mellitus, hyperlipidemia, history of previous stroke, a trial fibrillation, smoking, and alcohol consumption. Stroke severity in stroke patients is assessed by the National Institute of Health stroke scale (NIHSS) score, with the baseline NIHSS score indicating the NIHSS score before thrombolytic administration.

Hypertension [29] diabetes mellitus, coronary artery disease, hyperlipidemia, atrial fibrillation, smoking, and alcohol consumption were defined according to international standards for diagnosis; previous stroke history included previous ischemic stroke, hemorrhagic stroke, and transient ischemic attack history[31].

AIS patients were divided into anterior and posterior circulation groups based on different lesion infarct sites. The etiological diagnosis is based on the classical 1993 TOAST staging proposed by Adams et al. in the USA 32forlarge artery atherosclerotic type, cardiogenic embolism, small artery occlusion, stroke of other known etiology and stroke of unknown cause.

Predictive Model Scoring Scale

AllAIS patients were scored using the five predictive model scales ASPECTS, ASTRAL, DRAGON, THRIVE-c and START, which were assessed by two senior stroke neurologists, and in case of inconsistent scoring, a third senior physician made the scoring decision.

ASPECTS Scores: Anterior circulation ASPECTS score: 10 regions in 2 levels of the middle cerebral artery blood supply area were selected on CT images.

(1) At the level of the nucleus accumbens (i.e., thalamus and striatum planes), which is divided into 7 regions: anterior cortical region of the middle cerebral artery, lateral cortical region of the insula of the middle cerebral artery, posterior cortical region of the middle cerebral artery, insula, nucleus accumbens, caudate nucleus, and posterior limb of the internal capsule.

(2) The level above the nucleus accumbens (2 cm above the level of the nucleus accumbens), including the middle cerebral artery cortex above the anterior middle cerebral artery cortical area, the middle cerebral artery cortex above the lateral middle cerebral artery insula cortical area, and the middle cerebral artery cortex above the posterior middle cerebral artery cortical area.

The boundary between the two is the head of the caudate nucleus, and any ischemic changes in the caudate nucleus and below are defined as the nucleus accumbens level in cross-sectional CT images, while ischemic changes above the head of the caudate nucleus are defined as the supranucleusaccumbens level.

These 10 regions were given the same weight of 1 point. The number of regions with EIC is subtracted from the score of 10, with a score of 10 indicating a normal CT scan and a score of 0 indicating extensive ischemia in the MCA blood supply area.

pc-ASPECTS scores the posterior circulation into 10 points.

A score of 1 is for the left or right thalamus, cerebellum, or posterior cerebral artery region; a score of 2 is for the midbrain or pontine brain.

ASTRAL Score: Six were included: age, NIHSS score, onset to admission time DNT, visual field range, glucose, and level of consciousness.

DRAGON Score: Six were included: arterial CT hyperdensity sign/early infarct sign, pre-stroke mRS score, age, baseline glucose, onset to time of administration OTT and baseline NIHSS score with a total score of 10.

THIRVE-cscore

The predictors of the model included two continuous variables (baseline NIHSS score, age) and one dichotomous variable, the Chronic Disease Scale (CDS), which was scored as 1 point each for hypertension, diabetes mellitus, and atrial fibrillation.

THRIVE-c model calculation formula (P is the probability of good prognosis):

3.4.4 START Score: Predictors of the model included baseline NIHSS score, age, mRS score before the current stroke and onset-to-treatment time (OTT).

START model calculation formula (P is the probability of poor prognosis).

Ending events and follow-up

The evaluation index was a 3-month poor functional prognosis, evaluated by the mRS score, obtained by a 3-month face-to-face visit or telephone follow-up [33].

The mRS score [34-35] was evaluated as follows.

A score of 0 indicates complete absence of symptoms.

A score of 1 indicates no significant functional impairment despite symptoms and no assistance with daily living.

A score of 2 indicates a mild disability, unable to perform all previous tasks and activities, but able to manage personal matters without assistance from others.

A score of 3 indicates a moderate disability, requiring some assistance but walking without assistance

A score of 4 indicates a severe disability, unable to walk without the help of others and unable to care for his or her own physical needs

A score of 5 indicates severe disability, bedridden, incontinent and requiring constant care and attention

A score of 6 is death.

The mRS score of 0-2 in this study was defined as a good functional prognosis, and the mRS score of 3-6 was defined as a poor functional prognosis, which is consistent with the definition of the original study that developed these models.

Statistical Methods

For continuous variables in this study, we first evaluated the normality of the data using the Kolmogorov-Smirnov test. Those that conformed to a normal distribution were expressed as mean â± standard deviation, non-normally distributed continuous variables were expressed as median, and categorical variables were expressed as frequency and percentage. The t-test was used to make two-by-two comparisons for continuous-type variables conforming to a normal distribution, the Mann-Whitney U-test for variables with a non-normal distribution, and the chi-square test for categorical variables.

The ASPECTS, ASTRAL, and DRAGON models predicted 3-month adverse prognosis of AIS patients using respective scales, and the probabilities of the THRIVE-c and START models were calculated using their respective logistic formulas. Model performance was evaluated in two ways: discrimination and calibration. The discrimination reflects the ability of the prediction model to discriminate between the occurrence and non-occurrence of outcome events, as assessed by the area under the receiver operating characteristic curve (AUROC). Good discriminative ability, and 1.0 indicates perfect discriminative ability [36]. Calibration refers to the agreement between the risk of occurrence of an outcome event predicted by the model and the probability of the actual observed outcome event, and this study used two indicators, calibration curve and Brier score, to evaluate the calibration of the model. The calibration curve was plotted based on the probability of predicted adverse prognosis and the probability of actual observed adverse prognosis, and the closer the curve was to a 45â° straight line, the better the calibration of the model. The Hosmer-Lemeshow (H-L) goodness-of-fit [χ2 (P)] was applied to test the fit of each evaluation model to the actual outcome, and P> 0.05 suggested that the model was a good fit to the actual outcome. The lower the Brier score, the better the model calibration is indicated. In addition, because the Brier score can quantitatively evaluate the accuracy of the model, it can be used to compare the predictive ability of five models. Statistical analyses in this study were performed in R (Version 4.0.2; R Foundation for Statistical Computing, Vienna, Austria), and a two-sided P≤ 0.05 was considered statistically different.

Results

Baseline Information of the Validation Cohort

A total of 835 patients with AIS treated with intravenous thrombolysis with alteplase were screened, of whom 107 were excluded. Of the excluded patients, 26 received bridging therapy, 54 had incomplete data, 22 were lost to follow-up, and 5 were diagnosed with stroke-like disease. The patient screening process is shown in Figure 1. Finally, we included data from 728 patients for statistical analysis.