Cerebral microbleeds development after stroke thrombolysis: A secondary analysis of the THAWS randomized clinical trial

Prevalence, Risk Factors, and Clinical Outcomes of New Cerebral Microbleeds After Intravenous Thrombolysis in Acute Ischemic Stroke: a Systematic Review and Meta-analysis

BACKGROUND

Cerebral microbleeds (CMBs) are common in the elderly population, and are associated with an increased risk of stroke and dementia. An acute ischemic stroke event can make CMBs develop rapidly. However, the progression of CMBs after intravenous thrombolysis is not well understood.

METHODS

Following a previously registered protocol, PubMed, Web of Science, and Embase databases were systematically searched to identify relevant literature up to August 2022. Cohort studies that reported new CMBs in patients with acute ischemic stroke undergoing intravenous thrombolysis were included. Random effects models were used to calculate the pooled estimates.

RESULTS

Seven studies with 1079 patients were included in the meta-analysis. The pooled new CMBs prevalence was 7.6% (95% CI 3.9-14.3%) and 63.6% new CMBs were located in the cerebral lobes. Compared with patients without new CMBs, those with new CMBs were older, had a higher proportion of hypertension, and had higher systolic blood pressure and baseline CMBs burden. The presence of new CMBs increased the likelihood of remote intracerebral hemorrhage (OR 28.75, 95% CI 8.58-96.38) and symptomatic intracerebral hemorrhage (OR 15.49, 95% CI 3.21-74.73) but was not related to functional outcomes or hemorrhagic transformation.

CONCLUSIONS

The prevalence of new CMBs after intravenous thrombolysis was approximately 7.6%. The presence of new CMBs is associated with remote and symptomatic intracerebral hemorrhage following intravenous thrombolysis. Considering the potential long-term adverse effects of CMBs progression, patients at a high risk of developing new CMBs should be identified based on potential risk factors.

Magnetic Resonance Imaging-Guided Intravenous Thrombolysis in Cardioembolic Stroke Patients With Unknown Time of Onset - Subanalysis of the THAWS Randomized Control Trial

BACKGROUND

We investigated the clinical effect of intravenous thrombolysis using a magnetic resonance imaging (MRI)-guided approach in cardioembolic stroke (CE) patients with unknown time of onset.Methods and Results: This subanalysis of the THAWS trial assessed the efficacy and safety of alteplase 0.6 mg/kg in CE patients with unknown time of onset and showing diffusion-weighted imaging-fluid-attenuated inversion recovery mismatch. Patients were classified as CE and non-CE using the SSS-TOAST classification system during the acute period. The efficacy outcome was a modified Rankin Scale score of 0-1 at 90 days. In all, 126 patients from the THAWS trial were included in this study, of whom 45 (35.7%) were diagnosed with CE. In the CE group, a favorable outcome was numerically more frequent in the alteplase than control group (52% vs. 35%; adjusted odds ratio [aOR] 2.25; 95% confidence interval [CI] 0.50-9.99). However, in the non-CE group, favorable outcomes were comparable between the alteplase and control groups (44% vs. 55%, respectively; aOR 0.39; 95% CI 0.12-1.21). Treatment-by-cohort interaction for a favorable outcome was modestly significant between the CE and non-CE groups (P=0.069). In the CE group, no patients experienced symptomatic intracranial hemorrhage (ICH) or parenchymal hematoma Type II following thrombolysis.

CONCLUSIONS

When an MRI-guided approach is used, CE patients with unknown time of onset appear to be suitable candidates for thrombolysis.

Association of Atrial Fibrillation with Remote Intracerebral Hemorrhage After Intravenous Thrombolysis: Results from a Multicenter Study in China

INTRODUCTION

This study aimed to investigate the association between atrial fibrillation (AF), particularly newly diagnosed AF, and remote intracerebral hemorrhage (rICH) in patients with ischemic stroke who were treated with intravenous thrombolysis (IVT).

METHODS

This observational study was conducted on patients with ischemic stroke who received IVT with recombinant tissue-type plasminogen activator. The data were taken from a multicenter prospective registry of a Chinese population. rICH was defined as any extraischemic hemorrhage detected on computerized tomography (CT) 24 h after intravenous thrombolysis. We collected and compared the demographic data and clinical characteristics of all the patients with rICH to those of patients without any type of hemorrhagic transformation. The association between AF and rICH was analyzed using univariate analysis and binary logistic regression.

RESULTS

A total of 20,697 patients were included in the study, with 1566 (7.6%) experiencing intracerebral hemorrhage (ICH), 586 (2.8%) experiencing rICH, and 19,131 (92.4%) not experiencing any form of hemorrhagic transformation. Univariate analysis revealed significant differences in age, pre-thrombolysis systolic blood pressure, baseline National Institute of Health Stroke Scale score, previously known AF, newly diagnosed AF, coronary heart disease, congestive heart failure, hyperhomocysteinemia, and history of thrombolysis between the rICH and control groups (P < 0.05). Further multivariate logistic regression analysis indicated that total AF (OR 1.821, 95% CI 1.082-3.065, P < 0.05), previously known AF (OR 1.470, 95% CI 1.170-1.847), and newly diagnosed AF (OR 1.920, 95% CI 1.304-2.825) were independently associated with rICH.

CONCLUSIONS

This study suggests that AF, regardless of whether it is newly diagnosed or previously known, may be associated with the occurrence of rICH following intravenous thrombolysis. Interestingly, our findings suggest that newly diagnosed AF may have a stronger impact on rICH than previously known AF, although confirmation from more studies is needed.

De novo appearance of cerebral microbleeds in community-dwelling older adults. Neuroimaging and clinical correlates

BACKGROUND AND PURPOSE

Prospective studies on cerebral microbleeds (CMB) have departed from individuals who already have CMB at baseline. Therefore, main outcomes have usually been the composite of new lesions appearing on the follow-up among patients who already had CMB together with those who de novo developed CMB. Using the Atahualpa Project Cohort, we aimed to assess correlates of incident CMB in community-dwelling older adults free of CMB at baseline.

METHODS

Atahualpa residents aged ≥ 60 years received baseline clinical interviews and a brain MRI. Those who were free of CMB at baseline and received follow-up brain MRI at the end of the study were included. Multivariate logistic and Poisson regression models were fitted to assess the association and the incidence rate ratio (IRR) of incident CMB according to clinical and neuroimaging variables.

RESULTS

The mean age of 241 study participants was 65.6 ± 6.1 years (57% women). After 6.5 years of follow-up, 25 subjects (10.4%) developed incident CMB. A total of 37 CMB were noticed in these 25 patients. A parsimonious logistic regression model demonstrated an association between the Edmonton Frail Scale (EFS) and incident CMB (p = .043). Multivariate logistic regression models showed an association between WMH progression and incident CMB (p = .011). Using Poisson regression models, the IRR for WMH progression at follow-up was increased in subjects with incident CMB (p = .029).

CONCLUSIONS

Study results show a significant relationship between the EFS, WMH progression, and incident CMB. This knowledge will allow the implementation of preventive policies to reduce incident CMB and its consequences.

Thrombolysis for Acute Wake-Up and Unclear-Onset Strokes with Alteplase at 0.6 mg/kg in Clinical Practice: THAWS2 Study

INTRODUCTION

The aim of this study was to determine the safety and efficacy of intravenous (IV) alteplase at 0.6 mg/kg for patients with acute wake-up or unclear-onset strokes in clinical practice.

METHODS

This multicenter observational study enrolled acute ischemic stroke patients with last-known-well time >4.5 h who had mismatch between DWI and FLAIR and were treated with IV alteplase. The safety outcomes were symptomatic intracranial hemorrhage (sICH) after thrombolysis, all-cause deaths, and all adverse events. The efficacy outcomes were favorable outcome defined as an mRS score of 0-1 or recovery to the same mRS score as the premorbid score, complete independence defined as an mRS score of 0-1 at 90 days, and change in NIHSS at 24 h from baseline.

RESULTS

Sixty-six patients (35 females; mean age, 74 ± 11 years; premorbid complete independence, 54 [82%]; median NIHSS on admission, 11) were enrolled at 15 hospitals. Two patients (3%) had sICH. Median NIHSS changed from 11 (IQR, 6.75-16.25) at baseline to 5 (3-12.25) at 24 h after alteplase initiation (change, -4.8 ± 8.1). At discharge, 31 patients (47%) had favorable outcome and 29 (44%) had complete independence. None died within 90 days. Twenty-three (35%) also underwent mechanical thrombectomy (no sICH, NIHSS change of -8.5 ± 7.3), of whom 11 (48%) were completely independent at discharge.

CONCLUSIONS

In real-world clinical practice, IV alteplase for unclear-onset stroke patients with DWI-FLAIR mismatch provided safe and efficacious outcomes comparable to those in previous trials. Additional mechanical thrombectomy was performed safely in them.

Intravenous Alteplase at 0.6 mg/kg for Unknown Onset Stroke with Prior Antithrombotic Medication: THAWS Randomized Clinical Trial

AIM

This study aimed to assess the potential effect of prior antithrombotic medication for thrombolysis in an unknown onset stroke.

METHODS

This was a predefined sub-analysis of the THAWS trial. Stroke patients with a time last known well ＞4.5 h who had a DWI-fluid-attenuated inversion recovery mismatch were randomly assigned (1:1) to receive alteplase at 0.6 mg/kg (alteplase group) or standard medical treatment (control group). Patients were dichotomized by prior antithrombotic medication.

RESULTS

Of 126 patients (intention-to-treat population), 40 took antithrombotic medication (24 with antiplatelets alone, 13 with anticoagulants alone, and 3 with both), and the remaining 86 did not before stroke onset. Of these, 17 and 52 patients, respectively, received alteplase, and 23 and 34, respectively, had standard medical treatment. Antithrombotic therapy was initiated within 24 h after randomization less frequently in the alteplase group (12% vs. 86%, p＜0.01). Both any intracranial hemorrhage within 22-36 h (26% vs. 14%) and a modified Rankin Scale score of 0-1 at 90 days (good outcome) (47% vs. 48%) were comparable between the two groups. A good outcome was more common in the alteplase group than in the control group in patients with prior antithrombotic medication [relative risk (RR) 2.25, 95% confidence interval (CI) 1.02-4.99], but it tended to be less common in the alteplase group in those without (RR 0.69, 95% CI 0.46-1.03) (p＜0.01 for interaction). The frequency of any intracranial hemorrhage did not significantly differ between the two groups in any patients dichotomized by prior antithrombotic medication.

CONCLUSION

Alteplase appears more beneficial in patients with prior antithrombotic medication.

New Remote Cerebral Microbleeds on T2*-Weighted Echo Planar MRI After Intravenous Thrombolysis for Acute Ischemic Stroke

Background

The main and well-defined complication of intravenous administration of recombinant tissue plasminogen activator (tPA) in patients with acute ischemic stroke (AIS) is symptomatic intracranial hemorrhage (sICH). However, rtPA might also be connected with the formation of cerebral microbleeds (CMBs), located remotely from the ischemic lesions, that may remain clinically silent. This association might be important because the load of CMBs has been associated with cognitive impairment. We investigated whether administration of rtPA in AIS results in the appearance of new CMBs and if the initial load of CMBs is associated with hemorrhagic transformation.

Methods

A total of fifty-nine consecutive patients with AIS treated with rtPA underwent MRI including T2^*-weighted Echo Planar Imaging (T2^*-EPI) shortly before and 7–9 days after rtPA administration. We calculated the load of new CMBs located outside the MR diffusion restriction area in the follow-up imaging and assessed hemorrhagic transformation with ECASS-II scoring.

Results

A total of forty-nine patients were included for the final analysis. On initial T2^*-EPI-GRE, 37 baseline microbleeds (CMBs) were observed in 14 patients (28.6%). On follow-up T2^*-EPI-GRE amount of CMBs increased to a total number of 103. New CMBs were found in 5 (14.3%) of 35 patients without and in 9 (64.3%) of 14 with any baseline CMBs. Multiple logistic regression analysis indicated that presence of baseline CMBs (risk ratio [RR] 5.95, 95% CI 2.69–13.20, p < 0.001) and lower platelets level (risk ratio [RR] 0.992, 95% CI 0.986–0.998, p = 0.007) were independently associated with new CMBs. The baseline load of CMBs was not associated with the risk of hemorrhagic transformation.

Conclusion

In this study, new CMBs were found in nearly 30% of patients with AIS on the 7–9 days after rtPA treatment. Baseline CMBs correlated with a higher risk of new CMBs appearing after the rtPA treatment, independently of other factors. At the same time, in our sample, baseline CMBs did not correlate with an increased risk of hemorrhagic transformation. Since the associations between the CMBs load and cognitive impairment have already been proved, further studies are warranted to investigate possible associations between the thrombolytic treatment of patients with AIS, mainly those with baseline CMBs, and the risk of earlier cognitive decline.