Antithrombotic dilemmas in stroke medicine: new data, unsolved challenges

A Retrospective Study of Brain-Heart Syndrome in Patients with Acute Cerebrovascular Diseases

Objective

To investigate the clinical characteristics, risk factors and outcomes of brain-heart syndrome (BHS) in patients with acute cerebrovascular diseases (ACVDs).

Methods

A retrospective analysis was conducted of 100 patients who were admitted to our hospital with ACVDs between January 2023 and December 2023. The demographic, clinical, laboratory and imaging data of the patients were collected, and the presence and severity of BHS were evaluated. The neurological and cardiac outcomes of the patients at discharge and at 12-month follow-up were also assessed.

Results

Out of the 100 patients, 38% had BHS, classified as mild (18%), moderate (12%) and severe (8%). The most prevalent ACVDs were cerebral infarction (58%), cerebral haemorrhage (32%) and subarachnoid haemorrhage (10%). Cardiac complications included arrhythmia (26%), myocardial ischaemia (18%) and heart failure (10%). Patients with BHS had higher results for blood pressure, heart rate, white blood cell count, C-reactive protein, IL-6, D-dimer and troponin, more severe neurological deficits, higher mortality and poorer functional outcomes. Multivariable analysis identified age, hypertension, diabetes, coronary artery disease, prior cardiovascular events, cerebral haemorrhage, brainstem infarction and hypothalamic or insular lesions as independent risk factors for BHS.

Conclusion

Brain-heart syndrome is a frequent, severe complication in patients with ACVD, linked with multiple risk factors and poor prognosis. Prompt diagnosis and treatment are crucial for improving patient outcomes.

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.

Secondary stroke prevention in people with atrial fibrillation: treatments and trials

Atrial fibrillation is one of the most common cardiac arrhythmias and is a major cause of ischaemic stroke. Recent findings indicate the importance of atrial fibrillation burden (device-detected, subclinical, or paroxysmal and persistent or permanent) and whether atrial fibrillation was known before stroke onset or diagnosed after stroke for the risk of recurrence. Secondary prevention in patients with atrial fibrillation and stroke aims to reduce the risk of recurrent ischaemic stroke. Findings from randomised controlled trials assessing the optimal timing to introduce direct oral anticoagulant therapy after a stroke show that early start (ie, within 48 h for minor to moderate strokes and within 4-5 days for large strokes) seems safe and could reduce the risk of early recurrence. Other promising developments regarding early rhythm control, left atrial appendage occlusion, and novel factor XI inhibitor oral anticoagulants suggest that these therapies have the potential to further reduce the risk of stroke. Secondary prevention strategies in patients with atrial fibrillation who have a stroke despite oral anticoagulation therapy is an unmet medical need. Research advances suggest a heterogeneous spectrum of causes, and ongoing trials are investigating new approaches for secondary prevention in this vulnerable patient group. In patients with atrial fibrillation and a history of intracerebral haemorrhage, the latest data from randomised controlled trials on stroke prevention shows that oral anticoagulation reduces the risk of ischaemic stroke but more data are needed to define the safety profile.

Association between antithrombotic therapy after stroke in patients with atrial fibrillation and the risk of net clinical outcome: an observational cohort study

AIMS

Data on the optimal use of antithrombotic drugs and associated clinical outcomes in patients with atrial fibrillation (AF) and acute ischaemic stroke (IS) are limited. We investigated the prescription patterns of antithrombotics in community practice and long-term clinical prognosis according to early post-stroke antithrombotic therapy in patients with AF and acute IS.

METHODS AND RESULTS

Patients with AF who were admitted for acute IS at a single tertiary hospital in 2010-2020 were retrospectively reviewed. Clinical profiles including the aetiology of stroke and prescription patterns of antithrombotics were identified. The net clinical outcome (NCO)-the composite of recurrent stroke, any bleeding, hospitalization or emergency department visits for cardiovascular (CV) events, and death-was compared according to the antithrombotic therapy at the first outpatient clinic visit [oral anticoagulation (OAC) alone vs. antiplatelet (APT) alone vs. OAC/APT(s)] following discharge. A total of 918 patients with AF and acute IS (mean age, 72.6 years; male, 59.3%; mean CHA₂DS₂-VASc score 3.3) were analysed. One-third (33.9%, n = 310) of patients were simultaneously diagnosed with AF and IS. The most common aetiology of IS was cardioembolism (71.2%), followed by undetermined aetiology (19.8%) and large artery atherosclerosis (6.0%). OAC, APT(s), and concomitant OAC and APT(s) were prescribed in 33.4%, 11.1%, and 53.4% of patients during admission that changed to 67.0%, 9.1%, and 21.7% at the first outpatient clinic, and were mostly continued up to one year after IS. Non-prescription of OAC was observed in 11.3% of post-stroke patients with AF. During a median follow-up of 2.1 years, the overall incidence rate of NCO per 100 patient-year (PY) was 20.14. APT(s) monotherapy presented the highest cumulative risk of NCO (adjusted hazard ratio 1.47, 95% confidence interval 1.08-2.00, P = 0.015; with reference to OAC monotherapy) mainly driven by the highest rates of recurrent stroke and any bleeding. OAC/APT(s) combination therapy was associated with a 1.62-fold significantly higher risk of recurrent stroke (P = 0.040) and marginally higher risk of any bleeding than OAC monotherapy.

CONCLUSION

Approximately one-third of acute IS in AF have a distinctive mechanism from cardioembolism. Although APT was frequently prescribed in post-stroke patients with AF, no additive clinical benefit was observed. Adherence to OAC treatment is essential to prevent further CV adverse events in patients with AF and IS.

Combined use of anticoagulant and antiplatelet on outcome after stroke in patients with nonvalvular atrial fibrillation and systemic atherosclerosis

This study aimed to investigate whether there was a difference in one-year outcome after stroke between patients treated with antiplatelet and anticoagulation (OAC + antiplatelet) and those with anticoagulation only (OAC), when comorbid atherosclerotic disease was present with non-valvular atrial fibrillation (NVAF). This was a retrospective study using a prospective cohort of consecutive patients with ischemic stroke. Patients with NVAF and comorbid atherosclerotic disease were assigned to the OAC + antiplatelet or OAC group based on discharge medication. All-cause mortality, recurrent ischemic stroke, hemorrhagic stroke, myocardial infarction, and bleeding events within 1 year after the index stroke were compared. Of the 445 patients included in this study, 149 (33.5%) were treated with OAC + antiplatelet. There were no significant differences in all outcomes between groups. After inverse probability of treatment weighting, OAC + antiplatelet was associated with a lower risk of all-cause mortality (hazard ratio 0.48; 95% confidence interval 0.23-0.98; P = 0.045) and myocardial infarction (0% vs. 3.0%, P < 0.001). The risk of hemorrhagic stroke was not significantly different (P = 0.123). OAC + antiplatelet was associated with a decreased risk of all-cause mortality and myocardial infarction but an increased risk of ischemic stroke among patients with NVAF and systemic atherosclerotic diseases.

Antiplatelet Agent Use After Stroke due to Intracerebral Hemorrhage

This focused update about antiplatelet agents to reduce the high risk of major adverse cardiovascular events after stroke due to spontaneous (nontraumatic) intracerebral hemorrhage (ICH) complements earlier updates about blood pressure-lowering, lipid-lowering, and oral anticoagulation or left atrial appendage occlusion for atrial fibrillation after ICH. When used for secondary prevention in people without ICH, antiplatelet agents reduce the risk of major adverse cardiovascular event (rate ratio, 0.81 [95% CI, 0.75-0.87]) and might increase the risk of ICH (rate ratio, 1.67 [95% CI, 0.97-2.90]). Before 2019, guidance for clinical decisions about antiplatelet agent use after ICH has focused on estimating patients' predicted absolute risks and severities of ischemic and hemorrhagic major adverse cardiovascular event and applying the known effects of these drugs in people without ICH to estimate whether individual ICH survivors in clinical practice might be helped or harmed by antiplatelet agents. In 2019, the main results of the RESTART (Restart or Stop Antithrombotics Randomized Trial) randomized controlled trial including 537 survivors of ICH associated with antithrombotic drug use showed, counterintuitively, that antiplatelet agents might not increase the risk of recurrent ICH compared to antiplatelet agent avoidance over 2 years of follow-up (12/268 [4%] versus 23/268 [9%]; adjusted hazard ratio, 0.51 [95% CI, 0.25-1.03]; P=0.060). Guidelines in the United States, Canada, China, and the United Kingdom and Ireland have classified the level of evidence as B and indicated that antiplatelet agents may be considered/reasonable after ICH associated with antithrombotic agent use. Three subsequent clinical trials have recruited another 174 participants with ICH, but they will not be sufficient to determine the effects of antiplatelet therapy on all major adverse cardiovascular events reliably when pooled with RESTART. Therefore, ASPIRING (Antiplatelet Secondary Prevention International Randomized Study After Intracerebral Hemorrhage) aims to recruit 4148 ICH survivors to determine the effects of antiplatelet agents after ICH definitively overall and in subgroups.

Atrial Fibrillation and Ischemic Stroke despite Oral Anticoagulation

Patients with atrial fibrillation (AF) experiencing ischemic stroke despite oral anticoagulation (OAC), i.e., breakthrough strokes, are not uncommon, and represent an important clinical subgroup in view of the consistently high risk of stroke recurrence and mortality. The understanding of the heterogenous potential mechanism underlying OAC failure is essential in order to implement specific therapeutic measures aimed at reducing the risk of recurrent ischemic stroke. However, due to the incomplete comprehension of this phenomenon and the limited available data, secondary stroke prevention in such high-risk patients represents a clinical dilemma. There are several available strategies to prevent ischemic stroke recurrence in AF patients with breakthrough stroke in the absence of competing causes unrelated to AF, and these include continuation or change in the type of OAC, addition of antiplatelet therapy, left atrial appendage closure, or any combination of the above options. However, due to the limited available data, the latest guidelines do not provide any specific recommendations about which of the above strategies may be preferred. This review describes the incidence, the clinical impact and the potential mechanisms underlying OAC failure in AF patients. Furthermore, the evidence supporting each of the above therapeutic options for secondary stroke prevention and the potential future directions will be discussed.