Antiplatelet therapy as a modulator of stroke aetiology: a meta-analysis

A Review of Post-Stroke Cognitive Impairment and the Potential Benefits of Stingless Bee Honey Supplementation

Post-stroke cognitive impairment (PSCI) is a common decline in cognitive abilities that occurs within 3 months after a stroke. During recovery, stroke survivors often experience varying degrees of cognitive decline, with some patients experiencing permanent cognitive deficits. Thus, it is crucial to prioritise recovery and rehabilitation after a stroke to promote optimal protection of and improvement in cognitive function. Honey derived from stingless bees has been linked to various therapeutic properties, including neuroprotective effects. However, scientific evidence for the mechanisms through which these honey supplements enhance cognitive function remains limited. This narrative review aims to provide an overview of the causes of PSCI, current treatments, the biomarkers influencing cognition in post-stroke patients and the potential of stingless bee honey (SBH) as a neuroprotective agent against the progression of PSCI.

Alterations of Hemostatic Molecular Markers During Acute Large Vessel Occlusion Stroke

BACKGROUND

This study aimed to investigate regional levels of TAT (thrombin-antithrombin complex), PIC (plasmin-α2 plasmin inhibitor complex), t-PAIC (tissue plasminogen activator-plasminogen activator inhibitor complex), sTM (soluble thrombomodulin), and D-dimer, along with their associations with clinical and procedural characteristics in patients with acute ischemic stroke undergoing endovascular thrombectomy.

METHODS AND RESULTS

We retrospectively analyzed 166 consecutive patients with acute ischemic stroke (62±11.54 years of age, 34.3% women) using prospectively maintained clinical databases and blood samples from local ischemic (proximal to thrombus) and systemic (femoral artery, self-control) arterial compartments. Levels of TAT, PIC, t-PAIC, and D-dimer were significantly elevated, whereas sTM was significantly reduced, in local ischemic regions compared with their systemic levels. Each 1-unit increase in ischemic TAT (adjusted odds ratio [aOR], 1.086 [95% CI, 1.03-1.145]; P=0.002; area under the curve [AUC], 0.833) and PIC (aOR, 1.337 [95% CI, 1.087-1.644]; P=0.006; AUC, 0.771) correlated significantly with higher symptomatic intracranial hemorrhage risk. Additionally, each 1-unit increase in ischemic TAT (aOR, 1.076 [95% CI, 1.016-1.139]; P=0.013; AUC, 0.797), PIC (aOR, 1.554 [95% CI, 1.194-2.022]; P=0.001; AUC, 0.798), and sTM (aOR, 0.769 [95% CI, 0.615-0.961]; P=0.021; AUC, 0.756) was significantly associated with an increased risk of an unfavorable 90-day outcome (modified Rankin scale of 3-6). These hemostatic molecules, individually or combined, significantly improved the predictive power of conventional risk factors, as evidenced by significant increases in net reclassification improvement and integrated discrimination improvement (all P<0.01).

CONCLUSIONS

We observed a hyperactive state of the coagulation-fibrinolysis system within the local ischemic region during hyperacute stroke. Rapid automated measurement of hemostatic molecular markers, particularly TAT, PIC, and sTM, during intra-arterial procedures may provide additional information for stroke risk stratification and therapeutic decision-making, and warrants further investigation.

Ischaemic stroke despite antiplatelet therapy: Causes and outcomes

BACKGROUND

Ischaemic stroke may occur despite antiplatelet therapy (APT). We aimed to investigate frequency, potential causes and outcomes in patients with ischaemic stroke despite APT.

METHODS

In this cohort study, we enrolled patients with imaging-confirmed ischaemic stroke from the Swiss Stroke Registry (01/2014-07/2022). We determined the frequency of prior APT, assessed stroke aetiology (modified TOAST classification) and determined the association of prior APT with unfavourable functional outcome (modified Rankin Scale score 3-6) and recurrent ischaemic stroke at 3 months using regression models.

RESULTS

Among 53,352 patients, 27,484 (51.5%) had no prior antithrombotic treatment, 17,760 (33.3%) were on APT, 7039 (13.2%) on anticoagulation and 1069 (2.0%) were on APT + anticoagulation. In patients with a history of ischaemic stroke/TIA (n = 11,948; 22.4%), 2401 (20.1%) had no prior antithrombotic therapy, 6594 (55.2%) were on APT, 2489 (20.8%) on anticoagulation and 464 (3.9%) on APT + anticoagulation. Amongst patients with ischaemic stroke despite APT, aetiology was large artery atherosclerosis in 19.8% (n = 3416), cardiac embolism in 23.6% (n = 4059), small vessel disease in 11.7% (n = 2011), other causes in 7.4% (n = 1267), more than one cause in 6.3% (n = 1078) and unknown cause in 31.3% (n = 5388). Prior APT was not independently associated with unfavourable outcome (aOR = 1.06; 95% CI: 0.98-1.14; p = 0.135) or death (aOR = 1.10; 95% CI: 0.99-1.21; p = 0.059) at 3-months but with increased odds of recurrent stroke (6.0% vs 4.3%; aOR 1.26; 95% CI: 1.11-1.44; p < 0.001).

CONCLUSIONS

One-third of ischaemic strokes occurred despite APT and 20% of patients with a history of ischaemic stroke had no antithrombotic therapy when having stroke recurrence. Aetiology of breakthrough strokes despite APT is heterogeneous and these patients are at increased risk of recurrent stroke.

Platelet surface receptor glycoprotein VI-dimer is overexpressed in stroke: The Glycoprotein VI in Stroke (GYPSIE) study results

Objectives

Platelet activation underpins thrombus formation in ischemic stroke. The active, dimeric form of platelet receptor glycoprotein (GP) VI plays key roles by binding platelet ligands collagen and fibrin, leading to platelet activation. We investigated whether patients presenting with stroke expressed more GPVI on their platelet surface and had more active circulating platelets as measured by platelet P-selectin exposure.

Methods

129 ischemic or hemorrhagic stroke patients were recruited within 8h of symptom onset. Whole blood was analyzed for platelet-surface expression of total GPVI, GPVI-dimer, and P-selectin by flow cytometry at admission and day-90 post-stroke. Results were compared against a healthy control population (n = 301).

Results

The platelets of stroke patients expressed significantly higher total GPVI and GPVI-dimer (P<0.0001) as well as demonstrating higher resting P-selectin exposure (P<0.0001), a measure of platelet activity, compared to the control group, suggesting increased circulating platelet activation. GPVI-dimer expression was strongly correlated circulating platelet activation [r² = 0.88, P<0.0001] in stroke patients. Furthermore, higher platelet surface GPVI expression was associated with increased stroke severity at admission. At day-90 post-stroke, GPVI-dimer expression and was further raised compared to the level at admission (P<0.0001) despite anti-thrombotic therapy. All ischemic stroke subtypes and hemorrhagic strokes expressed significantly higher GPVI-dimer compared to controls (P<0.0001).

Conclusions

Stroke patients express more GPVI-dimer on their platelet surface at presentation, lasting at least until day-90 post-stroke. Small molecule GPVI-dimer inhibitors are currently in development and the results of this study validate that GPVI-dimer as an anti-thrombotic target in ischemic stroke.

Relation of Pre-Stroke Aspirin Use With Cerebral Infarct Volume and Functional Outcomes

Objective

We investigated (1) the associations of pre‐stroke aspirin use with thrombus burden, infarct volume, hemorrhagic transformation, early neurological deterioration (END), and functional outcome, and (2) whether stroke subtypes modify these associations in first‐ever ischemic stroke.

Methods

This multicenter magnetic resonance imaging (MRI)‐based study included 5,700 consecutive patients with acute first‐ever ischemic stroke, who did not undergo intravenous thrombolysis or endovascular thrombectomy, from May 2011 through February 2014. Propensity score‐based augmented inverse probability weighting was performed to estimate adjusted effects of pre‐stroke aspirin use.

Results

The mean age was 67 years (41% women), and 15.9% (n = 907) were taking aspirin before stroke. Pre‐stroke aspirin use (vs nonuse) was significantly related to a reduced infarct volume (by 30%), particularly in large artery atherosclerosis stroke (by 45%). In cardioembolic stroke, pre‐stroke aspirin use was associated with a ~50% lower incidence of END (adjusted difference = −5.4%, 95% confidence interval [CI] = −8.9 to −1.9). Thus, pre‐stroke aspirin use was associated with ~30% higher likelihood of favorable outcome (3‐month modified Rankin Scale score < 3), particularly in large artery atherosclerosis stroke and cardioembolic stroke (adjusted difference = 7.2%, 95% CI = 1.8 to 12.5 and adjusted difference = 6.4%, 95% CI = 1.7 to 11.1, respectively). Pre‐stroke aspirin use (vs nonuse) was associated with 85% less frequent cerebral thrombus‐related susceptibility vessel sign (SVS) in large artery atherosclerosis stroke (adjusted difference = −1.4%, 95% CI = −2.1 to −0.8, p < 0.001) and was associated with ~40% lower SVS volumes, particularly in cardioembolic stroke (adjusted difference = −0.16 cm³, 95% CI = −0.29 to −0.02, p = 0.03). Moreover, pre‐stroke aspirin use was not significantly associated with hemorrhagic transformation (adjusted difference = −1.1%, p = 0.09).

Interpretation

Pre‐stroke aspirin use associates with improved functional independence in patients with first‐ever ischemic large arterial stroke by reducing infarct volume and/or END, likely by decreasing thrombus burden, without increased risk of hemorrhagic transformation. ANN NEUROL 2021;90:763–776

Prevention of stroke in patients with chronic coronary syndromes or peripheral arterial disease

Stroke is a common and devastating condition caused by atherothrombosis, thromboembolism, or haemorrhage. Patients with chronic coronary syndromes (CCS) or peripheral artery disease (PAD) are at increased risk of stroke because of shared pathophysiological mechanisms and risk-factor profiles. A range of pharmacological and non-pharmacological strategies can help to reduce stroke risk in these groups. Antithrombotic therapy reduces the risk of major adverse cardiovascular events, including ischaemic stroke, but increases the incidence of haemorrhagic stroke. Nevertheless, the net clinical benefits mean antithrombotic therapy is recommended in those with CCS or symptomatic PAD. Whilst single antiplatelet therapy is recommended as chronic treatment, dual antiplatelet therapy should be considered for those with CCS with prior myocardial infarction at high ischaemic but low bleeding risk. Similarly, dual antithrombotic therapy with aspirin and very-low-dose rivaroxaban is an alternative in CCS, as well as in symptomatic PAD. Full-dose anticoagulation should always be considered in those with CCS/PAD and atrial fibrillation. Unless ischaemic risk is particularly high, antiplatelet therapy should not generally be added to full-dose anticoagulation. Optimization of blood pressure, low-density lipoprotein levels, glycaemic control, and lifestyle characteristics may also reduce stroke risk. Overall, a multifaceted approach is essential to best prevent stroke in patients with CCS/PAD.

Effect of platelet count on long-term prognosis of cerebral infarction

OBJECTIVE

This study aimed to analyze the correlation between platelet (PLT) count and the modified Rankin scale (mRS) in patients with cerebral infarction (CI) at the later stage of rehabilitation, which can be used to guide the secondary prevention strategy of CI.

METHODS

A total of 180 CI patients were divided into three groups according to PLT count: low PLT group (<125×109/L), medium PLT group (126- 225×109/L) and high PLT group (>226×109/L). The mRS was evaluated after three months and one year, respectively, and the difference in long-term prognosis between groups was analyzed. The mRS is an ordered scale coded from 0 (no symptoms at all) through 5 (severe disability) 6 (death).

RESULTS

Finally, a total of 99 patients had complete data. The results of the multiple comparisons among the three groups were as follows: the analysis of variance of the mRS at three months after onset yielded F = 6.714 and P = 0.002, and the difference was statistically significant. The mRS was lowest in the medium PLT group (2.09±1.465), and neurological function recovery was the best. After one year, the mRS for the medium PLT group was the lowest (1.49±1.523), with F = 6.860 and P = 0.002. The repeated measures analysis of variance revealed that the effect of continuous rehabilitation was significant in the interval from three months to one year after onset (F = 35.528, P < 0.001). This was very significant, especially for patients taking aspirin (F = 50.908, P < 0.001). However, for patients who did not take aspirin, the effect of continuous rehabilitation was not obvious during the nine months, and the difference between the results of two mRS measurements was not statistically significant (F = 1.089, P = 0.308).

CONCLUSIONS

Patients with a PLT count of 126- 225×109/L had the lowest mRS between three months and one year after onset, but had the best recovery of nerve function. Patients who persisted in taking aspirin continued to significantly recover during the 9-month period, from three months to one year after onset. Aspirin is not only a secondary preventive drug, but also an important drug to promote the rehabilitation of CI patients.

Antithrombotic dose: Some observations from published clinical trials

The clinical doses of antithrombotics-antiplatelet and anticoagulant agents-need to balance efficacy and safety. It is not clear from the published literature how the doses currently used in clinical practice have been derived from preclinical and clinical data. There are few large randomised controlled trials (RCTs) that compare outcomes with different doses vs placebo. For newer antithrombotics, RCT doses appear to have been chosen to maximise the probability of demonstrating noninferiority when compared to established agents such as warfarin or clopidogrel. Data from RCTs show that aspirin is an effective antithrombotic at doses below 75 mg daily, and that direct oral anticoagulants reduce the risk of stroke in patients with coronary disease at doses 1/4 of those recommended in atrial fibrillation. Lower doses than those currently recommended are safer and still maintain substantial efficacy.

Left atrial size and risk of stroke in patients in sinus rhythm

Little is known about the risk of stroke associated with left atrial enlargement in patients in sinus rhythm, and whether such patients may have an unmet need for thromboprophylaxis. In this systematic review we summarise the existing evidence concerning left atrial size and risk of stroke in patients in sinus rhythm. Nine cohort studies were identified, analysing a total of 67,875 participants and 3,093 stroke outcomes. Rates of stroke per 100 person-years in patients with left atrial enlargement and in sinus rhythm ranged from 0.59 in a population-based cohort to 2.06 in patients referred for echocardiography. All studies reported a higher risk of stroke with larger/enlarged left atrium compared to smaller/normal sized left atrium. Two studies found indications of modification by sex, with only positive associations observed in women. Left atrial enlargement may represent an important predictor of stroke across a variety of patient populations in sinus rhythm. The underlying aetiology explaining this observed higher risk is likely to be multifactorial and not confined to a potential direct effect of left atrial enlargement on thromboembolic risk. Formal stroke risk stratification among patients with left atrial enlargement may further help identify patients who stand to gain from preventive antithrombotic therapy.

Supplementary Material to this article is available online at www.thrombosis-online.com.