QT Interval Dispersion as a Predictor of Clinical Outcome in Acute Ischemic Stroke

Background and Purpose: QT dispersion (QTd) abnormalities are widely documented in stroke patients. This study aims to investigate the association between QTd and clinical outcomes in IS patients.

Methods: IS patients registered in the Blood Pressure and Clinical Outcome in transient ischemic attack (TIA) or IS (BOSS) registry between 2012 and 2014 within 24 h of onset were analyzed. In this prospective observational study, we identified 1,522 IS cases with adequate electrocardiographic evaluations to assess QTd after the index stroke. Patients were classified into four groups based on the quartile of QTd, with the lowest group as the reference. The primary stroke outcome was defined as a modified Rankin Scale score ≥3 at 1-year. Multiple logistic regressions were utilized to investigate the association between QTd and outcome events.

Results: The mean QTd across all cases was 57 ms (40–83). Functional dependency or death was documented in 214 (14.98%) cases at 1 year. After adjusting for confounders, the prevalence of death and major disability (mRS ≥ 3) showed significant differences according to the quartile of QTd, with the risk of death and major disability (mRS ≥ 3) at 1 year being significantly higher for patients in Q4 than for those in Q1 (adjusted OR = 1.626, 95% CI:1.033–2.560). However, there were no significant correlation between QTd and the event outcomes at 1 year.

Conclusions: QTd was associated with poor functional outcomes at 1 year. QTd is a useful surrogate marker for adverse functional prognosis, which might help to stratify risk in patients with acute IS.

Association of platelet-derived microvesicles with high on-treatment platelet reactivity in convalescent ischemic stroke patients treated with acetylsalicylic acid

INTRODUCTION

Elevated concentrations of platelet-derived microvesicles are found in cerebrovascular diseases. The impact of acetylsalicylic acid on these microvesicles remains inconsistent, despite its well-established effect on platelet aggregation. High residual platelet aggregation is defined as high on-treatment platelet reactivity, while “treatment failure” is the occurrence of vascular events despite antiplatelet treatment. The aim of this study was to determine whether the antiaggregatory effect of acetylsalicylic acid correlates with platelet-derived microvesicles in convalescent ischaemic stroke patients and cardiovascular risk factor controls as well as to evaluate the association between high on-treatment platelet reactivity and recurrent vascular events with the studied platelet-derived microvesicle parameters.

MATERIAL AND METHODS

The study groups consisted of 76 convalescent stroke patients and 74 controls. Total platelet-derived microvesicles, annexino-positive microvesicles number, and platelet-derived microvesicles with surface expression of proinflammatory (CD40L, CD62P, CD31) and procoagulant (PS, GPIIb/IIIa) markers were characterized and quantified using flow cytometry. Cyclooxygenase-1-specific platelet responsiveness, with whole blood impedance platelet aggregation under arachidonic acid stimulation and the serum concentration of thromboxane B2, were evaluated.

RESULTS

Neither acetylsalicylic acid intake nor modification of its daily dose caused statistically significant differences in the studied microvesicle parameters. Additionally, no statistically significant differences in the studied microvesicle parameters were revealed between high on-treatment platelet reactivity and non-high on-treatment platelet reactivity subjects in either study subgroup. However, elevated concentrations of PAC-1+/CD61+, CD62P+/CD61+ and CD31+/CD61+ microvesicles were found in stroke patients with treatment failure, defined in this study as a recurrent vascular events in a one-year follow-up period.

CONCLUSIONS

This study revealed no relationship between circulating microvesicle number and platelet aggregation. The procoagulant and proinflammatory phenotype of circulating platelet-derived microvesicles might contribute to acetylsalicylic acid treatment failure.

The associations of stroke, transient ischemic attack, and/or stroke-related recurrent vascular events with Lipoprotein-associated phospholipase A2: A systematic review and meta-analysis

BACKGROUND

Studies on stroke and lipoprotein-associated phospholipase A2 (Lp-PLA2) have produced conflicting results.

OBJECTIVE

The aim of the study was to assess the associations of Lp-PLA2 levels (mass and activity) with recurrent vascular events in patients with transient ischemic attack (TIA) and/or first ischemic stroke and with stroke in the general population.

METHODS

The MEDLINE, Embase, the Cochrane Library, Web of Science, Science Direct, China National Knowledge Infrastructure, China Biology Medical Disc (CBMdisc), and WanFang were searched for prospective observational studies reported until January 2017. Eligible studies reported Lp-PLA2 levels and adjusted risk estimates of recurrent vascular events and/or stroke. Risk ratio (RR) with corresponding 95% confidence intervals (CIs) were used to express the pooled data in a random-effects model.

RESULTS

A total of 11 studies that comprised 20,284 participants (4,045 were TIA and/or first ischemic stroke patients and 16,239 were residents in general population) were identified, which reported either Lp-PLA2 mass levels (4 studies) or Lp-PLA2 activity levels (10 studies). The pooled RR of recurrent vascular events (467 cases) in TIA and/or first ischemic group was 2.24 (95% CI, 1.33-3.78), whereas the pooled RR of stroke (1604 cases) in the general population was 1.47 (95% CI, 1.10-1.97). The pooled RRs of Lp-PLA2 mass and activity levels with the risk of stroke in the general population were 1.69 (95% CI, 1.03-2.79) and 1.28 (95% CI, 0.88-1.85), respectively.

CONCLUSIONS

In patients with TIA and first ischemic stroke, elevated Lp-PLA2 activity levels were associated with recurrent vascular events. And in the general population elevated Lp-PLA2 levels were associated with the risk of stroke, although the association between Lp-PLA2 activity levels and the risk of stroke was less profound compared with the corresponding association of stroke risk with the Lp-PLA2 mass levels.