An analysis of discrepancy between point-of-care and central laboratory international normalized ratio testing in ED patients with cerebrovascular disease

Effect of warfarin versus aspirin on blood viscosity in cardioembolic stroke with atrial fibrillation: a prospective clinical trial

Background

Warfarin is evidence-based therapy for the prevention of cardioembolic stroke, but has not been studied for its effects on whole blood viscosity (WBV). This study investigated the effect of warfarin versus aspirin on WBV in patients presenting with non-valvular atrial fibrillation (NVAF) and acute cardioembolic stroke.

Methods

We enrolled patients with acute cerebral infarction, aged 56–90 years who had NVAF, CHADS₂ score ≥ 2, presenting with mild-to-moderate stroke (National Institute of Health Stroke Scale (NIHSS) score < 20 and modified Rankin Scale (2mRS) score < 4) in a single center. The patients were alternately assigned to warfarin or aspirin groups. Post-treatment WBV was assessed after international normalized ratio (INR) reached target range [2, 3] for patients in the warfarin group, and 5 days after baseline in the aspirin group.

Results

Total 67 patients were included, and 56 completed this study (33 warfarin and 23 aspirin). Compared to baseline values, warfarin reduced post-treatment BV at all shear rates. The BV reductions greater than 1 cP measured at shear rates of 300, 150, 5, and 1 s^− 1 were independently and significantly associated with warfarin treatment compared to aspirin after adjusting for age, sex, CHA₂DS₂-VASc scores, and baseline hematocrit.

Conclusions

Warfarin confers greater reductions in BV than aspirin in patients with acute cardioembolic stroke. BV could be a useful method to estimate thrombotic risk in patients receiving warfarin.

Trial registration

KCT0001291, Date of Registration: 2014-12-01

Point-of-Care-Testing in Acute Stroke Management: An Unmet Need Ripe for Technological Harvest

Stroke, the second highest leading cause of death, is caused by an abrupt interruption of blood to the brain. Supply of blood needs to be promptly restored to salvage brain tissues from irreversible neuronal death. Existing assessment of stroke patients is based largely on detailed clinical evaluation that is complemented by neuroimaging methods. However, emerging data point to the potential use of blood-derived biomarkers in aiding clinical decision-making especially in the diagnosis of ischemic stroke, triaging patients for acute reperfusion therapies, and in informing stroke mechanisms and prognosis. The demand for newer techniques to deliver individualized information on-site for incorporation into a time-sensitive work-flow has become greater. In this review, we examine the roles of a portable and easy to use point-of-care-test (POCT) in shortening the time-to-treatment, classifying stroke subtypes and improving patient's outcome. We first examine the conventional stroke management workflow, then highlight situations where a bedside biomarker assessment might aid clinical decision-making. A novel stroke POCT approach is presented, which combines the use of quantitative and multiplex POCT platforms for the detection of specific stroke biomarkers, as well as data-mining tools to drive analytical processes. Further work is needed in the development of POCTs to fulfill an unmet need in acute stroke management.

Identification of Rate-Limiting Steps in the Provision of Thrombolytics for Acute Ischemic Stroke

Background:

Tissue plasminogen activator (tPA) is the only pharmacotherapy shown to improve outcomes in acute ischemic stroke. The American Heart Association (AHA) recommends a door-to-needle (DTN) time of <60 minutes in at least 50% of patients presenting with acute ischemic stroke.

Objective:

The purpose of this study was to analyze the possible barriers that may delay tPA administration within the emergency department (ED) of an academic medical center.

Methods:

A retrospective chart review was conducted from February 2011 to October 2013. Patients were included if they were admitted through the ED with a diagnosis of acute ischemic stroke and received tPA.

Results:

Of the 130 patients who met inclusion criteria, 43.1% received tPA in ≤60 minutes. Several factors were identified to be significantly different in those with a DTN time of >60 minutes—time to ED physician consultation, neurologist arrival, blood sample acquisition, and result time ( P < .05 for all comparisons). Correlation analysis demonstrated several independent variables associated with DTN time of ≤60 minutes—time from admission to ED physician consultation, receipt of computed tomography (CT) scan, blood sample acquisition, laboratory results, and neurology service arrival ( P < .05 for all comparisons).

Conclusion:

The findings from this study highlight the importance of prompt physician evaluation, direct transfer to the CT scanner, and a quick turnaround time on laboratory values. The development of protocols to ensure the rapid receipt of tPA therapy should focus on limiting any potential delay these steps may cause.

Reliability of a point-of-care device for international normalized ratio testing during the three surgical phases of orthotopic liver transplantation: a retrospective observational study

PURPOSE

To investigate the reliability of a point-of-care device, the HEMOCHRON(®) Jr. Signature, for measuring the international normalized ratio (INR) during the three surgical phases of liver transplantation.

METHODS

A retrospective review was performed on patients undergoing liver transplantation during July to December 2013. Thirty-one patients who had simultaneous laboratory and point-of-care INR readings from each phase of liver transplant surgery (paleohepatic, anhepatic, and neohepatic) were eligible for inclusion. Bland-Altman analysis, Spearman's rank correlation, and four quadrant plots were used to compare INR results from the point-of-care device (pocINR) with those from the laboratory (labINR).

RESULTS

Based on the Bland-Altman analysis, mean biases (95% prediction interval) were 0.10 (0.03 to 0.17), 0.19 (0.12 to 0.27), and 0.21 (0.01 to 0.43) for the paleohepatic, anhepatic, and neohepatic phases, respectively. The pocINR device showed a systematic underestimation of the labINR. The Spearman's rank correlation coefficients (95% confidence interval [CI]) were: Ρ = 0.90 (95% CI 0.80 to 0.95); Ρ = 0.92 (95% CI 0.71 to 0.93); and Ρ = 0.71 (95% CI 0.46 to 0.85), respectively. Direction-of-change analysis between the paleohepatic to anhepatic and the anhepatic to neohepatic phases showed strong concordance of 84% and, also considering the small bias between the measurements, supports the use of the pocINR device in the clinical management of liver transplant surgery.

CONCLUSION

Point-of-care INR was accurate prior to hepatic reperfusion, but reliability decreased in the neohepatic phase.