Point-of-care international normalized ratio testing accelerates thrombolysis in patients with acute ischemic stroke using oral anticoagulants

Prospective comparison of point-of-care international normalised ratio measurement versus plasma international normalised ratio for acute traumatic coagulopathy

OBJECTIVE

Early detection of acute traumatic coagulopathy (ATC) might be useful to guide trauma resuscitation. This study aimed to compare results from a point-of-care (POC) international normalised ratio (INR) measuring device with plasma INR in acute trauma patients.

METHODS

This was a single-centre, prospective, blinded comparative study. All trauma patients meeting trauma call-out criteria in a major trauma centre were screened. Patients predicted to have ATC were identified by the Coagulopathy of Severe Trauma score and a convenience sample of 72 patients included in this study. Whole blood was used to measure INR at the bedside, whereas blood from the same sample was sent to the hospital laboratory for plasma INR testing. Agreement between the laboratory and bedside INR was determined using a Bland-Altman plot.

RESULTS

There were 38 (52.8%) patients with ATC by laboratory measure, defined as INR >1.5 or activated partial thrombin time >60 s, whereas the POC system identified 28 (38.9%) patients with an INR >1.5. Assuming the laboratory measure as the gold standard, the POC system had a specificity of 88.2% (95% confidence interval 71.6-96.2) and a sensitivity of 63.1% (95% confidence interval 46.0-77.7). Bland-Altman plots demonstrated inadequate agreement between the two methods of INR measurement for the major trauma patient.

CONCLUSIONS

POC INR measurements using this method during the trauma reception and resuscitative phases cannot be used to identify or exclude patients with ATC. Further studies are required to determine if there is any role for POC INR measures during trauma resuscitation.

A Parallel Thrombolysis Protocol with Nurse Practitioners As Coordinators Minimized Door-to-Needle Time for Acute Ischemic Stroke

Introduction. Quick thrombolysis after stroke improved clinical outcomes. The study objective was to shorten door-to-needle time for thrombolysis. Methods. After identifying the sources of in-hospital delays, we developed a protocol with a parallel algorithm and recruited nurse practitioners into the acute stroke team. We applied the new protocol on stroke patients from October 2009 to September 2010. Patients from the previous two years were used for comparison. Results. For ischemic stroke patients within 3 hours of onset, the median time from arrival to computed tomography scanning was reduced from 29 to 20 minutes (P < 0.001) and the median time from arrival to neurology evaluation decreased from 61 to 43 minutes (P < 0.001). For those patients who received thrombolysis, the median door-to-needle time was shortened from 68.5 to 58 minutes (P < 0.05). Conclusions. The parallel thrombolysis protocol successfully improved the median door-to-needle time to below the guideline-recommended 60 minutes.

Rapid reversal of anticoagulation prevents excessive secondary hemorrhage after thrombolysis in a thromboembolic model in rats

BACKGROUND AND PURPOSE

Thrombolysis is the only approved therapy for ischemic stroke, but secondary hemorrhage is a severe complication. Because oral anticoagulants are believed to increase the risk of hemorrhage, thrombolysis is usually contraindicated in patients on vitamin K antagonists. We studied whether thrombolysis in a thromboembolic middle cerebral artery occlusion model in rats pretreated with warfarin increases secondary hemorrhage, and whether substitution of coagulation factors before thrombolysis prevents hemorrhagic complications.

METHODS

Wistar rats were anticoagulated using warfarin in drinking water (0.4 mg/kg per 24 hours). Strength of anticoagulation was monitored using benchside international normalized ratio (INR) coagulometry. Two hours after middle cerebral artery occlusion, recombinant tissue-type plasminogen activator (9 mg/kg) was administered. Two of 5 groups of animals received prothrombin complex concentrate (PCC, 50 U/kg) 15 minutes before thrombolysis. Serial magnetic resonance imaging was performed 20 minutes, 2.5 hours, and 24 hours after middle cerebral artery occlusion. Secondary hemorrhage was quantified on T2* magnetic resonance images as previously established.

RESULTS

Severity of hypoperfusion on initial perfusion-weighted imaging -magnetic resonance did not differ among groups. Thrombolysis resulted in successful reperfusion in all groups. Anticoagulated animals had significantly more secondary hemorrhage and a higher mortality rate compared with nonanticoagulated animals. PCC rapidly reversed the increased international normalized ratio. Although PCC failed to prevent hemorrhage in the strongly anticoagulated, it reduced the incidence of severe hemorrhage in moderately anticoagulated rats (INR, 2-3) to the level of nonanticoagulated controls.

CONCLUSIONS

Preceding anticoagulation increases risk and extent of secondary hemorrhage after thrombolysis. Reversal of moderate anticoagulation using PCC may allow thrombolytic therapy without increasing the risk of secondary hemorrhage.

[Difficult decisions in stroke therapy]

In numerous situations stroke physicians face a lack of evidence during their daily practice. In this report the authors address some of the difficult treatment decisions encountered in acute therapy and secondary prevention. Examples include off-label thrombolysis and prevention in high-risk situations. The available data from trials and registries are discussed, and personal views and recommendations are expressed.

Fast point-of-care coagulometer guided reversal of oral anticoagulation at the bedside hastens management of acute subdural hemorrhage

BACKGROUND

Emergency reversal of the international normalized ratio (INR) in patients who develop nontraumatic subdural hemorrhage (SDH) due to oral anticoagulants (OAC) represents a primary treatment strategy but it is difficult to predict the amount of prothrombin complex concentrate (PCC) needed for reversal treatment. Moreover, repeated INR testings in central laboratories (CL) are time consuming. The usefulness of point-of-care INR coagulometers (POC) to test the success of INR reversal in OAC-SDH has not yet been investigated.

METHODS

Prospectively, INR reversal was performed by administering PCC to patients suffering from acute SDH-OAC using a predefined dosing schedule. Accuracy and time gained by using POC were assessed and compared with CL measurements.

RESULTS

A total of 10 patients were treated according to the protocol (male: 5). Bland-Altman analysis between POC and CL revealed a mean INR deviation of 0.013 for initial INR values and of 0.081 during reversal treatment. Using POC, the median initial net time gain (accounting for clinical examination and CT) for the start of PCC was 21 min. Median total time for POC-documented reversal was 27 min, as compared to 70 min for CL. The shortest interval between head CT and start of emergency SDH evacuation surgery was 37 min. By employing stepwise POC-guided reversal of the anticoagulatory effect of OAC, the calculated PCC dose could be reduced by 25% in the median.

CONCLUSIONS

Using POC to measure INR values and patient-adapted PCC administration is a fast and economic method to reverse anticoagulation in patients with acute OAC-SDH.

Point-of-care laboratory halves door-to-therapy-decision time in acute stroke

Currently, stroke laboratory examinations are usually performed in the centralized hospital laboratory, but often planned thrombolysis is given before all results are available, to minimize delay. In this study, we examined the feasibility of gaining valuable time by transferring the complete stroke laboratory workup required by stroke guidelines to a point-of-care laboratory system, that is, placed at a stroke treatment room contiguous to the computed tomography, where the patients are admitted and where they obtain neurological, laboratory, and imaging examinations and treatment by the same dedicated team. Our results showed that reconfiguration of the entire stroke laboratory analysis to a point-of-care system was feasible for 200 consecutively admitted patients. This strategy reduced the door-to-therapy-decision times from 84 ± 26 to 40 ± 24 min (p < 0.001). Results of most laboratory tests (except activated partial thromboplastin time and international normalized ratio) revealed close agreement with results from a standard centralized hospital laboratory. These findings may offer a new solution for the integration of laboratory workup into routine hyperacute stroke management.

Avoiding in hospital delays and eliminating the three-hour effect in thrombolysis for stroke

BACKGROUND

Intravenous thrombolysis for acute stroke is more efficient the earlier the treatment is initiated. In-hospital delays account for a significant proportion of avoidable time loss before treatment is initiated. Paradoxically, studies have reported longer door-to-needle times the earlier the patients arrive ('three-hour effect'). Hypothesis We hypothesized that a standardized thrombolysis procedure carried out in a specialized neurological emergency room can minimize in-hospital delays and erase the 'three-hour effect'.

METHODS

Onset-to-door and door-to-needle times of 246 consecutive thrombolysis patients were analyzed. A standardized protocol designed to minimize in-hospital delays was tested using a resident-based stroke team within a neurological emergency room. Correlation of onset-to-door and door-to-needle times was measured as well as differences in treatment times for daytime versus night hours and weekend vs. weekday. Outcome, rate of symptomatic intracranial hemorrhage and mortality were compared with the results of SITS-MOST.

RESULTS

Median door-to-needle time was 25 min compared with a mean of 68 min in SITS-MOST. door-to-needle time did not correlate with onset-to-door time (Pearson's r = -0 · 097; P = 0 · 13) and patients arriving within 90 min from symptom onset showed comparable door-to-needle times with patients arriving within 90-180 min. Neither treatment on weekends nor during night hours led to significant in-hospital treatment delays. Outcome and safety parameters were comparable with those observed in SITS-MOST.

CONCLUSIONS

By applying a standardized and diligently monitored thrombolysis protocol, carried out by a specialized stroke team within a neurological emergency room, in-hospital delays can be minimized. This allows improvement of door-to-needle times irrespective of the time to arrival and treatment during off-hours.