Erroneous POC INR results led to inadequate anticoagulation therapy and valve obstruction. ⢠Accurate INR self-monitoring is needed for proper anticoagulation ...
Current Practices in Point-of-Care Testing: An Evidence-Based Approach to Hospital, Urgent, and Disaster Care Gerald J. Kost, MD, PhD, MS, FACB1; Corbin M. Curtis1; Richard F. Louie, PhD1; and Kenneth M. Shermock, PhD, PharmD2 1Point-of-Care
Testing Center for Teaching and Research (POCT•CTR) Center for Point-of-Care Technologies [NIBIB, NIH] Pathology and Laboratory Medicine, School of Medicine University of California, Davis
2Director,
Center for Pharmaceutical Outcomes and Policy The Johns Hopkins Hospital, Baltimore, MD
Copyright 2011—All Rights Reserved [Version C] http://www.ucdmc.ucdavis.edu/pathology/poctcenter/
Learning Objectives… • Differentiate and deal with instrument, management, and medical challenges when implementing point-of-care (POC) testing for hematology and coagulation patients • Become familiar with emerging biosensor-based POC technologies, potential roles in different practice settings, and basic methods of evaluating performance
…Cases, Logic, and the Future! Errors in POC INR Results Lead to Prosthetic Heart Valve Thrombosis Point-of-Care Testing Could Enable Intravenous Thrombolysis Treatment in Stroke Patients Logic: The “Case” for Decision-Making Assessment of INR Performance Value of a Mobile Point-of-Care Anticoagulation Therapy Management Program Point-of-Care Monitoring of Anticoagulant Therapy in Rural Community Pharmacies Logic: A “Case” of Evidence-Based Management–CLSI Criteria for POC Ddimer Testing The Future? POC Thrombin Generation Biosensor—Facilitated Risk Assessment of Venous Thromboembolism in Earthquake Victims
Error in POC INR Results Lead to Prosthetic Heart Valve Thrombosis Main Point Illustrates how errors with POC international normalized ratio (INR) results adversely affected anticoagulation therapy Case Objective To show the need for more accurate POC technologies for outpatient self-monitoring van den Brule JM, Romkes JH, Brouwer MA, et al. An error in the CoaguChek S® device results in prosthetic heart valve thrombosis. Interact Cardiovasc Thorac Surg. 2010;11:123-124.
Case Data •
A 45 year old man with triucuspid valve replacement 4 years ago now on warfarin, digitalis, and a beta blocker, presents with complaints of sudden onset of dyspnea lasting one month.
•
On examination, soft prosthetic valve sounds and a soft diastolic murmur were heard. Transthoracal echocardiography detected a dilated right ventricle with impaired function. Cine-fluoroscopy confirmed tricuspid valve dysfunction with one valve door immobile. Problem resolved after heparin and fibrinolytic. INR Results Before Hospitalization (Past 6 months)— Corresponding Laboratory Values POC INR 2.6-3.9 (CoaguChek S) 2.1-3.1 (below the therapeutic target) INR Results in Hospital Laboratory INR POC INR (S)
Initial 2.9 4.3
Double Check 3.1 5.3
Therapeutic Target 3.0-4.0 3.0-4.0
van den Brule JM, Romkes JH, Brouwer MA, et al. An error in the CoaguChek S® device results in prosthetic heart valve thrombosis. Interact Cardiovasc Thorac Surg. 2010;11:123-124.
Interpretation • Patient diagnosed with obstructive thrombosis of the tricuspid prosthetic valve because of insufficient anticoagulation therapy as an outpatient • Fibrinolytic therapy in the hospital proved effective–louder valve sounds, slower velocity across the tricuspid valve, and mobile valve doors • After discharge, CoaguCheck S was replaced with XS to improve high range accuracy INR > 3 to keep the patient in the therapeutic range
Lessons Learned • Erroneous POC INR results led to inadequate anticoagulation therapy and valve obstruction • Accurate INR self-monitoring is needed for proper anticoagulation management • According to the authors, the POC INR device must be selected for accuracy in the therapeutic range
POC Testing Could Enable Intravenous Thrombolysis Treatment in Stroke Patients Main Point Proposes POC improves therapeutic turnaround time (TTAT)for stroke patients to safely initiate thrombolytic therapy Case Objective To support the need for rapid TTAT and avoid proceeding with risky treatment before receiving test results Lippi G, Favaloro EJ. Unsuspected coagulopathy rarely prevents IV thrombolysis in acute ischemic stroke. Neurology. 2010;74:1477; author reply 1477-1478. Rost NS, Masrur S, Pervez MA, et al. Unsuspected coagulopathy rarely prevents IV thrombolysis in acute ischemic stroke. Neurology. 2009;73:1957-1962.
Patient Evaluation Flowchart • Retrospective review based on “Get With the Guidelines Stroke” database, January 2003 to April 2008 • Patients were evaluated for thrombolytic therapy eligibility using the stratification scheme on the right
Abbreviations: DBP, diastolic blood pressure; ED, emergency department; ICH, intracerebral hemorrhage; OSH, outside hospital; SBP, systolic blood pressure Rost NS, Masrur S, Pervez MA, et al. Unsuspected coagulopathy rarely prevents IV thrombolysis in acute ischemic stroke. Neurology. 2009;73:1957-1962.
Patient Data •
Patients presented to the emergency department (ED) with onset of stroke symptoms within ≤ 3 hours (N = 470) Total Cases
Patient management •
Not given thrombolysis treatment per other underlying or past health conditions
68.7%
(323/470)
•
Intravenous tPA given
31.3%
(147/470)
•
Potential for thrombolysis treatment when INR ≥1.7 or platelets ≤1x105/μL
6.4%
(30/470)
•
Underlying coagulation abnormalities prevented thrombolysis treatment
0.4%
(2/470)
Median turnaround time for STAT test orders PT/INR Creatinine and glucose Complete blood count
22.0 min 20.0 min 11.0 min
Abbreviations: INR, international normalised ratio; PT, prothrombin time; tPA, tissue plasminogen activator. Rost NS, Masrur S, Pervez MA, et al. Unsuspected coagulopathy rarely prevents IV thrombolysis in acute ischemic stroke. Neurology. 2009;73:1957-1962.
Interpretation • Patients with coagulation abnormalities represent a small fraction of patients with acute ischemic stroke that are ineligible for thrombolysis1 • Rost et al.1 suggest benefits of prompt administration of intravenous tPA outweighs the risk of potential complications • Lippi et al.2 pointed out that with the availability of POC devices, treatment before receiving laboratory results represents an unnecessary risk
1Rost
NS, Masrur S, Pervez MA, et al. Unsuspected coagulopathy rarely prevents IV thrombolysis in acute ischemic stroke. Neurology. 2009;73:1957-1962. 2Lippi G, Favaloro EJ. Unsuspected coagulopathy rarely prevents IV thrombolysis in acute ischemic stroke. Neurology. 2010;74:1477; author reply 1477-1478.
Lessons Learned •
In acute stroke, POC INR testing accelerates thrombolysis in patients on oral anticoagulants (faster by 28 ± 12 minutes), while POC results agree closely with laboratory results (r = 0.98; P
