Outpatient Anticoagulation Clinic Research Articles

Changes in Time in Therapeutic Range Within a Warfarin Anticoagulation Clinic Following Introduction of Direct Oral Anticoagulants.

Background: As direct oral anticoagulants (DOACs) have become widely recommended as first-line anticoagulation therapy, patients who remain on warfarin are likely those unable to afford, adhere to, or utilize DOAC therapy due to the presence of a contraindication. It is currently unknown how availability of DOACs have affected populations being managed at warfarin (VKA) anticoagulation clinics. Methods: This was a retrospective chart review assessing warfarin-treated patients at an outpatient anticoagulation clinic. The primary endpoint was the 6-month time in therapeutic range (TTR) before and after DOACs were recommended as first-line therapy by clinical guidelines. Study periods were January to June 2015, before DOACs were recommended over VKA, and January to June 2022, when DOACs were often recommended over VKA. TTR, demographic changes, and the presence of contraindications to DOAC therapy in the clinic population between the two time periods were assessed. Results: No difference in 6-month TTR was observed between study periods (59% in 2015 vs 63% in 2022; P = .45). Patient demographics did not significantly vary, which may be due to the clinic retaining 45% of patients between both time periods. Contraindications to DOAC therapy were identified in 39% of the 2015 group and 49% of the 2022 group (P = .18). The most common contraindication was indication for anticoagulation. Conclusion: Availability of DOACs did not seem to significantly affect the population or management of warfarin-treated patients at an outpatient anticoagulation clinic, however, contraindications and potential challenges to use of DOAC therapy are present in many patients.

A call to action for anticoagulation stewardship

A call to action for anticoagulation stewardship

Impact of pharmacist intervention to deprescribe inappropriate aspirin therapy in an outpatient anticoagulation clinic at a community hospital

Study objectiveThis study describes a pharmacist-led process to identify and discontinue inappropriate aspirin in patients receiving concomitant anticoagulant therapy and to evaluate the effectiveness of the intervention. SettingThe study took place in an outpatient anticoagulation clinic within a small community hospital. ParticipantsPatients ≥40 years old on indefinite anticoagulation therapy for atrial fibrillation and/or venous thromboembolism were included. DesignThis is a quality improvement initiative. InterventionsUtilizing the electronic medical record and patient interview, use and indication for daily aspirin therapy was confirmed. Prospectively collected patient demographics and past medical history were used to determine appropriateness of aspirin therapy. For patients identified as receiving inappropriate aspirin therapy, a fax was sent to the referring provider recommending aspirin discontinuation. Main outcome measuresTo assess the effectiveness of the intervention, outcomes were retrospectively measured. The primary outcome was the percentage of “accepted” recommendations. Secondary outcomes included the prevalence, dosing, and indications for aspirin therapy. ResultsEighty (33 %) of 242 patients were on aspirin. Fifty-two patients with atrial fibrillation and/or venous thromboembolism were assessed and aspirin was deemed inappropriate in 22 patients. The provider agreed with deprescribing aspirin therapy in 45 %. The most common dose and indication of aspirin therapy was 81 mg (98 %) and primary prevention (40 %) respectively. ConclusionsIn our small practice, pharmacist-led interventions were an effective means to recommend aspirin discontinuation in our identified patients. Further studies are needed to optimize a pharmacist's role and address the long-term effects of deprescription.

The Impact of Adding Aspirin to Warfarin without an Apparent Indication: An Exploration of Patients Anticoagulated for Atrial Fibrillation or Venous Thromboembolic Disease

▪Introduction: Warfarin and aspirin (ASA) are widely used to prevent or treat thromboembolic and atherosclerotic diseases. The most common indications for warfarin use are stroke prevention in atrial fibrillation (AF) and for the treatment of venous thromboembolic disease (VTE). When patients are started on warfarin, many are already taking ASA or they are subsequently placed on ASA due to other co-morbidities. There are limited indications for the combination of warfarin plus ASA, including mechanical heart valves, after percutaneous coronary intervention (PCI), or after acute coronary syndromes. Evidence suggests combination warfarin-ASA may offer no benefit, but place patients at increased bleeding risk outside of these indications.We sought to assess the patient characteristics and outcomes of patients on warfarin for AF or VTE, comparing those who were on concurrent ASA without a strong indication (myocardial infarction [MI] within 6 months, mechanical heart valve or PCI) to those not on ASA. We hypothesized that combination therapy (warfarin-ASA) would result in increased bleeding rates with similar rates of MI, recurrent VTE, stroke, or death.Methods: We conducted a retrospective cohort study of adult patients, initiated on warfarin for AF or VTE between January 2009 and June 2017. Patients were recruited through the Michigan Anticoagulation Quality Improvement Initiative, a collaborative of six outpatient anticoagulation clinics throughout the state of Michigan. Patients with less than three months of follow-up, a MI within six months, and/or history of valve replacement were excluded. Patients were analyzed based on their aspirin use at the time of study enrollment. A HAS-BLED score, modified to exclude aspirin use, and a Charlson Co-morbidity Index was calculated for each patient at enrollment.Analyses were performed using Student's t-tests, Wilcoxon Rank-sum tests, chi-square tests and Fisher's exact tests when appropriate. Survival and Poisson regression analyses were used to evaluate the effect of ASA use on various outcomes.Results: A total of 6,572 patients met the inclusion criteria, with a mean duration of follow-up of 21.2 months; 38% were on warfarin-ASA compared to 62% on warfarin monotherapy. Patients on warfarin-ASA were older (mean 70.2±12.7 vs. 63.7±16.5, p<0.001), more often male (56.7% vs. 47.3%, p<0.001), and were more likely anticoagulated for AF (66.3% vs. 42.3%, p<0.001). Warfarin-ASA patients were more likely to have cardiovascular risk factors (diabetes mellitus, tobacco use, or hypertension), a history of stroke, heart failure, or a history of coronary artery disease (CAD). Patients on warfarin-ASA had a higher HAS-BLED score (mean 2.4±1.2 vs. 1.8±1.2, p<0.001), and Charlson Co-morbidity Index (mean 4.8±2.0 vs. 3.6±2.1, p<0.001).Patients treated with warfarin-ASA vs. warfarin alone experienced less DVTs (0.7/100 patient years [pt-yr] vs. 1.3/100-pt-yr, p=0.002) and PE (0.1/100-pt-yr vs. 0.4/100-pt-yr, p=0.002), but had a higher rate of ischemic/embolic strokes (0.7/100-pt-yr vs. 0.4/100-pt-yr, p=0.02). Emergency department visits and hospitalizations for thromboembolic events were similar. Patients treated with warfarin-ASA vs. warfarin alone had a higher 1-year probability of having a major bleeding event (6.1% vs. 3.2%, p<0.001) or non-major bleeding event (22.9% vs. 18.7%, p=0.004). Warfarin-ASA treated patients had a higher rate of hospitalizations for bleeding (8.4/100-pt-yr vs. 5.7/100-pt-yr, p<0.001), blood transfusions (5.2/100-pt-yr vs. 4.1/100-pt-yr, p=0.009) and all-cause mortality relative to warfarin alone (4.1/100-pt-yr vs. 3.1/100-pt-yr, p=0.005). Kaplan-Meier curves for any clotting event, all bleeding events, major bleeding events, and death are shown (figure 1). A sensitivity analysis was performed that further excluded any history of MI, CAD, PCI, peripheral arterial disease, or coronary artery bypass grafting, and showed similar results.Conclusion: Over one-third of patients in an unselected practice-based setting are treated with warfarin-ASA for AF and/or VTE without a clear indication. Compared to warfarin monotherapy, this was associated with minimally increased protection against VTE but with a significant increase in bleeding and perhaps mortality. Further research is needed to better stratify who should receive aspirin while on warfarin. [Display omitted] DisclosuresSood:Bayer: Research Funding. Kline-Rogers:Janssen: Consultancy; ACP: Consultancy; AC Forum: Membership on an entity's Board of Directors or advisory committees. Almany:Trice Orthopedics: Consultancy; Micardia: Consultancy; Ablative Solutions: Equity Ownership; Kona: Consultancy; Biostar Ventures: Equity Ownership; Boston Scientific Watchman: Research Funding; Abbott Absorb Trial: Research Funding. Kaatz:Daiichi Sankyo: Consultancy, Honoraria; CSL Behring: Honoraria; Boehringer Ingelheim: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Portola: Consultancy. Froehlich:Merck: Consultancy; Fibromuscular Disease Society of America: Research Funding; Blue Cross/Blue Shield of Michigan: Research Funding; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Novartis: Consultancy; Pfizer: Membership on an entity's Board of Directors or advisory committees. Barnes:Pfizer: Research Funding; Bristol Myers Squibb: Research Funding; Blue Cross/Blue Shield of Michigan: Research Funding; Aralez: Consultancy.

A case series of the rifampin-warfarin drug interaction: focus on practical warfarin management.

To provide practical guidance by providing weekly descriptions of warfarin requirements for the onset and offset of the rifampin-warfarin interaction. A retrospective chart review within an outpatient Anticoagulation Clinic (AC). Patients were eligible for the onset phase provided they had known ambulatory-based warfarin steady-state requirements prior to rifampin initiation. For the offset phase, warfarin must be managed by the AC following rifampin discontinuation. Each phase was described separately with warfarin proportionate dose changes (median, IQR) for weeks 1, 2, and 4 as well as the change required to reach warfarin steady state. Ten patients with 11 courses of warfarin-rifampin were included. For onset, clinicians should anticipate proportionate warfarin dose increases of 30-80% from week 1 to week 2 and a further 20-100% from week 2 to 4, with an overall warfarin dose increase of 165% (IQR 99, 227) to reach steady state at 30days. For offset, clinicians should anticipate proportionate warfarin dose decreases of 15-25% for both week 1 and 2, and a further 20% for both week 3 and 4, resulting in an overall warfarin decrease of 67% (IQR - 70, - 58) to reach steady state at 4weeks for most patients. Close monitoring with at least twice weekly INRs for weeks 1 to 2 of both phases is needed to respond to substantially changing warfarin dose requirements. While inter- and intra-patient variability for proportionate warfarin dose changes for both the onset and offset of this drug interaction exists, our data provides general guidance.

Open-Heart Surgery in Low-Income Settings: The Experience of &lt;i&gt;Salam&lt;/i&gt; Centre for Cardiac Surgery in Sudan (2007–2019)

Background: Despite the need for cardiac surgery in Sub-Saharan Africa, access is still very limited. Active since 2007, the Salam Centre for Cardiac Surgery, run by EMERGENCY NGO and co-financed by the Sudanese government, offers heart surgery free of charge. Methods: Retrospective cohort study of 8369 consecutive patients undergoing open-heart surgery between 2007 and 2019, from Sudan (81%) and from neighbouring countries (19%). Findings: Rheumatic heart disease (RHD) was prevalent in 80% of adults (median age 28, Q1-Q3 20-37); with 43% isolated mitral, 11% aortic and 46% multiple valve procedures. Out of the 1396 (17%) patients with congenital heart disease (CHD), 74% were children (< 15 years). Continuity over the years and the low hospital/ 30 days mortality (2·9% RHD; 3·4% CHD) reflect the quality of in-hospital care. Outpatient and oral anticoagulation clinics ensured care after discharge, leading to a 5-years loss-to-follow-up for RHD patients of 18% and a 5-years overall survival of 89.6% (95% CI: 88.9-90.3), with values over 90% for MV and AV surgeries . The programme has also provided training for more than 400 local healthcare workers (2013–2019). Interpretation: The overall favorable results strongly support the original hypothesis that quality, gratuity, and long-term commitment represent the key elements in the collaboration between a humanitarian independent NGO and institutional actors, paving the way for wider, sustainable developments. Funding: The SALAM Centre is funded by EMERGENCY-NGO and by the Sudanese Government. The average Government Contribution in 2007-2019 amounts to 32% of the project’s overall costs, reaching 50% in 2014-2017. Declaration of Interest: We declare no competing interests. Ethical Approval: The institutional ethics board of the University of Milan have approved this study and, due to the nature of retrospective chart reviews, waived the need for informed consent from individual patients.

Determinants of Anticoagulation Control in Patients Receiving Warfarin Therapy

Background: Warfarin, nowadays is considered one of the most prescribed anticoagulant medications. In England for example, there is at least 1% of the whole population being prescribed warfarin. Despite the emergence of new agents of anticoagulants like NOACS, warfarin still prevail in most prescriptions knowing that it can’t be substituted in certain indications. Objectives: To assess different factors associated with International Normalized Ratio (INR) control in patients who are on warfarin therapy for different indications. Methods: A retrospective cohort study conducted in National Heart Institute Outpatient Anticoagulation Clinic over six-month period. It included 250 patients on warfarin therapy for different indications. Results: After calculating Time in Therapeutic Range (TTR) of each patient the level of anticoagulation control was determined using the following cut off values: a) Good control: TTR>70%, b) Intermediate control: TTR 50 -70 %, c) Poor control: TTR <50%. Majority of patients in our study 62% had poor control with TTR less than 50%. Conclusion: Majority of patients have poor anticoagulation control by means of TTR. Male gender, higher education and employment status are associated with higher mean TTR and better anticoagulation control. Male gender and employment were significant predictors for good INR control.

Determinants of Anticoagulation Control in Patients Receiving Warfarin Therapy

Background: Warfarin, nowadays is considered one of the most prescribed anticoagulant medications. In England for example, there is at least 1% of the whole population being prescribed warfarin. Despite the emergence of new agents of anticoagulants like NOACS, warfarin still prevail in most prescriptions knowing that it can’t be substituted in certain indications. Objectives: To assess different factors associated with International Normalized Ratio (INR) control in patients who are on warfarin therapy for different indications. Methods: A retrospective cohort study conducted in National Heart Institute Outpatient Anticoagulation Clinic over six-month period. It included 250 patients on warfarin therapy for different indications. Results: After calculating Time in Therapeutic Range (TTR) of each patient the level of anticoagulation control was determined using the following cut off values: a) Good control: TTR>70%, b) Intermediate control: TTR 50 -70 %, c) Poor control: TTR <50%. Majority of patients in our study 62% had poor control with TTR less than 50%. Conclusion: Majority of patients have poor anticoagulation control by means of TTR. Male gender, higher education and employment status are associated with higher mean TTR and better anticoagulation control. Male gender and employment were significant predictors for good INR control.

Warfarin therapy adherence and health-related quality of life among patients using warfarin in Saudi Arabia.

Treatment satisfaction and medication adherence to oral anticoagulant therapy are important measures that often decrease morbidity and mortality. Though warfarin is a frequently prescribed oral anticoagulant, warfarin therapy adherence (WTA) and its impact on overall Health-Related Quality of Life (HRQoL) has not been studied in Saudi Arabia. To assess the association between WTA and HRQoL among patients on warfarin in Saudi Arabia. A prospective, cross-sectional, descriptive study was conducted on 387 patients on warfarin therapy attending an outpatient anticoagulation clinic in Alkharj, Saudi Arabia. WTA was assessed using medication adherence measuring scale (MAMS) whereas HRQoL was measured using World Health Organization QOL-BREF (WHOQOL-BREF). Descriptive and inferential statistics were used to examine patients' demographic characteristics and to determine the association among different variables. Spearman's correlation coefficient was used to determine the association between various study variables. Of the total 387 participants, there were more females than males (n=257, 66.4%, and n=130, 33.6% respectively). The mean adherence score for the study population was 5.86±1.21. Mean HRQoL score for physical health domain, psychological domain, social relationships domain, and environment domain were 62.11±15.53, 68.20±16.11, 64.46±26.19 and 63.43±17.60 respectively. The correlation coefficients for all the four domains of the WHOQOL-BREF vs total mean score of warfarin therapy adherence were 0.124, 0.051, 0.063 and 0.083 respectively indicating a weak positive association between warfarin therapy adherence and physical health domain (P < 0.005). Study results indicate a positive association between WTA and the physical health domain of the WHOQOL-BREF among patients on warfarin. Better warfarin therapy adherence can improve the physical health of patients on warfarin.

Quality of Oral Anticoagulation with Vitamin K Antagonists in ‘Real-World’ Patients: Lessons from a Six Years Audit Study

Introduction: Among patients receiving vitamin K antagonists (VKA) therapy, maintenance of an international normalized ratio (INR) in the therapeutic range is essential for treatment efficacy and safety. This requires regular monitoring and appropriate dose adjustment. It has been reported that anticoagulation clinics should aim for a time in therapeutic range (TTR) between 70-80% to optimize benefit and minimize the risk of adverse events. Previously (in a study between September 2006 and June 2012), we have reported that patients with longer INR recall interval (4-8 weeks) showed no decrease of monitoring quality and that it would be safe to increase time between measurements. Aim: Since actual recommendations for improving TTR include shortening INR recall interval (Lip et al. 2018) we aimed to evaluate the quality of anticoagulation monitoring after having increased time between measurements beyond the 4-8 weeks recall interval. Methodology: We retrospectively analyzed 37931 appointments of 6 consecutive years (July 2012 to July 2018) corresponding to 1587 patients that are regularly followed up at an outpatient Anticoagulation Clinic of a central hospital under anticoagulation for at least 8 weeks, using TTR determined by Rosendaal method. Patients were divided according to target INR in three groups: Group 1 with target INR 2-3, including 1430 patients corresponding to 30743 appointments with mean age 69±15 years (mean±SD), majority (46.4%) with atrial fibrillation (AF); Group 2 with target INR 2.5-3.5, including 125 patients corresponding to 5439 appointments with mean age 67±12 years, majority (85.6%) with mechanical heart valves; Group 3 with target INR 3-4, including 32 patients corresponding to 1749 appointments with mean age 62±14 years, majority (62.5%) with antiphospholipid syndrome. Descriptive statistics (mean, standard deviation, minimum, maximum, chi-square), inferential statistics (t-test, A-Nova and effect sizes) tests and correlations were performed. Results: The 1587 patient population, 50.5% male, mean age of 68±17 years and 90.1% in Group 1, showed a mortality of 18%. A point-biserial correlation was run to determine the relationship between mortality and gender, age, INR group and diagnostic. Mortality was correlated with diagnosis (57.2% with AF) (rpb = -.071, n = 1587, p = .004), male gender (60%) (rpb = -.089, n = 1587, p &lt;.001) and age (75±12) (rpb = .175, n= 1587, p&lt;.001) but not with INR group (rpb = -.017, n = 1587, p = .499). Indeed, between groups mortality was not different [Χ2(2)=.492; p=.782; φ=.018] nor mean age [F(2, 1584)=2.588; p=.078; η2=.003], but gender distribution was unequal [Χ2(2)= 10.815; p=.004; φ=.083] with male predominating in Group 1 (51.9%) and female in Group 2 (60.8%) and 3 (65.6%). Patients in Group 1, corresponding to 90.1% of the total population, had TTR of 72%, patients in Group 2 had TTR of 69% and patients in Group 3 had TTR of 60%. Comparatively to the previous study (2006-2012), we noticed a significant decrease in patient population / appointments size (2087/ 61988) (p &lt;.001) with a decrease of TTR in Group 1 (1927 patients) (83%) and Group 2 (120 patients) (74%) but a TTR increase in Group 3 (40 patients) (54%) (p &lt;.001). Conclusions and Discussion: More than 90% of the population under VKA treatment showed effective TTR which may infer safety in increasing INR recall interval. The TTR decrease with a smaller population may be explained by the introduction of direct oral anticoagulants in patients with less comorbidities. The increase of TTR in patients with higher INR target suggests a better management of patients under VKA therapy that is actually the only choice for challenging patients. Disclosures No relevant conflicts of interest to declare.

Stroke : Highlights of Selected Articles

<i>Stroke</i> : Highlights of Selected Articles

Processes and barriers to implementation of point-of-care genotype-guided dosing of warfarin into UK outpatient anticoagulation clinics.

Processes and barriers to implementation of point-of-care genotype-guided dosing of warfarin into UK outpatient anticoagulation clinics.

Generational performance of three point-of-care testing devices compared with standard laboratory measurement of the international normalised ratio across extended ranges

Point-of-care testing (POCT) of the international normalised ratio (INR) is recognised as a rapid and reliable alternative to venous INR measurement for titration and monitoring of patients anticoagulated with vitamin...

Policy Change for Deep Vein Thrombosis: Effects on Length of Stay and Hospitalization Costs of Moving From Warfarin to Direct Oral Anticoagulants

PurposeRenown Health (Reno, Nevada), a large, locally owned, not-for-profit integrated health care network, has developed an institution-wide policy to shift the treatment of deep vein thrombosis (DVT) from a short-acting anticoagulant and vitamin K antagonist to the direct oral anticoagulant rivaroxaban combined with pharmacy-directed follow-up at an outpatient anticoagulation clinic. We examined data on hospitalizations and costs pre–/post–policy change. MethodsData were obtained from the electronic health records of adults with newly diagnosed DVT treated at Renown Health. A quasi-experimental design was used to evaluate patients who received a DVT diagnosis before versus after the policy change. Primary outcomes were number of all-cause inpatient nights at 30 and 60 days post–DVT index date. Secondary outcomes were costs of all-cause overnight stays at 30 and 60 days post–DVT index. Outcomes were evaluated in propensity-weighted logistic regression and generalized linear models. FindingsThere were 343 patients pre–policy change and 266 post–policy change. In the first 30 days postindex, the mean (95% CI) numbers of propensity-weighted all-cause inpatient nights were 1.27 (0.83–1.95) prechange and 0.66 (0.42–1.02) postchange (P = 0.038). Mean propensity-weighted estimated all-cause hospital costs in patients diagnosed as outpatients were $7848 ($4990–$12,344) prechange and $2466 ($1553–$3915) postchange (P <0.001). Mean costs of all-cause overnight stays in inpatient-diagnosed DVT patients were $8907 prechange and $7449 postchange (P = 0.600). In the first 60 days postindex, the mean number of all-cause inpatient nights (P = 0.219) and mean costs of all-cause overnight stays (P = 0.275) were not significantly different before and after the policy change. ImplicationsChanging institutional policy to increase the utilization of a direct oral anticoagulant and pharmacist-led outpatient anticoagulation clinics may reduce length of hospital stay and decrease health care expenditures in the treatment of DVT.

Barriers to integrating direct oral anticoagulants into anticoagulation clinic care: A mixed‐methods study

BackgroundOutpatient anticoagulation clinics were initially developed to care for patients taking vitamin K antagonists such as warfarin. There has not been a systematic evaluation of the barriers and facilitators to integrating direct oral anticoagulant (DOAC) care into outpatient anticoagulation clinics. MethodsWe performed a mixed methods study consisting of an online survey of anticoagulation clinic providers and semi‐structured interviews with anticoagulation clinic leaders and managers between March and May of 2017. Interviews were transcribed and coded, exploring for themes around barriers and facilitators to DOAC care within anticoagulation clinics. Survey questions pertaining to the specific themes identified in the interviews were analyzed using summary statistics. ResultsSurvey responses were collected from 159 unique anticoagulation clinics and 20 semi‐structured interviews were conducted. Three primary barriers to DOAC care in the anticoagulation clinic were described by the interviewees: (a) a lack of provider awareness for ongoing monitoring and services provided by the anticoagulation clinic; (b) financial challenges to providing care to DOAC patients in an anticoagulation clinic model; and (c) clinical knowledge versus scope of care by the anticoagulation staff. These themes linked to three key areas of variation, including: (a) the size and hospital affiliation of the anticoagulation clinic; (b) the use of face‐to‐face versus telephone‐based care; and (c) the use of nurses or pharmacists in the anticoagulation clinic. ConclusionsAnticoagulation clinics in the United States experience important barriers to integrating DOAC care. These barriers vary based on the clinic size, model for warfarin care, and staff credentials (nursing or pharmacy).

Peri-procedural antithrombotic management: time to burn the bridge?

Emerging evidence suggests the use of peri-procedural bridging during interruptions in warfarin therapy increases bleed risk without reducing thromboembolic events. We implemented a peri-procedural anticoagulant management risk assessment tool in a single, outpatient anticoagulation clinic within an academic teaching institution. In this retrospective, pre-post observational study, we evaluated adults who required an interruption in warfarin therapy for an invasive procedure. The primary outcome was the proportion of patients who received bridging prior to and following implementation of the tool. Secondary outcomes included major bleeding, clinically relevant non-major bleeding, thromboembolic events, and other surgical complications within 30days of the index procedure. In total, 149 patients were included. Bridging was recommended in 60% of the pre-intervention group and in 39.3% of the post-intervention group (p = 0.012). There were no significant differences in the secondary outcomes between the groups. However, patients who received bridging had numerically more bleeding events than patients who did not (12.3 vs. 3.9%, p = 0.102), and patients who received therapeutic dose bridging had more bleeding events than those who received modified dose bridging (10.9 vs. 1.4%, p = 0.466). Following implementation of the tool, there was a statistically significant decrease in the number of patients who received bridging without an increase in thromboembolic events. There were numerically higher rates of bleeding in those who received bridging. Additional research is needed to evaluate efficacy and safety of prophylactic versus treatment dose bridging and how implementation of peri-procedural antithrombotic tools reflecting the emerging evidence will affect patient outcomes, satisfaction and healthcare costs.

Prospective Comparison of Point-of-Care Device and Standard Analyzer for Monitoring of International Normalized Ratio in Outpatient Oral Anticoagulant Clinic.

Point-of-care testing (POCT) coagulometers are increasingly being used in the hospital setting and patients’ self-testing. We determined the agreement of prothrombin time international normalized ratio (INR) results by POCT coagulometer and laboratory instrument through a comparative analysis and investigated whether the results of POCT coagulometer can reliably be used without being confirmed by standard laboratory analyzer. A total of 200 INR measurements by POCT coagulometer (CoaguChek XS Pro) and laboratory analyzer (Sysmex CS2000i) were compared using Passing-Bablok regression analysis and Bland-Altman plot. Agreement of the INR measurement was further analyzed in relation to dosing decision. The correlation of INR measurements between CoaguChek XS Pro and Sysmex CS2000i was excellent (correlation coefficient = 0.973). The overall mean difference was 0.21 INR ± 0.32 (range: 1.7-0.44). The mean difference was found to get increased as INR results increased and was 0.09 in the subtherapeutic range (≤1.9 INR), 0.29 INR in the therapeutic range (2.0-3.0 INR), while 0.4 INR in the supratherapeutic range (>3.0 INR). The overall agreement was excellent (κ = 0.916) and overall 11 (5.5%) of 200 INR measurements showed a difference in dosing decision between the 2 instruments. The positive bias of POC-INR is evident in the supratherapeutic range which could affect the dosing decision requiring confirmation with the laboratory INR measurement.

SAMe-TT2R2 Score: A Useful Tool in Oral Anticoagulation Decision-Making for Venous Thromboembolism Patients?

Abstract Background: The SAMe-TT2R2 score was introduced to identify atrial fibrillation patients with a high risk of not achieving a good time in therapeutic range (TTR) during vitamin K antagonists (VKA) therapy. Objective: The aim of this study was to evaluate this score in venous thromboembolism (VTE) patients. Patients and methods: A retrospective cohort study of patients receiving care at the outpatient anticoagulation clinic of a tertiary care teaching hospital. Patients were classified as having low (score 0-1) or high risk (score ≥ 2) of not achieving a good TTR. The area under the ROC curve was calculated to assess the ability of the score to predict a TTR ≥ 65%. Adverse event-free survival curves according to the SAMe-TT2R2 score were calculated by the Kaplan-Meier method and compared by the log-rank test. A p-value < 0.05 was considered statistically significant. Results: We investigated 111 patients during a median follow-up of 2.3 (0.7-6.4) years. Mean age was 54.1 ± 15.7 years and 71 (64.0%) were women. Low- and high-risk groups had similar mean TTR (51.9 vs. 49.6%; p = 0.593). The two groups did not differ significantly in the percentage of patients achieving a TTR ≥ 65% (35.6 vs. 25.8%; p = 0.370). The c-statistic was 0.595 (p = 0.113) for TTR ≥ 65%. Adverse event-free survival during anticoagulation was also similar in both groups (p = 0.136). Conclusions: The SAMe-TT2R2 score does not seem to be a useful tool in oral anticoagulation decision-making for patients with VTE and should not be used in this setting.

Influence of Kidney Transplant Status on Warfarin Dose, Anticoagulation Control, and Risk of Hemorrhage.

To assess whether warfarin dose requirement, anticoagulation control, and risk of hemorrhage differ in kidney transplant recipients (KTRs) compared with patients without kidney transplants (non-KTRs). Analysis of data from the Warfarin Pharmacogenetics Cohort, a prospective cohort of first-time warfarin users followed at two anticoagulation clinics. Two outpatient anticoagulation clinics at two large, academic, tertiary care hospitals. Adults aged 20years or older starting warfarin for anticoagulation with a therapeutic international normalized ratio (INR) goal of 2-3 who were KTRs (n=65) or non-KTRs (n=1630). Warfarin dose requirement, anticoagulation control, and risk of hemorrhage were assessed in each group. KTRs required an approximately 20% lower warfarin dose (4.7 vs 5.6mg/day, p=0.0005) compared with non-KTRs. Genetic variants had similar effects on dose in both groups. Mean percentage of time in therapeutic range (PTTR) was similar among KTRs and non-KTRs. Although the proportion of patients achieving good anticoagulation control (PTTR≥60%) was low in both groups, it was similar among KTRs and non-KTRs. KTRs had a higher risk of major hemorrhage (hazard ratio 2.1, p=0.0081), but this difference was not statistically significant after controlling for kidney function, clinical, and genetic factors. KTRs initiating warfarin require lower doses and closer monitoring to optimize anticoagulation therapy. Additional studies are needed to confirm these findings.

SAMe-TT2R2 Score in the Outpatient Anticoagulation Clinic to Predict Time in Therapeutic Range and Adverse Events.

BackgroundThe SAMe-TT2R2 score was developed to predict which patients on oral anticoagulation with vitamin K antagonists (VKAs) will reach an adequate time in therapeutic range (TTR) (> 65%-70%). Studies have reported a relationship between this score and the occurrence of adverse events.ObjectiveTo describe the TTR according to the score, in addition to relating the score obtained with the occurrence of adverse events in patients with nonvalvular atrial fibrillation (AF) on oral anticoagulation with VKAs.MethodsRetrospective cohort study including patients with nonvalvular AF attending an outpatient anticoagulation clinic of a tertiary hospital. Visits to the outpatient clinic and emergency, as well as hospital admissions to the institution, during 2014 were evaluated. The TTR was calculated through the Rosendaal´s method.ResultsWe analyzed 263 patients (median TTR, 62.5%). The low-risk group (score 0-1) had a better median TTR as compared with the high-risk group (score ≥ 2): 69.2% vs. 56.3%, p = 0.002. Similarly, the percentage of patients with TTR ≥ 60%, 65% or 70% was higher in the low-risk group (p < 0.001, p = 0.001 and p = 0.003, respectively). The high-risk group had a higher percentage of adverse events (11.2% vs. 7.2%), although not significant (p = 0.369).ConclusionsThe SAMe-TT2R2 score proved to be effective to predict patients with a better TTR, but was not associated with adverse events.