Time to therapeutic range (TtTR), anticoagulation control, and cardiovascular events in vitamin K antagonists-naive patients with atrial fibrillation

Oral Anticoagulants after Heart Transplantation-Comparison between Vitamin K Antagonists and Direct Oral Anticoagulants

AIMS

Patients after heart transplantation (HTX) often require oral anticoagulants (OACs) due to atrial arrhythmias or thromboembolic events but little is known about the post-transplant use of direct oral anticoagulants (DOACs). We investigated the frequency, indications, and complications of DOACs and vitamin K antagonists (VKAs) after HTX.

METHODS

We screened all adult patients for the use of post-transplant OACs who underwent HTX at Heidelberg Heart Center between 2000 and 2021. Patients were stratified by type of OAC (DOAC or VKA) and by DOAC agents (apixaban, dabigatran, edoxaban, or rivaroxaban). Indications for OACs comprised atrial fibrillation, atrial flutter, pulmonary embolism, upper and lower extremity deep vein thrombosis, as well as intracardiac thrombus.

RESULTS

A total of 115 of 459 HTX recipients (25.1%) required OACs, including 60 patients with DOACs (52.2%) and 55 patients with VKAs (47.8%). Concerning DOACs, 28 patients were treated with rivaroxaban (46.7%), 27 patients with apixaban (45.0%), and 5 patients with edoxaban (8.3%). We found no significant differences between both groups concerning demographics, immunosuppressive drugs, concomitant medications, indications for OACs, ischemic stroke, thromboembolic events, or OAC-related death. Patients with DOACs after HTX had a significantly lower one-year rate of overall bleeding complications (p = 0.002) and a significantly lower one-year rate of gastrointestinal hemorrhage (p = 0.011) compared to patients with VKAs after HTX in the Kaplan-Meier estimator.

CONCLUSIONS

DOACs were comparable to VKAs concerning the risk of ischemic stroke, thromboembolic events, or OAC-related death but were associated with significantly fewer bleeding complications in HTX recipients.

Associated factors and safety of the rapidly achieving first therapeutic target of warfarin in hospitalized patients: a retrospective cohort study

BACKGROUND

Warfarin is a commonly used anticoagulant drug in clinical practice. Rapidly achieving the first therapeutic international normalized ratio (INR) of warfarin may reduce the hospital length of stay. However, little research has been carried out to evaluate the influencing factors and the safety of rapidly achieving the first therapeutic INR target of warfarin.

AIM

To investigate the associated factors and the safety of rapidly achieving the first therapeutic INR target of warfarin.

METHOD

A retrospective cohort study was conducted in inpatients who took warfarin from November 2018 to October 2019. Patients' information was retrieved from medical records.

RESULTS

487 patients were included. The mean achieving first therapeutic target time was 6.0 ± 3.2 days (median, 5.0 days). Age > 65 years, body mass index < 24 kg/m², and initial warfarin dose ≥ 3 mg/d were independent factors associated with the rapidly achieving first INR target of warfarin therapy. The incidence of INR ≥ 4 was higher in patients achieving the first INR target rapidly than those achieving the first INR target slowly, while there were no significant differences in bleeding events between the two groups.

CONCLUSION

Hospitalized patients aged > 65 years, with a body mass index < 24 kg/m², or receiving an initial warfarin dose ≥ 3 mg/d were more likely to achieve the first INR target of warfarin rapidly. Closer INR monitoring and appropriate warfarin dose adjustment are recommended to improve the safety for patients achieving the first INR ≥ 1.8 within 6 days after beginning oral warfarin.

Relation of the 'Atrial Fibrillation Better Care (ABC) Pathway' to the Quality of Anticoagulation in Atrial Fibrillation Patients Taking Vitamin K Antagonists

The Atrial Fibrillation Better Care (ABC) pathway was proposed for a more integrated atrial fibrillation (AF) care. We investigated if adherence to the ABC pathway was associated to the quality of anticoagulation control in a cohort of AF outpatients starting vitamin K antagonists (VKAs) between July 2016 and June 2018. Patients were considered adherent to the ABC pathway if they met all of its components. The time in therapeutic range (TTR) was estimated at one year. In total, 1045 patients (51.6% female; median age 77 years; 63% ABC pathway adherent) were included. At one year, 474 (51.6%) of 919 patients with international normalized ratio (INR) data for TTR estimation had a TTR < 65%. Among ABC pathway non-adherent patients, a greater proportion had TRT < 65% (56.4% vs. 43.6%, p = 0.025), and TTR < 70% (64.9% vs. 35.1%, p = 0.033), with lower mean TTR in non-adherent patients (59.4 ± 22.3% vs. 63.9 ± 21.1%; p = 0.004). Logistic regression models demonstrated that the ABC pathway adherence in its continuous (aOR: 0.75, 95% CI 0.59−0.96) and categorical (aOR: 0.75, 95% CI 0.57−0.98) forms was independently associated with TTR ≥ 65%. In this ‘real-world’ cohort of AF patients starting VKAs, the ABC pathway adherent patients had better TTR, and more ABC criteria fulfilled increased the probability of achieving good TTR.

Anticoagulation Control in Different Ethnic Groups Receiving Vitamin K Antagonist for Stroke Prevention in Atrial Fibrillation

Vitamin K antagonist such as warfarin reduces the risk of stroke in atrial fibrillation (AF) patients. Since warfarin has a narrow therapeutic index, its administration needs to be regularly monitored to avoid any adverse clinical outcomes such as stroke and bleeding. The quality of anticoagulation control with warfarin therapy can be measured by using time in therapeutic range (TTR). This review focuses on the prevalence of AF, quality of anticoagulation control (TTR) and adverse clinical outcome in AF patients within different ethnic groups receiving warfarin therapy for stroke prevention. A literature search was conducted in Embase and PubMed using keywords of “prevalence,” “atrial fibrillation,” “stroke prevention,” “oral anticoagulants,” “warfarin,” “ethnicities,” “race” “time in therapeutic range,” “adverse clinical outcome,” “stroke, bleeding.” Articles published by 1st February 2020 were included. Forty-one studies were included in the final review consisting of AF prevalence (n = 14 studies), time in therapeutic range (n = 18 studies), adverse clinical outcome (n = 9 studies) within different ethnic groups. Findings indicate that higher prevalence of AF but better anticoagulation control among the Whites as compared to other ethnicities. Of note, non-whites had higher risk of strokes and bleeding outcomes while on warfarin therapy. Addressing disparities in prevention and healthcare resource allocation could potentially improve AF-related outcomes in minorities.

The SAMe-TT2R2 score as an indicator of warfarin control for patients with deep vein thrombosis in Queensland, Australia

Oral anticoagulation options for patients with venous thromboembolism (VTE) include vitamin K antagonists like warfarin. Good warfarin control is linked to outcomes of therapy, and the SAMe-TT₂R₂ model has been reported to predict control in atrial fibrillation patients with scores ≥ 2 linked to poor control. There has been limited and conflicting data in VTE populations, therefore this study aimed at determining the predictive ability of this model in Australian patients with deep vein thrombosis. Retrospective data of patients receiving warfarin care at a private pathology clinic in Queensland was collected. The time in therapeutic range (TTR) and SAMe-TT₂R₂ score was calculated for individual patients. Mean TTR and patients with TTR ≥ 65% were used for analysis and comparison across patients categorised as a score of 0-1 and ≥ 2. Of the 533 patients, the majority had a SAMe-TT₂R₂ score of 0-1. No significant difference was found in mean TTR between patients with a score of 0-1 and ≥ 2 but there was a significantly higher percentage of patients with a TTR ≥ 65% between groups (93.8% vs. 69.2%, p < 0.0001, respectively). The SAMe-TT₂R₂ score may assist in identifying patients with VTE likely to achieve good control (TTR ≥ 65%), but further investigation is required to determine the most suitable model for predicting warfarin control in this population.

Variables affecting the quality of anticoagulation in atrial fibrillation patients newly initiating vitamin K antagonists: insights from the national and multicentre SULTAN registry

AIMS

Vitamin K antagonists (VKAs) are effective drugs reducing the risk for stroke in atrial fibrillation (AF), but the benefits derived from such therapy depend on the international normalized ratio (INR) maintenance in a narrow therapeutic range. Here, we aimed to determine independent variables driving poor anticoagulation control [defined as a time in therapeutic range (TTR) <65%] in a 'real world' national cohort of AF patients.

METHODS AND RESULTS

The SULTAN registry is a multicentre, prospective study, involving patients with non-valvular AF from 72 cardiology units expert in AF in Spain. At inclusion, all patients naïve for oral anticoagulation were started with VKAs for the first time. For the analysis, the first month of anticoagulation and those patients with <3 INR determinations were disregarded. Patients were followed up during 1 year. A total of 870 patients (53.9% male, the mean age of 73.6 ± 9.2 years, mean CHA2DS2-VASc and HAS-BLED of 3.3 ± 1.5 and 1.4 ± 0.9, respectively) were included in the full analysis set. In overall, 7889 INR determinations were available. At 1-year, the mean TTR was 63.1 ± 22.1% and 49.2% patients had a TTR < 65%. Multivariate Cox regression analysis showed that coronary artery disease [odds ratio (OR) 1.81, 95% confidence interval (CI) 1.14-2.87; P = 0.012] and amiodarone use (OR 1.54, 95% CI 1.01-2.34; P = 0.046) were independently associated with poor quality of anticoagulation (TTR <65%).

CONCLUSION

This study demonstrated that the quality of anticoagulation in AF patients newly starting VKAs is sub-optimal. Previous coronary artery disease and concomitant use of amiodarone were identified as independent variables affecting the poor quality of VKA therapy during the first year.

Apixaban or Vitamin K Antagonists and Aspirin or Placebo According to Kidney Function in Patients With Atrial Fibrillation After Acute Coronary Syndrome or Percutaneous Coronary Intervention: Insights From the AUGUSTUS Trial

BACKGROUND

In the AUGUSTUS trial (An Open-Label, 2×2 Factorial, Randomized Controlled, Clinical Trial to Evaluate the Safety of Apixaban Versus Vitamin K Antagonist and Aspirin Versus Aspirin Placebo in Patients With Atrial Fibrillation and Acute Coronary Syndrome or Percutaneous Coronary Intervention), apixaban resulted in less bleeding and fewer hospitalizations than vitamin K antagonists, and aspirin caused more bleeding than placebo in patients with atrial fibrillation and acute coronary syndrome or percutaneous coronary intervention treated with a P2Y₁₂ inhibitor. We evaluated the risk-benefit balance of antithrombotic therapy according to kidney function.

METHODS

In 4456 patients, the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) formula was used to calculate baseline estimated glomerular filtration rate (eGFR). The effect of apixaban versus vitamin K antagonists and aspirin versus placebo was assessed across kidney function categories by using Cox models. The primary outcome was International Society on Thrombosis and Haemostasis major or clinically relevant nonmajor bleeding. Secondary outcomes included death or hospitalization and ischemic events (death, stroke, myocardial infarction, stent thrombosis [definite or probable], or urgent revascularization). Creatinine clearance <30 mL/min was an exclusion criterion in the AUGUSTUS trial.

RESULTS

Overall, 30%, 52%, and 19% had an eGFR of >80, >50 to 80, and 30 to 50 mL·min^-1·1.73 m^-2, respectively. At the 6-month follow-up, a total of 543 primary outcomes of bleeding, 1125 death or hospitalizations, and 282 ischemic events occurred. Compared with vitamin K antagonists, patients assigned apixaban had lower rates for all 3 outcomes across most eGFR categories without significant interaction. The absolute risk reduction with apixaban was most pronounced in those with an eGFR of 30 to 50 mL·min^-1·1.73 m^-2 for bleeding events with rates of 13.1% versus 21.3% (hazard ratio, 0.59; 95% CI, 0.41-0.84). Patients assigned aspirin had a higher risk of bleeding in all eGFR categories with an even greater increase among those with eGFR >80 mL·min^-1·1.73 m^-2: 16.6% versus 5.6% (hazard ratio, 3.22; 95% CI, 2.19-4.74; P for interaction=0.007). The risk of death or hospitalization and ischemic events were comparable to aspirin and placebo across eGFR categories with hazard ratios ranging from 0.97 (95% CI, 0.76-1.23) to 1.28 (95% CI, 1.02-1.59) and from 0.75 (95% CI, 0.48-1.17) to 1.34 (95% CI, 0.81-2.22), respectively.

CONCLUSIONS

The safety and efficacy of apixaban was consistent irrespective of kidney function, compared with warfarin, and in accordance with the overall trial results. The risk of bleeding with aspirin was consistently higher across all kidney function categories. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02415400.

A nurse-led atrial fibrillation clinic: Impact on anticoagulation therapy and clinical outcomes

BACKGROUND

Nurses play a central role in the management of atrial fibrillation (AF) patients. An unresolved question is whether a nurse-led clinic would improve clinical outcomes. Herein, we investigated the impact of a nurse-led clinic on anticoagulation therapy and clinical outcomes in a cohort of naïve AF patients.

METHODS

Prospective study including AF patients starting vitamin K antagonists (VKAs) into a nurse-led AF clinic. These patients were followed in this specific AF clinic. Additionally, AF patients already taking VKAs for 6 months followed according to the routine clinical practice were included as comparison group. The quality of anticoagulation was assessed at 6 months. Efficacy and safety endpoints were recorded during follow-up.

RESULTS

We included 223 patients (Nurse-led clinic: 107; Usual care: 116). The mean time in therapeutic range and the proportion of INRs within the therapeutic range were similar in both groups. During 2.06 (IQR 1.01-2.94) years of follow-up, 64 (28.7%) patients changed to direct-acting oral anticoagulants. The proportion of switchers was higher in the nurse-led clinic (37.4%) than in the usual care group (20.7%) (P = .006) and these patients spent less time to switch (2.0 [IQR 0.7-2.9] vs 6.0 [IQR 3.7-11.2] years; P < .001). Importantly, the annual rate of ischaemic stroke/TIA was significantly lower in the nurse-led clinic (0.47%/year vs 3.88%/year, P = .016), without differences in safety endpoints.

CONCLUSION

A nurse-led AF clinic may offer a "patient-centered" review and holistic follow-up, and it would be associated with a reduction of ischaemic stroke/TIA, without increasing bleeding complications. Further studies should confirm these results.

Randomized controlled trial of genotype-guided warfarin anticoagulation in Chinese elderly patients with nonvalvular atrial fibrillation

WHAT IS KNOWN AND OBJECTIVE

Warfarin is an oral anticoagulant which has been widely used to treat and prevent thromboembolic events. Managing warfarin therapy requires careful monitoring and dose titration. This randomized controlled study was designed to assess the effect of genotype-guided warfarin anticoagulation in Chinese elderly patients with nonvalvular atrial fibrillation.

METHODS

507 adults were randomized to receive initial dosing as determined by an algorithm containing genetic (VKORC1 and CYP2C9) plus clinical information or only clinical information. The primary endpoint was the time in therapeutic range (TTR) over 90 days. Secondary end points included haemorrhagic events, thrombotic events and mortality.

RESULTS

The TTR was significantly different between genetic group and control group. The average TTR was (70.80 ± 24.39) % in the genotype-guided group as compared with (53.44 ± 26.73) % in the control group. This represents a difference of 17.36% (95% CI, 11.82 to 22.89, P < .001). The cumulative incidence of total haemorrhagic events, minor haemorrhagic events, gastrointestinal bleeding and intracerebral bleeding events was not significantly different between two groups (P > .05). Follow-up showed that the cumulative incidence of ischaemic stroke events occurred in the genetic group was significantly lower than that in the control group (2.39% vs 6.82%), and the genetic group had a significant lower risk than control group in cumulative incidence of ischaemic stroke events [HR 0.22, (95% CI 0.065 to 0.77), P < .05].

WHAT IS NEW AND CONCLUSION

Genotype-guided dosing could improve the average TTR, and follow-up result showed that genotype-guided therapy resulted in a significantly lower risk of ischaemic stroke events. Further research is required to focus on the clinical benefit of genotype-guided dosing.

Determinants of low-quality warfarin anticoagulation in patients with mechanical prosthetic heart valves. The nationwide PLECTRUM study

Quality of warfarin therapy in patients with a mechanical prosthetic heart valve (MPHV) has been barely investigated. We analysed determinants of low time in the therapeutic range (TiTR <60%) in 2111 patients with MPHVs from the nationwide PLECTRUM study by the Italian Federation of Anticoagulation Clinics. Overall, 48·5% of patients had a TiTR of < 60%. At logistic regression analysis, arterial hypertension (odds ratio [OR] 1·502, P < 0·001), diabetes (OR 1·732, P < 0·001), heart failure (OR 1·484, P = 0·004), mitral site (vs. aortic) (OR 1·399, P = 0·006), international normalised ratio (INR) ranges of 2·5-3·5 (OR 2·575, P < 0·001) and 3·0-4·0 (OR 8·215, P < 0·001) associated with TiTR < 60%. TiTR is substantially suboptimal in MPHV patients, particularly in higher INR ranges.

The SAMe-TT2R2 Score Predicts Warfarin Control in an Australian Population with Atrial Fibrillation

Background: Warfarin requires regular monitoring with the time in therapeutic range (TTR), a common indicator of control and TTR > 70% is indicative of efficient anticoagulation. The SAMe-TT₂R₂ (sex, age, medical history, treatment, tobacco use, race) model has been utilised as a predictor of warfarin control, with a score ≥ 2 indicative of poor control. However, it has been suggested that race may be over-represented in this model. To date, no Australian studies have applied this model, possibly because race is not routinely recorded. Therefore, the aim of this study was to apply the SAMe-TT₂R₂ model in an Australian population on warfarin managed by both a warfarin care program (WCP) and general practitioner (GP). Methods: Retrospective data was collected for patients receiving warfarin via a WCP in Queensland and whilst being managed by a GP. Patient data was used to calculate the SAMe-TT₂R₂ score and the TTR for each patient. Mean TTR was used for analysis and comparison with the categorised SAMe-TT₂R₂ score. Results: Of the 3911 patients managed by a WCP, there was a significantly lower mean TTR for patients with a SAMe-TT₂R₂ score ≥ 2 compared to 0–1 (78.6 ± 10.7% vs. 80.9 ± 9.5%, p < 0.0001). Of these patients, 200 were analysed whilst managed by a GP and the categorised SAMe-TT₂R₂ score did not result in a statistically different mean TTR (69.3 ± 16.3% with 0–1 vs. 63.6 ± 15.0% with ≥2, p = 0.089), but a score ≥2 differentiated patients with a TTR less than 65%. Conclusions: The SAMe-TT₂R₂ model differentiated Australian patients with reduced warfarin control, despite the exclusion of race. In Australia, the SAMe-TT₂R₂ score could assist clinicians in identifying Australian patients who may obtain reduced warfarin control and benefit from additional interventions such as a dedicated WCP.

Tailored Practical Management of Patients With Atrial Fibrillation: A Risk Factor-Based Approach

The management of antithrombotic therapy for thromboprophylaxis in patients with atrial fibrillation (AF) has been recently evolved by the progressive replacement of vitamin K antagonists with the non-vitamin K antagonist oral anticoagulants (NOACs). However, while these drugs are effective in reducing ischemic stroke/systemic embolism, a still high rate of cardiovascular events is present in the AF population. A tailored integrated approach to patients with AF is therefore necessary to reduce both thromboembolic events and cardiovascular disease. This approach should consist in the assessment of individual risk factors for ischemic and bleeding events in order to choose the most appropriate anticoagulant treatment according to patient's characteristics and preference. To this purpose, several risk scores have been developed and validated to stratify thromboembolic and hemorrhagic risk. This review provides an individual-based strategy for the management of patients with AF, from a risk-factor based approach to a tailored prescription and monitoring of NOACs. In particular, we reported an updated practical management strategy for AF patients in specific clinical situations such as those (1) experiencing a major bleeding, (2) requiring a switch to another antithrombotic regimen, (3) restarting anticoagulation after acute ischemic stroke, (4) suffering from an acute coronary artery disease (acute coronary syndrome or undergoing cardiac revascularization).