Outcomes associated with warfarin time in therapeutic range among US veterans with nonvalvular atrial fibrillation

Men who live alone have worse anticoagulation control: A Danish registry study

Men living alone may have particular difficulty in managing chronic medical conditions. Anticoagulation control, a sensitive indicator of self-management, was significantly worse among men living alone.

[Time in therapeutic range and incidence of warfarin complications in a 20-year retrospective cohort]

Objetivo

Caracterizar el tiempo en rango terapéutico (TTR) y estimar la tasa de incidencia de complicaciones (PTIRc) en adultos con protocolo de warfarina.

Diseño

Cohorte retrospectiva basada en registros médicos de pacientes mayores de 18 años entre 1996 a 2016 y seguidos al menos tres meses.

Emplazamiento

Unidad de Hematología de un centro especializado cardiovascular venezolano.

Participantes

Registros médicos electrónicos.

Mediciones principales

TTR y PTIRc. Las variables fueron: sexo, analfabetismo funcional, ocupación, international normalized ratio (INR) y tiempo de seguimiento, que fueron analizados con TTR and PTIRc mediante modelos de logística binomial y regresión de Poisson, respectivamente.

Resultados

Un total de 2.770 pacientes fueron seguidos durante 1.201.380 días; el 42,3% tuvieron un TTR < 65% y el 3,5% tuvieron indicación de INR 2,5-3,5. El 61,8% presentaron complicaciones. La PTIRc fue de 6,84/100 personas-mes (IC 95%: 6,56-7,15). TTR < 65% mostró OR ajustadas significativas con analfabetismo funcional e INR 2,5-3,5, mientras que para la mayor PTIRc se encontró un RR significativo en los dos factores mencionados, menor tiempo de seguimiento, TTR < 65% y en mujeres.

Conclusiones

A pesar de nuevos tratamientos anticoagulantes, la warfarina es útil. A medida que aumentó el tiempo de seguimiento el control fue mejor y la velocidad de aparición de complicaciones disminuyó; sin embargo, las condiciones que mostraron menor TTR y mayor velocidad de aparición de complicaciones requieren una profunda revisión del seguimiento, de manera especial en pacientes con analfabetismo funcional.

The Immediate Effect of COVID-19 Vaccination on Anticoagulation Control in Patients Using Vitamin K Antagonists

Background  In January 2021, the Dutch vaccination program against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was started. Clinical studies have shown that systemic reactions occur in up to 50% of vaccine recipients. Therefore, COVID-19 vaccination could affect anticoagulation control, potentially leading to an increased risk of thrombotic events and bleeding complications.

Aims  This article investigates whether the BNT162b2 vaccine affects anticoagulation control in outpatients using vitamin K antagonists (VKAs).

Methods  A case-crossover study was performed in a cohort of outpatient VKA users from four Dutch anticoagulation clinics who received a BNT162b2 vaccine. International normalized ratio (INR) results and VKA dosages before the first vaccination, the reference period, were compared with those after the first and second vaccination.

Results  A total of 3,148 outpatient VKA users were included, with a mean age (standard deviation) of 86.7 (8.7) years, of whom 43.8% were male, 67.0% used acenocoumarol, and 33.0% phenprocoumon. We observed a decrease of 8.9% of INRs within range in the standard intensity group (target INR 2.0–3.0). There was both an increased risk of supratherapeutic (odds ratio [OR] = 1.34 [95% confidence interval [CI] 1.08–1.67]) and subtherapeutic levels (OR = 1.40 [95% CI 1.08–1.83]) after first vaccination. In the high-intensity group (target INR 2.5–3.5), the risk of a supratherapeutic INR was 2.3 times higher after first vaccination (OR = 2.29 [95% CI 1.22–4.28]) and 3.3 times higher after second vaccination (OR = 3.25 [95% CI 1.06–9.97]).

Conclusion  BNT162b2 was associated with an immediate negative effect on anticoagulation control in patients treated with VKAs, so it is advisable to monitor the INR shortly after vaccination, even in stable patients.

How to level the risk of bleeding while taking anticoagulant therapy in patients with atrial fibrillation?

Atrial fibrillation (AF) is one of the most common types of cardiac arrhythmias, while AF is the main risk factor for ischemic stroke. For a long time, vitamin K antagonists, primarily warfarin, have been the standard for the prevention of thromboembolic complications in patients with AF. 5 years ago, dabigatran, rivaroxaban and apixaban occupied the 2nd place in the structure of anticoagulant prescribing (AC), giving way to warfarin. The well-known reason for the inadequate use of AC is the risk of bleeding. There are a large number of validated scales for assessing the risk of hemorrhagic complications, in particular HAS-BLED, ABC, HEMORRHR2HAGES, ATRIA, ORBIT, but the estimated high risk of bleeding should not be the only and absolute limitation to the appointment of AC. Despite the real risk of bleeding on the background of taking AC in patients with AF, an integrated approach taking into account not only the risk factors of the thromboembolic complications, but also hemorrhagic complications, with an emphasis on the existing comorbidities, the presence of comorbidity, old age, etc., will allow an individual approach to the choice of AC and its dose, contributing to the optimization of the management of such kind of patients.

Clinical Impact of the Time in Therapeutic Range on Early Hospital Readmission in Patients with Acute Heart Failure Treated with Oral Anticoagulation in Internal Medicine

Background and objectives: Patients with heart failure (HF) often present with non-valvular atrial fibrillation and require oral anticoagulation with coumarin anticoagulants such as acenocoumarol. The objective of this study was to evaluate the relationship between time in therapeutic range (TTR) and the risk of early readmission. Materials and Methods: A retrospective descriptive study was carried out on hospitalized patients with a diagnosis of HF between 2014 and 2018 who had adverse effects due to oral anticoagulation with acenocoumarol (underdosing, overdosing, or hemorrhage). Clinical, analytical, therapeutic, and prognostic variables were collected. TTR is defined as the duration of time in which the patient’s International Normalized Ratio (INR) values were within a desired range. Early readmission was defined as readmission within 30 days after hospital discharge. Patients were divided into two groups depending on whether or not they had a TTR less than 60% (TTR < 60%) over the 6 months prior to the adverse event. Results: In the cohort of 304 patients, the mean age was 82 years, 59.9% of the patients were female, and 54.6% had a TTR < 60%. Patients with TTR < 60% had a higher HAS-BLED score (4.04 vs. 2.59; p < 0.001) and INR (6 vs. 5.31; p < 0.05) but lower hemoglobin (11.67 vs. 12.22 g/dL; p < 0.05). TTR < 60% was associated with early readmission after multivariate analysis (OR: 2.05 (CI 95%: 1.16–3.61)). They also had a higher percentage of hemorrhagic events and in-hospital mortality but without reaching statistical significance. Conclusions: Patients with HF and adverse events due to acenocoumarol often have poor INR control, which is independently associated with a higher risk of early readmission.

Time to Stable Therapeutic Range on Initiation of Warfarin as an Indicator of Control

OBJECTIVES

Warfarin remains widely used with a time in therapeutic range (TiTR) above 65% recommended for best outcomes. Patients not achieving or maintaining this warfarin control may be better suited to alternate anticoagulants. Despite this, there is limited data defining a suitable trial time in patients initiating warfarin therapy, therefore the aim of this study was to determine the mean time to stable therapeutic range (TtSTR).

MATERIALS AND METHODS

Retrospective data was collected for patients with atrial fibrillation enrolled in a dedicated warfarin program at a private pathology practice within 7 days of warfarin initiation. TiTR at specified timepoints was calculated and median TtSTR determined as defined by TiTR ≥ 65% over three months. Comparisons were made of populations with TtSTR above or below the median.

RESULTS

The 566 patients included in the study had a mean TiTR of 64.9±16.5% at month three and median TtSTR of six months. Patients with TtSTR≤6 months achieved a mean TiTR of 68.9±12.8% at month two and maintained a TiTR over 75% from month 3 to 24. Patients with a TtSTR>6 months obtained a TiTR of 66.4±10.6% at month nine and continued to achieve lower TiTR throughout the 24 months study period.

CONCLUSIONS

A majority of patients can achieve a stable TiTR above 65% within six months so review at six to nine months is likely to be a good indicator of warfarin control and to determine if patients should continue warfarin or switch to alternate anticoagulant therapy.

Cost and burden of poor anticoagulation control with vitamin K antagonists in patients with nonvalvular atrial fibrillation in Spain

INTRODUCTION AND OBJECTIVES

The aim of this analysis was to evaluate the burden and cost of complications due to poor anticoagulation control in patients with nonvalvular atrial fibrillation (NVAF) treated with vitamin K antagonists (VKA) in Spain.

METHODS

An analytical model was used to estimate annual differences in ischemic stroke, major bleeding, deaths, costs, and potential years of life lost between patients with poor anticoagulation control (time in therapeutic range <65%) and adequate control (time in therapeutic range ≥ 65%) with a 1-year time horizon. Information on the target population (patients ≥ 65 years), event rates, and costs were obtained from national sources. Direct costs in euros (2018) were included from the perspective of the national health system (NHS) and direct and indirect costs from the societal perspective. A sensitivity analysis was performed with post-hoc data from the SPORTIF III/V trials.

RESULTS

We analyzed a hypothetical cohort of 594 855 patients, 48.3% with poor anticoagulation control, with an increase of 2321 ischemic strokes, 2236 major bleeding events and 14 463 deaths, and an annual incremental cost between €29 578 306 from the NHS perspective and €75 737 451 from the societal perspective. The annual impact of mortality was 170 502 potential years of life lost. The results of the sensitivity analysis showed that the annual cost would reach €97 787 873 from the societal perspective.

CONCLUSIONS

Poor anticoagulation control with AVK has a strong impact on loss of health and on increased spending for the NHS.

[Prevention of thromboembolic and hemorrhagic events in patients with atrial fibrillation undergoing elective surgery]

OBJECTIVE

To compare incidence of thromboembolic and hemorrhagic complications in patients with atrial fibrillation (AF) undergoing elective surgery on different schemes of perioperative anticoagulant therapy (ACT).

MATERIAL AND METHODS

There were 86 patients (56 (65.1%) men and 30 (34.9%) women, mean age was 69 (64; 78) years) with non-valvular AF who underwent elective interventions. Forty (46.5%) patients underwent abdominal surgery, 34 (39.5%) - cardiovascular procedures, 12 (14.0%) patients underwent surgery for malignant diseases. We have analyzed incidence of thromboembolic and hemorrhagic events and compliance of perioperative ACT modes with current international guidelines.

RESULTS

Thromboembolic and hemorrhagic events developed in 14 (16.3%) patients. Thromboembolic complications were noted in 6 (7.0%) patients, hemorrhagic events - in 8 (9.3%) cases. Maximum complication rate was observed in case of bridge-therapy (n=12, 20.0%). Cancellation of ACT was followed by 2 (9.5%) complications, bridge-therapy - by 4 (6.7%) thromboembolic complications. Hemorrhagic events were 2 times more common in case of this therapy (n=8, 13.3%). It was found that ESC guidelines for perioperative ACT were applied in less than half of patients (41, 47.7% patients with AF undergoing elective surgery). Half of complications (8 out of 16) occurred if unapproved modes of ACT were used (including 7 cases of bridge-therapy was not necessary). The causes of these complications were inadequate assessment of perioperative risk of thromboembolic and hemorrhagic events; unreasonable administration of bridge therapy.

CONCLUSION

An unambiguous clinical effect of bridge therapy has not been confirmed in patients with high risk of thromboembolic complications. Cancer patients have higher risk of complications compared with others. These events occur mainly due to non-compliance with clinical guidelines and insufficient prevention of thromboembolic events.

Warfarin in nonvalvular atrial fibrillation-Time for a change?

Warfarin is the most commonly prescribed anticoagulant in hemodialysis (HD) patients with nonvalvular atrial fibrillation (NVAF). Recent trends show that Nephrologists are increasingly prescribing novel oral anticoagulants, despite the fact that no randomized clinical trials have been conducted in dialysis patients. Difficulties maintaining international normalized ratio in the therapeutic range, increased risk of intracranial hemorrhage and concerns regarding warfarin-induced vascular calcification and calciphylaxis may be responsible. Anticoagulation quality is poor in HD patients. A variety of factors contribute to this: increased antibiotic exposure; comorbid illness; decreased adherence and vitamin K deficiency. Attempts to address this with standardized protocols have been uniformly unsuccessful. In nonadherent patients, thrice weekly observed therapy improved quality. Low-dose vitamin K supplementation improves time in the therapeutic range (TTR) in those with normal kidney function and should be studied in HD patients given their high frequency of vitamin K deficiency. Vascular and valvular calcification associated with warfarin could result from reduced carboxylation of matrix Gla protein (MGP), a well-known inhibitor of vascular calcification. Multiple observational studies also link calciphylaxis to warfarin; warfarin-induced hypercoagulability and decreased carboxylation of MGP could explain this. A large observational study, two meta-analyses, and a systematic review in HD patients with NVAF showed reduced bleeding with apixaban compared to warfarin with similar efficacy in reducing stroke and systemic embolism. Given these results, apixaban is a reasonable alternative to warfarin for anticoagulation of HD patients with NVAF, especially in those with low TTR, until data from randomized clinical trials become available.

Influence of andrographolide on the pharmacokinetics of warfarin in rats

CONTEXT

Andrographolide and warfarin are often used together in clinics in China. However, the herb-drug interaction between andrographolide and warfarin is still unknown.

OBJECTIVE

This study investigates the herb-drug interaction between andrographolide and warfarin in vivo and in vitro.

MATERIALS AND METHODS

A sensitive and reliable LC-MS/MS method was developed for the determination of warfarin in male Sprague-Dawley rats plasma, and then the pharmacokinetics of orally administered warfarin (0.5 mg/kg) with or without andrographolide (30 mg/kg/day for 7 days) pretreatment was investigated. In addition, Sprague-Dawley rat liver microsomes incubation systems were used to support the in vivo pharmacokinetic data and investigate its potential mechanism.

RESULTS

The method validation results showed that a sensitive and reliable LC-MS/MS method was developed for the determination of warfarin in rat plasma samples. The pharmacokinetic results indicated that co-administration of andrographolide could increase the systemic exposure of warfarin significantly, including area under the curve (118.92 ± 18.08 vs. 60.58 ± 9.46 μg × h/mL), maximum plasma concentration (3.32 ± 0.41 vs. 2.35 ± 0.25 μg/mL) and t_1/2 (22.73 ± 3.28 vs. 14.27 ± 2.67 h). Additionally, the metabolic stability of warfarin increased from 23.5 ± 4.7 to 38.7 ± 6.1 min with the pretreatment of andrographolide, and the difference was significant (p < 0.05).

DISCUSSION AND CONCLUSION

In conclusion, andrographolide could increase the systemic exposure of warfarin in rats when andrographolide and warfarin were co-administered, and possibly by slowing down the metabolism of warfarin in rat liver by inhibiting the activity of CYP3A4 or CYP2C9.

One-year risks of stroke and mortality in patients with atrial fibrillation from different clinical settings: The Gulf SAFE registry and Darlington AF registry

BACKGROUND

Differences exist in oral anticoagulation (OAC) use between different populations with atrial fibrillation (AF), which may be associated with varying outcomes.

PURPOSE

We aimed to provide patient level comparisons of two cohorts of patients with AF, from the United Kingdom (UK) and Middle East (ME).

METHODS

The clinical characteristics, prescription of OAC, one-year risk of stroke and mortality were compared between individual patients with AF included into the Darlington AF registry (UK, n = 2258) and the Gulf SAFE (Survey of atrial fibrillation events) registry (ME, n = 1740).

RESULTS

A high percentage of patients from the Darlington registry were candidates for OAC (i.e., CHA₂DS₂-VASc score ≥2 in males or ≥3 in females; 82.0% in Darlington and 57.1% in Gulf SAFE). OAC use was suboptimal (52.0% in Darlington vs 58.4% in Gulf SAFE). One-year rates of stroke and mortality were high in both populations, especially in those with CHA₂DS₂-VASc score ≥2 in males and ≥3 in females (Darlington vs. Gulf SAFE: 3.51% vs. 5.63 for stroke; 11.4% vs. 16.8% for mortality). On multivariate analyses, female sex and previous stroke were independently associated with stroke events; while elderly age, female sex, vascular disease and heart failure were independent risk factors for mortality (all p < 0.05). Patients from Gulf SAFE registry had higher risk of stroke (odds ratio, 2.18 [1.47-3.23]) and mortality (odds ratio, 1.67 [1.31-2.14]) compared with those from Darlington registry. The CHA₂DS₂-VASc score showed good discrimination in predicting one-year risk of stroke (area under curve, 0.71 [0.65-0.76] in non-anticoagulated patients) and mortality (area under curve, 0.70 [0.68-0.72]) in the whole study population, as well as in Darlington or Gulf SAFE registry separately.

CONCLUSIONS

Stroke prevention was generally suboptimal in patient cohorts from the two registries, which was associated with high one-year risks of stroke and mortality, particularly so among patients from the Gulf SAFE registry. The higher risks for stroke and mortality in AF patients from the Gulf SAFE registry (compared to a UK cohort) merit further implementation of cardiovascular prevention strategies.

COMPARISON OF SCHEMES OF PERIOPERATIONAL ANTICOAGULATION IN ATRIAL FIBRILLATION PATIENTS DEMANDING FOR SURGERY

A literature review provided, on the usage of various schemes of perioperational anticoagulation therapy (ACT) in atrial fibrillation patients undergoing scheduled surgery. It is noted that clinicians quite often pass through a situation when patients taking ACT require invasive investigations and surgery. Perioperational management of such category of patients is complicated as, on the one hand, the surgery under ACT is associated with intraoperational hemorrhagic complications, and, on the other hand, ACT cessation might increase the risk of thrombotic complications. The variants assessed, of different periprocedural ACT in patients taking vitamin K antagonists. It was found that as an alternative to continuous ACT recently, bridge therapy with low molecular weight heparins applied, aiming the decrease of the risk of bleeding in adequate thromboprophylaxis. The results of clinical trials provided on the assessment of bridge therapy in surgery. Risk stratification approaches presents for thromboembolic and hemorrhagic complications in surgery.