New Insights into the Pros and Cons of the Clinical Use of Vitamin K Antagonists (VKAs) Versus Direct Oral Anticoagulants (DOACs)

Vitamin K for Vascular Calcification in Kidney Patients: Still Alive and Kicking, but Still a Lot to Learn

Patients with chronic kidney disease (CKD) suffer disproportionately from a high burden of cardiovascular disease, which, despite recent scientific advances, remains partly understood. Vascular calcification (VC) is the result of an ongoing process of misplaced calcium in the inner and medial layers of the arteries, which has emerged as a critical contributor to cardiovascular events in CKD. Beyond its established role in blood clotting and bone health, vitamin K appears crucial in regulating VC via vitamin K-dependent proteins (VKDPs). Among these, the matrix Gla protein (MGP) serves as both a potent inhibitor of VC and a valuable biomarker (in its inactive form) for reflecting circulating vitamin K levels. CKD patients, especially in advanced stages, often present with vitamin K deficiency due to dietary restrictions, medications, and impaired intestinal absorption in the uremic environment. Epidemiological studies confirm a strong association between vitamin K levels, inactive MGP, and increased CVD risk across CKD stages. Based on the promising results of pre-clinical data, an increasing number of clinical trials have investigated the potential benefits of vitamin K supplementation to prevent, delay, or even reverse VC, but the results have remained inconsistent.

Michael Acceptors as Anti-Cancer Compounds: Coincidence or Causality?

Michael acceptors represent a class of compounds with potential anti-cancer properties. They act by binding to nucleophilic sites in biological molecules, thereby disrupting cancer cell function and inducing cell death. This mode of action, as well as their ability to be modified and targeted, makes them a promising avenue for advancing cancer therapy. We are investigating the molecular mechanisms underlying Michael acceptors and their interactions with cancer cells, in particular their ability to interfere with cellular processes and induce apoptosis. The anti-cancer properties of Michael acceptors are not accidental but are due to their chemical structure and reactivity. The electrophilic nature of these compounds allows them to selectively target nucleophilic residues on disease-associated proteins, resulting in significant therapeutic benefits and minimal toxicity in various diseases. This opens up new perspectives for the development of more effective and precise cancer drugs. Nevertheless, further studies are essential to fully understand the impact of our discoveries and translate them into clinical practice.

Comparative effectiveness of factor Xa non-vitamin K antagonist oral anticoagulants versus phenprocoumon in patients with non-valvular atrial fibrillation

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) have largely supplanted vitamin K antagonists (VKAs) for oral anticoagulation in non-valvular atrial fibrillation (NVAF). However, data on the real-world effectiveness of NOACs vs. phenprocoumon, a VKA widely used in Germany, are limited. The RELOADED study aimed to compare effectiveness of factor Xa NOACs and phenprocoumon in NVAF in clinical practice.

METHODS

Patients who started on a factor Xa NOAC or phenprocoumon for NVAF during the study period were enrolled from the Institute for Applied Healthcare Research Berlin. Patients were followed from first prescription until the end of exposure or available data. Primary outcomes were analyzed by Cox proportional hazard regression models and included ischemic stroke and systemic embolism for effectiveness, and intracranial hemorrhage (ICH) for safety. Subgroups of interest were patients with diabetes and patients with renal impairment.

RESULTS

The total study population was 64,920; 36.3% of patients initiated phenprocoumon, 34.4% initiated rivaroxaban, 25.0% apixaban, and 4.4% edoxaban. Treatment with phenprocoumon is associated with a similar risk of ischemic stroke/systemic embolism as treatment with rivaroxaban or apixaban; while rivaroxaban (adjusted hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.43-0.75) and apixaban (adjusted HR 0.43, 95% CI 0.31-0.6) were associated with a lower risk of ICH compared to phenprocoumon in NVAF patients. The use of rivaroxaban and apixaban was associated with a lower risk of developing kidney failure in patients with diabetes or renal impairment in comparison to those treated with phenprocoumon.

CONCLUSION

The factor Xa NOACs rivaroxaban and apixaban demonstrated similar effectiveness and lower rates of ICH compared with phenprocoumon in this study.

Effect of direct oral anticoagulant dabigatran on early bone healing: An experimental study in rats

Background

Dabigatran belongs to the new generation of direct oral anticoagulants (DOACs). Its advantages are oral administration and no need for international normalized ratio (INR) monitoring. Although its use has increased, its potential side effects on bone healing and remodeling have not been fully investigated. The present study aimed to evaluate the possible effects of dabigatran on early bone healing.

Methods

Sixteen male Wistar rats were divided into two groups; in group A, 20-mg/kg dabigatran dose was administered orally daily for 15 days, while group B served as a control. Two circular bone defects (d=6 mm) were created on either side of the parietal bones. Two weeks after surgery and euthanasia of the animals, tissue samples (parietal bones that contained the defects) were harvested for histological and histomorphometric analysis. Statistical analysis was performed with a significance level of α=0.5.

Results

No statistically significant differences were found between the two groups regarding the regenerated bone (21.9% vs. 16.3%, P=0.172) or the percentage of bone bridging (63.3% vs. 53.5%, P=0.401).

Conclusion

Dabigatran did not affect bone regeneration, suggesting that it might be a safer drug compared to older anticoagulants known to lead to bone healing delay.

How I approach the prevention and treatment of thrombotic complications in hospitalized patients

This article uses case-based discussion to review prevention and management of thrombotic problems in hospitalized patients that involve a clinical hematologist. There is variation in the clinical hematologist's role in thrombosis practice throughout the world, and we discuss this where indicated. Hospital-associated venous thromboembolism (VTE), or hospital-associated thrombosis (HAT), is the term to cover VTE occurring during admission and for 90 days postdischarge and is a common patient safety problem. HATs are the most common cause of VTE accounting for 55% to 60% of all VTE, with an estimated 10 million occurring globally. VTE risk assessment alongside evidence-based thromboprophylaxis reduces this risk significantly. Many hospitalized patients, especially older patients, use direct oral anticoagulants (DOACs), mainly to prevent stroke in atrial fibrillation. DOACs require perioperative management and may need urgent reversal. Other complex interventions such as extracorporeal membrane oxygenation which require anticoagulation are also discussed. Lastly, those with uncommon high-risk thrombophilias, especially those with antithrombin deficiency, produce unique challenges when hospitalized.

Elzeftawy M, Abdelazeem B. The efficacy and safety of direct factor Xa inhibitors versus vitamin K antagonists for atrial fibrillation in patients on hemodialysis: a meta-analysis of randomized controlled trials

Background

Direct factor Xa inhibitors have been extensively prescribed for multiple indications; however, hemodialysis patients have been excluded from most of the randomized controlled trials (RCTs) of direct factor Xa inhibitors. Therefore, the efficacy and safety of direct factor Xa inhibitors versus vitamin K antagonists (VKAs) in hemodialysis patients is uncertain.

Methods

A systematic review and meta-analysis of RCTs was conducted by systematically searching PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane through November 25, 2022. We used the fixed-effect model to pool the risk ratio (RR) with a 95% confidence interval (CI). RevMan v5.4 software was used to pool dichotomous outcomes using RR and continuous outcomes using mean difference presented with the corresponding CI.

Results

Three RCTs with a total of 341 patients were included in our analysis. There was no difference between direct factor Xa inhibitors and VKAs regarding all-cause mortality (RR, 0.99; 95% CI [0.76, 1.30]; P = 0.96), cardiovascular mortality (RR, 1.35; 95% CI [0.71, 2.60]; P = 0.36), noncardiovascular mortality (RR, 0.75; 95% CI [0.53, 1.05]; P = 0.09), sudden mortality (RR, 1.33; 95% CI [0.53, 3.33]; P = 0.54), any cerebrovascular event (RR, 0.52; 95% CI [0.21, 1.29]; P = 0.16), ischemic stroke (RR, 0.51; 95% CI [0.19, 1.37]; P = 0.18), and hemorrhagic stroke (RR, 0.61; 95% CI [0.10, 3.70]; P = 0.59).

Conclusion

In patients with atrial fibrillation who are on hemodialysis, direct factor Xa inhibitors and VKAs were similar in terms of efficacy and safety outcomes. However, evidence is still sparse, warranting dedicated RCTs.

Effect of Genotype on the Pharmacokinetics and Bleeding Events of Direct Oral Anticoagulants: A Systematic Review and Meta-analysis

This meta-analysis aimed to investigate the effect of the genotype on the pharmacokinetics and bleeding events of direct oral anticoagulants (DOACs) and comprehensively searched electronic databases. Weighted mean difference (WMD) was used to assess the kinetic indicators, odds ratio, and 95% confidence interval (CI) were used to calculate the clinical outcomes. Thirteen articles with 1543 participants were finally included in this study. The peak concentration (C_max ) and area under the plasma concentration-time curve from time 0 to infinity of individuals with the ABCB1 rs 1045642 CT + TT were higher than that of the CC (WMD = -31.9, 95% CI [-49.94, -12.24], P = .02; WMD = -79.97, 95%CI [-152.38 to -7.56], P = .03, I² = 0). The C_max of individuals with mutated genes in ABCB1 2677-3435 is higher than that the wild type (WMD = -19.20, 95%CI [36.62 to -1.79], P = .03, I² = 0). Carriers of the CYP3A5 rs776746 GG genotype had a higher C_max than the GA gene (WMD = -51.22, 95%CI [-92.26 to -10.19], P = .01, I² = 0). Bleeding events were more common in the CES1 rs 2244613 AA + AC than in the CC (odds ratio, 2.62, 95%CI [1.06, 6.47], P = .04; I² = 0). The C_max of DOACs was affected by individuals with ABCB1 rs 1045642, ABCB1 2677-343, and cytochrome P450 3A5 rs 776746. Carriers of the ABCB1 rs 1045642 affected the change of area under the plasma concentration-time curve from time 0 to infinity of DOACs. Bleeding events were affected by CES1 rs 2244613.

Evidence-based Management of Major Bleeding in Patients Receiving Direct Oral Anticoagulants: An Updated Narrative Review on the Role of Specific Reversal Agents

The indications of direct oral anticoagulants (DOACs) have expanded over the past 15 years. DOACs are effective and safe oral anticoagulants associated with lower bleeding risks and mortality than vitamin K antagonists. However, DOAC users are prone to a considerable bleeding risk, which can occur at critical sites or lead to severe life-threatening conditions. Recent statistics indicated that major bleeding occurs in up to 6.62 DOAC users per 100 treatment years. With the increased use of DOACs in clinical practice, DOAC-associated major bleeding is expected to be encountered more frequently in the emergency department. The current international guidelines recommend specific reversal agents for the management of DOAC users with severe bleeding to reverse the anticoagulant effect and restore normal hemostasis. An individualized assessment was incorporated in specific clinical situations to guide the decision pathway of major bleeding management. However, specific reversal agents are unavailable or have limited availability in many countries, which is expected to negatively impact the clinical outcomes of DOAC-associated major bleeding. Limited real-world evidence is available from these countries regarding the clinical outcomes of patients with DOAC-associated major bleeding. This narrative review provided an updated assessment of the evidence-based approaches for the management of major bleeding in DOAC users. We also explored the clinical outcomes of patients with major bleeding from clinical settings where specific reversal agents are unavailable.

Gerinnungsmanagement in der schweren, fortgeschrittenen Niereninsuffizienz

Patienten mit chronischer Niereninsuffizienz (CKD) haben ein hohes Risiko für nicht valvuläres Vorhofflimmern (NVAF) und häufig ein höheres Risiko für venöse Thromboembolien (VTE) aufgrund ihrer Grunderkrankungen wie z. B. Diabetes. Bisher kamen Vitamin-K-Antagonisten (VKA) auch bei diesen Patienten in Deutschland zum Einsatz. VKA haben ein erhöhtes Blutungsrisiko und werden als Risikofaktor für eine Verschlechterung der Nierenfunktion und/oder Gefäßsituation (Athero- und Mediasklerose) von Patienten diskutiert. Aus diesen Gründen und den vorliegenden Studiendaten werden deshalb direkt wirkende orale Antikoagulanzien (DOAC) auch bei Patienten mit NVAF und CKD (G1–G3) in den Leitlinien empfohlen. Allerdings kann keine klare Empfehlung für den Einsatz von DOAC bei Dialysepatienten gegeben werden. Heparine spielen in diesem Zusammenhang nur eine untergeordnete Rolle.

Clinical significance of the series of CYP2C9*non3 variants, an unignorable predictor of warfarin sensitivity in Chinese population

Backgrounds

Gene polymorphisms are critical for variations in warfarin dose. To date, more than 70 CYP2C9 alleles have been identified. This study was designed to clarify the clinical significance of CYP2C9*non-3 variants to warfarin sensitivity in Chinese Han patients.

Methods

The entire CYP2C9 gene region was sequenced in 1,993 individuals, and clinical data and VKORC1 genotypes were collected from 986 patients with atrial fibrillation treated with warfarin. The SKAT-O method was used to analyze the effects of CYP2C9*non-3 variants on warfarin sensitivity.

Results

A total of 20 CYP2C9 variants were identified, of which four were novel. Carriers with CYP2C9*non-3 variants may have lower warfarin dose requirements, and similar to CYP2C9*3, CYP2C9*non-3 variants are clearly relevant to warfarin-sensitive and highly sensitive responders.

Conclusion

Our results showed that, besides CYP2C9*3, the series of CYP2C9*non-3 variants is an unignorable predictor for warfarin sensitivity in Chinese population. From a safety consideration, people carried such variants may need a preferred choice of NOACs when they started anticoagulation therapy.

Acute Kidney Injury in Patients with Non-Valvular Atrial Fibrillation Treated with Rivaroxaban or Warfarin: A Population-Based Study from the United Kingdom

PURPOSE

To compare the risk of acute kidney injury (AKI) among users of rivaroxaban vs warfarin.

PATIENTS AND METHODS

We identified two cohorts of patients with non-valvular atrial fibrillation (NVAF) who initiated rivaroxaban (15/20 mg/day, N = 6436) or warfarin (N = 7129) excluding those without estimated glomerular filtration rate values recorded in the year before oral anticoagulant (OAC) initiation and those with a history of end-stage renal disease or AKI. We used two methods to define AKI during follow-up (mean 2.5 years): coded entries (method A) and the Aberdeen AKI phenotyping algorithm (method B) using recorded renal function laboratory values during the study period to identify a sudden renal deterioration event. Cox regression was used to calculate hazard ratios (HRs) for AKI with rivaroxaban vs warfarin use, adjusted for confounders.

RESULTS

The number of identified incident AKI cases was 249 (method A) and 723 (method B). Of the latter, 104 (14.4%) were also identified by method A. After adjusting for age, sex, baseline renal function and comorbidity, HRs (95% CIs) for AKI were 1.19 (0.92-1.54; p=0.18) using method A and 0.80 (0.68-0.93; p<0.01) using method B. Estimates stratified by baseline level of chronic kidney disease were largely consistent with the main estimates.

CONCLUSION

Our results support a beneficial effect of rivaroxaban over warfarin in terms of AKI occurrence in patients with NVAF. More research into how best to define AKI using primary care records would be valuable for future studies.

Impact of CYP2C19 gene polymorphisms on warfarin dose requirement: a systematic review and meta-analysis

Background: Various genetic factors influence warfarin maintenance dose. Methods: A literature search was performed on PubMed, Embase and the Cochrane Library, and a meta-analysis to analyze the impact of CYP2C19 polymorphisms on warfarin maintenance dose was conducted. Results: From nine studies encompassing 1393 patients, three CYP2C19 SNPs were identified: rs4244285, rs4986893 and rs3814637. Warfarin maintenance dose was significantly reduced by 10% in individuals with the rs4986893 A allele compared with the GG carriers and was 34%, 16% and 18% lower in patients with rs3814637 TT and CT genotypes and T allele, respectively, than that in CC carriers. No significant dose difference was observed among the rs4244285 genotypes. Conclusion: CYP2C19 rs4986893 and rs3814637 are associated with significantly reduced warfarin dose requirements.

Managing thrombotic risk in patients with diabetes

It is well known that diabetes is a prominent risk factor for cardiovascular (CV) events. The level of CV risk depends on the type and duration of diabetes, age and additional co-morbidities. Diabetes is an independent risk factor for atrial fibrillation (AF) and is frequently observed in patients with AF, which further increases their risk of stroke associated with this cardiac arrhythmia. Nearly one third of patients with diabetes globally have CV disease (CVD). Additionally, co-morbid AF and coronary artery disease are more frequently observed in patients with diabetes than the general population, further increasing the already high CV risk of these patients. To protect against thromboembolic events in patients with diabetes and AF or established CVD, guidelines recommend optimal CV risk factor control, including oral anticoagulation treatment. However, patients with diabetes exist in a prothrombotic and inflammatory state. Greater clinical benefit may therefore be seen with the use of stronger antithrombotic agents or innovative drug combinations in high-risk patients with diabetes, such as those who have concomitant AF or established CVD. In this review, we discuss CV risk management strategies in patients with diabetes and concomitant vascular disease, stroke prevention regimens in patients with diabetes and AF and how worsening renal function in these patients may complicate these approaches. Accumulating evidence from clinical trials and real-world evidence show a benefit to the administration of non-vitamin K antagonist oral anticoagulants for stroke prevention in patients with diabetes and AF.

Vitamin K antagonists and cardiovascular calcification: A systematic review and meta-analysis

Background

Many patients treated with Vitamin K antagonists (VKA) for anticoagulation have concomitant vascular or valvular calcification. This meta-analysis aimed to evaluate a hypothesis that vascular and valvular calcification is a side-effect of VKA treatment.

Methods

We conducted a systematic literature search to identify studies that reported vascular or valvular calcification in patients treated with VKA. The associations between VKA use and calcification were analyzed with random-effects inverse variance models and reported as odds ratios (OR) and 95% confidence intervals (95% CI). In addition, univariate meta-regression analyses were utilized to identify any effect moderators.

Results

Thirty-five studies were included (45,757 patients; 6,251 VKA users). The median follow-up was 2.3 years [interquartile range (IQR) of 1.2–4.0]; age 66.2 ± 3.6 years (mean ± SD); the majority of participants were males [77% (IQR: 72–95%)]. VKA use was associated with an increased OR for coronary artery calcification [1.21 (1.08, 1.36), p = 0.001], moderated by the duration of treatment [meta-regression coefficient B of 0.08 (0.03, 0.13), p = 0.0005]. Extra-coronary calcification affecting the aorta, carotid artery, breast artery, and arteries of lower extremities, was also increased in VKA treated patients [1.86 (1.43, 2.42), p < 0.00001] and moderated by the author-reported statistical adjustments of the effect estimates [B: −0.63 (−1.19, −0.08), p = 0.016]. The effect of VKA on the aortic valve calcification was significant [3.07 (1.90, 4.96), p < 0.00001]; however, these studies suffered from a high risk of publication bias.

Conclusion

Vascular and valvular calcification are potential side effects of VKA. The clinical significance of these side effects on cardiovascular outcomes deserves further investigation.

Worsening of kidney function in patients with atrial fibrillation and chronic kidney disease: evidence from the real-world CALLIPER study

OBJECTIVE

Evidence is needed on the impact of anticoagulation therapy on kidney function in patients with atrial fibrillation (AF). The objective of this analysis, which is part of the CALLIPER study, was to investigate the risk of worsening kidney function with rivaroxaban 15 mg once daily compared with warfarin in patients with AF and moderate-to-severe chronic kidney disease (CKD) in routine clinical practice in the United States.

METHODS

CALLIPER was an observational, retrospective, new-user cohort study. Adult patients with AF in the US IBM Watson MarketScan databases who newly initiated anticoagulation with rivaroxaban 15 mg once daily or warfarin between January 2013 and December 2017 were included. Comparative analysis was performed using Cox proportional hazards regression after adjustment for potential confounding by the stabilized inverse probability of treatment weighting approach and propensity score matching. One of the main study outcomes was worsening kidney function (composite of progression to CKD stage 5, kidney failure, or need for dialysis), besides traditional AF-related outcomes.

RESULTS

The cohort included 7368 patients: 5903 (80.1%) initiating warfarin and 1465 (19.9%) initiating rivaroxaban 15 mg once daily. Rivaroxaban 15 mg was associated with a significant 47% reduction in the risk of worsening kidney function versus warfarin (hazard ratio 0.53; 95% confidence interval 0.35-0.78). Similar results were observed in the subgroup of patients with type 2 diabetes.

CONCLUSIONS

Rivaroxaban 15 mg may be associated with a lower risk of worsening kidney function as compared with warfarin in the atrial fibrillation population with moderate-to-severe CKD.

TRIAL REGISTRATION NUMBER

NCT03359876.

[Safety and effectiveness of oral anticoagulation in patients with atrial fibrillation and renal insufficiency - a real-world perspective]

Non-vitamin-K dependent oral anti-coagulants (NOAC) are the current therapeutic standard for preventing strokes in patients with atrial fibrillation (AF) and should be preferred over vitamin K antagonists (VKA) in this indication. This recommendation applies also to patients with VHF and concomitant chronic kidney disease (CKD). Real World Evidence (RWE), i. e., structured data from clinical practice, extends and confirms the clinical evidence generated in more formalized clinical trials with NOAC and VKA. In addition, RWE in respect to the indication showed that the superiority of NOAC versus the VKA warfarin can also be extrapolated to phenprocoumon, the commonly used VKA in Germany. Furthermore, data include evidence that the typical progression of CKD appears to be less pronounced in individuals treated with NOAC compared to those treated with VKA.

The Connubium among diabetes, chronic kidney disease and atrial fibrillation

The burden of cardiovascular comorbid conditions was significantly higher in patients with Atrial Fibrillation (AF); most of them are affected by hypertension, Chronic Kidney Disease (CKD) and/or Diabetes Mellitus (DM). DM represents a well-known risk factor for the development and maintenance of AF; the coexistence of DM and AF is also associated with an increased risk of mortality and stroke. Moreover, DM is currently the main cause of renal impairment and the leading cause of dialysis in the world. The hyperglycemia is responsible for inducing redox imbalance and both systemic and intrarenal inflammation, playing a critical role in the pathogenesis of diabetic kidney disease. Long-term thromboembolic preventive therapy in AF patients with DM and CKD may be more challenging because both DM and CKD have been independently associated with an increased thromboembolic and bleeding risk, which results from the prothrombotic and pro-inflammatory status. Vitamin K Antagonists (VKAs) are characterized by numerous critical issues such as a narrow therapeutic window, increased tissue calcification and an unfavourable risk/benefit ratio with low stroke prevention effect and augmented risk of major bleeding. On the other hand, Direct Oral Anticoagulants (DOACs) are currently contraindicated in dialysis patients even if mounting evidence suggests that they may have a nephroprotective role in AF patients with DM and CKD. Consequently, the choice of anticoagulant therapy in this setting of patient seems to be very challenging. The aim of this review is to investigate the role of DOACs in diabetic patients and its nephroprotective role by reviewing the current literature.

Renal decline in patients with non-valvular atrial fibrillation treated with rivaroxaban or warfarin: A population-based study from the United Kingdom

BACKGROUND

Reports suggest that renal decline is greater among patients with non-valvular atrial fibrillation (NVAF) treated chronically with warfarin vs. some non-vitamin K antagonist oral anticoagulants.

METHODS AND RESULTS

Using primary care electronic health records from the United Kingdom we followed adults with NVAF and who started rivaroxaban (20 mg/day, N = 5338) or warfarin (N = 6314), excluding those with estimated glomerular filtration rate (eGFR) <50 ml/min/1.73m², end-stage renal disease (ESRD) or no eGFR or serum creatinine (SCr) values recorded in the previous year. Outcomes were: doubling SCr levels, ≥30% decline in eGFR and progression to ESRD. We calculated adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for each outcome. Average eGFR slope was estimated using mixed model regression. After a mean follow-up 2.5 years, the number of incident cases of adverse renal events within the two cohorts was: doubling SCr (n = 322), ≥30% decline in eGFR (n = 1179), and progression to ESRD (n = 22). Adjusted HRs (95% CIs) for the renal outcomes among rivaroxaban vs. warfarin users were: doubling SCr, 0.63 (0.49-0.81); ≥30% decline in eGFR, 0.76 (0.67-0.86); ESRD, 0.77 (0.29-2.04). Similar results were observed among patients with diabetes or heart failure. Estimated mean decline in renal function over the study period was 2.03 ml/min/1.73 m²/year among warfarin users and 1.65 ml/min/1.73 m²/year among rivaroxaban users (p = 0.03).

CONCLUSIONS

We found clear evidence that patients with NVAF, preserved renal function at baseline and treated with rivaroxaban had a markedly reduced risk and rate of renal decline compared with those treated with warfarin.

Overexpression of protein disulfide isomerase enhances vitamin K epoxide reductase activity

Vitamin K epoxide reductase (VKOR) activity is catalyzed by the VKORC1 enzyme. It is the target of vitamin K antagonists (VKA). Numerous mutations of VKORC1 have been reported and have been suspected to confer resistance to VKA and/or affect its velocity. Nevertheless, the results between studies have been conflicting, the functional characterization of these mutations in a cell system being complex due to the interweaving of VKOR activity in the vitamin K cycle. In this study, a new cellular approach was implemented to globally evaluate the vitamin K cycle in the HEK293 cells. This global approach was based on the vitamin K quinone/vitamin K epoxide (K/KO) balance. In the presence of VKA or when the VKORC1/VKORC1L1 were knocked out, the K/KO balance decreased significantly due to an accumulation of vitamin KO. On the contrary, when VKORC1 was overexpressed, the balance remained unchanged, demonstrating a limitation of the VKOR activity. This limitation was shown to be due to an insufficient expression of the activation partner of VKORC1, as overexpressing the protein disulfide isomerase (PDI) overcomes the limitation. This study is the first to demonstrate a functional interaction between VKORC1 and the PDI enzyme.

The impact on renal function after long-term use of anticoagulants in atrial fibrillation patients

OBJECTIVE

Long-term oral anticoagulant should be considered or recommended in patients with atrial fibrillation (AF) and CHA2DS2VASc score ≥ 1 for stroke prevention. Warfarin and different direct oral anticoagulants (DOACs) are metabolized differently by the kidney. The impact on renal function after long-term use of anticoagulants in the patients with AF remains unclear. This study aimed to compare DOACs and warfarin's impact on the decline in renal function from a large cohort with AF.

METHODS

This study included patients with nonvalvular AF from 2000 to 2018, mainly through the medical history (ICD code) of the Chang Gung Research Database. Baseline estimated glomerular filtration rate (eGFR), follow-up eGFR and the change in eGFR between 2-year eGFR and baseline eGFR were compared between different DOACs and warfarin after propensity score matching. The primary study endpoint was acute kidney injury (AKI).

RESULTS

3657 patients were enrolled in this study and the mean observation time was 3.3 ± 0.9 years. During the observation period, there was a significantly higher incidence of AKI during follow-up in the warfarin group than in the different DOAC groups before and after propensity score matching (before: warfarin vs. DOAC: 9.2% vs. 5.2%, p <  0.001; after: warfarin vs. DOAC: 8.9% vs. 4.4%, p <  0.001). There was no difference in the incidence of AKI between dabigatran group and anti-factor Xa inhibitor group after propensity score matching. The incidence of AKI was similar among rivaroxaban, apixaban and edoxaban groups after propensity score matching. The change in eGFR between 2-year eGFR and baseline eGFR did not differ between the warfarin and DOAC groups after propensity score matching (warfarin vs. DOAC: - 1.27 ± 20.32 vs. -1.94 ± 17.24 mL/min/1.73 m2, p = 0.461).

CONCLUSIONS

During the mean observation time of 3.3 ± 0.9 years, warfarin was associated with a higher incidence of AKI compared with DOACs. The decline in renal function did not differ among warfarin and different DOAC groups.

Medical therapies for prevention of cardiovascular and renal events in patients with atrial fibrillation and diabetes mellitus

Atrial fibrillation (AF), type 2 diabetes mellitus (DM), and chronic kidney disease (CKD) are three global epidemics with significant effects on morbidity and mortality. Diabetes is a risk factor for AF, and a risk factor for thromboembolism, comorbidity, and mortality when AF is present. The pathophysiology of diabetes-related AF and interrelationships with cardiovascular events and renal events is not fully understood but is in part related to structural, electrical, electromechanical, and autonomic remodelling. The current practice guidelines offer limited recommendations on the management of patients with AF (or risk of AF) and diabetes with its own heterogeneity for the prevention of cardiovascular and renal events. This document discusses possible clinical approaches for these patients. In the last decade, there have been major improvements for the prevention of stroke in AF patients with direct oral anticoagulants, which are preferable to vitamin K antagonists for stroke prevention in DM. Because of the increased risk rate for several cardiovascular adverse events in diabetic patients, a similar relative risk reduction generally translates into greater absolute risk reduction in the diabetic population. Recent trials with non-insulin diabetes drugs using glucagon-like peptide-1 agonists and sodium-glucose cotransporter-2 inhibitors showed a significant reduction for the risk of major adverse cardiovascular events in patients with type 2 DM. Sodium-glucose cotransporter-2 inhibitors also showed a large reduction in hospitalization for heart failure and renal events, which need to be more completely evaluated in patients with AF. Mechanisms, risks, and optimal management of AF patients with DM who have or are under risk of developing heart failure or CKD are also discussed in this document. The benefits of medical therapies for these patients still need to be put into perspective, and gaps in evidence on some of these issues are likely to be addressed in future years.

The Effects of Osteoporotic and Non-osteoporotic Medications on Fracture Risk and Bone Mineral Density

Osteoporosis is a highly prevalent bone disease affecting more than 37.5 million individuals in the European Union (EU) and the  United States of America (USA). It is characterized by low bone mineral density (BMD), impaired bone quality, and loss of structural and biomechanical properties, resulting in reduced bone strength. An increase in morbidity and mortality is seen in patients with osteoporosis, caused by the approximately 3.5 million new osteoporotic fractures occurring every year in the EU. Currently, different medications are available for the treatment of osteoporosis, including anti-resorptive and osteoanabolic medications. Bisphosphonates, which belong to the anti-resorptive medications, are the standard treatment for osteoporosis based on their positive effects on bone, long-term experience, and low costs. However, not only medications used for the treatment of osteoporosis can affect bone: several other medications are suggested to have an effect on bone as well, especially on fracture risk and BMD. Knowledge about the positive and negative effects of different medications on both fracture risk and BMD is important, as it can contribute to an improvement in osteoporosis prevention and treatment in general, and, even more importantly, to the individual's health. In this review, we therefore discuss the effects of both osteoporotic and non-osteoporotic medications on fracture risk and BMD. In addition, we discuss the underlying mechanisms of action.

[Features of anticoagulant therapy of atrial fibrillation in combination with impaired renal function]

This review focuses on issues of anticoagulant therapy in patients with atrial fibrillation (AF) associated with chronic kidney disease (CKD). Such patients are at high risk of stroke whereas the choice of an anticoagulant is difficult. A wealth of information about a negative effect of warfarin on the kidney function has accumulated. A need for an alternative therapy to warfarin for patients with stage 3-4 CKD has become imminent. In this regard, rivaroxaban seems to be an appropriate replacement for warfarin in such patients. In randomized, controlled studies that evaluated the efficacy of direct oral anticoagulants in comparison with warfarin, the efficacy and safety profile of a "kidney" dose in moderate disorders of kidney function has been studied only for rivaroxaban. Moreover, both randomized, controlled studies and studies performed in the conditions of clinical practice, have demonstrated a more favorable effect of rivaroxaban on kidney function compared to warfarin. Patients with AF associated with CKD require a comprehensive protection, which, according to results of clinical studies, may be provided by rivaroxaban.

Kidney, limb and ophthalmic complications, and death in patients with nonvalvular atrial fibrillation and type 2 diabetes prescribed rivaroxaban or warfarin: an electronic health record analysis

BACKGROUND

Patients with nonvalvular atrial fibrillation (NVAF) and type 2 diabetes are at risk of kidney, limb, and ophthalmic complications. We evaluated the rate of these complications and death in patients with NVAF and type 2 diabetes prescribed rivaroxaban or warfarin.

METHODS

We analyzed Optum de-Identified electronic health record (EHR) data from 11/2010-12/2019. We included adults with NVAF and T2D newly initiated on rivaroxaban or warfarin with ≥12 months of prior EHR activity. Patients with another indication for anticoagulation, valve disease, history of end-stage renal disease, major adverse limb events (MALE), diabetic retinopathy or pregnancy were excluded. We evaluated the incidence rate of developing a composite outcome of >40% decrease in estimated glomerular filtration incidence rate (eGFR) from baseline, eGFR < 15 mL/minute/1.73 m2, need for dialysis or kidney transplant, MALE, diabetic retinopathy or death. Overlap weighting was used to balance baseline characteristics between cohorts while preserving sample size. Hazard ratios with 95% confidence intervals were calculated using propensity score-overlap weighted Cox regression.

RESULTS

We included 24,912 rivaroxaban and 58,270 warfarin users. The mean ± standard deviation (SD) CHA2DS2VASc score was 4.3 ± 1.5 and modified HASBLED score was 1.5 ± 0.8. Thirty percent of rivaroxaban patients were started on 15 mg once daily, with the rest prescribed 20 mg once daily. Warfarin patients had a mean time in therapeutic range of 47 ± 28%. Patients were followed for a mean of 2.89 ± 1.95 years. Rivaroxaban was associated with a reduced hazard of the composite outcome (HR = 0.93, 95%CI = 0.91-0.95; absolute risk reduction = 1.97 events per 1000 patient-years; number needed-to-treat = 51) versus warfarin. Rivaroxaban was also associated with significant reductions in the relative hazard of > 40% decrease in eGFR from baseline (HR = 0.96), need for dialysis or renal transplant (HR = 0.81), and limb revascularization or major amputation (HR = 0.85). Death occurred at a lower incidence rate with rivaroxaban (HR = 0.92, 95%CI = 0.89-0.95).

CONCLUSIONS

Rivaroxaban was associated with reduced incidence rates of kidney and limb complications, and death in NVAF patients with type 2 diabetes compared to warfarin. ClinicalTrials.gov Identifier: NCT04509193.

Vitamin K and cardiovascular complications in CKD patients

Vitamin K, well known for its role in coagulation, encompasses two major subgroups: Vitamin K1 is exclusively synthesized by plants, whereas vitamin K2 mostly originates from bacterial synthesis. Vitamin K serves as a cofactor for the enzyme γ-glutamyl carboxylase, which carboxylates and thereby activates various vitamin K dependent proteins. Several vitamin K-dependent proteins are synthesized in bone but the role of vitamin K for bone health in CKD patients, in particular the prevention of osteoporosis is still not firmly established. Here we focus on another prominent action of vitamin K, in particular vitamin K2, namely the activation of matrix Gla protein (MGP), the most potent inhibitor of cardiovascular calcifications. Multiple observational studies link relative vitamin K deficiency or low intake to cardiovascular calcification progress, morbidity and mortality. Patients with advanced chronic kidney disease (CKD) are particularly vitamin K deficient, in part because of dietary restrictions but possibly also due to impaired endogenous recycling of vitamin K. At the same time this population is characterized by markedly accelerated cardiovascular calcifications and mortality. High dose dietary supplementation with vitamin K2, in particular the most potent form menaquinone-7 (MK7), can potently reduce circulating levels of dephosphorylated uncarboxylated, i.e. inactive MGP in patients with end stage kidney disease. However, despite this compelling data basis, several randomized controlled trials with high dose MK7 supplements in patients with advanced CKD have failed to confirm cardiovascular benefits. Here we discuss potential reasons and solutions for this.

Rivaroxaban vs. warfarin and renal outcomes in non-valvular atrial fibrillation patients with diabetes

AIMS

Vascular calcification is common in diabetic patients. Warfarin has been associated with renovascular calcification and worsening renal function; rivaroxaban may provide renopreservation by decreasing vascular inflammation. We compared the impact of rivaroxaban and warfarin on renal outcomes in diabetic patients with non-valvular atrial fibrillation (NVAF).

METHODS AND RESULTS

Using United States IBM MarketScan data from January 2011 to December 2017, we identified adults with both NVAF and diabetes, newly-initiated on rivaroxaban or warfarin with ≥12-month insurance coverage prior to anticoagulation initiation. Patients with Stage 5 chronic kidney disease (CKD) or undergoing haemodialysis at baseline were excluded. Differences in baseline covariates between cohorts were adjusted using inverse probability-of-treatment weighting (IPTW) based on propensity scores (absolute standardized differences <0.1 achieved for all after adjustment). Outcomes included incidence rates of emergency department/hospital admissions for acute kidney injury (AKI) and the composite of the development of Stage 5 CKD or need for haemodialysis. Patients were followed until an event, index anticoagulant discontinuation/switch, insurance disenrollment, or end-of-data availability. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox regression. We assessed 10 017 rivaroxaban (22.6% received a reduced dose) and 11 665 warfarin users. In comparison to warfarin, rivaroxaban was associated with lower risks of AKI (HR = 0.83, 95% CI = 0.74-0.92) and development of Stage 5 CKD or need for haemodialysis (HR = 0.82, 95% CI = 0.70-0.96). Sensitivity and subgroup analyses had similar effects as the base-case analysis.

CONCLUSION

Rivaroxaban appears to be associated with lower risks of undesirable renal outcomes vs. warfarin in diabetic NVAF patients.

Affinity ultrafiltration and UPLC-HR-Orbitrap-MS based screening of thrombin-targeted small molecules with anticoagulation activity from Poecilobdella manillensis

This study aims to screen potential anticoagulant components from leeches, a representative animal-sourced traditional Chinese medicine using thrombin (THR)-targeted ultrafiltration combined with ultrahigh performance liquid chromatography and high-resolution Orbitrap mass spectrometry (UPLC-HR-Orbitrap-MS). As a result, five small molecules in leech extract were discovered to interact with THR for the first time. Among them, two new compounds were isolated and their structures were identified by IR, HR-MS and NMR data. Furthermore, their THR inhibitory activity was confirmed with IC₅₀ values of 4.74 and 8.31 μM, respectively. In addition, molecular docking analysis showed that the active (catalytic) site of THR might be the possible binding site of the two hits. Finally, reverse screening analysis indicated that LTA4-H, ACE and ALOX5AP were potential anticoagulant targets of the two new compounds. This study will broaden our understanding of the medicinal substance basis in leeches and further contribute to the discovery and development of clinical anticoagulant drugs from leeches.

Arrhythmia Recurrence After Atrial Fibrillation Ablation: Impact of Warfarin vs. Non-Vitamin K Antagonist Oral Anticoagulants

PURPOSE

Both warfarin and non-vitamin K antagonist oral anticoagulants (NOACs) have pleiotropic effects including anti-inflammatory and anti-fibrotic properties. This study aims to explore whether arrhythmia recurrence after AF ablation is influenced by the choice of oral anticoagulant.

METHODS

We retrospectively studied all patients who underwent primary AF ablation between 2011 and 2017 and divided them into two groups according to the anticoagulant used: Warfarin vs. NOACs. The primary endpoint was atrial tachyarrhythmia recurrence after ablation.

RESULTS

Of the 1106 patients who underwent AF ablation in the study period (median age 62.5 years; 71.5% males, 48.2% persistent AF), 697 (63%) received warfarin and 409 (37%) received NOACs. After a median of 26.4 months follow-up, arrhythmia recurrence was noted in 368 patients in warfarin group and 173 patients in NOACs group, with a 1-year recurrence probability of 35% vs. 36% (log rank P = 0.81) and 5-year recurrence probability of 62% vs. 63% (Log rank P = 0.32). However, NOACs use was associated with a higher probability of recurrence (46% for 1 year, 68% for 5 years) in patients with persistent AF compared with those taking warfarin (34% for 1 year, 63% for 5 years; log rank P = 0.01 and P = 0.02 respectively). Multivariate analysis indicated that in patients with persistent AF, use of NOACs was an independent risk factor of atrial tachyarrhythmia recurrence after ablation (HR 1.39, 95% CI 1.07-1.81, P = 0.013).

CONCLUSION

In this large contemporary cohort, overall AF recurrence after ablation was similar with NOACs or warfarin use. However, in patients with persistent AF, NOACs use was associated with a higher probability of arrhythmia recurrence and was an independent risk factor of recurrence at long-term follow-up.

Off-target effects of oral anticoagulants - vascular effects of vitamin K antagonist and non-vitamin K antagonist oral anticoagulant dabigatran etexilate

INTRODUCTION

Vitamin K antagonists (VKA) and non-vitamin K oral antagonist anticoagulants (NOAC) are used in the clinic to reduce risk of thrombosis. However, they also exhibit vascular off-target effects. The aim of this study is to compare VKA and NOAC on atherosclerosis progression and calcification in an experimental setup.

MATERIAL AND METHODS

Female Apoe-/- mice (age 12 weeks) were fed Western-type diet as control or supplemented with dabigatran etexilate or warfarin for 6 or 18 weeks. Vascular calcification was measured in whole aortic arches using µCT and [18 F]-NaF. Atherosclerotic burden was assessed by (immuno)histochemistry. Additionally, in vitro effects of warfarin, thrombin, and dabigatran on primary vascular smooth muscle cells (VSMC) were assessed.

RESULTS

Short-term treatment with warfarin promoted formation of atherosclerotic lesions with a pro-inflammatory phenotype, and more rapid plaque progression compared with control and dabigatran. In contrast, dabigatran significantly reduced plaque progression compared with control. Long-term warfarin treatment significantly increased both presence and activity of plaque calcification compared with control and dabigatran. Calcification induced by warfarin treatment was accompanied by increased presence of uncarboxylated matrix Gla protein. In vitro, both warfarin and thrombin significantly increased VSMC oxidative stress and extracellular vesicle release, which was prevented by dabigatran.

CONCLUSION

Warfarin aggravates atherosclerotic disease activity, increasing plaque inflammation, active calcification, and plaque progression. Dabigatran lacks undesired vascular side effects and reveals beneficial effects on atherosclerosis progression and calcification. The choice of anticoagulation impacts atherosclerotic disease by differential off target effect. Future clinical studies should test whether this beneficial effect also applies to patients.

Astragalin Inhibits Cigarette Smoke-Induced Pulmonary Thrombosis and Alveolar Inflammation and Disrupts PAR Activation and Oxidative Stress-Responsive MAPK-Signaling

Epidemiological evidence shows that smoking causes a thrombophilic milieu that may play a role in the pathophysiology of chronic obstructive pulmonary disease (COPD) as well as pulmonary thromboembolism. The increased nicotine level induces a prothrombotic status and abnormal blood coagulation in smokers. Since several anticoagulants increase bleeding risk, alternative therapies need to be identified to protect against thrombosis without affecting hemostasis. Astragalin is a flavonoid present in persimmon leaves and green tea seeds and exhibits diverse activities of antioxidant and anti-inflammation. The current study investigated that astragalin attenuated smoking-induced pulmonary thrombosis and alveolar inflammation. In addition, it was explored that molecular links between thrombosis and inflammation entailed protease-activated receptor (PAR) activation and oxidative stress-responsive mitogen-activated protein kinase (MAPK)-signaling. BALB/c mice were orally administrated with 10-20 mg/kg astragalin and exposed to cigarette smoke for 8 weeks. For the in vitro study, 10 U/mL thrombin was added to alveolar epithelial A549 cells in the presence of 1-20 µM astragalin. The cigarette smoking-induced the expression of PAR-1 and PAR-2 in lung tissues, which was attenuated by the administration of ≥10 mg/kg astragalin. The oral supplementation of ≥10 mg/kg astragalin to cigarette smoke-challenged mice attenuated the protein induction of urokinase plasminogen activator, plasminogen activator inhibitor-1and tissue factor, and instead enhanced the induction of tissue plasminogen activator in lung tissues. The astragalin treatment alleviated cigarette smoke-induced lung emphysema and pulmonary thrombosis. Astragalin caused lymphocytosis and neutrophilia in bronchoalveolar lavage fluid due to cigarette smoke but curtailed infiltration of neutrophils and macrophages in airways. Furthermore, this compound retarded thrombin-induced activation of PAR proteins and expression of inflammatory mediators in alveolar cells. Treating astragalin interrupted PAR proteins-activated reactive oxygen species production and MAPK signaling leading to alveolar inflammation. Accordingly, astragalin may interrupt the smoking-induced oxidative stress-MAPK signaling-inflammation axis via disconnection between alveolar PAR activation and pulmonary thromboembolism.

The Effects of Warfarin and Direct Oral Anticoagulants on Systemic Vascular Calcification: A Review

Warfarin has been utilized for decades as an effective anticoagulant in patients with a history of strong risk factors for venous thromboembolism (VTE). Established adverse effects include bleeding, skin necrosis, teratogenicity during pregnancy, cholesterol embolization, and nephropathy. One of the lesser-known long-term side effects of warfarin is an increase in systemic arterial calcification. This is significant due to the association between vascular calcification and cardiovascular morbidity and mortality. Direct oral anticoagulants (DOACs) have gained prominence in recent years, as they require less frequent monitoring and have a superior side effect profile to warfarin, specifically in relation to major bleeding. The cost and lack of data for DOACs in some disease processes have precluded universal use. Within the last four years, retrospective cohort studies, observational studies, and randomized trials have shown, through different imaging modalities, that multiple DOACs are associated with slower progression of vascular calcification than warfarin. This review highlights the pathophysiology and mechanisms behind vascular calcification due to warfarin and compares the effect of warfarin and DOACs on systemic vasculature.

Endoplasmic Reticulum Stress Mediates Vascular Smooth Muscle Cell Calcification via Increased Release of Grp78 (Glucose-Regulated Protein, 78 kDa)-Loaded Extracellular Vesicles

OBJECTIVE

Vascular calcification is common among aging populations and mediated by vascular smooth muscle cells (VSMCs). The endoplasmic reticulum (ER) is involved in protein folding and ER stress has been implicated in bone mineralization. The role of ER stress in VSMC-mediated calcification is less clear. Approach and Results: mRNA expression of the ER stress markers PERK (PKR (protein kinase RNA)-like ER kinase), ATF (activating transcription factor) 4, ATF6, and Grp78 (glucose-regulated protein, 78 kDa) was detectable in human vessels with levels of PERK decreased in calcified plaques compared to healthy vessels. Protein deposition of Grp78/Grp94 was increased in the matrix of calcified arteries. Induction of ER stress accelerated human primary VSMC-mediated calcification, elevated expression of some osteogenic markers (Runx2 [RUNX family transcription factor 2], OSX [Osterix], ALP [alkaline phosphatse], BSP [bone sialoprotein], and OPG [osteoprotegerin]), and decreased expression of SMC markers. ER stress potentiated extracellular vesicle (EV) release via SMPD3 (sphingomyelin phosphodiesterase 3). EVs from ER stress-treated VSMCs showed increased Grp78 levels and calcification. Electron microscopy confirmed the presence of Grp78/Grp94 in EVs. siRNA (short interfering RNA) knock-down of Grp78 decreased calcification. Warfarin-induced Grp78 and ATF4 expression in rat aortas and VSMCs and increased calcification in an ER stress-dependent manner via increased EV release.

CONCLUSIONS

ER stress induces vascular calcification by increasing release of Grp78-loaded EVs. Our results reveal a novel mechanism of action of warfarin, involving increased EV release via the PERK-ATF4 pathway, contributing to calcification. This study is the first to show that warfarin induces ER stress and to link ER stress to cargo loading of EVs.

Use of Non-vitamin K Antagonist Oral Anticoagulants for Stroke Prevention across the Stroke Spectrum: Progress and Prospects

Multiple randomized controlled trials and many real-world evidence studies have consistently shown that non-vitamin K antagonist oral anticoagulants (NOACs) are preferable to vitamin K antagonists for thromboembolic stroke prevention in the majority of patients with atrial fibrillation (AF). However, their role in the management of patients with AF and comorbidities, as well as in other patient populations with a high risk of stroke, such as patients with prior embolic stroke of undetermined source (ESUS) and those with atherosclerosis, is less clear. There is now increasing evidence suggesting that NOACs have a beneficial effect in the prevention of stroke in patients with AF and comorbidities, such as renal impairment and diabetes. In addition, while studies investigating the efficacy and safety of NOACs for the prevention of secondary stroke in patients with a history of ESUS demonstrated neutral results, subanalyses suggested potential benefits in certain subgroups of patients with ESUS. One NOAC, rivaroxaban, has also recently been found to be effective in reducing the risk of stroke in patients with chronic cardiovascular disease including coronary artery disease and peripheral artery disease, further broadening the patient groups that may benefit from NOACs. In this article, we will review recent evidence for the use of NOACs across the stroke spectrum in detail, and discuss the progress and future prospects in the different stroke areas.

Concomitant diabetes with atrial fibrillation and anticoagulation management considerations

Atrial fibrillation is a highly prevalent cardiac arrhythmia. It is associated with numerous co mobilities. Approximately 30% of diabetic patients have atrial fibrillation and 15% of atrial fibrillation regulation patients have diabetes mellitus. Diabetes increases the likelihood of the development of atrial fibrillation and contributes to the high risk of thromboembolism seen in patients with both diabetes and atrial fibrillation. Chronic kidney disease is often a consequence of diabetes and presents an additional challenge to the management of patients with both atrial fibrillation and diabetes. All non-vitamin K oral anticoagulants are partially eliminated via the kidney and must be carefully prescribed according to strict dosing schedules to avoid anticoagulation overdose. However, NOACs have the advantage of being associated with less progressive impairment of renal function compared with vitamin K antagonist therapy in both diabetics and non-diabetics. Otherwise, diabetic patients benefit from NOAC therapy as opposed to vitamin K antagonists to a similar extent as patients without diabetes. This review deals with anticoagulation treatment in patients with fibrillation and diabetes mellitus, often complicated by progressive renal impairment.

[How to anticoagulate elderly and fragile patients?]

Risks of thrombosis, bleeding and renal impairment are increasing with age. The efficacy and safety of the direct oral anticoagulants (DOACs) in fragile patients (age > 75 years and/or creatinine clearance levels < 50 ml/min and/or body weight below 50 kg) with indication for anticoagulation is one of the most challenging topic in cardiovascular medicine. New registry data from subgroup analyses of landmark studies and registries point towards to superiority of DOACs. This article summarizes new insights and describes pathways for anticoagulation in fragile patients.

Incidence of Direct Oral Anticoagulant Prescriptions in Kidney Transplant Recipients in Ontario, Canada

BACKGROUND

Kidney transplant recipients (KTRs) are routinely excluded from direct oral anticoagulant (DOAC) trials. Given the lack of safety and efficacy data in this population, we examined real-world prescribing practices of DOACs in KTRs.

METHODS

We conducted a retrospective cohort study using linked administrative data sets in Ontario, Canada. All adult KTRs (n = 5580) from June 23, 2009, to March 31, 2017, were included. The primary outcomes were the first prescription for a DOAC or warfarin. Patients were censored on graft failure, death, or end of follow-up.

RESULTS

The mean age was 55 (SD, 14) years; 63% were male, and 65% had received a deceased donor kidney. Over a median follow-up of 5.5 and 4.7 years, 224 KTRs (4.0%) and 824 KTRs (14.8%) were prescribed DOACs and warfarin, respectively. The rates of DOAC and warfarin prescriptions were 8.1 and 32.6 per 1000 person-years, respectively. Older age, receipt of a kidney transplant in more recent years, and higher baseline estimated glomerular filtration rate were associated with DOAC prescription compared with warfarin. Patients with multiple comorbidities and a history of deep venous thromboembolism had a lower risk of DOAC prescription compared with warfarin. When examined by era, the incidence rate of both DOAC and warfarin prescriptions increased significantly over time.

CONCLUSIONS

Despite limited safety and efficacy data, DOACs are prescribed to KTRs. However, warfarin still remains more commonly prescribed in this selected patient population. Anticoagulant prescriptions overall are on the rise in KTRs. Further study is needed to determine the safety and efficacy of DOACs in KTRs.

Performance of the LumiraDx Platform INR Test in an Anticoagulation Clinic Point-of-Care Setting Compared With an Established Laboratory Reference Method

Vitamin K antagonists, such as warfarin, have a narrow therapeutic window; patients on these therapies therefore require regular international normalized ratio (INR) monitoring to maintain optimal dosing. This involves periodic checks and laboratory testing using venepuncture, which are often perceived as a burden. This study aimed to determine the accuracy and precision of the LumiraDx INR Test, a new point-of-care in vitro diagnostic platform, in an anticoagulation clinic setting. In this observational, cross-sectional study, precision of the LumiraDx INR Test was assessed using paired replicate samples (n = 366) and 3 test strip lots. Accuracy was determined by comparing capillary blood INR, ascertained by the LumiraDx INR Test, with venous plasma INR, measured by the laboratory reference instrument, the IL ACL ELITE Pro. Furthermore, INR was assessed across a range of hematocrit (25%-55%). In addition, feedback was collected from health-care professionals via a self-completed questionnaire. This trial was registered at ClinicalTrials.gov (NCT03682419). The precision (% coefficient of variation) of the LumiraDx INR Test was <4 when samples were applied by direct application or via a capillary transfer pipette, as well as between test strip lots. Accuracy of the LumiraDx INR Test, across the INR range of 0.8 to 7.5, was confirmed by a strong correlation of 0.965 (95% confidence interval: 0.959-0.970) when compared with the IL ACL ELITE Pro, which was maintained across the hematocrit range. Feedback from health-care professionals indicated that the instructions given by the system were easy to follow. In conclusion, the strong agreement between the LumiraDx Platform INR point-of-care test and the IL ACL ELITE Pro laboratory reference system, as well as between the different application methods and test lots, indicates that it can provide a rapid, accurate, and reliable INR analysis.

[Stroke Prevention in Patients with Atrial Fibrillation in Real Clinical Practice, Emphasis on Efficacy and Safety of Anticoagulant Therapy]

Aim To evaluate frequency of administration of anticoagulant therapy (ACT) for atrial fibrillation and to study the effect of chronic antithrombotic therapy (ATT) on kidney function.Material and methods Due to a high medical and social significance of AF, much attention is presently paid to appropriate administration of ACT for AF in clinical practice. The study retrospectively analyzed 776 case reports of hospitalized patients with AF. The effect of chronic ATT on kidney function was studied in 70 patients who were rehospitalized, including 25 patients treated with warfarin, 25 patients treated with direct oral anticoagulants (DOAC), and 20 patients treated with acetylsalicylic acid (ASA).Results In January 2014, at the prehospital stage, 74.3 % of patients did not receive ATT, 14.7 % of patients received antiplatelet therapy, and only 11 % received anticoagulants. In the hospital in January 2014, ACTs were administered to 74.3 % of patients (warfarin, 58.6 %; DOAC, 15.7 %), 20.6 % of patients received antiplatelet drugs, and 5.1 % of patients were discharged without ATT. In January 2019, the number of patients receiving ACT at the prehospital stage increased to 58.1 % (warfarin, 13.8 %; DOAC, 44.3 %); 12 % of patients received antiplatelet drugs; and 29.9 % of patients did not receive ATT. The number of patients treated with warfarin and DOAC in the hospital increased to 14.8 % and 70.6 % (rivaroxaban, 33.4 %; apixaban, 25.5 %, and dabigatran, 11.7 %), respectively. The number of patients taking antiplatelet drugs decreased to 3.7 %, and the number of patients without ATT decreased to 10.9 %. There were no statistically significant differences in glomerular filtration rate (GFR) between these three groups at baseline. Only in the warfarin treatment group, GFR was significantly decreased from baseline during the follow-up period. Comparison of GFR in three study groups at the finale stage of the study showed significant differences between mean GFRs in the warfarin treatment group and the DOAC treatment group and between the warfarin treatment group and the ASA treatment group.Conclusion Among the prescribed and taken anticoagulants, DOACs are presently in the first place. Among DOACs, the most frequently prescribed drug is rivaroxaban. GFR decreases with the DOAC treatment slower than with the warfarin treatment. Despite the slower decrease in GFR with the ASA treatment compared to warfarin, ASA is not indicated for prevention of stroke in AF due to its low efficacy.

Vitamin K as a Diet Supplement with Impact in Human Health: Current Evidence in Age-Related Diseases

Vitamin K health benefits have been recently widely shown to extend beyond blood homeostasis and implicated in chronic low-grade inflammatory diseases such as cardiovascular disease, osteoarthritis, dementia, cognitive impairment, mobility disability, and frailty. Novel and more efficient nutritional and therapeutic options are urgently needed to lower the burden and the associated health care costs of these age-related diseases. Naturally occurring vitamin K comprise the phylloquinone (vitamin K1), and a series of menaquinones broadly designated as vitamin K2 that differ in source, absorption rates, tissue distribution, bioavailability, and target activity. Although vitamin K1 and K2 sources are mainly dietary, consumer preference for diet supplements is growing, especially when derived from marine resources. The aim of this review is to update the reader regarding the specific contribution and effect of each K1 and K2 vitamers in human health, identify potential methods for its sustainable and cost-efficient production, and novel natural sources of vitamin K and formulations to improve absorption and bioavailability. This new information will contribute to foster the use of vitamin K as a health-promoting supplement, which meets the increasing consumer demand. Simultaneously, relevant information on the clinical context and direct health consequences of vitamin K deficiency focusing in aging and age-related diseases will be discussed.

Rivaroxaban-Induced Acute Interstitial Nephritis: A Case Report

Patient: Male, 70

Final Diagnosis: Acute interstitial nephritis

Symptoms: Dark color urine, difficult voiding

Medication: Rivaroxaban

Clinical Procedure: —

Specialty: General and Internal Medicine

Effect of anticoagulation therapy in older patients with chronic kidney disease and atrial fibrillation: A meta-analysis

BACKGROUND

The role of anticoagulation therapy for stroke prevention in older atrial fibrillation (AF) patients with chronic kidney disease (CKD) remains unclear. Therefore, we conducted a meta-analysis to explore the efficacy and safety of anticoagulation therapy in this population.

METHODS

The Cochrane Library, PubMed, and Embase databases were systematically searched for studies reporting the effect of anticoagulation therapy in older patients with AF and CKD. The risk ratios (RRs) and 95% confidence intervals (CIs) were regarded as the risk estimates. A random-effects model selected was to evaluate the treatment outcomes. The presentations were based on the Preferred Reporting Items for reporting systematic reviews and meta-analyses statement.

RESULTS

A total of 7 studies with 24,794 older patients with AF and CKD were included. The follow-up of the included studies ranged from 0.9 to 9.0 years. In older patients with no dialysis, compared with nonanticoagulants, anticoagulants reduced the risk of all-cause death (RR 0.66, 95% CI 0.54-0.79), but had comparable risks of ischemic stroke/transient ischemic attack (TIA, RR 0.91, 95% CI 0.46-1.79) and bleeding (RR 1.17, 95% CI 0.86-1.60). In older patients with dialysis, compared with nonanticoagulants, anticoagulants increased the risk of bleeding (RR 1.37, 95% CI 1.09-1.74), but had similar risks of ischemic stroke/TIA (RR 1.18, 95% CI 0.88-1.58) and death (RR 0.87, 95% CI 0.60-1.27).

CONCLUSION

Compared with nonanticoagulation, anticoagulation therapy is associated with a reduced risk of death in older AF patients with nondialysis, but an increased risk of bleeding in older patients with dialysis.

Discovery of novel, potent, isosteviol-based antithrombotic agents

Thrombosis is a pathological coagulation process and can lead to many serious thrombotic diseases. Here, we report a novel potent antithrombotic compound (6k) based on isosteviol with anticoagulant and antiplatelet activities. 6k selectively inhibited FXa (K_i = 0.015 μM) against a panel of serine proteases and showed excellent anticoagulant activity (significant prolongation of ex vivo PT and aPTT over the vehicle, p < 0.01). 6k also significantly inhibited ADP-induced platelet aggregation in rats relative to the vehicle (p < 0.01). Furthermore, 6k exhibited potent ex vivo and in vivo antithrombotic activity in rats relative to the vehicle (p < 0.01 and p < 0.0001, respectively). Novel structure 6k, with potent antithrombotic activity, is expected to lead a promising approach for the development of antithrombotic agents.

Role of Vascular Smooth Muscle Cell Phenotypic Switching and Calcification in Aortic Aneurysm Formation

Aortic aneurysm is a vascular disease whereby the ECM (extracellular matrix) of a blood vessel degenerates, leading to dilation and eventually vessel wall rupture. Recently, it was shown that calcification of the vessel wall is involved in both the initiation and progression of aneurysms. Changes in aortic wall structure that lead to aneurysm formation and vascular calcification are actively mediated by vascular smooth muscle cells. Vascular smooth muscle cells in a healthy vessel wall are termed contractile as they maintain vascular tone and remain quiescent. However, in pathological conditions they can dedifferentiate into a synthetic phenotype, whereby they secrete extracellular vesicles, proliferate, and migrate to repair injury. This process is called phenotypic switching and is often the first step in vascular pathology. Additionally, healthy vascular smooth muscle cells synthesize VKDPs (vitamin K-dependent proteins), which are involved in inhibition of vascular calcification. The metabolism of these proteins is known to be disrupted in vascular pathologies. In this review, we summarize the current literature on vascular smooth muscle cell phenotypic switching and vascular calcification in relation to aneurysm. Moreover, we address the role of vitamin K and VKDPs that are involved in vascular calcification and aneurysm. Visual Overview- An online visual overview is available for this article.

The Relationships Between Vitamin K and Cognition: A Review of Current Evidence

Vitamin K is a fat-soluble nutrient discovered in 1935 and its role in blood coagulation has been thoroughly explored. In recent years, studies conducted in vitro and on animals highlighted vitamin K involvement in brain cells development and survival. In particular, vitamin K seems to have an antiapoptotic and anti-inflammatory effect mediated by the activation of Growth Arrest Specific Gene 6 and Protein S. Moreover, this vitamin is involved in sphingolipids metabolism, a class of lipids that participate in the proliferation, differentiation, and survival of brain cells. An altered expression in sphingolipids profile has been related to neuroinflammation and neurodegeneration. This review stems from a growing interest in the role of vitamin K in brain functions, especially in cognition, also in view of an expected increase of prevalence of Alzheimer's disease and other forms of dementia. It collects recent researches that show interesting, even though not definitive, evidence of a direct correlation between vitamin K levels and cognitive performance. Moreover, vitamin K antagonists, used worldwide as oral anticoagulants, according to recent studies may have a negative influence on cognitive domains such as visual memory, verbal fluency and brain volume. The aim of this review is to analyze the evidence of clinical studies carried out up to date on the relationship between vitamin K intake and cognitive performances. The involvement of vitamin K antagonists (VKAs) in declining cognitive performances is also addressed separately.

Vitamin K: Double Bonds beyond Coagulation Insights into Differences between Vitamin K1 and K2 in Health and Disease

Vitamin K is an essential bioactive compound required for optimal body function. Vitamin K can be present in various isoforms, distinguishable by two main structures, namely, phylloquinone (K1) and menaquinones (K2). The difference in structure between K1 and K2 is seen in different absorption rates, tissue distribution, and bioavailability. Although differing in structure, both act as cofactor for the enzyme gamma-glutamylcarboxylase, encompassing both hepatic and extrahepatic activity. Only carboxylated proteins are active and promote a health profile like hemostasis. Furthermore, vitamin K2 in the form of MK-7 has been shown to be a bioactive compound in regulating osteoporosis, atherosclerosis, cancer and inflammatory diseases without risk of negative side effects or overdosing. This review is the first to highlight differences between isoforms vitamin K1 and K2 by means of source, function, and extrahepatic activity.

Bleeding assessment in oral surgery: A cohort study comparing individuals on anticoagulant therapy and a non-anticoagulated group

Some prospective studies have been designed specifically to investigate perioperative bleeding in dental surgery. The quantitative assessment of intraoperative blood loss can be useful for indicating the real risk of bleeding complications, especially in medically compromised individuals. The aim of this study was to evaluate the pattern of bleeding in individuals under vitamin K antagonist (VKA) therapy and non-anticoagulated individuals submitted to dental extractions. Perioperative bleeding was evaluated by using a total collected bleeding corrected by absorbance reading (dental bleeding score). 138 procedures were performed. When the perioperative dental bleeding score was correlated with the number of extracted teeth, the quantity of bleeding was found to be directly proportional to the procedure. Extractions of two or more teeth presented higher scores than single extractions (p = 0.003). In a comparative analysis between the VKA and non-anticoagulated groups, no significant difference in the scores was found. The previous history of complications in dental procedures (p = 0.001) and the use of additional hemostatic measures were higher in the VKA group (p = 0.017). VKA therapy did not impact significantly the volume of blood lost during dental extractions. Perioperative bleeding assessment might be a useful parameter for evaluating patients under antithrombotic treatment.

NOACs in Anesthesiology

Background

Due to increasing use of new oral anticoagulants (NOACs), clinicians are faced more and more frequently with clinical issues related to these drugs.

Objective

The objective of this publication is to make practical suggestions for the perioperative management of NOACs as well as for their handling in overdoses and bleedings.

Recommendations

In elective surgery and creatinine clearance ≥ 50 ml/min, a NOAC should be discontinued 24-36 h before the intervention, and even earlier in case of reduced kidney function. In emergency interventions that cannot be delayed, the management is dependent on the NOAC plasma levels. With levels ≤ 30 ng/ml, surgery can be performed. With levels >30 ng/ml, reversal agents should be considered. In low bleeding risk surgery, NOACs can be re-started 24 h after the intervention, which is prolonged to 48-72 h after surgery with high bleeding risk. In case of NOAC overdose and minor bleedings, temporary discontinuation and supportive care are usually sufficient to control the situation. In severe or life-threatening bleedings, nonspecific and specific reversal agents should be considered.