DOACs in Mechanical and Bioprosthetic Heart Valves: A Narrative Review of Emerging Data and Future Directions

Direct Oral Anticoagulants: Navigating Through Clinical Challenges

PURPOSE

Direct oral anticoagulants (DOACs) have been approved, for over a decade, by both European and American medicine agencies, for treatment and prevention of several cardiovascular conditions. Since then, an increasing amount of data has been added to the medical literature day by day, resulting in a dichotomy in selection of the appropriate agent, dosage, and duration of treatment for special populations with multiple comorbidities. Considering these issues, we have prepared a comprehensive review for the clinical practitioner, to optimize the DOAC utilization in clinical practice.

METHODS

A thorough literature search and review was conducted, concerning mainly the last decade. Our review focused on the current guidelines and the most recently published studies in PubMed, Science Direct Scopus, and Google Scholar to date.

CONCLUSION

The purpose of this study is to provide guidance for healthcare professionals for making proper decisions when confronted with clinical challenges. Nevertheless, further research is required to establish DOAC superiority in complicated cases, where there is clinical uncertainty.

Evaluation of warfarin management in primary health care centers in Qatar: A retrospective cross-sectional analysis of the national dataset

BACKGROUND

Warfarin management is associated with severe complications, highlighting the critical need to evaluate the quality of its administration.

OBJECTIVES

To evaluate the quality of warfarin management for patients managed in primary healthcare centers by measuring the percentage of Time in Therapeutic Range (TTR) and the proportion of extreme out-of-range international normalized ratio (INR) values.

METHODS

This is a cross-sectional study. Data was extracted from a national dataset retrieved from the largest primary healthcare provider in Qatar. TTR was calculated using the traditional method. Inferential and descriptive analyses were performed as appropriate.

RESULTS

Four hundred ninety-four patients met the inclusion criteria. The mean (SD) TTR was 45.3 % (17.5). This was significantly lower than the recommended cutoff value (P<0.001). Extreme out-of-range INR accounted for 24.7 % of total INR readings.

CONCLUSIONS

The management of patients taking warfarin in Qatar is inadequate. More effective strategies are warranted to ensure safe and effective therapy.

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Reversing the Tide: A Case of a Mechanical Aortic Valve Recipient Lost to Follow-up, Education on Rivaroxaban Contraindications, and the Vital Role of Acenocoumarol in Preventing Valve Thrombosis

Aortic stenosis is the most common heart valve disease, especially among the elderly. Symptomatic aortic valve stenosis is linked to a poor prognosis and a high mortality rate if left untreated. The only effective treatment for severe symptomatic aortic stenosis is aortic valve replacement using either a mechanical or a biological prosthesis. Mechanical valve prostheses, while highly durable, are thrombogenic, necessitating lifelong anticoagulation with oral anti-vitamin K agents, such as acenocoumarol. Conversely, bioprosthetic valves, though less durable, carry a minimal thrombogenic risk and do not require anticoagulation. Currently, there is no proven role for direct-acting oral anticoagulants (DOACs) in patients with mechanical heart valves due to insufficient clinical trial data regarding their safety in this patient population. Herein, we present the case of a 59-year-old female known to have aortic stenosis, who underwent surgical treatment with mechanical aortic valve replacement eight years ago. Post-surgery, acenocoumarol was initiated. However, 18 months prior to presenting at our institution, the patient started taking rivaroxaban (a DOAC) instead of acenocoumarol due to the unavailability of acenocoumarol during the ongoing economic crisis in Lebanon, without consulting her cardiologist. Although she was followed up by her general practitioner and reported having a mechanical valve, her son contradicted this, claiming she had a biological valve. After thorough investigations, including chest X-ray, echocardiography, and fluoroscopy, it was confirmed that the patient indeed had a normally functioning mechanical aortic valve. Immediate corrective measures were taken, starting with IV unfractionated heparin and acenocoumarol, targeting an International Normalized Ratio (INR) between 2.5 and 3, while educating the patient about her condition and the importance of adhering to acenocoumarol therapy.

Factor XI/XIa inhibitors for the prevention and treatment of venous and arterial thromboembolism: A narrative review

During the past decade, direct oral anticoagulants (DOACs) have advanced and simplified the prevention and treatment of venous thromboembolism (VTE). However, there remains a high incidence of bleeds, which calls for agents that have a reduced risk of bleeding. Factor XI (FXI) deficiency is associated with lower rates of venous thrombosis and stroke compared to the general population with a lower risk of bleeding. In conjunction with this, phase 2 studies have demonstrated safety and the potential for reduced thrombotic events with FXI inhibitors as compared to currently available medications. The aim of this review is to summarize key data on the clinical pharmacology of FXI, the latest developments in clinical trials of FXI inhibitors, and to describe the efficacy and safety profiles of FXI inhibitors for the prevention of venous and arterial thromboembolism.

Oral Anticoagulants Beyond Warfarin

Direct oral anticoagulants (DOACs) have largely replaced vitamin K antagonists, mostly warfarin, for the main indications for oral anticoagulation, prevention and treatment of venous thromboembolism, and prevention of embolic stroke in atrial fibrillation. While DOACs offer practical, fixed-dose anticoagulation in many patients, specific restrictions or contraindications may apply. DOACs are not sufficiently effective in high-thrombotic risk conditions such as antiphospholipid syndrome and mechanical heart valves. Patients with cancer-associated thrombosis may benefit from DOACs, but the bleeding risk, particularly in those with gastrointestinal or urogenital tumors, must be carefully weighed. In patients with frailty, excess body weight, and/or moderate-to-severe chronic kidney disease, DOACs must be cautiously administered and may require laboratory monitoring. Reversal agents have been developed and approved for life-threatening bleeding. In addition, the clinical testing of potentially safer anticoagulants such as factor XI(a) inhibitors is important to further optimize anticoagulant therapy in an increasingly elderly and frail population worldwide.

Sailing between scylla and charybdis-anticoagulation dilemma in a patient with calciphylaxis and mechanical cardiac valve replacement: a case report and literature review

Calciphylaxis is a rare and life-threatening condition in patients with end-stage kidney disease (ESKD). In this case report, we reported a 72-year-old female who had undergone aortic and mitral mechanical valve replacement 22 years ago due to rheumatic aortic and mitral stenosis. Following the valve replacement, she initiated warfarin treatment. Five years ago, she received a diagnosis of uremia and has since been undergoing regular hemodialysis. Ten months prior to her current admission, she experienced excruciating pain and was diagnosed with calciphylaxis. Additionally, an electrocardiogram revealed atrial fibrillation, while echocardiography indicated that the aortic and mitral mechanical valves were appropriately positioned, with normal perivalvular surroundings and good valve leaflet activity. No noticeable thrombosis was observed in the left atrium or left atrial appendage. Color Doppler imaging showed moderate stenosis in the lower extremity arteries, with no venous thromboembolism present. Extensive eggshell-like calcification within the arterial media was detected. The patient was managed with regular hemodialysis, symptomatic treatments (including anticoagulation and analgesia), and sodium thiosulfate. Unfortunately, symptomatic management provided limited relief, and during the one-month follow-up period, the patient passed away due to septic shock. Currently, there is insufficient conclusive evidence regarding alternative influential anticoagulants or appropriate prosthetic valve selection. For individuals with ESKD receiving maintenance hemodialysis, early identification, diagnosis, and treatment of calciphylaxis are of paramount importance.

Direct oral anticoagulants versus vitamin K antagonists: Which one is more effective in atrial fibrillation

BACKGROUND

The optimal approach for anticoagulation in patients with bioprosthetic valves and atrial fibrillation (AF) remains a subject of debate. A meta-analysis using updated evidence to evaluate the efficacy and safety of direct oral anticoagulants (DOACs) compared to vitamin K antagonists (VKAs) in patients with AF and bioprosthetic valves to address this controversy.

METHODS

A comprehensive search was conducted in multiple databases, including PubMed, Scopus, Web of Science, ProQuest, and the Cochrane Central Register of Controlled Trials, up until March 2023. The search aimed to identify relevant randomized controlled trials (RCTs) that examined the efficacy and safety outcomes of both direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) in patients with bioprosthetic valves and atrial fibrillation. The primary outcomes of interest were major bleeding and all-cause mortality.

RESULTS

Our study demonstrated that despite the difference was not significant, the hazard of all-cause mortality was 2.5% higher in the DOAC group (HR = 1.03, 95% CI = [0.88, 1.19], p-value = .75). Similarly, the hazard of stroke (HR = 1.03, 95% CI = [0.87, 1.32], p-value = .71) and major bleeding (HR = 1.11, 95% CI = [0.89, 1.38], p-value = .36) were found to be respectively 3.2 and 10.7% higher in the DOAC group, although the difference was not significant. However, the hazard of intracranial hemorrhage was found to be 28.8 lower in the DOAC treatment group (HR = 0.71, 95% CI = [0.39, 1.31], p-value = .27), which again was not statistically significant.

CONCLUSIONS

Our meta-analysis demonstrates that in patients undergoing bioprosthetic valve surgery and presenting with AF afterward, DOAC and VKA are similar regarding life-threatening and all-cause mortality outcomes, including major bleeding, stroke, and intracranial hemorrhage.

Maternal and Fetal Outcomes in Pregnant Patients With Mechanical and Bioprosthetic Heart Valves

Background Guidelines for choice of prosthetic heart valve in people of reproductive age are not well established. Although biologic heart valves (BHVs) have risk of deterioration, mechanical heart valves (MHVs) require lifelong anticoagulation. This study aimed to characterize the association of prosthetic valve type with maternal and fetal outcomes in pregnant patients. Methods and Results Using the 2008 to 2019 National Inpatient Sample, we identified all adult patients hospitalized for delivery with prior heart valve implantation. Multivariable regressions were used to analyze the primary outcome, major adverse cardiovascular events, and secondary outcomes, including maternal and fetal complications, length of stay, and costs. Among 39 871 862 birth hospitalizations, 4152 had MHVs and 874 had BHVs. Age, comorbidities, and cesarean birth rates were similar between patients with MHVs and BHVs. The presence of a prosthetic valve was associated with over 22-fold increase in likelihood of major adverse cardiovascular events (MHV: adjusted odds ratio, 22.1 [95% CI, 17.3-28.2]; BHV: adjusted odds ratio, 22.5 [95% CI, 13.9-36.5]) as well as increased duration of stay and hospitalization costs. However, patients with MHVs and BHVs had no significant difference in the odds of any maternal outcome, including major adverse cardiovascular events, hypertensive disease of pregnancy, and ante/postpartum hemorrhage. Similarly, fetal complications were more likely in patients with valve prostheses, including a 4-fold increase in odds of stillbirth, but remained comparable between MHVs and BHVs. Conclusions Patients hospitalized for delivery with prior valve replacement carry substantial risk of adverse maternal and fetal events, regardless of valve type. Our findings reveal comparable outcomes between MHVs and BHVs.

Potential Association of Holidays on Internationalized Normalized Ratio in Warfarin-Users at a Multidisciplinary Clinic

Background

Warfarin is approved by the United States Food and Drug Administration for numerous clinical indications. The effectiveness of warfarin is highly dependent on the time-in-therapeutic range based on the international normalized ratio (INR) goal, which may be altered by changes in diet, alcohol intake, concomitant drugs, and travel, all of which are prevalent during the holidays. At this time, there are no published studies assessing the impact of holidays on INR in warfarin-users.

Methods

A retrospective chart review was conducted on all adult patients taking warfarin and managed at a multidisciplinary clinic. Patients were included if they were taking warfarin at home regardless of indication for anticoagulation. The INR pre- and post-holiday was assessed.

Results

Of a total of 92 patients, the mean age was 71.5 ± 14.3 years, and most patients were on warfarin with an INR goal of 2 - 3 (89%). There were significant differences in INR before and after Independence Day (2.55 vs. 2.81, P = 0.043) and Columbus Day (2.39 vs. 2.82, P < 0.001). The remaining holidays showed no significant differences in INR before and after each respective holiday.

Conclusions

There may be factors related to Independence and Columbus Day that are increasing the level of anticoagulation in warfarin-users. Although the mean post-holiday INR values, in essence, maintained within the typical target of 2 - 3, our study underscores the specialized care that is warranted in higher risk patients to prevent a continued increase in INR and subsequent toxicities. We hope our results would be hypothesis-generating and aid in the development of larger, prospective evaluations to validate the findings of our present study.

Direct Oral Anticoagulants use in Patients with Stable Coronary Artery Disease, Acute Coronary Syndrome or Undergoing Percutaneous Coronary Intervention

The investigation for the optimal anticoagulation strategy for patients with stable coronary artery disease, acute coronary syndromes, and undergoing percutaneous coronary intervention constitutes a great challenge for physicians and is a field of extensive research. Although aspirin is commonly recommended as a protective measure for all patients with coronary artery disease and dual antiplatelet therapy for those undergoing procedures, such as percutaneous coronary intervention or coronary artery bypass graft surgery, the risk of recurrent cardiovascular events remains significant. In this context, the shortcomings associated with the use of vitamin K antagonists have led to the assessment of direct oral anticoagulants as promising alternatives. This review will explore and provide a comprehensive analysis of the existing data regarding the use of direct oral anticoagulants in patients with stable coronary artery disease or acute coronary syndrome, as well as their effectiveness in those undergoing percutaneous coronary intervention or coronary artery bypass graft surgery.

Management of atrial fibrillation in rheumatic heart disease

Rheumatic heart disease (RHD) is the underlying cause of a significant proportion of atrial fibrillation (AF) in the low- and middle-income countries, while nonvalvular AF is the most common cause of AF in high-income countries. RHD is also common among African Americans, migrants, and the indigenous population of high-income countries. The onset of AF in RHD patients is a clinical marker of worse outcomes and is associated with significant morbidity and mortality. Despite RHD being a major cause of morbidity and mortality in the young in many parts of the world, it is often neglected by policymakers, the media, and even the medical fraternity. Stroke risk assessment using various risk scores has not been systematically evaluated in rheumatic AF patients. Rate control may not be ideal for symptom control in rheumatic AF patients considering the young age and an active lifestyle. There is limited information regarding the nonpharmacological management of rheumatic AF. The current management guidelines based on nonvalvular AF do not apply to rheumatic AF patients who are often younger, are women, and have fewer comorbidities. This review critically looks at specific areas such as stroke prevention with reference to direct oral anticoagulants, cardioversion, rate and rhythm control strategies, and the role of nonpharmacological methods in rheumatic AF management. Future recommendations must be cognizant of local health care systems and resourcing considering the geographic distribution of the disease.

Vitamin-K Antagonists vs. Direct Oral Anticoagulants on Severity of Upper Gastrointestinal Bleeding: A Retrospective Analysis of Italian and UK Data

Background: Gastrointestinal bleeding (GIB) is one of most frequent and significant challenges for emergency physicians and gastroenterologists. Mortality for upper (U) GIB is high, especially in the elderly and comorbid patients. However, there is scant evidence in the literature concerning an assessment of warfarin (VKA) and direct oral anticoagulants (DOACs) in terms of upper gastrointestinal bleeding (UGIB) severity. Aims: Using data from two different settings (Italy and the UK), we aimed to compare the impact of VKA and DOACs on the severity of UGIB. Methods: Retrospective bicentric study on adult patients under VKA or DOACs admitted either to the emergency department at the Gemelli Hospital in Rome, Italy or University College Hospital in London, UK, with suspected UGIB from 01/01/2017 to 31/12/2018. Univariate analysis with Fisher’s exact test, and analysis of variance (ANOVA) were used. Results: 106 patients (62 M/44 F; mean age 71.2 ± 16.9 yrs) were enrolled and divided into the VKA group (N = 57; M: 56%, mean age: 64.9 ± 21.3 yrs) and the DOAC group (N = 49; M: 61%; mean age: 77.6 ± 12.5 yrs). At univariate analysis, the VKA group presented two endoscopic diagnoses more frequently than the DOAC group (26% vs. 8%, p < 0.05), were more frequently endoscopically treated (44% vs. 22%, p < 0.05), rescoped (12% vs. 2%, p = 0.048) and hospitalized (79% vs. 53%, p = 0.01) with a longer length of stay, LOS (VKA: 58% > 5 days vs. DOAC: 68% < 5 days, p = 0.01). There was no difference in terms of hemoglobin level on admission, however the requirement of blood transfusions was higher in the VKA group (60% vs. 41%, p = 0.041). One third of the VKA group showed a lower platelet count than the DOAC group (33% vs. 8%, p = 0.01). No statistically significant differences for in-hospital mortality were observed. For the ANOVA, the type of anticoagulant used was the only significant predictor of need to rescope (p = 0.041) and a significant co-predictor for a LOS > 5 days (p = 0.009; as well as cirrhosis, p = 0.013 and age, p = 0.005). Conclusions: Our outcomes revealed a more severe UGIB in patients on VKA, but the impact of comorbidities (i.e., more cirrhotic patients in the VKA group) cannot be disregarded. DOAC subgroup descriptive analysis, even though on a little cohort, showed higher bleeding severity for rivaroxaban.