Economic evaluation of percutaneous left atrial appendage occlusion, dabigatran, and warfarin for stroke prevention in patients with nonvalvular atrial fibrillation

Cost-effectiveness of left atrial appendage closure for stroke prevention in atrial fibrillation: a systematic review appraising the methodological quality

BACKGROUND

The increasing global prevalence of atrial fibrillation (AF) has led to a growing demand for stroke prevention strategies, resulting in higher healthcare costs. High-quality economic evaluations of stroke prevention strategies can play a crucial role in maximising efficient allocation of resources. In this systematic review, we assessed the methodological quality of such economic evaluations.

METHODS

We searched electronic databases of PubMed, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, and Econ Lit to identify model-based economic evaluations comparing the left atrial appendage closure procedure (LAAC) and oral anticoagulants published in English since 2000. Data on study characteristics, model-based details, and analyses were collected. The methodological quality was evaluated using the modified Economic Evaluations Bias (ECOBIAS) checklist. For each of the 22 biases listed in this checklist, studies were categorised into one of four groups: low risk, partial risk, high risk due to inadequate reporting, or high risk. To gauge the overall quality of each study, we computed a composite score by assigning + 2, 0, - 1 and - 2 to each risk category, respectively.

RESULTS

In our analysis of 12 studies, majority adopted a healthcare provider or payer perspective and employed Markov Models with the number of health states varying from 6 to 16. Cost-effectiveness results varied across studies. LAAC displayed a probability exceeding 50% of being the cost-effective option in six out of nine evaluations compared to warfarin, six out of eight evaluations when compared to dabigatran, in three out of five evaluations against apixaban, and in two out of three studies compared to rivaroxaban. The methodological quality scores for individual studies ranged from 10 to - 12 out of a possible 24. Most high-risk ratings were due to inadequate reporting, which was prevalent across various biases, including those related to data identification, baseline data, treatment effects, and data incorporation. Cost measurement omission bias and inefficient comparator bias were also common.

CONCLUSIONS

While most studies concluded LAAC to be the cost-effective strategy for stroke prevention in AF, shortcomings in methodological quality raise concerns about reliability and validity of results. Future evaluations, free of these shortcomings, can yield stronger policy evidence.

Left Atrial Appendage Occlusion: Current Stroke Prevention Strategies and a Shift Toward Data-Driven, Patient-Specific Approaches

The left atrial appendage (LAA) is a complex structure with unknown physiologic function protruding from the main body of the left atrium. In patients with atrial fibrillation, the left atrium does not contract effectively. Insufficient atrial and LAA contractility predisposes the LAA morphology to hemostasis and thrombus formation, leading to an increased risk of cardioembolic events. Oral anticoagulation therapies are the mainstay of stroke prevention options for patients; however, not all patients are candidates for long-term oral anticoagulation. Percutaneous occlusion devices are an attractive alternative to long-term anticoagulation therapy, although they are not without limitations, such as peri-implant leakage and device-related thrombosis. Although efforts have been made to reduce these risks, significant interpatient heterogeneity inevitably yields some degree of device-anatomy mismatch that is difficult to resolve using current devices and can ultimately lead to insufficient occlusion and poor patient outcomes. In this state-of-the-art review, we evaluated the anatomy of the LAA as well as the current pathophysiologic understanding and stroke prevention strategies used in the management of the risk of stroke associated with atrial fibrillation. We highlighted recent advances in computed tomography imaging, preprocedural planning, computational modeling, and novel additive manufacturing techniques, which represent the tools needed for a paradigm shift toward patient-centric LAA occlusion. Together, we envisage that these techniques will facilitate a pipeline from the imaging of patient anatomy to patient-specific computational and bench-top models that enable customized, data-driven approaches for LAA occlusion that are engineered specifically to meet each patient's unique needs.

Actual management costs of patients with non-valvular atrial fibrillation treated with percutaneous left atrial appendage closure or oral anticoagulation

AIMS

Comparing actual management costs in patients with non-valvular atrial fibrillation (AF) treated with percutaneous left atrial appendage closure (LAAC) or OAC only.

METHODS AND RESULTS

Patients undergoing percutaneous LAAC and AF patients treated with OAC only were matched for gender, age, and diagnosis related groups (DRG) clinical complexity level (CCL). Costs for cardiovascular outpatient clinic visits and hospitalizations were derived from the actual reimbursement records. Between 1/2012 and 12/2016, 8478 patients were referred: 7801 (92%) managed with OAC and 677 (8%) with percutaneous LAAC. Matching resulted in 558 patients (279 per group) for final analysis. Age was 74.9 ± 7.5 years, 244 were female (43.7%), and DRG CCL was 1.8 ± 1.1. Annualized management cost before percutaneous LAAC was € 3110 (IQR: € 1281-8127). After 4.5 ± 1.4 years follow-up, annualized management cost was € 1297 (IQR: € 607-2735) in OAC patients and € 1013 (IQR: € 0-4770) in patients after percutaneous LAAC (p = 0.003). Percutaneous LAAC was the strongest independent determinant to reduce follow-up costs (B = -0.8; CI: -1.09 ̶̶̶̶̶ -0.6; p < 0.0001). Estimated 3-year survival was 92% in percutaneous LAAC and 90% in OAC patients (p = 0.7).

CONCLUSION

Percutaneous LAAC significantly reduces management costs. Management costs are significantly higher for patients treated with only OAC compared to patients after percutaneous LAAC. In spite of their complex comorbid profile, percutaneous LAAC patients show a follow-up survival rate similar to patients solely treated with OAC. Future studies are necessary to investigate the potential net economic and clinical benefit of percutaneous LAAC in patients treated with OAC only.

Left atrial appendage closure with the watchman device reduces atrial fibrillation management costs

AIMS

To report hospitalization costs of patients with non-valvular atrial fibrillation (AF) submitted to percutaneous left atrial appendage closure (LAAC) with the Watchman device.

METHODS

Pre- and post-procedural hospitalization AF-related costs were calculated using the DRG system (diagnosis-related groups) and compared.

RESULTS

Between 2012 and 2016, 677 non-valvular AF patients underwent LAAC. Median time from first cardiac hospitalization to LAAC was 5.9 years (IQR 1.6-9.1) and median follow-up after LAAC was 4.8 years (IQR 3.6-5.6). LAAC mortality was 1.3% and follow-up mortality 16.9%. Median pre-LAAC hospitalization cost was € 17,867 (IQR € 7512-35,08) and post-LAAC € 8772 (IQR € 1183-25,159) (p < 0.0001). Annualized cost pre-LAAC was 3773 € (IQR € 1644-8,493) and post-LAAC 2,001 € (IQR € 260-6913) (p < 0.0001). Follow-up survivors had significantly lower post-LAAC costs (p < 0.0001) and after a survival cut-off time of 4.6 years LAAC procedural and post-procedural hospitalization costs achieved parity with pre-LACC costs (AUC 0.64; p = 0.02). CHA2DS2-VASc score (B = 0.04; p = 0.02; 95% CI 0.006-0.08), and HAS-BLED score (B = 0.08; p = 0.004; 95% CI 0.02-0.14) were independent determinants for annualized hospitalization costs post-LAAC. At Cox-regression analysis the DRG mean clinical complexity level (CCL) was the only independent determinant for follow-up mortality (OR = 2.2; p < 0.0001; 95% CI 1.6-2.8) with a cut-off value of 2.25 to predict follow-up mortality (AUC 0.72; p < 0.0001; Spec. 70%; Sens. 70%).

CONCLUSION

Hospitalization costs pre-LAAC are consistent, and after LAAC, they are significantly reduced. Costs seem related to the patient's risk profile at the time of the procedure. With the increase in post-LAAC survival time, the procedure becomes economically more profitable.

Health Technology Assessment for Cardiovascular Digital Health Technologies and Artificial Intelligence: Why Is It Different?

Innovations in health care are growing exponentially, resulting in improved quality of and access to care, as well as rising societal costs of care and variable reimbursement. In recent years, digital health technologies and artificial intelligence have become of increasing interest in cardiovascular medicine owing to their unique ability to empower patients and to use increasing quantities of data for moving toward personalised and precision medicine. Health technology assessment agencies evaluate the money spent on a health care intervention or technology to attain a given clinical impact and make recommendations for reimbursement considerations. However, there is a scarcity of economic evaluations of cardiovascular digital health technologies and artificial intelligence. The current health technology assessment framework is not equipped to address the unique, dynamic, and unpredictable value considerations of these technologies and highlight the need to better approach the digital health technologies and artificial intelligence health technology assessment process. In this review, we compare digital health technologies and artificial intelligence with traditional health care technologies, review existing health technology assessment frameworks, and discuss challenges and opportunities related to cardiovascular digital health technologies and artificial intelligence health technology assessment. Specifically, we argue that health technology assessments for digital health technologies and artificial intelligence applications must allow for a much shorter device life cycle, given the rapid and even potentially continuously iterative nature of this technology, and thus an evidence base that maybe less mature, compared with traditional health technologies and interventions.

Boundary-Condition Analysis of an Idealized Left Atrium Model

The most common type of cardiac arrhythmia is atrial fibrillation (AF), which is characterised by irregular and ineffective atrial contraction. This behaviour results into the formation of thrombi, mainly in the left atrial appendage (LAA), responsible for thromboembolic events. Very different approaches are considered as therapy for AF patients. Therefore, it is necessary to yield insight into the flow physics of thrombi formation to determine which is the most appropriate strategy in each case. Computational Fluid Dynamics (CFD) has proven successful in getting a better understanding of the thrombosis phenomenon, but it still requires validation by means of accurate flow field in vivo atrial measurements. As an alternative, in this paper it is proposed an in vitro flow validation, consisting in an idealised model that captures the main flow features observed in the human LA which, once combined with Particle Image Velocimetry (PIV) measurements, provides readily accessible, easy to emulate, detailed velocity fields. These results have been used to validate our laminar and Large Eddy Simulation (LES) simulations. Besides, we have run a parametric study of different boundary conditions sets previously employed in the literature. These data can be used as a benchmark for further development of LA CFD models.

Cost-effectiveness of antithrombotic agents for atrial fibrillation in older adults at risk for falls: a mathematical modelling study

BACKGROUND

Antithrombotic drugs decrease stroke risk in patients with atrial fibrillation, but they increase bleeding risk, particularly in older adults at high risk for falls. We aimed to determine the most cost-effective antithrombotic therapy in older adults with atrial fibrillation who are at high risk for falls.

METHODS

We conducted a mathematical modelling study from July 2019 to March 2020 based on the Ontario, Canada, health care system. We derived the base-case age, sex and fall risk distribution from a published cohort of older adults at risk for falls, and the bleeding and stroke risk parameters from an atrial fibrillation trial population. Using a probabilistic microsimulation Markov decision model, we calculated quality-adjusted life years (QALYs), total cost and incremental cost-effectiveness ratios (ICERs) for each of acetylsalicylic acid (ASA), warfarin, apixaban, dabigatran, rivaroxaban and edoxaban. Cost data were adjusted for inflation to 2018 values. The analysis used the Ontario public payer perspective with a lifetime horizon.

RESULTS

In our model, the most cost-effective antithrombotic therapy for atrial fibrillation in older patients at risk for falls was apixaban, with an ICER of $8517 per QALY gained (5.86 QALYs at $92 056) over ASA. It was a dominant strategy over warfarin and the other antithrombotic agents. There was moderate uncertainty in cost-effectiveness ranking, with apixaban as the preferred choice in 66% of model iterations (given willingness to pay of $50 000 per QALY gained); edoxaban, 30 mg, was preferred in 31% of iterations. Sensitivity analysis across ranges of age, bleeding risk and fall risk still favoured apixaban over the other medications.

INTERPRETATION

From a public payer perspective, apixaban is the most cost-effective antithrombotic agent in older adults at high risk for falls. Health care funders should implement strategies to encourage use of the most cost-effective medication in this population.

The Ross procedure versus mechanical aortic valve replacement in young patients: a decision analysis

OBJECTIVES

Our goal was to determine the range of perioperative mortality rates associated with the Ross procedure that results in a life expectancy similar to that seen with mechanical aortic valve replacement (mAVR) in young patients with aortic valve disease.

METHODS

A fully probabilistic Markov microsimulation model with 1000 outer loops and 10 000 inner loops was constructed to compare gain in life expectancy and quality-adjusted life years between the index treatment with the Ross procedure versus mAVR for a theoretical cohort of young patients with aortic valve disease. Inputs for early deaths and late complications (death, stroke, bleeding, reoperation) were obtained from a single-centre study of 208 propensity score matched patients. In the primary analysis, the perioperative mortality rate for the Ross procedure was varied by increments of 0.5% to determine its impact on life expectancy and quality-adjusted life years. A 2-way sensitivity analysis was conducted to determine simultaneously the impact of the Ross reoperation rate and Ross reoperative mortality rate on life expectancy.

RESULTS

Life expectancy was improved with the Ross procedure when the perioperative mortality rate with the Ross procedure was <2.5% and was equivalent to mAVR when the mortality rate was 2.5% to 5%. Similarly, when the perioperative mortality rate of the Ross procedure was between 4% and 5.5%, the quality-adjusted life years gained were similar between the Ross procedure and mAVR. Life expectancy was improved when the Ross procedure reoperative mortality rate was <7% at an incidence of Ross reoperations of 18% at 20 years.

CONCLUSIONS

Improved life expectancy can be expected with the Ross procedure when the operative mortality rate is less than 2.5%.

Evaluating the Cost Effectiveness of a Suicide Prevention Campaign Implemented in Ontario, Canada

BACKGROUND

Although suicide-prevention campaigns have been implemented in numerous countries, Canada has yet to implement a strategy nationally. This is the first study to examine the cost utility of the implementation of a multidimensional suicide-prevention program that combines several interventions over a 50-year time horizon.

METHODS

We used Markov modeling to capture the dynamic changes to health status and estimate the incremental cost per quality-adjusted life-year gained over a 50-year period for Ontario residents for a suicide-prevention strategy compared to no intervention. The strategy consisted of a package of interventions geared towards preventing suicide including a public health awareness campaign, increased identification of individuals at risk, increased training of primary-care physicians, and increased treatment post-suicide attempt. Four health states were captured by the Markov model: (1) alive and no recent suicide attempt; (2) suicide attempt; (3) death by suicide; (4) death (other than suicide). Analyses were from a societal perspective where all costs, irrespective of payer, were included. We used a probabilistic analysis to test the robustness of the model results to both variation and uncertainty in model parameters.

RESULTS

Over the 50-year period, the suicide-prevention campaign had an incremental cost-effectiveness ratio (ICER) of $18,853 (values are in Canadian dollars) per QALY gained. In all one-way sensitivity analyses, the ICER remained under $50,000/QALY. In the probabilistic analysis, there was a probability of 94.8% that the campaign was cost effective at a willingness-to-pay of $50,000/QALY (95% confidence interval of ICER probabilistic distribution: 2650-62,375). Among the current population, the intervention was predicted to result in the prevention of 4454 suicides after 50 years (1033 by year 10; 2803 by year 25). A healthcare payer perspective sensitivity analysis showed an ICER of $21,096.14/QALY.

INTERPRETATION

These findings demonstrate that a suicide-prevention campaign in Ontario is very likely a cost-effective intervention to reduce the incidence of suicide and suggest suicide-prevention campaigns are likely to be cost effective for some other Canadian provinces and potentially other countries.

Implantable cardiac monitors to detect atrial fibrillation after cryptogenic stroke: a systematic review and economic evaluation

BACKGROUND

Cryptogenic stroke is a stroke for which no cause is identified after standard diagnostic tests. Long-term implantable cardiac monitors may be better at diagnosing atrial fibrillation and provide an opportunity to reduce the risk of stroke recurrence with anticoagulants.

OBJECTIVES

The objectives were to assess the diagnostic test accuracy, clinical effectiveness and cost-effectiveness of three implantable monitors [BioMonitor 2-AF™ (Biotronik SE & Co. KG, Berlin, Germany), Confirm Rx™ (Abbott Laboratories, Lake Bluff, IL, USA) and Reveal LINQ™ (Medtronic plc, Minneapolis, MN, USA)] in patients who have had a cryptogenic stroke and for whom no atrial fibrillation is detected after 24 hours of external electrocardiographic monitoring.

DATA SOURCES

MEDLINE, EMBASE, The Cochrane Library, Database of Abstracts of Reviews of Effects and Health Technology Assessment databases were searched from inception until September 2018.

REVIEW METHODS

A systematic review was undertaken. Two reviewers agreed on studies for inclusion and performed quality assessment using the Cochrane Risk of Bias 2.0 tool. Results were discussed narratively because there were insufficient data for synthesis. A two-stage de novo economic model was developed: (1) a short-term patient flow model to identify cryptogenic stroke patients who have had atrial fibrillation detected and been prescribed anticoagulation treatment (rather than remaining on antiplatelet treatment) and (2) a long-term Markov model that captured the lifetime costs and benefits of patients on either anticoagulation or antiplatelet treatment.

RESULTS

One randomised controlled trial, Cryptogenic Stroke and underlying Atrial Fibrillation (CRYSTAL-AF) (Sanna T, Diener HC, Passman RS, Di Lazzaro V, Bernstein RA, Morillo CA, et al. Cryptogenic stroke and underlying atrial fibrillation. N Engl J Med 2014;370:2478-86), was identified, and no diagnostic test accuracy study was identified. The CRYSTAL-AF trial compared the Reveal™ XT (a Reveal LINQ predecessor) (Medtronic plc) monitor with standard of care monitoring. Twenty-six single-arm observational studies for the Reveal devices were also identified. The only data for BioMonitor 2-AF or Confirm Rx were from mixed population studies supplied by the companies. Atrial fibrillation detection in the CRYSTAL-AF trial was higher with the Reveal XT than with standard monitoring at all time points. By 36 months, atrial fibrillation was detected in 19% of patients with an implantable cardiac monitor and in 2.3% of patients receiving conventional follow-up. The 26 observational studies demonstrated that, even in a cryptogenic stroke population, atrial fibrillation detection rates are highly variable and most cases are asymptomatic; therefore, they probably would not have been picked up without an implantable cardiac monitor. Device-related adverse events, such as pain and infection, were low in all studies. The de novo economic model produced incremental cost effectiveness ratios comparing implantable cardiac monitors with standard of care monitoring to detect atrial fibrillation in cryptogenic stroke patients based on data for the Reveal XT device, which can be related to Reveal LINQ. The BioMonitor 2-AF and Confirm RX were included in the analysis by making a strong assumption of equivalence with Reveal LINQ. The results indicate that implantable cardiac monitors could be considered cost-effective at a £20,000-30,000 threshold. When each device is compared incrementally, BioMonitor 2-AF dominates Reveal LINQ and Confirm RX.

LIMITATIONS

The cost-effectiveness analysis for implantable cardiac monitors is based on a strong assumption of clinical equivalence and should be interpreted with caution.

CONCLUSIONS

All three implantable cardiac monitors could be considered cost-effective at a £20,000-30,000 threshold, compared with standard of care monitoring, for cryptogenic stroke patients with no atrial fibrillation detected after 24 hours of external electrocardiographic monitoring; however, further clinical studies are required to confirm their efficacy in cryptogenic stroke patients.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018109216.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 5. See the NIHR Journals Library website for further project information.

Level of Evidence in Economic Evaluations of Left Atrial Appendage Closure Devices: A Systematic Review

OBJECTIVES

The objective of the present work was to assess the level of evidence in economic evaluations of percutaneous left atrial appendage closure devices, and to test the complementarity of three different tools for assessing the quality of economic evaluations.

METHODS

We conducted a systematic review of articles in English or French listed in MEDLINE, Embase, Cochrane, the Cost-Effectiveness Analysis registry and the National Health Service Economic Evaluation Database. We included only economic evaluations concerning left atrial appendage closure devices. Data were extracted from articles by two authors working independently and using three analysis grids to measure the quality of economic evaluations [the British Medical Journal (BMJ) checklist, the hierarchy scale developed by Cooper et al. (J Health Serv Res Policy 10:245-50, 2005) and the Quality of Health Economic Studies (QHES) instrument].

RESULTS

Seven economic evaluations met our inclusion criteria. All were published between 2013 and 2016. All were cost-utility analyses, and fully complied with the BMJ checklist. According to the hierarchy scale developed by Cooper et al., the quality of data used was heterogeneous. Finally, the mean score for the seven economic studies was 90/100 with the QHES instrument.

CONCLUSIONS

Despite the recent development of left atrial appendage closure devices, most economic evaluations conducted here were well-designed studies. Furthermore, different tools used to assess the quality of these studies were complementary, but none gave a global vision of the quality of economic studies.

Computational Fluid Dynamic Analysis of the Left Atrial Appendage to Predict Thrombosis Risk

During Atrial Fibrillation (AF) more than 90% of the left atrial thrombi responsible for thromboembolic events originate in the left atrial appendage (LAA), a complex small sac protruding from the left atrium (LA). Current available treatments to prevent thromboembolic events are oral anticoagulation, surgical LAA exclusion, or percutaneous LAA occlusion. However, the mechanism behind thrombus formation in the LAA is poorly understood. The aim of this work is to analyse the hemodynamic behaviour in four typical LAA morphologies - "Chicken wing", "Cactus", "Windsock" and "Cauliflower" - to identify potential relationships between the different shapes and the risk of thrombotic events. Computerised tomography (CT) images from four patients with no LA pathology were segmented to derive the 3D anatomical shape of LAA and LA. Computational Fluid Dynamic (CFD) analyses based on the patient-specific anatomies were carried out imposing both healthy and AF flow conditions. Velocity and shear strain rate (SSR) were analysed for all cases. Residence time in the different LAA regions was estimated with a virtual contrast agent washing out. CFD results indicate that both velocity and SSR decrease along the LAA, from the ostium to the tip, at each instant in the cardiac cycle, thus making the LAA tip more prone to fluid stagnation, and therefore to thrombus formation. Velocity and SSR also decrease from normal to AF conditions. After four cardiac cycles, the lowest washout of contrast agent was observed for the Cauliflower morphology (3.27% of residual contrast in AF), and the highest for the Windsock (0.56% of residual contrast in AF). This suggests that the former is expected to be associated with a higher risk of thrombosis, in agreement with clinical reports in the literature. The presented computational models highlight the major role played by the LAA morphology on the hemodynamics, both in normal and AF conditions, revealing the potential support that numerical analyses can provide in the stratification of patients under risk of thrombus formation, towards personalised patient care.

THE GAP BETWEEN ECONOMIC EVALUATIONS AND CLINICAL PRACTICE: A SYSTEMATIC REVIEW OF ECONOMIC EVALUATIONS ON DABIGATRAN FOR ATRIAL FIBRILLATION

OBJECTIVES

As model-based economic evaluations (MBEEs) are widely used to make decisions in the context of policy, it is imperative that they represent clinical practice. Here, we assess the relevance of MBEEs on dabigatran for the prevention of stroke in patients with atrial fibrillation (AF).

METHODS

We performed a systematic review on the basis of a developed questionnaire, tailored to oral anticoagulation in patients with AF. Included studies had a full body text in English, compared dabigatran with a vitamin K antagonist, were not dedicated to one or more subgroup(s), and yielded an incremental cost-effectiveness ratio. The relevance of all MBEEs was assessed on the basis of ten context-independent factors, which encompassed clinical outcomes and treatment duration. The MBEEs performed for the United States were assessed on the basis of seventeen context-dependent factors, which were related to the country's target population and clinical environment.

RESULTS

The search yielded twenty-nine MBEEs, of which six were performed for the United States. On average, 54 percent of the context-independent factors were included per study, and 37 percent of the seventeen context-dependent factors in the U.S.

STUDIES

The share of relevant factors per study did not increase over time.

CONCLUSIONS

MBEEs on dabigatran leave out several relevant factors, limiting their usefulness to decision makers. We strongly urge health economic researchers to improve the relevance of their MBEEs by including context-independent relevance factors, and modeling context-dependent factors befitting the decision context concerned.

Cost-Effectiveness of Percutaneous Closure of the Left Atrial Appendage in Atrial Fibrillation Based on Results From PROTECT AF Versus PREVAIL

BACKGROUND

Randomized trials of left atrial appendage (LAA) closure with the Watchman device have shown varying results, and its cost effectiveness compared with anticoagulation has not been evaluated using all available contemporary trial data.

METHODS AND RESULTS

We used a Markov decision model to estimate lifetime quality-adjusted survival, costs, and cost effectiveness of LAA closure with Watchman, compared directly with warfarin and indirectly with dabigatran, using data from the long-term (mean 3.8 year) follow-up of Percutaneous Closure of the Left Atrial Appendage Versus Warfarin Therapy for Prevention of Stroke in Patients With Atrial Fibrillation (PROTECT AF) and Prospective Randomized Evaluation of the Watchman LAA Closure Device in Patients With Atrial Fibrillation (PREVAIL) randomized trials. Using data from PROTECT AF, the incremental cost-effectiveness ratios compared with warfarin and dabigatran were $20 486 and $23 422 per quality-adjusted life year, respectively. Using data from PREVAIL, LAA closure was dominated by warfarin and dabigatran, meaning that it was less effective (8.44, 8.54, and 8.59 quality-adjusted life years, respectively) and more costly. At a willingness-to-pay threshold of $50 000 per quality-adjusted life year, LAA closure was cost effective 90% and 9% of the time under PROTECT AF and PREVAIL assumptions, respectively. These results were sensitive to the rates of ischemic stroke and intracranial hemorrhage for LAA closure and medical anticoagulation.

CONCLUSIONS

Using data from the PROTECT AF trial, LAA closure with the Watchman device was cost effective; using PREVAIL trial data, Watchman was more costly and less effective than warfarin and dabigatran. PROTECT AF enrolled more patients and has substantially longer follow-up time, allowing greater statistical certainty with the cost-effectiveness results. However, longer-term trial results and postmarketing surveillance of major adverse events will be vital to determining the value of the Watchman in clinical practice.

Dealing With the Left Atrial Appendage for Stroke Prevention: Devices and Decision-Making

Left atrial appendage (LAA) device occlusion represents a major evolution in stroke prevention for atrial fibrillation (AF). Left atrial appendage device occlusion is now a proven strategy which provides long-term thromboembolic stroke prevention for patients with non-rheumatic AF. Evidence supports its benefit as an alternative to long-term anticoagulation while mitigating long-term bleeding risks and improving cardiovascular mortality. The therapy offers expanded options to physicians and patients negotiating stroke prevention (both primary and secondary prevention), but a good understanding of the risks and benefits is required for decision-making. This review aims to summarise the evolution of LAA device occlusion therapy, current knowledge in the field and a snapshot of current status of the therapy in clinical practice in Australia and around the world.

ANMCO/AIAC/SICI-GISE/SIC/SICCH Consensus Document: percutaneous occlusion of the left atrial appendage in non-valvular atrial fibrillation patients: indications, patient selection, staff skills, organisation, and training

Atrial fibrillation (AF) is the most common arrhythmia and its prevalence is increasing due to the progressive aging of the population. About 20% of strokes are attributable to AF and AF patients are at five-fold increased risk of stroke. The mainstay of treatment of AF is the prevention of thromboembolic complications with oral anticoagulation therapy. Drug treatment for many years has been based on the use of vitamin K antagonists, but recently newer and safer molecules have been introduced (dabigatran etexilate, rivaroxaban, apixaban, and edoxaban). Despite these advances, many patients still do not receive adequate anticoagulation therapy because of contraindications (relative and absolute) to this treatment. Over the last decade, percutaneous closure of left atrial appendage, main site of thrombus formation during AF, proved effective in reducing thromboembolic complications, thus offering a valid medical treatment especially in patients at increased bleeding risk. The aim of this consensus document is to review the main aspects of left atrial appendage occlusion (selection and multidisciplinary assessment of patients, currently available methods and devices, requirements for centres and operators, associated therapies and follow-up modalities) having as a ground the significant evolution of techniques and the available relevant clinical data.

Outcomes and costs of left atrial appendage closure from randomized controlled trial and real-world experience relative to oral anticoagulation

AIMS

The aim of this study was to analyse randomized controlled study and real-world outcomes of patients with non-valvular atrial fibrillation (NVAF) undergoing left atrial appendage closure (LAAC) with the Watchman device and to compare costs with available antithrombotic therapies.

METHODS AND RESULTS

Registry data of LAAC from two centres were prospectively collected from 110 patients with NVAF at risk of stroke, suitable and unsuitable for long-term anticoagulation (age 71.3 ± 9.2 years, CHADS2 2.8 ± 1.2, CHA2DS2-VASc 4.5 ± 1.6, and HAS-BLED 3.8 ± 1.1). Outcomes from PROTECT AF and registry study LAAC were compared with warfarin, dabigatran, rivaroxaban, apixaban, aspirin, and no treatment using a network meta-analysis. Costs were estimated over a 10-year horizon. Uncertainty was assessed using sensitivity analyses. The procedural success rate was 92% (103/112). Follow-up was 24.1 ± 4.6 months, during which annual rates of stroke, major bleeding, and all-cause mortality were 0.9% (2/223 patient-years), 0.9% (2/223 patient-years), and 1.8% (4/223 patient-years), respectively. Anticoagulant therapy was successfully stopped in 91.2% (93/102) of implanted patients by 12 months. Registry study LAAC stroke and major bleeding rates were significantly lower than PROTECT AF results: mean absolute difference of stroke, 0.89% (P = 0.02) and major bleeding, 5.48% (P < 0.001). Left atrial appendage closure achieved cost parity between 4.9 years vs. dabigatran 110 mg and 8.4 years vs. warfarin. At 10 years, LAAC was cost-saving against all therapies (range £1162-£7194).

CONCLUSION

Left atrial appendage closure in NVAF in a real-world setting may result in lower stroke and major bleeding rates than reported in LAAC clinical trials. Left atrial appendage closure in both settings achieves cost parity in a relatively short period of time and may offer substantial savings compared with current therapies. Savings are most pronounced among higher risk patients and those unsuitable for anticoagulation.

The Cost Effectiveness of LAA Exclusion

Left atrial appendage (LAA) exclusion strategies are increasingly utilized for stroke prevention in lieu of oral anticoagulants. Reductions in bleeding risk and long-term compliance issues bundled with comparable stroke prevention benefits have made these interventions increasingly attractive. Unfortunately, healthcare funding remains limited. Comparative cost economic analyses are therefore critical in optimizing resource allocation. In this review we seek to discourse the cost economics analysis of LAA exclusion over available therapeutic alternatives (warfarin and the new oral anticoagulants (NOACs)). .

Cost-effectiveness analysis of left atrial appendage occlusion compared with pharmacological strategies for stroke prevention in atrial fibrillation

BACKGROUND

Transcatheter left atrial appendage occlusion (LAAO) is a promising therapy for stroke prophylaxis in non-valvular atrial fibrillation (NVAF) but its cost-effectiveness remains understudied. This study evaluated the cost-effectiveness of LAAO for stroke prophylaxis in NVAF.

METHODS

A Markov decision analytic model was used to compare the cost-effectiveness of LAAO with 7 pharmacological strategies: aspirin alone, clopidogrel plus aspirin, warfarin, dabigatran 110 mg, dabigatran 150 mg, apixaban, and rivaroxaban. Outcome measures included quality-adjusted life years (QALYs), lifetime costs and incremental cost-effectiveness ratios (ICERs). Base-case data were derived from ACTIVE, RE-LY, ARISTOTLE, ROCKET-AF, PROTECT-AF and PREVAIL trials. One-way sensitivity analysis varied by CHADS2 score, HAS-BLED score, time horizons, and LAAO costs; and probabilistic sensitivity analysis using 10,000 Monte Carlo simulations was conducted to assess parameter uncertainty.

RESULTS

LAAO was considered cost-effective compared with aspirin, clopidogrel plus aspirin, and warfarin, with ICER of US$5,115, $2,447, and $6,298 per QALY gained, respectively. LAAO was dominant (i.e. less costly but more effective) compared to other strategies. Sensitivity analysis demonstrated favorable ICERs of LAAO against other strategies in varied CHADS2 score, HAS-BLED score, time horizons (5 to 15 years) and LAAO costs. LAAO was cost-effective in 86.24 % of 10,000 simulations using a threshold of US$50,000/QALY.

CONCLUSIONS

Transcatheter LAAO is cost-effective for prevention of stroke in NVAF compared with 7 pharmacological strategies. The transcatheter left atrial appendage occlusion (LAAO) is considered cost-effective against the standard 7 oral pharmacological strategies including acetylsalicylic acid (ASA) alone, clopidogrel plus ASA, warfarin, dabigatran 110 mg, dabigatran 150 mg, apixaban, and rivaroxaban for stroke prophylaxis in non-valvular atrial fibrillation management.

Percutaneous closure of the left atrial appendage for stroke prevention in atrial fibrillation: an alternative to lifelong anticoagulation?

Atrial fibrillation is an important risk factor for thromboembolic stroke and it significantly increases the risk of stroke. The left atrial appendage (LAA) is the most common site of thrombus formation in nonvalvular atrial fibrillation, and the recent applications of percutaneous LAA closure devices offer a promising alternative for patients who are unable to tolerate lifelong anticoagulation. Critical care nurses who understand the procedures and are familiar with the various devices used for LAA closure will be well prepared to provide optimum care and appropriate education for these patients.

Cost-Effectiveness of Novel Oral Anticoagulants for Stroke Prevention in Non-Valvular Atrial Fibrillation

Recently, novel oral anticoagulants (NOACs) have been approved for stroke prevention in patients with atrial fibrillation (AF). Although these agents overcome some disadvantages of warfarin, they are associated with increased costs. In this review, we will provide an overview of the cost-effectiveness of NOACs for stroke prevention in AF. Our comments and conclusions are limited to studies directly comparing all available NOACs within the same framework. The available cost-effectiveness analyses suggest that NOACs are cost-effective compared to warfarin, with apixaban likely being most favorable. However, significant limitations in these models are present and should be appreciated when interpreting their results.

Time to Cost-Effectiveness Following Stroke Reduction Strategies in AF: Warfarin Versus NOACs Versus LAA Closure

BACKGROUND

Left atrial appendage closure (LAAC) and nonwarfarin oral anticoagulants (NOACs) have emerged as safe and effective alternatives to warfarin for stroke prophylaxis in patients with nonvalvular atrial fibrillation (AF).

OBJECTIVES

This analysis assessed the cost-effectiveness of warfarin, NOACs, and LAAC with the Watchman device (Boston Scientific, Marlborough, Massachusetts) for stroke risk reduction in patients with nonvalvular AF at multiple time points over a lifetime horizon.

METHODS

A Markov model was developed to assess the cost-effectiveness of LAAC, NOACs, and warfarin from the perspective of the Centers for Medicare & Medicaid Services over a lifetime (20-year) horizon. Patients were 70 years of age and at moderate risk for stroke and bleeding. Clinical event rates, stroke outcomes, and quality of life information were drawn predominantly from PROTECT AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) 4-year data and meta-analyses of warfarin and NOACs. Costs for stroke risk reduction therapies, treatment of associated acute events, and long-term care following disabling stroke were presented in 2015 U.S. dollars.

RESULTS

Relative to warfarin, LAAC was cost-effective at 7 years ($42,994/quality-adjusted life-years [QALY]), and NOACs were cost-effective at 16 years ($48,446/QALY). LAAC was dominant over NOACs by year 5 and warfarin by year 10. At 10 years, LAAC provided more QALYs than warfarin and NOACs (5.855 vs. 5.601 vs. 5.751, respectively). In sensitivity analyses, LAAC remained cost-effective relative to warfarin ($41,470/QALY at 11 years) and NOACs ($21,964/QALY at 10 years), even if procedure costs were doubled.

CONCLUSIONS

Both NOACs and LAAC with the Watchman device were cost-effective relative to warfarin, but LAAC was also found to be cost-effective and to offer better value relative to NOACs. The results of this analysis should be considered when formulating policy and practice guidelines for stroke prevention in AF.

Left Atrial Appendage Closure -The WATCHMAN Device

Atrial fibrillation (AF) is one of the most common arrhythmias seen in clinical cardiology practice. Patients with non-valvular AF have an approximately 5-fold increase in the risk of stroke, with an exponential increase with advancing age. Cardioembolic strokes carry a high mortality risk. Although the potential of warfarin to reduce systemic embolization in AF patients is well established, its use is difficult due to narrow therapeutic windows and additional complications (e.g. increased risk of bleeding), especially for aging patients. Therefore, alternative means of treatment to reduce stroke risk in these patients are needed. The left atrial appendage is the major source of thrombus formation in patients with non-valvular AF. The WATCHMAN device (Boston Scientific, MA) is a percutaneous left atrial appendage closure device which has been tested prospectively in multiple randomized trials. It offers a new stroke risk reduction option for high-risk patients with non-valvular atrial fibrillation who are seeking an alternative to long-term warfarin therapy. Based on the robust WATCHMAN clinical program which consists of numerous studies, with more than 2,400 patients and nearly 6,000 patient-years of follow-up, the WATCHMAN LAAC Device is approved by FDA. In this article we reviewed the preclinical studies and clinical trials, as well as the next generation of the device.

Cost-effectiveness of clopidogrel, prasugrel and ticagrelor for dual antiplatelet therapy after acute coronary syndrome: a decision-analytic model

BACKGROUND

The use of prasugrel or ticagrelor as part of dual antiplatelet therapy with acetylsalicylic acid after acute coronary syndrome (ACS) improves clinical outcomes relative to clopidogrel. The relative cost-effectiveness of these agents are unknown. We conducted an economic analysis evaluating 12 months of treatment with clopidogrel, prasugrel or ticagrelor after ACS.

METHODS

We developed a fully probabilistic Markov cohort decision-analytic model using a lifetime horizon, from the perspective of the Ontario Ministry of Health and Long-Term Care. The model incorporated risks of death, recurrent ACS, heart failure, major bleeding and other adverse effects of treatment. Data on probabilities and utilities were obtained from the published literature where available. The primary outcome was quality-adjusted life-years (QALYs).

RESULTS

Treatment with clopidogrel was associated with the lowest effectiveness (7.41 QALYs, 95% confidence interval [CI] 1.05-14.79) and the lowest cost ($39 601, 95% CI $8434-$111 186). Ticagrelor treatment had an effectiveness of 7.50 QALYs (95% CI 1.13-14.84) at a cost of $40 649 (95% CI $9327-$111 881). The incremental cost-effectiveness ratio (ICER) for ticagrelor relative to clopidogrel was $12 205 per QALY gained. Prasugrel had an ICER of $57 630 per QALY gained relative to clopidogrel. Ticagrelor was the preferred option in 90% of simulations at a willingness-to-pay threshold of $50 000 per QALY gained.

INTERPRETATION

Ticagrelor was the most cost-effective agent when used as part of dual antiplatelet therapy after ACS. This conclusion was robust to wide variations in model parameters.

Left atrial appendage occlusion for stroke prevention

Atrial fibrillation (AF) remains the most common arrhythmia encountered in clinical practice. One of its more common deleterious effects is the development of thromboembolism leading to stroke. The left atrial appendage (LAA) has been shown to the site of the majority of thrombus formation leading to stroke. Anticoagulation with warfarin has been the treatment of choice for prevention of embolic events. Newer anticoagulants have been developed but they still have the potential side effect of causing major bleeding. Occlusion of the LAA has emerged as an alternative therapeutic approach to medical therapy. The aim of this article is to discuss in detail the role of the LAA in thromboembolism in AF, role of device and surgical therapies, and the current clinical data supporting their use. This is particularly timely in that there is now an approved LAA closure device approved in the US for stroke prevention in patients with nonvalvular AF.

Optimization Of Stroke Prophylaxis Strategies In Nonvalvular AF -Drugs, Devices Or Both?

Atrial fibrillation (AF) is the most common cardiac arrhythmia with the prevalence increasing over time. AF probably afflicts ≥2% of worldwide adult population and increases with age.[1-3] In the Framingham Heart Study, the lifetime risk of having at least one episode of AF for 40-year-old men and women was 26% and 23% respectively.[4].

Left atrial appendage closure is preferred to chronic warfarin therapy: the pro perspective

Atrial fibrillation (AF) is associated with increased rates of death, stroke, heart failure, hospitalization, degraded quality of life, reduced exercise capacity, and left ventricular dysfunction. An oral anticoagulant reduces the risk of stroke; however, it places the patient at risk for bleeding complications. Weighing the stroke and bleeding risks remains the key for optimal treatment. Cardiac interventions that can obviate long-term oral anticoagulation hold great promise for the future care of patients with AF and high stroke risk. The percutaneously deployable Watchman device is a paradigm shift in how clinicians can abate the need for continued oral anticoagulation.

Left Atrial Appendage: Physiology, Pathology, and Role as a Therapeutic Target

Atrial fibrillation (AF) is the most common clinically relevant cardiac arrhythmia. AF poses patients at increased risk of thromboembolism, in particular ischemic stroke. The CHADS2 and CHA2DS2-VASc scores are useful in the assessment of thromboembolic risk in nonvalvular AF and are utilized in decision-making about treatment with oral anticoagulation (OAC). However, OAC is underutilized due to poor patient compliance and contraindications, especially major bleedings. The Virchow triad synthesizes the pathogenesis of thrombogenesis in AF: endocardial dysfunction, abnormal blood stasis, and altered hemostasis. This is especially prominent in the left atrial appendage (LAA), where the low flow reaches its minimum. The LAA is the remnant of the embryonic left atrium, with a complex and variable morphology predisposing to stasis, especially during AF. In patients with nonvalvular AF, 90% of thrombi are located in the LAA. So, left atrial appendage occlusion could be an interesting and effective procedure in thromboembolism prevention in AF. After exclusion of LAA as an embolic source, the remaining risk of thromboembolism does not longer justify the use of oral anticoagulants. Various surgical and catheter-based methods have been developed to exclude the LAA. This paper reviews the physiological and pathophysiological role of the LAA and catheter-based methods of LAA exclusion.

A Decision Analysis of Percutaneous Left Atrial Appendage Occlusion Relative to Novel and Traditional Oral Anticoagulation for Stroke Prevention in Patients with New-Onset Atrial Fibrillation

Background. Percutaneous left atrial appendage occlusion (LAAO) is a nonpharmacologic approach for stroke prevention in nonvalvular atrial fibrillation (NVAF). No direct comparisons to novel oral anticoagulants (OACs) exists, limiting decision making on the optimal strategy for stroke prevention in NVAF patients. Addressing this gap in knowledge is timely given the recent debate by the US Food and Drug Administration regarding the effectiveness of LAAO. Objective. To assess the cost-effectiveness of LAAO and novel OACs relative to warfarin in patients with new-onset NVAF without contraindications to OAC. Design. A cost-utility analysis using a patient-level Markov micro-simulation decision analytic model was undertaken to determine the lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) of LAAO and all novel OACs relative to warfarin. Effectiveness and utility data were obtained from the published literature and cost from the Ontario Drug Benefits Formulary and Case Costing Initiative. Results. Warfarin had the lowest discounted QALY (5.13 QALYs), followed by dabigatran (5.18 QALYs), rivaroxaban and LAAO (5.21 QALYs), and apixaban (5.25 QALYs). The average discounted lifetime costs were $15 776 for warfarin, $18 280 for rivaroxaban, $19 156 for apixaban, $20 794 for dabigatran, and $21 789 for LAAO. Apixaban dominated dabigatran and LAAO and demonstrated extended dominance over rivaroxaban. The ICER for apixaban relative to warfarin was $28 167/QALY. Apixaban was preferred in 40.2% of simulations at a willingness-to-pay threshold of $50 000/QALY. Limitations. Assumptions regarding clinical and methodological differences between published studies of each therapy were minimized. Conclusions. Apixaban is the most cost-effective therapy for stroke prevention in patients with new-onset NVAF without contraindications to OAC. Uncertainty around this conclusion exists, highlighting the need for further research.

Hospital costs associated with atrial fibrillation for patients with ischemic stroke aged 18-64 years in the United States

BACKGROUND AND PURPOSE

Hospital costs associated with atrial fibrillation (AFib) among patients with stroke have not been well-studied, especially among people aged <65 years. We estimated the AFib-associated hospital costs in US patients aged 18 to 64 years.

METHODS

We identified hospital admissions with a primary diagnosis of ischemic stroke from the 2010 to 2012 MarketScan Commercial Claims and Encounters inpatient data sets, excluding those with capitated health insurance plans, aged <18 or >64 years, missing geographic region, hospital costs below the 1st or above 99th percentile, and having carotid intervention (n=40 082). We searched the data for AFib and analyzed the costs for nonrepeat and repeat stroke admissions separately. We estimated the AFib-associated costs using multivariate regression models controlling for age, sex, geographic region, and Charlson comorbidity index.

RESULTS

Of the 33 500 nonrepeat stroke admissions, 2407 (7.2%) had AFib. Admissions with AFib cost $4991 more than those without AFib ($23 770 versus $18 779). For the 6582 repeat stroke admissions, 397 (6.0%) had AFib. The costs were $3260 more for those with AFib than those without ($24 119 versus $20 929). After controlling for potential confounders, AFib-associated costs for nonrepeat stroke admissions were $4905, representing 20.6% of the total costs for the admissions. Both the hospital costs and the AFib-associated costs were associated with age, but not with sex. AFib-associated costs for repeat stroke admissions were not significantly higher than for non-AFib patients, except for those aged 55 to 64 years ($3537).

CONCLUSIONS

AFib increased the hospital cost of ischemic stroke substantially. Further investigation on AFib-associated costs for repeat stroke admissions is needed.

An overview of left atrial appendage occlusion devices

Atrial fibrillation (AF) places patients at increased risk of thromboembolic events that can be devastating. The left atrial appendage (LAA) has been identified as the source of thrombus formation in nonvalvular AF. Traditionally, systemic anticoagulation has been used to reduce the risk of stroke and systemic embolism. However, anticoagulation is not well tolerated in all patients and is underutilized. As a potential alternative to anticoagulation, novel therapies have been developed to remove the LAA. Three main techniques are being utilized to accomplish LAA exclusion: percutaneous intracardiac, percutaneous epicardial, and surgical approaches. Emerging evidence suggests that LAA exclusion may be an effective means of reducing the risk of stroke in patients with nonvalvular AF.