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This study fills a gap in additive manufacturing life cycle assessments to improve decision-making in plastic product manufacturing. This assessment investigated cradle-to-gate life cycle energy co...

Electrification of delivery fleets has emerged as an important opportunity to reduce the transportation sector's environmental impact, including reducing greenhouse gas (GHG) emissions. When, where, and how vehicles are charged, however, impact the reduction potential. Not only does the carbon intensity of the grid vary across time and space, but charging decisions also influence battery degradation rates, resulting in more or less frequent battery replacement. Here, we propose a model that accounts for the spatial and temporal differences in charging emissions using marginal emission factors and degradation-induced differences in production emissions using a semi-empirical degradation model. We analyze four different charging strategies and demonstrate that a baseline charging scenario, in which a vehicle is fully charged immediately upon returning to a central depot, results in the highest emissions and employing alternative charging methods can reduce emissions by 8-37%. We show that when, where, and how batteries are charged also impact the total cost of ownership. Although the lowest cost and the lowest emitting charging strategies often align, the lowest cost deployment location for electric delivery vehicles may not be in the same location that maximizes environmental benefits.

Purpose Clinical decision making regarding the use of imaging is appropriately centered on diagnostic efficacy and individual patient factors. However, health policy and imaging guidelines may incorporate other inputs, such as cost-effectiveness and patient preference. In the context of climate change and resource scarcity, the environmental impacts of imaging modalities including ultrasound, CT, and MRI will also become relevant. The purpose of this study was to estimate the environmental impacts of various abdominal imaging examinations. Methods Using commercially available software (SimaPro) and data from user manuals and field experts, a streamlined life cycle assessment was performed to estimate multifactorial environmental impacts of the production and use of ultrasound, CT, and MRI per abdominal imaging examination. Results Ultrasound consumed less energy in both production and use phases (7.8 and 10.3 MJ/examination, respectively) than CT (58.9 and 41.1 MJ/examination) or MRI (93.2 and 216 MJ/examination). Ultrasound emitted fewer CO2 equivalents in production and use phases (0.5 and 0.65 kg/examination) than CT (4.0 and 2.61 kg/examination) or MRI (6.0 and 13.72 kg/examination). Potential human health effects from pollutant emissions were found to be smallest with ultrasound in both production and use phases. Conclusions Among the three imaging modalities, ultrasound was found to have the least environmental impact, by one or more orders of magnitude in various domains. This analysis provides an initial framework for comparing environmental impacts across imaging modalities, which may provide useful inputs for cost-effectiveness analyses and policymaking.

The United States transportation sector consumes 5 billion barrels of petroleum annually to move people and freight around the country by car, truck, train, ship and aircraft, emitting significant greenhouse gases in the process. Making the transportation system more sustainable by reducing these emissions and increasing the efficiency of this multimodal system can be achieved through several vehicle-centric strategies. We focus here on one of these strategies – reducing vehicle mass – and on collecting and developing a set of physics-based expressions to describe the effect of vehicle mass reduction on fuel consumption across transportation modes in the U.S. These expressions allow analysts to estimate fuel savings resulting from vehicle mass reductions (termed fuel reduction value, FRV), across modes, without resorting to specialized software or extensive modeling efforts, and to evaluate greenhouse gas emission and cost implications of these fuel savings. We describe how FRV differs from fuel intensity (FI) and how to properly use both of these metrics, and we provide a method to adjust FI based on mass changes and FRV. Based on this work, we estimate that a 10% vehicle mass reduction (assuming constant payload mass) results in a 2% improvement in fuel consumption for trains and light, medium, and heavy trucks, 4% for buses, and 7% for aircraft. When a 10% vehicle mass reduction is offset by an increase in an equivalent mass of payload, fuel intensity (fuel used per unit mass of payload) increases from 6% to 23%, with the largest increase being for aircraft.

Freight transportation by truck, train, and ship accounts for 5% of the United States’ annual energy consumption (U.S. Energy Information Administration, 2017a). Much of this freight is transported in shipping containers. Lightweighting containers is an unexplored strategy to decrease energy and GHG emissions. We evaluate life cycle fuel savings and environmental performance of lightweighting scenarios applied to a forty-foot (12.2 meters) container transported by ship, train, and truck. Use phase burdens for both conventional and lightweighted containers (steel reduction, substitution with aluminum, or substitution with high tensile steel) were compared to life cycle burdens. The study scope ranged from the transportation of one container 100 km to the lifetime movement of the global container fleet on ships. Case studies demonstrated the impact of lightweighting on typical multimodal freight deliveries to the United States. GREET 1 and 2 (Argonne National Laboratory, 2016a,b) were used to estimate the total fuel cycle burdens associated with use phase fuel consumption. Fuel consumption was determined using modal Fuel Reduction Values (FRV), which relate mass reduction to fuel reduction. A lifetime reduction of 21% in the fuel required to transport a container, and 1.4% in the total fuel required to move the vehicles, cargo, and containers can be achieved. It was determined that a 10% reduction in mass of the system will result in a fuel reduction ranging from 2% to 8.4%, depending on the mode. Globally, container lightweighting can reduce energy demand by 3.6 EJ and GHG emissions by 300 million tonnes CO2e over a 15-year lifetime.

Use phase fuel consumption is responsible for the majority of an automobile's life cycle energy consumption and greenhouse gas (GHG) emissions. Lightweighting is an important strategy to reduce use phase fuel consumption and potentially reduce vehicle life cycle impacts. A popular lightweighting technique is material substitution, in which conventional materials (e.g., iron, steel) are replaced with lighter ones (e.g., aluminum, magnesium). Material substitution, however, often results in higher material production impacts. A life cycle approach is useful in evaluating these material tradeoffs and assessing the overall energy and emissions benefits of lightweighting technologies. Thin-wall ductile cast iron (TWDCI) is a lightweighting fabrication technology that can provide comparable weight reduction to aluminum while having better mechanical properties. This study develops a parametric life cycle model to assess the life cycle performance of TWDCI compared to conventional cast iron and cast aluminum in terms of energy (MJ) and GHGs (as carbon dioxide equivalents - kg CO2e). This model was applied to three lightweighting cases: a differential casing, an engine block, and replacement of all cast iron parts. Fuel reduction values (FRVs) are used to calculate change in fuel consumption due to lightweighting. A sensitivity analysis on these lightweighting cases is employed to determine the mass reduction required to achieve net life cycle benefits and to show the effect of alloy composition on life cycle energy and emissions. Lightweighting by 2% results in equal life cycle energy and GHGs for TWDCI and conventional cast iron while 37% lightweighting is required for TWDCI to equal cast aluminum impacts. The implications of powertrain resizing afforded by lightweighting are also explored.

The objective of this work is to evaluate the life cycle impacts of recovering superabsorbent polymers from absorbent hygiene products (AHPs). AHPs, which include baby diapers, feminine hygiene products, and adult incontinence pads, have a considerable environmental impact. While convenient, the vast majority of these products, which typically contain combinations of polypropylene, polyethylene, elastics, cellulose, and superabsorbent polymers (SAPs), are single use. Current practice of AHP disposal results in the loss of valuable materials like SAPs, generation of large volumes of municipal solid waste, and increased manufacturing burdens. While recognition of AHP impacts is increasing, it is important to consider that the most significant life cycle impacts of AHPs stem from resource extraction and manufacturing, not disposal itself. The SAPs in these products are of particular importance as they contribute substantially to these upstream life cycle impacts. We aim to shed light on how we might lessen upstream impacts by focusing on the potential for SAP recovery and re-use. This research evaluates end-of-life options for baby diapers in Europe using a life cycle approach to explore alternative options to conventional disposal of AHPs. We analyze the environmental trade-offs under the following scenarios: 1) diaper disposal via landfill or incineration; 2) diaper recycling without SAP recovery; and 3) diaper recycling with theoretical SAP recovery. Each recycling scenario is analyzed under two allocation conditions for a total of five scenarios. Environmental impacts were modeled in the LCA software SimaPro using the ReCipe 2016 impact assessment framework. Results show that SAP recovery has potential to decrease life cycle emissions by 54% compared to standard landfilling and incineration and by 35% when compared to the recycling technologies assessed in the study. SAP recovery and reuse also results in large potential offsets of energy and water burdens involved in SAP manufacturing. By assessing these environmental impacts, we aim to clarify the point at which SAP recovery demonstrates potential for circular economy.

This article presents an algorithm to aid practitioners in determining the most appropriate method to estimate carbon dioxide emissions from an electricity load. Applications include sustainability assessments of products, processes, energy efficiency improvements, changes in generation infrastructure, and changes in electricity demand. Currently, there is no consensus on appropriate methods for calculating greenhouse gas emissions resulting from specific electricity loads. Previous research revealed significant differences in emissions when different methods were used, a situation that could result in divergent sustainability or policy recommendations. In this article, we illustrate the distribution of emissions estimates based on method characteristics such as region size, temporal resolution, average or marginal approaches, and time scales. Informed by these findings, a decision support algorithm is presented that uses a load's key features and an analyst's research question to provide recommendations on appropriate method types. We defined four different cases to demonstrate the utility of the algorithm and to illustrate the variability of methods used in previous studies. Prior research often employed simplifying assumptions, which, in some cases, can result in electricity being allocated to the incorrect generating resources and improper calculation of emissions. This algorithm could reduce inappropriate allocation, variability in assumptions, and increase appropriateness of electricity emissions estimates.

Wind turbine development in Ontario, Canada has been met with opposition yet will likely continue given broader environmental and economic forces. Ontario has ceased the use of coal for electricity generation and the populace has indicated that increased nuclear capacity is undesirable; renewables are a viable alternative. This paper captures experiences with and opinions of wind turbines in politicians and community members to determine which characteristics of development led to acceptance or opposition towards wind turbines, and which changes to policy and decision-making processes may address opposition. A constant-comparison case study, based largely on in-depth interviewing, was conducted with 24 participants who were MPPs, members of local government, and community members. The findings centre on two emergent themes: concerns with current decision-making processes, and options for addressing these concerns though changes to policy and development processes. Key findings were that perceived inequalities (between neighbours, within communities, and within the province) were the main source of opposition related to wind turbines and that future development may be more amenable if partnered with increased compensation or community ownership. Community members were absolutist in their opposition compared to politicians who identified advantages and disadvantages of wind turbines.

A large portion of life cycle transportation impacts occur during vehicle operation, and key improvement strategies include increasing powertrain efficiency, vehicle electrification, and lightweighting vehicles by reducing their mass. The potential energy benefits of vehicle lightweighting are large, given that 29.5 EJ was used in all modes of U.S. transportation in 2016, and roughly half of the energy spent in wheeled transportation and the majority of energy spent in aircraft is used to move vehicle mass. We collect and review previous work on lightweighting, identify key parameters affecting vehicle environmental performance (e.g., vehicle mode, fuel type, material type, and recyclability), and propose a set of 10 principles, with examples, to guide environmental improvement of vehicle systems through lightweighting. These principles, based on a life cycle perspective and taken as a set, allow a wide range of stakeholders (designers, policy-makers, and vehicle manufacturers and their material and component suppliers) to evaluate the trade-offs inherent in these complex systems. This set of principles can be used to evaluate trade-offs between impact categories and to help avoid shifting of burdens to other life cycle phases in the process of improving use-phase environmental performance.

The relationship between battery operation and their degradation and service life is complex and not well synthesized or communicated. There is a resulting lack of awareness about best practices that influence service life and degradation. Battery degradation causes premature replacement or product retirement, resulting in environmental burdens from producing and processing new battery materials, as well as early end-of-life burdens. It also imposes a significant cost on the user, as batteries can contribute to over 25% of the product cost for consumer electronics, over 35% for electric vehicles, and over 50% for power tools. We review and present mechanisms, methods, and guidelines focused on preserving battery health and limiting degradation. The review includes academic literature as well as reports and information published by industry. The goal is to provide practical guidance, metrics, and methods to improve environmental performance of battery systems used in electronics (i.e., cellphones and laptops), vehicles, and cordless power tools to ultimately better inform users as well as battery designers, suppliers, vehicle and device manufacturers, and material recovery and recycling organizations.

This study evaluates and provides guidance on improving the life cycle environmental performance of dishwashing in the typical U.S. household. Typical user behaviors and recommended best practices for manual dishwashing as well as machine dishwasher use are evaluated. A sensitivity analysis shows the influence of varying grid carbon intensity, water heater type, regional water scarcity, and behaviors such as pre-rinsing and machine loading on overall results. Use-phase behaviors are observed through a small-scale laboratory study. Dishwashing following typical manual and machine practices produces 5,620 and 2,090 kg CO2e life cycle greenhouse gas (GHG) emissions respectively based on washing 4 loads (8 place settings per load) a week for 10 years. Avoiding typical behaviors like pre-rinsing and selecting heated dry can decrease life cycle GHG emissions for machine dishwashing by 3% and 11%, respectively. The running tap style of manual dishwashing results in the highest life cycle GHG emissions of the alternatives in the lab study. Manual dishwashing has the potential to have the lowest GHG emmisions (1,610 kg) when recommended behaviors are followed, less than the 1,960 kg CO2e for recommended machine dishwasher use. When life cycle water consumption burdens are evaluated, typical manual and machine dishwashing use 34,200 and 16,300 gallons respectively and these results are contextualized to regions with different water scarcity. A life cycle cost (LCC) analysis finds that machine dishwashing costs more than manual dishwashing over a 10-year lifetime even if best practices are followed. However, when a user’s time spent washing is valued, machine dishwashers pay for themselves within a year of use.

Vehicle electrification is expanding worldwide and has the potential to reduce greenhouse gas emissions (GHGs) from the transportation sector. Batteries are a key component of energy storage systems for electric vehicles (EVs), and their integration into EVs can lead to a wide range of possible environmental outcomes. These outcomes depend on factors such as powertrain type, electricity source, charging patterns, and end-of-life management. Given the complexities of battery systems, a framework is needed to systematically evaluate environmental impacts across battery system life cycle stages, from material extraction and production to use in the EV, through the battery’s end-of-life. We have developed a set of ten principles to provide practical guidance, metrics, and methods to accelerate environmental improvement of mobile battery applications and facilitate constructive dialogue among designers, suppliers, original equipment manufacturers, and end-of-life managers. The goal of these principles, which should be implemented as a set, is to enhance stewardship and sustainable life cycle management by guiding design, material choice, deployment (including operation and maintenance), and infrastructure planning of battery systems in mobile applications. These principles are applicable to emerging battery technologies (e.g., lithium-ion), and can also enhance the stewardship of existing (e.g., lead-acid) batteries. Case study examples are used to demonstrate the implementation of the principles and highlight the trade-offs between them.

Green electricity generation can provide an indirect route to cleaner air: by displacing generation from fossil fuels, green electricity can reduce emissions of CO2 and conventional air pollutants. Several types of voluntary markets have emerged in the United States to take advantage of this relationship, including green electricity programs, carbon offsets, and renewable energy certificates. At the same time, regulators are favoring cap-and-trade mechanisms for regulating emissions. This paper describes the appropriate framing of environmental claims for green electricity products. We apply an accounting framework for evaluating claims made for capped pollutants, with entries for emissions, avoided emissions due to green electricity, and unused emission permits. This framework is applied in case studies of two major electric utilities that operate with green electricity programs and capped pollutants. The cases demonstrate that the relative magnitude of “unused permits” and “emissions avoided” is a key relationship for evaluating an emissions reduction claim. Lastly, we consider the evolution of the green electricity marketplace given the reliance on cap-and-trade. In this setting, pollution-emission products could be decoupled from one another and from the various green electricity products. Several positive consequences could transpire, including better transparency of products, lower certification costs, and more product choices.

There is an increasing interest in adding renewables such as wind to electricity generation portfolios in larger amounts as one response to concern about atmospheric carbon emissions from our energy system and the resulting climate change. Most policies with the aim of promoting renewables (e.g., RPS, FIT) do not explicitly address siting issues, which for wind energy are currently approached as the intersection of wind resource, land control, and transmission factors. This work proposes the use of locational marginal price (LMP), the location and time specific cost of electricity on the wholesale market, to signal locations where generation can address electricity system insufficiency. After an examination of the spatial and temporal behavior of LMP in Michigan over the first two years of wholesale market operation, this work combines LMP with wind speed data to generate a value metric. High value sites in Michigan tend to be sites with higher wind speeds, with the bulk of value accruing in the fall and winter seasons.

Wind and solar resources are, by nature, spatially distributed and temporally variable. The process of siting generators that use these renewable resources and integrating them into the electricity system therefore raises different issues than the same process for combustion facilities does. A method for discovering wind power sites with the highest value to the electricity system was developed and is illustrated here using data for the state of Michigan. This method combines readily available hourly average 10 m wind speed data with wholesale electricity price data, as hourly locational marginal price (LMP). The 10 m wind speed data from 72 sites were extrapolated vertically to 80 m turbine hub height, converted to wind power density, and interpolated horizontally via kriging to reconstruct a continuous surface. LMP data from 178 generator nodes were allocated across space using Thiessen polygons. High LMP was interpreted as a signal of insufficiency or weakness in the electricity system, and wind energy was considered a possible remedy. The method, implemented in a GIS, identifies when and where peaks in LMP and wind power density co-occur and highlights these events as high value. As the drive to incorporate more renewable generators into the electricity system increases, this method will help locate the most desirable sites based on wind resource characteristics and the structure of the larger electricity system. Proposing a new way to think about the value of the wind resource to the electricity system is a primary contribution of this work.

This paper describes the design and evaluation of a grid-tied photovoltaic (PV) system to be placed over the existing visitor center skylight for the Independence National Park in Philadelphia, Pa. using an integrated approach. The approach included calibrated building energy and lighting models (sensors and computational), estimation of the PV power produced, and cost taking into consideration the reduction based on cooling energy and emissions avoided by the displacement of purchased electricity (the mix of generating technologies in the local power control area was used to estimate avoided emissions). The design of the PV system was guided by the building orientation and skylight construction and was based on currently available PV modules. Several array sizes were considered since the choice of array size has implications for power production and shading, as well as for building cooling energy demand.

Debate on the sustainability of human settlements has recently been focused primarily on the urban portion of the land use pattern. However, urban areas rely on suburban, rural, and other less densely settled lands for their existence. In order to quantify the impacts of various land patterns on their supporting resources, these exurban lands must be included in any sustainability assessment. This need for a regional view has resulted in a measurement method that enables comparisons of relative sustainability between various regional land use patterns. Existing methods employed to assess urban sustainability are reviewed and compared with the regional characteristic curves method, introduced here, that takes a more holistic regional view. Results from the application of the method are presented, displaying the spatial dimension it brings to the analysis of illustrative primary metrics as well as demonstrating its ability to spatially quantify change in these metrics over time. © 2004 Elsevier B.V. All rights reserved.

Building integrated photovoltaics (BIPV) perform traditional architectural functions of walls and roofs while also generating electricity. The displacement of utility generated electricity and conventional building materials can conserve fossil fuels and have environmental benefits. A life cycle inventory model is presented that characterizes the energy and environmental performance of BIPV systems relative to the conventional grid and displaced building materials. The model is applied to an amorphous silicon PV roofing shingle in different regions across the US. The electricity production efficiency (electricity output/total primary energy input excluding insolation) for a reference BIPV system (2kWp PV shingle system with a 6% conversion efficiency and 20 year life) ranged from 3.6 in Portland OR to 5.9 in Phoenix, AZ indicating a significant return on energy investment. The reference system had the greatest air pollution prevention benefits in cities with conventional electricity generation mixes dominated by coal and natural gas, not necessarily in cities where the insolation and displaced conventional electricity were greatest.

Organizations are increasingly transitioning to a more sustainable management approach as a result of drivers related to corporate reputation, operational efficiency, and regulatory compliance. Accordingly, organizations that are proving resilient to this trend are gaining a competitive edge. This paper draws from the field of industrial ecology in terms of material flow analysis to set a foundation for organizations that wish to integrate sustainability principles into the management system. Though research has linked industrial ecology to sustainable business operations, there is a void on the practical level in terms of implementation and maintenance strategies, leaving businesses unequipped to adapt to a more sustainable approach, now commonly known as triple bottom line. In response, the framework of this paper uses the concept of material flow analysis, to guide a detailed process for achieving more sustainable business operations.

This paper highlights results from a collaborative life-cycle design project between the University of Michigan, the US Environment Protection Agency and United Solar Systems Corporation. Energy analysis is a critical planning and design tool for photovoltaic (PV) modules. A set of model equations for evaluating the life-cycle energy performance of PV systems and other electricity-generating systems are presented. The total PV life-cycle, encompassing material production, manufacturing and assembly, use and end-of-life management, was investigated. Three metrics—energy payback time, electricity production eAciency and lifecycle conversion eAciency—were defined for PV modules with and without balanceof-system (BOS) components. These metrics were evaluated for a United Solar UPM-880 amorphous silicon PV module based on average insolation in Detroit, Boulder and Phoenix. Based on these metrics, a minimum condition for assessing the sustainability of electricity-generating systems was proposed and discussed. The life-cycle energy analysis indicated that the aluminum frame is responsible for a significant fraction of the energy invested in the UPM-880 module. #1997 John Wiley & Sons, Ltd.

A 58-year-old man who was taking warfarin at a stable dosage was admitted to the hospital with a diagnosis of bacterial meningitis. Although he had previously been a smoker, after this admission, he decided to give up smoking. He was continued on his previous warfarin maintenance dosage when discharged, and his international normalized ratio (INR) soon began to climb substantially. When questioned, the patient reported no diet or lifestyle changes other than his smoking cessation. The patient's INR was stabilized at a warfarin dosage 23% lower than the maintenance dosage before he stopped smoking. This case report illustrates the potential for an interaction between warfarin and cigarette smoking and further suggests that the effect could be significant if a patient starts or stops smoking during warfarin therapy.

There is growing evidence that better outcomes are achieved when anticoagulation is managed by anticoagulation clinics rather than by family physicians. We carried out a randomized controlled trial to evaluate these 2 models of anticoagulant care.We randomly allocated patients who were expected to require warfarin sodium for 3 months either to anticoagulation clinics located in 3 Canadian tertiary hospitals or to their family physician practices. We evaluated the quality of oral anticoagulant management by comparing the proportion of time that the international normalized ratio (INR) of patients receiving warfarin sodium was within the target therapeutic range +/- 0.2 INR units (expanded therapeutic range) while they were managed in anticoagulation clinics as opposed to family physicians' care over 3 months. We measured the rates of thromboembolic and major hemorrhagic events and patient satisfaction in the 2 groups.Of the 221 patients enrolled, 112 were randomly assigned to anticoagulation clinics and 109 to family physicians. The INR values of patients who were managed by anticoagulation clinics were within the expanded therapeutic range 82% of the time versus 76% of the time for those managed by family physicians (p = 0.034). High-risk INR values (defined as being1.5 or5.0) were more commonly observed in patients managed by family physicians (40%) than in patients managed by anticoagulation clinics (30%, p = 0.005). More INR measurements were performed by family physicians than by anticoagulation clinics (13 v. 11, p = 0.001). Major bleeding events (2 [2%] v. 1 [1%]), thromboembolic events (1 [1%] v. 2 [2%]) and deaths (5 [4%] v. 6 [6%]) occurred at a similar frequency in the anticoagulation clinic and family physician groups respectively. Of the 170 (77%) patients who completed the patient satisfaction questionnaire, more were satisfied when their anticoagulant management was managed through anticoagulation clinics than by their family physicians (p = 0.001).Anticoagulation clinics provided better oral anticoagulant management than family physicians, but the differences were relatively modest.

Background Long-term anticoagulation prevents recurrent thrombosis in patients with idiopathic deep venous thrombosis or pulmonary embolism, but with a risk of clinically important so-called major bleeding. Physician- and patient-based decisions on the optimal duration of therapy are sensitive to the bleeding risk. The Outpatient Bleeding Risk Index potentially provides a means of calculating the potential risk of bleeding using easily elicited clinical findings, but, to our knowledge, the authors of the index have provided the only published validation of it. We sought to determine the accuracy of the index in our population of patients. Methods We prospectively applied the Outpatient Bleeding Risk Index to consecutive patients in our clinic who had been objectively diagnosed as having pulmonary embolism or deep venous thrombosis and who were about to undergo standard therapy. Standard therapy consisted of a minimum of 5 days of low-molecular-weight heparin therapy overlapped with warfarin sodium therapy, and continuation of warfarin therapy for at least 3 months, with a target international normalized ratio of 2.5. Patients were placed in 3 risk groups (low, moderate, or high), as defined by the index. The survival curves of the groups, using major hemorrhages as the events, were then compared by the log-rank test. Results Bleeding rates were lower than expected, but the index did discriminate between low- and moderate-risk groups ( P = .03, log-rank test). The rate of major hemorrhage per 100 person-years was 0% (95% confidence interval, 0%-2.8%) in the low-risk group and 4.3% (95% confidence interval, 1.1%-11.1%) in the moderate-risk group. The rate in the high-risk group could not be defined because only 2 patients were at high risk. Conclusion The Outpatient Bleeding Risk Index discriminates between low- and moderate-risk patients, and could be used to guide decisions on the optimal duration of anticoagulant therapy.