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There is a need for a consistent, reproducible, and cost-effective method of determining cardiac recovery in patients who receive emerging novel therapeutics for advanced and end-stage heart failure (HF). With the increasing use of ventricular assist devices (VADs) in end-stage HF, objective device diagnostics are available for analysis. Pulsatility, one of the accessible diagnostic measures, is a variable gage of the differential between peak systolic and minimum diastolic flow during a single cardiac cycle. Following implantation of the VAD, HeartWare's HVAD records pulsatility regularly. Thus, we hypothesize that this measurement relates to the contractility of the heart and could be utilized as a metric for determining patient response to various therapeutics. In this study, therefore, we develop a translatable and effective predictive model characterizing pulsatility to determine HF status and potential HF recovery using the SynCardia Total Artificial Heart (TAH) in conjunction with a Donovan Mock Circulation System to create a simulation platform for the collection of pulsatility data. We set the simulation platform to patient conditions ranging from critical heart failure to a normal operating condition through the variation preload, afterload, and left ventricular (LV) pumping force or TAH "contractility." By manipulating these variables, pulsatility was found to accurately indicate significant (p < 0.05) improvements in LV contractility at every recorded afterload and preload, suggesting that it is a valuable parameter for the assessment of cardiac recovery in patients.

There is no shortage of data demonstrating that diversified cropping systems can sustain high levels of productivity with fewer external inputs and lower externalities compared to more simplified systems. Similarly, data exist indicating diverse cropping systems have greater capacity to buffer against and adapt to weather extremes associated with climate change. Yet, agriculture in the US Corn Belt and other major crop production regions around the world continues to move toward simplified rotations grown over increasingly large acreages. If our goal is to see more of the agricultural landscape made up of diverse agricultural systems and the ecosystem services they provide, it is critical we understand and creatively address the factors that both give rise to monocultures and reinforce their entrenchment at the exclusion of more diversified alternatives. Using the current state of farming and agriculture policy in the US as a case study, we argue that a pernicious feedback exists in which economic and policy forces incentivize low diversity cropping systems which then become entrenched due, in part, to a lack of research and policy aimed at enabling farming practices that support the diversification of cropping systems at larger spatial scales. We use the recent example of dicamba-resistant crops to illustrate the nature of this pernicious feedback and offer suggestions for creating “virtuous feedbacks” aimed at achieving a more diversified agriculture.

Maintaining mechanical circulatory support (MCS) device patients in a specified therapeutic range for anticoagulation remains challenging. Subtherapeutic international normalized ratios (INRs) occur frequently while on warfarin therapy. An effective anticoagulant bridge strategy may improve the care of these patients. This retrospective review of MCS patients with subtherapeutic INRs compared an intravenous unfractionated heparin (UFH) strategy with a subcutaneous enoxaparin or fondaparinux strategy. Native thromboelastography (n-TEG) was used to evaluate anticoagulant effect with coagulation index (CI) as the primary outcome measure. Enoxaparin 0.5 mg/kg subcutaneously (SC) every 12 hours or fondaparinux 2.5-5 mg SC daily were compared with an initial UFH rate of 5 units/kg/hr and titrated to stated n-TEG goal range. The anticoagulant groups UFH, enoxaparin, and fondaparinux were found to be statistically similar with regard to frequency in n-TEG goal range, above range (hypercoagulability), or below range (hypocoagulability). Clinical outcomes were similar among groups with three gastrointestinal bleeds in UFH, one in enoxaparin, and one in fondaparinux groups. Device thrombosis occurred in one UFH patient, while UFH and fondaparinux groups had one ischemic cerebrovascular accident event each. These strategies provided comparable n-TEG results and clinical outcomes when compared with intravenous UFH. Low-dose enoxaparin or fondaparinux may provide an alternative anticoagulant bridging option in MCS patients presenting with subtherapeutic INR.

BACKGROUND We sought to better understand the patient population who receive a temporary total artificial heart (TAH) as bridge to transplant or as bridge to decision by evaluating data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database. METHODS We examined data related to survival, adverse events, and competing outcomes from patients who received TAHs between June 2006 and April 2017 and used hazard function analysis to explore risk factors for mortality. RESULTS Data from 450 patients (87% men; mean age, 50 years) were available in the INTERMACS database. The 2 most common diagnoses were dilated cardiomyopathy (50%) and ischemic cardiomyopathy (20%). Risk factors for right heart failure were present in 82% of patients. Most patients were INTERMACS Profile 1 (43%) or 2 (37%) at implantation. There were 266 patients who eventually underwent transplantation, and 162 died. Overall 3-, 6-, and 12-month actuarial survival rates were 73%, 62%, and 53%, respectively. Risk factors for death included older age (p = 0.001), need for pre-implantation dialysis (p = 0.006), higher creatinine (p = 0.008) and lower albumin (p < 0.001) levels, and implantation at a low-volume center (≤10 TAHs; p < 0.001). Competing-outcomes analysis showed 71% of patients in high-volume centers were alive on the device or had undergone transplantation at 12 months after TAH implantation vs 57% in low-volume centers (p = 0.003). CONCLUSIONS Patients receiving TAHs have rapidly declining cardiac function and require prompt intervention. Experienced centers have better outcomes, likely related to patient selection, timing of implantation, patient care, and device management. Organized transfer of knowledge to low-volume centers could improve outcomes.

Purpose To determine if an unexpectedly elevated international normalized ratio (INR) may be associated with symptomatic clinical change in mechanical circulatory support (MCS) patients on relatively stable doses of warfarin. We hypothesize that a significant INR rise while on consistent doses of warfarin may be a signal for current or pending declines in clinical status. Methods A retrospective review of 64 outpatient MCS recipients was performed during the period 9/2013-5/2018. Patient information regarding signs and symptoms of acute decompensation were collected. These included hospital admission for fluid overload, low-flow alarms with syncope, ventricular tachyarrhythmia with/without implantable cardiac defibrillator firing, right ventricular failure, or noted fluid overload at clinic visits necessitating diuretic increase. An INR rise to values >4.0 was compared to a concurrent incidence of changes in clinical status or need for intervention within the subsequent month after an unexplained labile INR. Results The cohort included both left ventricular assist device and total artificial heart patients. Sixty-two INR values >4.0 occurred at hospital admission or preceded a clinical event by 30 days or less. The average INR that fit these criteria was 5.0 +/- 1.3. The positive predictive value of an acute clinical change as a potential for INR elevation was 28.7% with a sensitivity of 0.54. Fifty-three instances of a herein defined decline in clinical status were not associated with elevated INR. The negative predictive value of an INR 4.0, nor in the 5,836 recorded INRs that were Conclusion An unexpected INR rise may be evidence of a worsening scenario for an MCS patient experiencing a change in clinical status.

The northern New England region includes the states of Vermont, New Hampshire, and Maine and encompasses a large degree of climate and edaphic variation across a relatively small spatial area, making it ideal for studying climate change impacts on agricultural weed communities. We sampled weed seedbanks and measured soil physical and chemical characteristics on 77 organic farms across the region and analyzed the relationships between weed community parameters and select geographic, climatic, and edaphic variables using multivariate procedures. Temperature-related variables (latitude, longitude, mean maximum and minimum temperature) were the strongest and most consistent correlates with weed seedbank composition. Edaphic variables were, for the most part, relatively weaker and inconsistent correlates with weed seedbanks. Our analyses also indicate that a number of agriculturally important weed species are associated with specific U.S. Department of Agriculture plant hardiness zones, implying that future changes in climate factors that result in geographic shifts in these zones will likely be accompanied by changes in the composition of weed communities and therefore new management challenges for farmers.

Device thrombosis is a devastating complication of left ventricular assist devices. The definitive treatment has been device exchange or explant. Evidence of increasing morbidity and mortality with device exchange has shifted strategies toward conservative management. In this report, we detail the use of thrombolytics as salvage therapy in a patient with an occlusive HeartWare ventricular assist device (HeartWare Inc., Framingham, MA) thrombus, resulting in long-term survival without further intervention.

Agricultural expansion contributes to the degradation of biodiverse ecosystems and the services these systems provide. Expansion of urban and peri-urban agriculture (UPA), on the other hand, may hold promise to both expand the portfolio of ecosystem services (ES) available in built environments, where ES are typically low and to reduce pressure to convert sensitive non-urban, non-agricultural ecosystems to agriculture. However, few data are available to support these hypotheses. Here we review and summarize the research conducted on UPA from 320 peer-reviewed papers published between 2000 and 2014. Specifically, we explored the availability of data regarding UPA's impact on ES and disservices. We also assessed the literature for evidence that UPA can contribute to land sparing. We find that the growth in UPA research over this time period points to the emerging recognition of the potential role that UPA systems play in food production worldwide. However, few studies (n= 15) place UPA in the context of ES, and no studies in our review explicitly quantify the land sparing potential of UPA. Additionally, while few studies (n= 19) quantify production potential of UPA, data that are necessary to accurately quantify the role these systems can play in land sparing, our rough estimates suggest that agricultural extensification into the world's urban environments via UPA could spare an area approximately twice the size of the US state of Massachusetts. Expanding future UPA research to include quantification of ES and functions would shed light on the ecological tradeoffs associated with agricultural production in the built environment. As food demand increases and urban populations continue to grow, it will be critical to better understand the role urban environments can play in global agricultural production and ecosystem preservation.

Purpose To study the frequency by which a significantly elevated international normalized ratio (INR) may be associated with a major bleeding event in mechanical circulatory support device (MCS) patients. Methods A retrospective review of mechanical circulatory support device recipients was performed for the years 9/2013-5/2018. The incidence of significant bleeding was determined using the MOMENTUM 3 major adverse event bleeding definition. The incidence of bleeding within 30 days of an INR>4.0 was assessed. Results Sixty-Four MCS patients (36 Heartware, 18 Heartmate II, 7 Heartmate III, 3 total artificial heart) were reviewed for INR data over the study period. Only ten patients never had any INR values above 4.0. A total of 217 INR measurements were found to be greater than 4.0. There was a total of 56 major bleeding events in 33 patients during the study period. Eleven patients experienced 17 major bleeding events associated with INR>4.0, however 39 bleeds did not register an INR>4.0. The incidence of bleeding and high INR as measured by positive predictive value was 8.3% with a sensitivity of 0.306. The negative predictive value for freedom from bleeding with INR 4.0 was 10.3 +/- 10.0 days. Both the bleeding and the non-bleeding groups had an average total number of INR values>4.0 for the study period of 3.9 +/- 3.5. There were 9 gastrointestinal bleeds (GIB), and 6 non GIBs that required transfusion, as well as 2 intracranial hemorrhages (ICH) in the elevated INR group. No bleeds within a month of an INR>4.0 group were fatal, whereas two ICHs in the INR Conclusion A single elevated INR>4.0 did not correlate strongly with an incidence of major bleeding in the subsequent 30 days. The amount of time to bleeding events after an elevated INR is also quite variable making the forecasting of potential bleeding difficult. Further study is warranted to improve our understanding of the link between the frequency, amount of time, and individual significance of supratherapeutic INR and bleeding complications.

Purpose Majority of patients who are BTT with a TAH are INTERMACS profiles 1 & 2. Few center-based reports document outcomes after HT for patients with TAH, which range from inferior to similar survival compared to a non-BTT population. We report the outcomes of HT after TAH placement from a national registry. Methods This analysis examined HT outcomes in patients BTT with TAH compared to BiVAD and LVAD, in a linked cohort from the INTERMACS & SRTR databases (2006-15). Survival was determined for LVAD vs BiVAD vs TAH BTT cohort. Risk factors for mortality were explored using multi-phase hazard modeling. Results Among 3143 adults supported with MCS at HT and linked in the INTERMACS & SRTR databases, there were 176 TAH, 2762 LVAD and 205 BiVAD. TAH group mean age: 48.6 ± 13.1 years; males 86.4%; diagnosis: DCM 69.9%, ICM 19.3%; donor mean age: 30.2± 10.8 years. Donor age ( 40 years) did not affect survival in the HT TAH (p = 0.2). Post-HT survival without risk adjustment with each MCS in Fig. After risk adjustment with multi-phase hazard model, LVAD alone was associated with less post-HT risk (HR=0.55 [95%CI]). TAH was not an independent risk factor compared to BiVAD, constant phase. HT survival at 1, 36, 60 months in TAH BTT vs ISHLT Registry was 89.2%, 69.8%, 61.3% vs 92%, 63.6%, 57.3%, respectively. Post-HT complications were LVAD vs BiVAD vs TAH: rejection 1st year 21.2%, 26.4%, 15.5% (p=0.1); stroke 3.4%, 5.9%, 5.7% (p=0.07); infection 15.3%, 27.3%, 21.6% (p Conclusion The LVAD, TAH and BTT cohorts show similar post-HT survival compared to the ISHLT. Donor age did not influence TAH BTT survival. TAH cohort had a higher incidence of H-KT. After risk adjustment: TAH & BiVAD post-HT survival were similar. Post-HT complications are similar among MCS groups, except higher infection risk with BiVAD. In patients with BiV failure, TAH is an option, with lower post-HT infection compared to BiVADs.

With the growth and diversity of mechanical circulatory support (MCS) systems entering clinical use, a need exists for a robust mock circulation system capable of reliably emulating and reproducing physiologic as well as pathophysiologic states for use in MCS training and inter-device comparison. We report on the development of such a platform utilizing the SynCardia Total Artificial Heart and a modified Donovan Mock Circulation System, capable of being driven at normal and reduced output. With this platform, clinically relevant heart failure hemodynamics could be reliably reproduced as evidenced by elevated left atrial pressure (+112%), reduced aortic flow (-12.6%), blunted Starling-like behavior, and increased afterload sensitivity when compared with normal function. Similarly, pressure-volume relationships demonstrated enhanced sensitivity to afterload and decreased Starling-like behavior in the heart failure model. Lastly, the platform was configured to allow the easy addition of a left ventricular assist device (HeartMate II at 9600 RPM), which upon insertion resulted in improvement of hemodynamics. The present configuration has the potential to serve as a viable system for training and research, aimed at fostering safe and effective MCS device use.

There is growing interest among farmers in the northeast US in silvopasture and other practices that would help them expand their agricultural land base in this forested region. Unfortunately, little quantitative data exist regarding forage performance and economic outcomes associated with different forest-to-agriculture conversion strategies, particularly for the northern tier of states. This research examined forage dry matter production and quality in six forage treatments (orchardgrass, bluegrass, brome, and perennial ryegrass bicultures with white clover; cut hay; and a control) in newly-established silvopastures and open pastures converted from an early successional northern hardwood forest in New York. In addition, we conducted a financial analysis of the establishment of both agricultural systems, as well as a thinned forest treatment managed solely for wood products. Total forage dry matter production (planted forages plus volunteer grasses) was greater in open pastures than silvopastures in the first year after establishment; however, no differences in total forage production were found between silvopastures and open pastures in June or August of the second year. Total forage dry matter production was greater in the orchardgrass-white clover biculture compared to the control treatment in both years. Orchardgrass percent crude protein was lower in open pastures (10.7%) compared to silvopastures (12.9%) in June of year two. The financial analysis indicated that silvopasture outperformed open pasture and thinned forest treatments in terms of both IRR and NPV. We conclude that forage production in silvopastures can be competitive with that in open pastures on sites with a similar, forested, starting condition.

Since the creation of SynCardia's 50 cc Total Artificial Hearts (TAHs), patients with irreversible biventricular failure now have two sizing options. Herein, a case series of three patients who have undergone successful 50 and 70 cc TAH implantation with complete closure of the chest cavity utilizing preoperative “virtual implantation” of different sized devices for surgical planning are presented. Computed tomography (CT) images were used for preoperative planning prior to TAH implantation. Three-dimensional (3D) reconstructions of preoperative chest CT images were generated and both 50 and 70 cc TAHs were virtually implanted into patients' thoracic cavities. During the simulation, the TAHs were projected over the native hearts in a similar position to the actual implantation, and the relationship between the devices and the atria, ventricles, chest wall, and diaphragm were assessed. The 3D reconstructed images and virtual modeling were used to simulate and determine for each patient if the 50 or 70 cc TAH would have a higher likelihood of successful implantation without complications. Subsequently, all three patients received clinical implants of the properly sized TAH based on virtual modeling, and their chest cavities were fully closed. This virtual implantation increases our confidence that the selected TAH will better fit within the thoracic cavity allowing for improved surgical outcome. Clinical implantation of the TAHs showed that our virtual modeling was an effective method for determining the correct fit and sizing of 50 and 70 cc TAHs.

Complications associated with long-term left ventricular assist device (LVAD) use may require pump exchange due to device thrombosis or thromboembolism. Minimally invasive off-pump procedures represent an advantageous alternative to standard full sternotomy exchanges and those performed with the use of cardiopulmonary bypass. By mitigating surgical invasion and trauma to the central chest, the potential for post-operative bleeding, transfusions and complications can be reduced. This case report describes the successful off-pump exchange of a HeartWare LVAD via left re-do-thoracotomy with the re-use of the original outflow graft.

We describe the off-pump insertion of a biventricular assist device with extra-corporeal membrane oxygenation (ECMO): a novel technique that allows for ambulatory central veno-arterial (VA) ECMO with direct biventricular decompression.

Converting non-agricultural land to agricultural uses can result in trade-offs in ecosystem services. As provisioning services increase on new agricultural land, supporting, regulating, and cultural services may decrease. An improved understanding of how stakeholders value different land use types in terms of their perceived ecosystem services, as well as the relative visual appeal of different agricultural landscape features, could assist policymakers and land use planners in decision-making related to agricultural land use in New England, USA. We surveyed two survey samples in New Hampshire, food system stakeholders (e.g., farmers, public health professionals, and technical assistance providers) and the general population, to explore how perception of the visual appeal of specific farmland use types and importance of ecosystem services specifically related to agricultural land might differ between survey samples. Our objectives were to (1) explore how New Hampshire residents perceive the importance of seven ecosystem services, (2) evaluate how two groups of New Hampshire residents—the general public and those who indicated working with or in a food systems sector (food system stakeholders)—perceive these ecosystem services provided by specific agricultural landscapes and determine how those perceptions relate to the visual appeal of each landscape, and (3) assess how eight socio-economic factors may account for the differences between each survey sample in terms of their landscape perception and preference. Roughly 600 New Hampshire residents completed the survey, including 494 individuals from the public and 103 food system stakeholders. From a list of seven ecosystem services, clean water was ranked as the most important across both survey samples, with no significant difference between samples, while food production was ranked significantly higher by the food system stakeholders (p ≤ 0.001). Likewise, on a scale of most (4) to least (1) appealing, food system stakeholders ranked photorealistic visualizations of cropland higher than the public (p ≤ 0.001). Additionally, food system stakeholders ranked the appeal of forestland lower than the public (p = 0.007). Our findings suggest that there are differences in landscape preferences and perception of ecosystem service benefits between the general public and those who work with or in the food system. Future research is needed to determine how these differences in perception might affect land use planning and policymaking related to agricultural expansion and forestland preservation.

Purpose Assess the feasibility of interfacility transfer via a mobile intensive care unit (MOBI) after a double lumen catheter cannulation at a referring facility for veno-venous extracorporeal membrane oxygenation (VV-ECMO). Methods This single center retrospective data analysis utilized our institutional data from January 2015-September 2019. We divided patients into 2 groups: Group A had a double lumen cannulation for in-hospital VV-ECMO; Group B had the same procedure for interfacility transfer via an MOBI. Cannulation was performed with fluoroscopic guidance at the referring facility by either one of its surgeons or the MOBI team. The MOBI consisted of an ECMO physician (either a surgeon or an intensivist), a respiratory therapist, an ECMO nurse, and a transport nurse. The 2 groups were compared in terms of pre support, complications during the ECMO support, and survival. Results There were no complications related to cannulation at the referring facility nor transfer. Group A had 33 patients (average age was 45.1 ± 18.0). Group B had 20 patients (average age was 48.4 ± 13.5). Pre ECMO pH, PCO2, PO2, and SaO2 were 7.2 ± 0.2, 7.3 ± 0.2 (p=0.08), 65.0 ± 21.6mmHg, 59.3 ± 24.2mmHg (p=0.27), 69.8 ± 26.3mmHg, 66.6 ± 45.0mmHg (p=0.18), 85.7 ± 9.7%, 82.5 ± 14.4% (p=0.61) in Group A and B, respectively. During ECMO support, Group A had 18 complications; Group B had 13 (p=0.57), including circuit component clots [5 and 4 (p=0.72)], circuit exchange [3 and 2 (p=1.00)], creatinine 1.5 - 3.0 [5 and 1 (p=0.39)], creatinine >3.0 [2 and 3 (p=0.35)], and renal replacement therapy [6 and 4 (p=1.00)]. Respectively, 69.7% and 50.0% of patients came off ECMO support, and 45.4% and 50.0% of patients survived to discharge (p=0.18). Conclusion Double lumen catheter cannulation at the referring facility with MOBI demonstrated equivalent results to in-house cannulation.

Interest in energy sustainability has grown exponentially in the past 20 years. Energy providers have always had to carefully consider the trade-offs of their near- and long-term decisions. Now, however, the need for greater transparency concerning associated trade-offs has driven energy companies to not only tackle these issues in their long-term planning but also to engage stakeholders along the way. As such, corporate social responsibility (CSR) reporting has become an important communication tool to engage varied stakeholders. While producing transparent and meaningful CSR communications can be a daunting task, a well-constructed CSR report can serve as a useful window into an industry filled with complex decision-making. Our findings and best practices are easily transferable to other companies seeking to create CSR reports for the first time or to optimize existing sustainability communications.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO)—also referred to as extracorporeal life support—is a form of temporary mechanical circulatory support and simultaneous extracorporeal gas exchange. The initiation of VA-ECMO has emerged as a salvage intervention in patients with cardiogenic shock, even cardiac arrest refractory to standard therapies. Analogous to veno-venous ECMO for acute respiratory failure, VA-ECMO provides circulatory support and allows time for other treatments to promote recovery or may be a bridge to a more durable mechanical solution in the setting of acute or acute on chronic cardiopulmonary failure. In this review, we provide a brief overview of VA-ECMO, the attendant physiological considerations of peripheral VA-ECMO, and its complications, namely that of left ventricular distention, bleeding, heightened systemic inflammatory response syndrome, thrombosis and thromboembolism, and extremity ischemia or necrosis.

Introduction: Cardiovascular complications represent the leading cause of morbidity and mortality in patients with Marfan syndrome. Here, we describe a unique case where a total artificial heart was implanted in a young Marfan syndrome woman. Methods: A 22-year-old postpartum African American female with Marfan syndrome developed multiple severe valve dysfunction and biventricular failure that was refractory to medical management. She previously had a Bentall procedure for Type A aortic dissection and repair of a Type B dissection. Results: We implanted a total artificial heart with a good outcome. Conclusion: Total artificial heart is a durable option for severe biventricular failure and multiple valvular dysfunction as a bridge to transplant in a young patient with Marfan syndrome.

Purpose To determine the chronic warfarin dose trends in mechanical circulatory support (MCS) device patients in the period after discharge from implantation. This may provide practitioners some general guidance when caring for an assortment of outpatient MCS recipients. Methods MCS patients implanted between 9/2013 and 5/2018 with warfarin dosing records during the first year after implant were evaluated. Average warfarin doses per day were tabulated and compared at months 1, 3, 6, and 12 post discharge. Data points were censored if a new significant drug interaction was noted to be influencing the subsequent analysis period. Results The study group totaled 49 patients. It was comprised of 31 Heartware, 12 Heartmate II, 4 total artificial heart, and 2 Heartmate III recipients. All patients were titrated towards an international normalized ratio (INR) goal of 2.0-3.0 initially. Eighty-two percent of the group was Male, the average age was 58.2 years old, and the average length of stay for the implant admission was 34.5 days. During the first year after discharge from receiving a MCS device, 34 patients experienced a net increase in the average warfarin dose per day, while 14 patients saw a net decrease. One patient's warfarin dosage remained the same from discharge until month 12. The mean increase in warfarin dose was 8.8%, 21.0%, 25.1%, and 26.5% at months 1, 3, 6, and 12 respectively. The dose increases were statistically significantly different at months 6 (p=0.023) and 12 (p=0.049) versus the dose increase at month 1. The dose increase comparison between month 1 and 3 were not statistically different (p=0.076). The median warfarin dose at discharge was 4mg per day with an interquartile range of 2.57 mg to 6 mg per day. By month 12, the median daily dose was 4.3 mg per day with an interquartile range of 3.9 mg to 6.4 mg per day derived from weekly totals. Conclusion MCS team members that manage warfarin dosing may expect gradual increases on average during the first year post discharge. This expectation may avert unwanted sub-therapeutic INRs in these MCS patients.

The SynCardia total artificial heart (TAH) has emerged as an effective, life-saving bi-ventricular replacement system for a wide variety of patients with end-stage heart failure. While the clinical performance of the TAH is established, modern physiologic characterization, in terms of elastance behavior and pressure-volume characterization has not been defined. Herein we examine the TAH in terms of elastance using a non-ejecting left-ventricle, and then characterize the pressure-volume relationship of the TAH by varying preload and afterload parameters using a Donovan Mock Circulatory System. We demonstrate that the TAH does not operate with time-varying elastance, differing from the human heart. Further, we show that the TAH has a pressure-volume relationship behavior that also differs from that of the human heart. The TAH does exhibit Starling-like behavior, with output increasing via preload dependent mechanisms, without reliance on an alteration of inotropic state within the operating window of the TAH. Within our testing range, the TAH is insensitive to variations in afterload, however this insensitivity has a limit, the limit being the maximum driving pressure of the pneumatic driver. Understanding the physiology of the TAH affords insight into the functional parameters that govern artificial heart behavior providing perspective on differences compared to the human heart.

Cardiogenic shock and cardiac arrest are life-threatening emergencies that result in high mortality rates. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) via peripheral cannulation is an option for patients who do not respond to conventional therapies. Left ventricular (LV) distention is a major limitation with peripheral VA-ECMO and is thought to contribute to poor recovery and the inability to wean off VA-ECMO. We report on a novel technique that combines peripheral VA-ECMO with off-pump insertion of a trans-apical LV venting cannula and a right ventricular decompression cannula.

The current United States heart allocation system faces 2 main challenges: an evolving landscape of device therapy in advanced heart failure and a rapidly increasing transplant waiting list. The proposed new heart allocation system involves expansion of the 3 tiers and enables greater distinction between different types of mechanical circulatory support devices. In this review, we discuss how the proposed revision reconciles key concerns of the current system to create a more fair and equitable allocation of hearts in the United States.

Weeds are able to establish in agricultural systems when and where resources are in excess of what the crop is able to utilize. We discuss four strategies for manipulating crop plants in order to increase resource utilization and improve weed suppression. First, cover plants can be used to usurp resources and suppress weeds during fallow periods between cash crops. In some cases, cover plants can also suppress weeds in subsequent cash crops by changing soil resource availability, production of allelopathic substances, and/or persistence of physically suppressive residues. Second, intercropping two or more functionally diverse cash crops can reduce weed abundance by increasing total resource utilization by the crop community. Thirdly, manipulating the density or spatial orientation of cash crops can reduce weed abundance by enhancing the competitiveness of the crop population. Finally, breeding for competitive cultivars by selecting traits that increase a crop plant’s ability to acquire resources has the potential to enhance the ability of crops to suppress and/or tolerate weeds. Weed suppression via crop plant manipulations is enhanced when multiple tactics are combined and will result in benefits such as reduction in the need for tillage and herbicides and their associated negative environmental impacts.

Annual cropping systems dominate the earth's global cropland and contribute significantly to agriculture's overall impact on the environment. Ecological succession and thermodynamics provide useful frameworks for conceptualizing these systems and elucidating the mechanistic basis for their associated impacts. Under a succession-energy framework, annual cropping systems represent a state of perpetual early secondary succession which can only be maintained through the application of management energy. It is this management energy – often in the form of herbicides, physical disturbance, or synthetic N fertilizer – which ultimately results in non-target impacts on the environment. Additional negative environmental impacts occur as a consequence of our ability to undermine ecological succession processes that would otherwise absorb or convert the applied energy and materials to biomass. A conceptual model based on the relationship between the rate of ecological succession and management energy highlights how these factors interact to influence the magnitude of non-target environmental impact associated with annual crop production. This model provides a context for understanding, predicting, and mitigating some of the environmental impacts of agricultural management practices. Viewing agroecosystems through the lens of succession suggests that management practices that effectively ‘perennialize’ annual systems – by maintaining living plant cover, integrating perennial crops, or mimicking or promoting later successional processes and functions – will reduce the overall environmental impacts associated with annual crop production.

Background Temporary mechanical circulatory support device without sternotomy has been highly advocated for severe cardiogenic shock patient but little is known when coupled with amniotic stem cell therapy. Case presentation This case reports the first dual therapy of temporary left ventricular extracorporeal device CentriMag with distal banding technique and human amniotic stem cell injection for treating a severe refractory cardiogenic shock of an 68-year-old female patient. A minimally-invasive off-pump LVAD was established by draining from the left ventricle and returning to the right axillary artery with distal arterial banding to prevent right upper extremity hyperperfusion. Amniotic stem cells were injected intramyocardially at the left ventricular apex, lateral wall, inferior wall, and right subclavian vein. Conclusion The concomitant use of the temporary minimally-invasive off-pump CentriMag placement and stem cell therapy not only provided an alternative to cardiopulmonary bypass and full-median sternotomy procedures but may have also synergistically enhanced myocardial reperfusion and regeneration.

Increasingly, funding agencies are investing in integrated and transdisciplinary research to tackle “grand challenge” priority areas, critical for sustaining agriculture and protecting the envi -ronment. Coordinating multidisciplinary research teams capable of addressing these priority areas, however, presents its own unique set of chal-lenges, ranging from bridging across multiple dis -ciplinary perspectives to achieve common ques-tions and methods to facilitating engagement in holistic and integrative thinking that promotes linkages from scholarship to societal needs. We propose that structural equation modeling (SEM) can provide a powerful framework for synergizing multidisciplinary research teams around grand challenge issues. Structural equation modeling can integrate both visual and statistical expres-sion of complex hypotheses at all stages of the research process, from planning to analysis. Three elements of the SEM framework are par-ticularly beneficial to multidisciplinary research teams; these include (i) a common graphical lan-guage that transcends disciplinary boundaries, (ii) iterative, critical evaluation of complex hypoth -eses involving manifest and latent variables and direct and indirect interactions, and (iii) enhanced opportunities to discover unanticipated interac-tions or causal pathways as empirical data are tested statistically against the model. Using our ongoing multidisciplinary, multisite field inves-tigation of climate change adaptation and miti-gation in annual row crop agroecosystems as a case study, we demonstrate the value of the SEM framework for project design, coordination, and implementation and provide recommendations for its broader application as a means to more effectively engage and address issues of critical societal concern.R.G. Smith, L.W. Atwood, A.B. Daly, and A.S. Grandy, Dep. of Natural Resources and the Environment, Univ. of New Hampshire, Durham, NH 03824; A.S. Davis, USDA-ARS Global Change and Photosynthesis Research Unit, Urbana, IL 61801; N.R. Jordan and P. Ewing, Dep. of Agronomy and Plant Genetics, Univ. of Minnesota, St. Paul, MN 55108; M.C. Hunter, and D.A. Mortensen, Dep. of Plant Science, The Pennsylvania State Univ., University Park, PA 16802; R.T. Koide, Dep. of Biology, Brigham Young Univ., Provo, UT 84602; D. Kane and S.S. Snapp, Dep. of Plant, Soil and Microbial Sciences, Michigan State Univ., East Lansing, MI 48824; M. Li, Dep. of Crop Sciences, Univ. of Illinois, Urbana, IL 61801; Y. Lou and A.C. Yannarell, Dep. of Natural Resources and Environmental Sciences, Univ. of Illinois, Urbana, IL 61801; K.A. Spokas, USDA-ARS Soil and Water Management Research Unit, St. Paul, MN 55108. Received 19 July 2013. *Corresponding author (richard.smith@unh.edu).

From the Division of Cardiothoracic Surgery, Banner University Medical Center–Tucson, Tucson, Ariz. Disclosures: Authors have nothing to disclose with regard to commercial support. Received for publication April 15, 2015; revisions received June 8, 2015; accepted for publication July 24, 2015; available ahead of print Aug 28, 2015. Address for reprints: Zain Khalpey, MD, PhD, Division of Cardiothoracic Surgery, The University of Arizona Medical Center, 1501 N Campbell Ave, Room 4302A, PO Box 245071, Tucson, AZ 85724-5071 (E-mail: zkhalpey@surgery.arizona.edu). J Thorac Cardiovasc Surg 2016;151:e5-7 0022-5223/$36.00 Copyright 2016 by The American Association for Thoracic Surgery http://dx.doi.org/10.1016/j.jtcvs.2015.07.074

Demand for locally-produced food is growing in areas outside traditionally dominant agricultural regions due to concerns over food safety, quality, and sovereignty, rural livelihoods, and environmental integrity. Strategies for meeting this demand rely upon agricultural land use change, in various forms of either intensification or extensification (converting non-agricultural land, including native landforms, to agricultural use). The nature and extent of the impacts of these changes on non-food-provisioning ecosystem services are determined by a complex suite of scale-dependent interactions among farming practices, site-specific characteristics, and the ecosystem services under consideration. Ecosystem modeling strategies which honor such complexity are often impenetrable by non-experts, resulting in a prevalent conceptual gap between ecosystem sciences and the field of sustainable agriculture. Referencing heavily forested New England as an example, we present a conceptual framework designed to synthesize and convey understanding of the scale- and landscape-dependent nature of the relationship between agriculture and various ecosystem services. By accounting for the total impact of multiple disturbances across a landscape while considering the effects of scale, the framework is intended to stimulate and support the collaborative efforts of land managers, scientists, citizen stakeholders, and policy makers as they address the challenges of expanding local agriculture.

For 15 years, we employed a consistent anticoagulation protocol in 99 consecutive SynCardia Systems total artificial heart (TAH) recipients. Thromboelastography and platelet aggregation studies were used for evaluating and modulating therapy with dipyridamole, pentoxiphylline, aspirin, and heparin. Partial thromboplastin times, international normalized ratios, and platelet counts were also followed. After the second post-implant day in patients who were free of endo-device infection (97 patients), the embolic stroke incidence was 0.08 per patient year. This included 23.6 patient years of device support. There were no spontaneous hemorrhagic strokes. Two patients had endo-device infections and both had strokes. Postimplantation bleeding was seen in 20% of patients. All but two of these were within the first postoperative week. In all, 4% of patients had gastrointestinal bleeding. We did not observe heparin-induced thrombocytopenia in any patient. We conclude that stroke rates on TAH support have been low, and recommend this protocol.

Definitive therapy of advanced heart failure, as classified by the American College of Cardiology/American Heart Association guidelines, is complicated because of the lack of donor organs for transplantation.1 This shortage has established a need for alternative heart failure therapies. In 2004, the Food and Drug Administration approval of a 70cc total artificial heart (TAH; SynCardia Systems Inc, Tucson, AZ) served as a valuable new treatment option offering a bridge to transplant, although patients await a donor heart. Recent studies demonstrated that the 70cc TAH has been successfully placed in 1300 patients worldwide and has served as a successful bridge to transplant in 79% of patients.2 However, the invasive removal of the atria and ventricles during placement of the TAH carries risks. Hematologic risks include hemopericardium and coagulopathy, which may further result in either pulmonary or neurological embolic events. The implanted device itself is not without risk given reported instances of infections, leaks, and malfunctioning-related kinking of either the TAH components surgical anastomoses or the drive lines. Despite the seriousness of the complications related to the 70cc TAH, these risks can be acceptably minimized with patient education relating to proper TAH care and with an appropriate social support network. Given the ability to manage and prevent device complications after implantation, a critical pretransplant complication that must be assessed before TAH placement is proper device fit within the patient’s thoracic cavity given the varying intrathoracic space related to body habitus and age-related difference. Although a body surface area of 1.7 to 2.5 cm2 has …

The SynCardia™ total artificial heart (TAH) is the only FDA-approved TAH in the world. The SynCardia™ TAH is a pneumatically driven, pulsatile system capable of flows of >9 L/min. The TAH is indicated for use as a bridge to transplantation (BTT) in patients at imminent risk of death from non-reversible bi-ventricular failure. In the Pivotal US approval trial the TAH achieved a BTT rate of >79%. Recently a multi-center, post-market approval study similarly demonstrated a comparable BTT rate. A major milestone was recently achieved for the TAH, with over 1100 TAHs having been implanted to date, with the bulk of implantation occurring at an ever increasing rate in the past few years. The TAH is most commonly utilized to save the lives of patients dying from end-stage bi-ventricular heart failure associated with ischemic or non-ischemic dilated cardiomyopathy. Beyond progressive chronic heart failure, the TAH has demonstrated great efficacy in supporting patients with acute irreversible heart failure associated with massive acute myocardial infarction. In recent years several diverse clinical scenarios have also proven to be well served by the TAH including severe heart failure associated with advanced congenital heart disease. failed or burned-out transplants, infiltrative and restrictive cardiomyopathies and failed ventricular assist devices. Looking to the future a major unmet need remains in providing total heart support for children and small adults. As such, the present TAH design must be scaled to fit the smaller patient, while providing equivalent, if not superior flow characteristics, shear profiles and overall device thrombogenicity. To aid in the development of a new “pediatric,” TAH an engineering methodology known as “Device Thrombogenicity Emulation (DTE)”, that we have recently developed and described, is being employed. Recently, to further our engineering understanding of the TAH, as steps towards next generation designs we have: (1) assessed of the degree of platelet reactivity induced by the present clinical 70 cc TAH using a closed loop platelet activity state assay, (2) modeled the motion of the TAH pulsatile mobile diaphragm, and (3) performed fluid-structure interactions and assessment of the flow behavior through inflow and outflow regions of the TAH fitted with modern bi-leaflet heart valves. Developing a range of TAH devices will afford biventricular replacement therapy to a wide range of patients, for both short and long-term therapy.

Background Right ventricular failure is a serious complication after left ventricular assist device placement. Case Presentation A 70-year-old male in decompensated heart failure with right ventricular failure after the placement of a left ventricular assist device. A single dual-lumen PROTEKDuo cannula was inserted percutaneously via the internal jugular vein to draw blood from the right atrium and return into the pulmonary artery using the CentriMag system, by passing the failing ventricle. The patient was successfully weaned from right ventricular assist device. Conclusions In comparison to two-cannula conventional procedures, this right ventrivular assist device system improves patient rehabilitation and minimizes blood loss and risk of infection, while shortening procedure time and improving clinical outcomes in right ventricular failure.

Cardiac power output has been shown to quantify cardiac reserve. Cardiac reserve is defined as the difference between basal and maximal cardiac performance. We compared cardiac power index to other commonly used hemodynamic parameters to validate its usefulness to stage heart failure patients and determine the optimal time for implantation of mechanical circulatory support. A retrospective study of twenty-eight heart failure patients implanted with mechanical circulatory support was analyzed at three levels of drug therapy. Subjects were further separated into two categories: survived versus deceased. Cardiac power index was the only statistically significant hemodynamic parameter that identified cardiac reserve (pConclusion: Cardiac reserve was a determinant of post-device survival; therefore, these data suggest that device implantation should occur prior to the 0.34 Watts/m2 threshold.

Agricultural weed management has become entrenched in a single tactic—herbicide—resistant crops—and needs greater emphasis on integrated practices that are sustainable over the long term. In response to the outbreak of glyphosate-resistant weeds, the seed and agrichemical industries are developing crops that are genetically modified to have combined resistance to glyphosate and synthetic auxin herbicides. This technology will allow these herbicides to be used over vastly expanded areas and will likely create three interrelated challenges for sustainable weed management. First, crops with stacked herbicide resistance are likely to increase the severity of resistant weeds. Second, these crops will facilitate a significant increase in herbicide use, with potential negative consequences for environmental quality. Finally, the short-term fix provided by the new traits will encourage continued neglect of public research and extension in integrated weed management. Here, we discuss the risks to sustainable agric...

Agroecosystems are inherently complex, and practices aimed at managing one component of the system can have unintended consequences for other components of the system. Management decisions, therefore, can be improved by assessing and understanding the multivariate nature of agricultural systems and the multifunctional character of particular agricultural management practices. The act of simultaneously assessing and evaluating multiple characteristics or functions in agriculture also can be a valuable education and extension activity, because it draws on active and experiential methods of learning and because the process effectively reveals important functions and tradeoffs associated with agroecosystems and their management. Here we introduce a tool (the spider plot) and present a case-study exercise in which we used this tool to evaluate the multiple characteristics and functions of different cover crops within a field day workshop format. We also provide examples of how this approach could be used to assess other management practices or properties of agroecosystems and communicate multivariate concepts within a weed science classroom or extension environment.

Anticoagulation of children on mechanical circulatory support presents a challenge. We implanted 28 devices in children and infants using a consistent anticoagulation protocol. We performed a retrospective review of all children implanted in our program with mechanical assist devices since 1997. Heparin, dipyridamole, and aspirin were used for anticoagulation and antiaggregation. Coagulation monitoring included thromboelastography (TEG), platelet aggregration studies, international normalized ratio, partial thromboplastin time, and platelet count. Twenty-eight children, ages 1 month to 16 years (mean 5.3; median 2.4 years), were implanted for 3-107 days (mean 27; median 17). Eighteen received left ventricular assist devices, seven received biventricular assist devices, and three received total artificial hearts. Adverse events during the 720 days of device support included the following: six (21%) reoperations for bleeding; seven strokes (25%): two fatal, two with a mild residual deficit, and three without deficit; and three (11%) visceral emboli: two fatal and one nonfatal. There were eight deaths (29%). Causes of death were embolic (four), graft failure post-transplantation (one), preimplant anoxic brain damage (two), and postexplant heart failure (one). 24/28 (86%) survived to transplantation or weaning from device and 20/28 (71%) were discharged from the hospital, 10 after transplantation and 10 after native heart recovery. All 20 early survivors survived long term. We describe an anticoagulation protocol based upon TEG and platelet aggregation studies and using heparin, aspirin, and dipyridamole. Adequate anticoagulation is more difficult in children. However, 71% of the patients in our study survived long term.

Most infants and children implanted with ventricular assist devices (VADs) go on to cardiac transplantation. Recovery of dilated cardiomyopathies with the combination left ventricular decompression with a VAD and treatment with maximal medical therapy has been possible in some adults, and may be more feasible in infants and children. We used pulsatile and continuous flow VADs and the total artificial heart (TAH) as bridges to transplantation or to recovery. Candidates for native heart recovery were treated with maximal medical therapy for congestive heart failure and short-term dobutamine prior to weaning off device support. Since 1997, 28 infants and children, ages 1 month to 16 years, were implanted for durations of 3-107 days (mean 27). Eighteen received left VADs (LVAD), seven biventricular assist devices (BiVADs), and three TAHs. Device-related mortality was 7/28 (25%), leaving 21/28 (75%) surviving to transplantation or weaning from device support and 20/28 (71%) discharged from the hospital and currently surviving for 2 months to 9 years. Ten of 11 transplant recipients (90%) have survived 2 to 9 years. All 10 with recovered hearts are alive and well for 2 months to 5 years. Eight of 12 (67%) LVAD patients with dilated hearts recovered. None of the recovery patients were over 6 years old. Infants and children who have failed inotropic therapy may be treated with an LVAD and medical therapy for congestive heart failure anticipating native heart recovery. A variety of devices have been tried. All small LVADs yielded comparable results. Larger and older children also have a chance of recovery, but our experience with them is too small except to note that they do well with larger devices and transplantation.

Keebler et al. [(1)][1] set out an interesting and useful study pertaining to some of the key management issues of veno-arterial extracorporeal membrane oxygenation (ECMO) for refractory cardiogenic shock. As the authors rightly note, avoiding left ventricular distention using a venting strategy is

Weed science has contributed much to agriculture, forestry and natural resource management during its history. However, if it is to remain relevant as a scientific discipline, it is long past time for weed scientists to move beyond a dominating focus on herbicide efficacy testing and address the basic science underlying complex issues in vegetation management at many levels of biological organization currently being solved by others, such as invasion ecologists and molecular biologists. Weed science must not be circumscribed by a narrowly-defined set of tools but rather be seen as an integrating discipline. As a means of assessing current and future research interests and funding trends among weed scientists, the Weed Science Society of America conducted an online survey of its members in summer of 2007. There were 304 respondents out of a membership of 1330 at the time of the survey, a response rate of 23%. The largest group of respondents (41%) reported working on research problems primarily focused on herbicide efficacy and maintenance, funded mainly by private industry sources. Another smaller group of respondents (22%) reported focusing on research topics with a complex systems focus (such as invasion biology, ecosystem restoration, ecological weed management, and the genetics, molecular biology, and physiology of weedy traits), funded primarily by public sources. Increased cooperation between these complementary groups of scientists will be an essential step in making weed science increasingly relevant to the complex vegetation management issues of the 21st century.

Understanding how communities of important soil invertebrates vary with land use may lead to the development of more sustainable land-use strategies. We assessed the abundance and species composition of earthworm communities across six replicated long-term experimental ecosystems that span a gradient in agricultural land-use intensity. The experimental systems include a conventional rowcrop agricultural system, two lower-intensity row-crop systems (no-till and tilled organic input), an early successional old-field system, a 40–60 years old coniferous forest plantation, and an old-growth deciduous forest system. Earthworm populations varied among systems; they were lowest in the most intensively managed row-crop system (107 m

Background. Safety and efficacy studies of various mechanical circulatory support devices are important, but may not be strictly comparable. Lacking prospective randomized studies for different devices, we believe that comparison of risk factor analyses may give the surgeon a tool more powerful than current studies for matching a patient with an appropriate device. In this paper, we report risk factor profiles for bridge to transplantation with the CardioWest total artificial heart and summarize reports for other devices. Methods. A multiinstitutional risk factor analysis of the CardioWest total artificial heart, as a bridge to transplantation in 81 patients, was conducted. Univariate analyses were performed on 43 preimplantation prognostic factors. From this group, eight factors were chosen for multivariate analysis. Our results were compared with all recent risk factor analyses for other devices. Results. Independent predictors for death at three intervals by multivariate analysis were as follows: “implant to transplant”: history of smoking (odds ratio, 34); “implant to 30 days after transplant”: history of smoking (odds ratio, 10.00), prothrombin time greater than 16 seconds (odds ratio, 4.76); and “implant to 1 year after transplant”: prothrombin time greater than 16 seconds (odds ratio, 3.85). The major difference between this experience and multiple reported experiences with left ventricular assist devices is that for left ventricular assist devices, but not for the temporary CardioWest total artificial heart, right heart failure, high central venous pressure, and being on a ventilator (with or without sepsis) were independent predictors of mortality. Conclusions. Risk factors for bridge to transplantation with the CardioWest total artificial heart are different from those reported for left ventricular assist devices. Recognition of these risk factor differences may facilitate appropriate device selection. (Ann Thorac Surg 2008;85:1639 ‐ 45) © 2008 by The Society of Thoracic Surgeons

The 70 cc total artificial heart (TAH) has been utilized as bridge to transplant (BTT) for biventricular failure. However, the utilization of 70 cc TAH has been limited to large patients for the low output from the pulmonary as well as systemic vein compression after chest closure. Therefore, the 50 cc TAH was developed by SynCardia (Tucson, AZ) to accommodate smaller chest cavity. We report the first TAH exchange from a 70 to 50 cc due to a fit difficulty. The patient failed to be closed with a 70 cc TAH, although the patient met the conventional 70 cc TAH fit criteria. We successfully closed the chest with a 50 cc TAH.

Shortly after SynCardia total artificial heart (TAH) implant, venovenous extracorporeal membrane oxygenation (ECMO) via a 31 Fr Avalon cannula was used for profound hypoxic lung dysfunction. Immediately after starting ECMO, TAH flow increased by 1.5-2.0 L/min, presumably because of augmented TAH filling by the ECMO jet.

This case study reports the operative management of a 63-year-old male patient following implantation of the HeartMate II (HMII) left ventricular assist device (LVAD), with a non-compliant left ventricle (LV) and a reduced right ventricular (RV) end-diastolic volume. Intraoperatively, the patient had a thin, fragile LV wall with laminated clot; a ventricular septal defect was encountered during removal of the clot. Along with an aortic valve repair, the LV and the septum were reconstructed with multiple bovine pericardium patches, thus, moderately reducing the RV and LV stroke volume. A difference in cardiac output via a Swan-Ganz catheter (approximately 1.5 l/min) was observed as opposed to the HMII’s estimated flow. The result was later replicated and verified in vitro via the Donovan Mock Circulation System (DMCS), where about 2 l/min lower flow on the HMII system was observed. In conclusion, the HMII flow rate displayed can be inaccurate and should only be used for trending.

Introduction: The Thoratec Corporation has over 10,000 patients registered as recipients of the HeartMate II left ventricular assist device (LVAD) worldwide. Although it has undoubtedly prolonged the lifespan of heart failure patients, the most recognized risk associated with these devices is the development of thrombus. In the presence of a small or developing clot, the HeartMate II display module and system monitor indicate that there is a decrease in pump flow, adjusts its pump power and is accompanied by audible and visual alarms when flow rates drop below a fixed threshold established by Thoratec. In contrast, when thrombus completely inhibits flow through the device, the display module and system monitor have failed in previous case studies to indicate that flow has reduced to zero and do not produce any corresponding alarms. Methods: To test the efficacy of the HeartMate II alarms, a cardiovascular simulation tank was used to reproduce the hemodynamics of a typical heart failure patient. The hemodynamics were then improved by the addition of the HeartMate II LVAD and different partial and complete occlusions were applied to the inlet and outlet of the HeartMate II pump. Conclusions: Partially occluding the inflow and/or outflow of the HeartMate II did display changes in flow and presented with alarms when flow was estimated to be below 2.5 L/min; however, complete occlusion of the inflow and/or outflow failed to produce any alarms or accurately measured changes in flow.