Bridging Over Troubled Waters-How the United States 2018 Heart Allocation System Altered Transplant Bridging Strategies.

As we approach the five-year anniversary of the 2018 heart allocation system in the United States, it is imperative to consider the changing landscape of mechanical circulatory support and the strategies used to bridge patients into heart transplants. This manuscript reviews the history of the heart allocation system, as well as the conditions that led to its multiple revisions. We discuss initial outcomes following the implementation of the new allocation system, including the impact on waitlist mortality and post-transplant outcomes. We also give special consideration to changes in bridging strategies using venoarterial extracorporeal membrane oxygenation (VA ECMO), intra-aortic balloon pumps, and durable left ventricular assist devices (LVADs).

A Novel Bridging Strategy for Patients Undergoing Emergent Non-Cardiac Surgery with a Recent Coronary Stent.

INTRODUCTION: Not infrequently, patients undergoing dual antiplatelet therapy for a recent cardiac stent develop a need for a non-cardiac surgery. Most of these surgeries can be delayed while the antiplatelet treatment is stopped and normal platelet function returns in order to avoid potential surgical complications and excessive bleeding. However, there are a number of patients who require urgent surgery where the procedure cannot be postponed. To date, no agents have been proven to bridge the patient off dual-antiplatelet therapy. METHODS: A 46-year-old man was admitted to the hospital with an acute anterior wall myocardial infarction. He was urgently taken to the catheterization lab where he was found to have a totally occluded proximal left anterior descending coronary artery (LAD). He was successfully stented with a drug-eluting stent of the LAD, but subsequently developed a sarcoma 2 months later that required urgent surgery. The novel direct-acting, reversible P2Y12 receptor inhibitor cangrelor was used to bridge this patient followed by ongoing antiplatelet treatment, allowing surgery for the removal of a soft tissue sarcoma. RESULTS: Cangrelor was successfully used to bridge a patient with a recent stent placement and current antiplatelet treatment undergoing the removal of a soft tissue sarcoma. CONCLUSION: This case report demonstrates the use of a novel, now currently available, short-acting antiplatelet agent that can be used for bridging patients undergoing non-cardiac surgery who had a recent myocardial infarction and stent placement.

Bridging Strategies to Allogeneic Transplant for Older AML Patients.

Treatment options for older patients with intermediate or high-risk acute myeloid leukemia (AML) remain unsatisfactory. Allogeneic stem cell transplantation, the treatment of choice for the majority of younger AML patients, has been hampered in elderly patients by higher treatment related mortality, comorbidities and lack of a suitable donor. With the higher availability of suitable donors as well as of reduced intensity conditioning regimens, novel low intensity treatments prior to transplantation and optimized supportive care, the number of older AML patients being successfully transplanted is steadily increasing. Against this background, we review current treatment strategies for older AML patients planned for allogeneic stem cell transplantation based on clinical trial data, discussing differences between approaches with advantages and pitfalls of each. We summarize pre-treatment considerations that need to be taken into account in this highly heterogeneous older population. Finally, we offer an outlook on areas of ongoing clinical research, including novel immunotherapeutic approaches that may improve access to curative therapies for a larger number of older AML patients.

A Review of Multiscale Computational Methods in Polymeric Materials.

Polymeric materials display distinguished characteristics which stem from the interplay of phenomena at various length and time scales. Further development of polymer systems critically relies on a comprehensive understanding of the fundamentals of their hierarchical structure and behaviors. As such, the inherent multiscale nature of polymer systems is only reflected by a multiscale analysis which accounts for all important mechanisms. Since multiscale modelling is a rapidly growing multidisciplinary field, the emerging possibilities and challenges can be of a truly diverse nature. The present review attempts to provide a rather comprehensive overview of the recent developments in the field of multiscale modelling and simulation of polymeric materials. In order to understand the characteristics of the building blocks of multiscale methods, first a brief review of some significant computational methods at individual length and time scales is provided. These methods cover quantum mechanical scale, atomistic domain (Monte Carlo and molecular dynamics), mesoscopic scale (Brownian dynamics, dissipative particle dynamics, and lattice Boltzmann method), and finally macroscopic realm (finite element and volume methods). Afterwards, different prescriptions to envelope these methods in a multiscale strategy are discussed in details. Sequential, concurrent, and adaptive resolution schemes are presented along with the latest updates and ongoing challenges in research. In sequential methods, various systematic coarse-graining and backmapping approaches are addressed. For the concurrent strategy, we aimed to introduce the fundamentals and significant methods including the handshaking concept, energy-based, and force-based coupling approaches. Although such methods are very popular in metals and carbon nanomaterials, their use in polymeric materials is still limited. We have illustrated their applications in polymer science by several examples hoping for raising attention towards the existing possibilities. The relatively new adaptive resolution schemes are then covered including their advantages and shortcomings. Finally, some novel ideas in order to extend the reaches of atomistic techniques are reviewed. We conclude the review by outlining the existing challenges and possibilities for future research.