Marc Leon

By Jakraphan Yu, Marc Leon, Manuel Quiroz-Flores and Chawannuch Ruaengsri

Atrial fibrillation (AF) is the most common cardiac arrhythmia that is related to an increased risk of ischemic stroke and systemic embolism. While oral anticoagulation drugs remain the primary treatment for stroke prevention in AF patients, certain individuals face absolute or relative contraindications that preclude oral anticoagulants use. The left atrial appendage (LAA) has been found to be the main source of intracardiac thrombi in AF patients, which result in embolic stroke, a devastating morbidity. Over the past years, the LAA exclusion technique has emerged as an alternative and complimentary therapeutic strategy for stroke prevention In this chapter, the current evidence regarding LAA closure procedure from multiple guidelines, clinical trials, as well as the technique of LAA exclusion including both surgical and transcatheter approaches will be discussed. Moreover, we will demonstrate the essential factors to achieve optimal closure and translate to favorable clinical results and the ongoing trials and future trends in LAA exclusion procedures.

Part of the book: Atrial Fibrillation

By Manuel Quiroz-Flores, Marc Leon, Ali Own, Akash Shah, Samuel Jacob and Chawannuch Ruaengsri

This chapter aims to explore the history of xenotransplant, contemporary practices, ethical considerations, and the challenges associated with xenotransplantation. Due to the persistent scarcity of donor organs available for transplantation, various alternative sources are under investigation, one of which is xenotransplantation—transplanting organs from one species to another. Among nonhuman primates, porcine is considered the most suitable species for organ usage, as they grow to human size in just a few months. Significant progress has been made in the genetic engineering of pigs, whose hearts closely resemble human hearts in both structure and function. Genetic engineering plays a crucial role in overcoming immune barriers in xenotransplantation, helping to prevent T-cell-mediated and hyperacute rejection. Although using large animal models for orthotopic heart transplants presents technical challenges, the approach holds promise. Despite some religious prohibitions on pork, leaders in Muslim and Jewish traditions generally consider porcine organ donation ethical, as it saves lives. While technological advances have reduced the risk of xenografts transmitting novel viruses, this danger remains and has serious implications for the informed consent process in clinical xenotransplantation research.

Part of the book: Bridging the Gap and Saving Lives