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ISHLT 2017 Pharmacy and Pharmacology Council Review: Weeding Through Science

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Edward Horn, PharmD, BCPS
Allegheny General Hospital
Pittsburgh, PA, USA

Just a few short weeks ago, ISHLT members convened in sunny San Diego to take in another year of fantastic educational content. Our council had four sponsored symposia during the meeting, and we were invited to be part of three others. Among these sessions, I would like to focus on two symposia that were conducted: Lifecycle Journey of Thrombosis in Mechanical Circulatory Support Patients and Weeding out Fact from Fiction - The Highs and Lows of Marijuana Use in Transplant. Both of these symposia provided interesting educational content of a commonly encountered issue of MCS thrombosis, as well as a novel perspective into the increasingly frequent dilemma of dealing with marijuana use in our transplant population.

The Lifecycle Journey is one of the main PHARM symposiums that is provided at the ISHLT annual meeting and encompass a patient's journey through a particular disease state. In past years, our council has examined therapeutic dilemmas with pulmonary hypertension, hepatitis C in transplantation and cystic fibrosis in lung transplantation. This year's Lifecycle Presentation surrounded thrombosis in mechanical support patients, but focused on specific aspects to patient care that are encountered in patients with this issue. This session was chaired by Dr. Christina Doligalski and Dr. Stephan Schueler. Dr. Daniel Zimpfer highlighted the importance of pristine surgical techniques during implantation and how pump positioning can lend itself to thrombosis. Our patient case was developed with nuances related to anticoagulation - particularly dealing with heparin induced thrombocytopenia in the setting of MCS. I was fortunate enough to be afforded the opportunity to discuss this issue, as well as the use of novel anticoagulant agents in MCS. Lastly, Dr. Lisa Baumann Kreuziger reviewed pathologic mechanisms of thrombosis in MCS and what insights can be gained by examining clots under the pathologists' microscope.

Clinical Pearls from the Lifecycle Journey in Thrombosis in MCS Session:

  • Surgical technique is paramount in reducing thrombosis risk.
  • There are potential mechanisms by where direct thrombin inhibitors may limit thrombin production more readily in MCS.
  • Data surrounding the use of direct acting oral anticoagulants is scarce in MCS; however, existing data suggests that they may serve as an alternative in select situations.
  • Thrombosis appears to consist of layers of fibrin-based clot in patients with early thrombosis, whereas late thrombosis has an element of platelet-based clot. The implications on antithrombotic therapy are unknown at this time, but suggest targeting fibrin production or platelet activation could depend on the timing of thrombosis occurrence after MCS implant.

"Weeding out Fact from Fiction," the PHARM council sponsored symposium elaborating on the use of marijuana, both medically and recreationally in thoracic transplant recipients, yielded a wealth of information on how to attack this dilemma from a pharmacologic, psychosocial, legal and medical perspective. Dr. Adam Cochrane and Dr. Vincent Valentine chaired this session, with presentations from Drs. Robert Page, Patrick Smith, Lianne Singer and Lorriana Leard. Lastly, Dr. Martin Zamora and Dr. Erik Verschuuren engaged in an entertaining, yet thought provoking, pro-con debate on the use of marijuana in the thoracic transplant recipient community. Dr. Page discussed the pharmacology of cannabis by reviewing the multiple metabolites present with this agent and their impact on immunosuppression with respect to drug interactions. Dr. Smith discussed screening and monitoring techniques to detect which patients may be at risk for adverse psychological effects with cannabis use. Dr. Singer reviewed data surrounding the anti-inflammatory effects and immunomodulation properties of cannabis and the potential impact on graft function. Lastly, Dr. Leard presented on the legal and regulatory issues surrounding cannabis use in transplant recipients, specifically discussing the Medical Cannabis Organ Transplant Act in California. This symposium was certainly buzz worthy, given recent stories in the media surrounding potential transplant recipients and how transplant centers have handled this issue. All of the speakers presented data to help the audience be more educated regarding the physiologic impact of cannabis in transplant patients, tools to monitor psychological effects, and how to navigate the complicated legal and regulatory aspects of use.

Clinical Pearls from "Weeding out Fact from Fiction:"

  • Cannabis is metabolized in to over 50 compounds with a variety of physiologic and metabolic effects. The main compounds, THC and CBD, are metabolized through CYP3A4, CYP2C9 (THC) and CYP2C19 (CBD) - which can adversely affect the metabolism of multiple immunosuppressants.
  • Questionnaires and surveys are available to providers to better help identify which patients could be at risk of the adverse psychological effects of cannabis use.
  • Regulatory and legal considerations surrounding cannabis are confusing to navigate - while cannabis remains regulated as a schedule I agent (no medical use), states have passed legislation for both medicinal and recreational use. State and federal regulations continue to be at odds, only confusing the matter with respect to how this is to be handled in a regulated medical field, such as transplantation.

Disclosure Statement: The author has no conflicts of interest to disclose.

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