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The presence of severe right ventricular outflow tract calcification may preclude safe and effective transcatheter pulmonary valve replacement in patients with pulmonary allograft stenosis owing to the risk of conduit tear and suboptimal annular expansion. Debulking calcium using intravascular lithotripsy within the right ventricular outflow tract may mitigate this risk and improve valve hemodynamics. (Level of Difficulty: Advanced.)

The reversed Potts shunt is designed to offload the right ventricle in severe pulmonary arterial hypertension. We present a case of bidirectional flow across a reversed Potts shunt leading to pulmonary edema, with clinical improvement after implantation of a transcatheter valve in the shunt to maintain unidirectional flow. (Level of Difficulty: Advanced.)

Marijuana use is on the rise in the United States. By the end of 2019, 33 states have legalized marijuana use and marijuana byproduct use for medical purposes. However, marijuana use does not come without side effects. This manuscript reviews the increasing usage of marijuana and the different forms (natural and synthetic) that patients may use when presenting to clinicians. It also addresses the biochemical and behavioral changes observed with marijuana use, including the location and changes associated with cannabinoid receptors (abbreviated CB1 and CB2). These two topics lead into an extensive review of the side effects of marijuana use. This manuscript discusses gastrointestinal side-effects, such as Cannabinoid Hyperemesis Syndrome, pancreatitis, and hepatotoxicity. It also briefly reviews cardiovascular, neurologic, and pulmonary side effects. This article provides an overview of therapeutic effects of marijuana including the antiemetic effect, its medical utility as an appetite stimulant, and usefulness in cancer patients post-chemotherapy. A thorough social history pertaining to marijuana use is an important consideration for clinicians in patients presenting with a variety of symptoms, including those effecting the gastrointestinal, cardiovascular, pulmonary, or neurologic systems.

Tenofovir is a broadly used drug used for the treatment of human immunodeficiency virus (HIV). Although the initial results of the clinical trials supported the renal safety of Tenofovir, clinical use of it has caused a low, albeit a significant, risk of renal damage either in the form of AKI or CKD. The pathophysiology has been linked to the effect of this medication on the proximal tubular cell. Although the exact mechanism is unknown, studies have suggested that Tenofovir accumulates in proximal tubular cells which are rich in mitochondria. It is both filtered in the glomerulus and actively secreted in the tubules for elimination and is excreted unchanged in the urine. Studies have shown an active transportation of 20-30% of this drug into the renal proximal tubule (PCT) cells via the organic anion transporters in the baso-lateral membrane (primarily hOAT1, and OAT3 to a lesser extent) and ultimate excretion of the drug into the tubular lumen via the transporters in the proximal tubular apical membrane MRP4 and MRP2 (multidrug resistance-associated proteins 2 & 4). Subsequently, the mitochondrial injury caused by Tenofovir can lead to the development of Fanconi’s syndrome which causes renal tubular acidosis, phosphaturia, aminoaciduria, glucosuria with normoglycemia, and tubular proteinuria. Here we present a case where Tenofovir treatment resulted in severe hypophosphatemia requiring hospitalization for parentral phosphate repletion.