Loop diuretic resistance complicating acute heart failure.

Acute heart failure hospitalizations complicated by diuretic resistance are associated with worse outcomes. Yet, quantification of the frequency and accompanying risk from loop diuretic resistance is limited by the absence of a comprehensive definition with universal clinical application. Herein, we outline limitations of the current metrics used to identify and define diuretic resistance. We discuss the best available methods to identify and prognosticate outcomes in diuretic resistance. We propose a mechanism-based classification system of diuretic resistance by anatomical location as follows: pre-nephron resistance, pre-loop of Henle resistance, loop of Henle resistance, and post-loop of Henle resistance. Within this paradigm, we compare and contrast historical beliefs of resistance mechanisms with current literature specific to patients with heart failure. We recommend a treatment pathway to restore diuretic efficacy with a literature review of the various combination diuretic strategies and ongoing clinical trials that may impact current best practices.