Cardiorenal syndrome type 3: pathophysiologic and epidemiologic considerations.

Cardiorenal syndrome (CRS) type 3 is a subclassification of the CRS whereby an episode of acute kidney injury (AKI) precipitates and contributes to the development of acute cardiac injury. There is limited understanding of the pathophysiologic mechanisms of how AKI contributes to acute cardiac injury and/or dysfunction. An episode of AKI may have effects that depend on the severity and duration of AKI and that both directly and indirectly predispose to an acute cardiac event. Moreover, baseline susceptibility will modify the subsequent risk for cardiac events associated with AKI. Experimental data suggest cardiac injury may be directly induced by inflammatory mediators, oxidative stress, apoptosis and activation of neuroendocrine systems early after AKI. Likewise, AKI may be associated with physiologic derangements (i.e. volume overload; metabolic acidosis, retention of uremic toxins, hyperkalemia; hypocalcemia), alterations to coronary vasoreactivity, and ventricular remodeling and fibrosis that indirectly exert negative effects on cardiac function. AKI may also adversely impact cardiac function by contributing to alternations in drug pharmacokinetics and pharmacodynamics. Additional experimental and translational investigations coupled with epidemiologic surveys are needed to better explore that pathophysiologic mechanisms underpinning acute cardiac events associated with AKI and their impact on outcomes.