Adenosine A1 receptor antagonists at a fork in the road.

Up to one half of patients with chronic heart failure and two thirds of patients with acute heart failure have concomitant renal dysfunction—a clinicopathophysiologic association that has been termed the cardiorenal syndrome.1 When present, baseline renal impairment contributes to adverse outcomes in both ambulatory and hospital settings, and the attributable risk increases with progression of both cardiac and renal disease. Although independent risk factors have been identified (eg, hypertension and diabetes) and underlying mechanisms described, targeted therapies are