The wide implementation of invasive procedures such as coronary angiography and percutaneous coronary intervention (PCI) into the routine care for patients with acute coronary syndromes (ACS) in the last 10 years has caused a notable improvement in their prognosis. Simultaneously, it has raised new problems and questions which are largely related to the fact that many elderly and/or polymorbid patients undergo these invasive procedures. One of the most important comorbidities is chronic kidney disease (CKD). The complex relations between cardiac and renal disease are sometimes referred to as “cardiorenal syndrome” (table 1). We do not use this term clinically because we consider it misleading—it is not a real syndrome, but rather a chain of pathophysiologic events (in a similar way we could have cardiopulmonary syndrome, cardiocerebral syndrome, cardiohepatic syndrome, etc). Patients with CKD and ACS usually present with more extensive atherosclerosis, including diffuse coronary calcifications (fig 1), which represents a challenge for the interventional cardiologist (higher risk of periprocedural complications, higher risk of restenosis, etc).

This review deals with most aspects of the complex ACS–CKD relation, focusing mainly on contrast induced nephropathy (CIN) and the appropriate use of angiographic contrast agents.