Anemia in Cardio-Renal Syndrome: clinical impact and pathophysiologic mechanisms.

Anemia is a disease that is often associated with heart failure (HF) and renal insufficiency (RI). This unfavorable triad of conditions has been called Cardio-Renal-Anemia Syndrome (CRS). The association of HF, RI, and anemia is poorly reported in multicenter clinical trials, so the pathophysiologic mechanisms and treatment options need to be better defined. When CRS patients develop anemia, a "perfect storm" often occurs: HF and RI cause anemia which will worsen the first two conditions. Anemia appears to be the result of complex interactions between cardiac performance, bone marrow homeostasis, renal dysfunction, and various drug side effects. However, neurohormonal and inflammatory activities play a key role in the beginning and progression of the disease. As a consequence, endogenous erythropoietin activity dysfunction with inadequate production and tissue resistance occurs. Despite the advances of therapy in the neurohormonal activation blockade, mortality and hospitalization in HF still remain unacceptably high, suggesting that specific comorbidity treatments could have a significant positive prognostic impact. Anemia should be recognized as one of the novel targets in HF treatment.