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Amino acids play a key role in multiple cellular processes. Amino acids availability is reduced in patients with heart failure (HF) with deleterious consequences on cardiac and whole-body metabolism. Several metabolic abnormalities have been identified in the failing heart, and many of them lead to an increased need of amino acids. Recently, several clinical trials have been conducted to demonstrate the benefits of amino acids supplementation in patients with HF. Although they have shown an improvement of exercise tolerance and, in some cases, of left ventricular function, they have many limitations, namely small sample size, differences in patients' characteristics and nutritional supplementations, and lack of data regarding outcomes. Moreover recent data suggest that a multi-nutritional approach, including also antioxidants, vitamins, and metals, may be more effective. Larger trials are needed to ascertain safety, efficacy, and impact on prognosis of such an approach in HF.

Renal dysfunction is often present and/or worsens in patients with heart failure and this is associated with increased costs of care, complications and mortality. The cardiorenal syndrome can be defined as the presence or development of renal dysfunction in patients with heart failure. Its mechanisms are likely related to low cardiac output, increased venous congestion and renal venous pressure, neurohormonal and inflammatory activation and local changes, such as adenosine release. Many drugs, including loop diuretics, may contribute to worsening renal function through the activation of some of these mechanisms. Renal damage is conventionally defined by the increase in creatinine and blood urea nitrogen blood levels. However, these changes may be not related with renal injury or prognosis. New biomarkers of renal injury seem promising but still need to be validated. Thus, despite the epidemiological evidence, we are still lacking of satisfactory tools to assess renal injury and function and its prognostic significance.

Most patients with heart failure (HF) already have or develop renal dysfunction; this might contribute to their poor outcome. Current treatment for HF can also contribute to worsen renal function. High furosemide doses are traditionally associated with worsening renal function (WRF), but patients with fluid overload may benefit of aggressive fluid removal. Unfortunately, promising therapies like vasopressin antagonists and adenosine antagonists have not been demonstrated to improve outcomes. Likewise, correction of low renal blood flow through dopamine, inotropic agents, or vasodilators does not seem to be associated with a clear benefit. However, transient WRF associated with acute HF treatment may not necessarily portend a poor prognosis. In this review, we focus on the strategies to detect renal dysfunction in acute HF, the underlying pathophysiological mechanisms, and the potential treatments.