Renal function as a predictor of prognosis in chronic heart failure

The incidence of chronic heart failure (CHF) has been increasing, particularly because of the aging of the population and the improved survival of patients with coronary artery disease. Therefore, the current pathophysiological and clinical considerations in the diagnosis and treatment of CHF will need further improvement in terms of cardiovascular risk profiling, preventive measures, earlier intervention, and patient-tailored disease management. To date, the role of the kidney in CHF is mainly considered within the context of excessive salt and water retention, due to reduced renal blood flow. However, recent data indicate that the kidney may play a more decisive role in the progression and prognosis of the disease. It has been demonstrated that renal function is independently associated with an increased risk for all-cause mortality and cardiovascular morbidity. Furthermore, moderate renal insufficiency is a common phenomenon in this patient population and, for example, left ventricular ejection fraction, glomerular filtration rate, and New York Health Association class are not only prognostically important but are also acting independently, and support the hypothesis that cardiac function, clinical status, and renal function represent, in part, different prognostic entities of CHF. It could be questioned why an impaired renal function adds prognostic risk to develop CHF? A subclinically decreased renal function is unlikely to be the direct cause. Renal function is known to correlate with a variety of cardiovascular risk factors. Similar risk factors could contribute to the pathogenesis of intrarenal disease. Furthermore, a large number of metabolic abnormalities are related to impaired renal function and induce myocardial dysfunction and damage. Finally, neurohormonal activation is apparent in patients with chronic heart failure. Angiotensin II, the central product of the renin-angiotensin system, may play a central role in the pathophysiology and progression of cardiovascular and renal diseases. In conclusion, to prevent cardiovascular morbidity and mortality, new therapeutic strategies might be triggered by focussing on increasing our knowledge concerning adaptive and maladaptive mechanisms of the kidney involved in CHF.