Nephrologists should promote the detection of CKD in heart disease patients. The evaluation should include estimation of GFR and detection of microalbuminuria in a recently voided urine sample by the albumin:creatinine ratio. Any patient with stage 3 or 4 CKD and rapid deterioration of GFR should be evaluated by the nephrologist. - Patients with CKD have a high risk of cardiovascular (CV) complications and heart disease patients have a high incidence of CKD and progression is also more rapid (Strength of Recommendation B). The most likely pathophysiological hypothesis is endothelial damage. - The CV risk profile should be established in each patient followed by adequate compliance with control goals for common CV risk factors: smoking, obesity, sedentarism, hypertension, dyslipidemia. Early treatment of anemia and bone mineral disease as CV risk factors requires special mention (Strength of Recommendation B). - Management of these patients will be based on individualization of treatment, close systematic follow-up, and integration between care levels: Specialized care (nephrologists and cardiologists) and primary care. - The cardiorenal syndrome (CRS) is a condition in which both organs are simultaneously affected and their deleterious effects are reinforced in a feedback cycle, with accelerated progression of renal and myocardial damage. Because of its prognostic value, treatment of HF takes precedence over CKD. Most studies on cardiovascular risk and on HF exclude patients with stage 4-5 CKD. We thus do not have sufficient strong evidence and recommendations are based on the extrapolation of data from studies with normal GFR or milder grades of CKD, and on the empirical use of certain treatments. - ARBs and ACEIs are the mainstays of treatment of HF with systolic and diastolic dysfunction, and have been shown to reduce mortality in studies in the general population (Strength of Recommendation A). The may also slow progression of CKD, especially in diabetics. Dual renin-angiotensin blockade with the combined use of lower doses of both drugs has shown promising results for control of CKD progression, but there are no data to recommend its use for control of HF in advanced stages of CKD (stage 4-5) (Strength of Recommendation C). - In these stages of CKD, only loop diuretics have sufficient potency. The therapeutic dose range should be achieved. Lowdose thiazides achieve diuretic synergy. The use of spironolactone and eplerenone has shown benefits in patients with AMI and HF with an ejection fraction < 40% without advanced CKD. They should always be used with strict control of GFR and K+. No benefit has been shown for the use of <<dopamine in diuretic doses>> (may even be harmful) or continuous infusion of furosemide (Strength of Recommendation B). The use of beta-blockers should be increased in these patients. - Treatment-refractory heart failure in the context of stage 3 CKD could be amenable to ultrafiltration techniques. Continuous ambulatory PD could be an alternative treatment to maintain hemodynamic equilibrium while also allowing pharmacological treatments to be prescribed that would not be feasible without dialysis and could even improve myocardial and kidney function (Strength of Recommendation C).