Chronic Kidney Disease and Heart Failure–Everyday Diagnostic Challenges

Figure 1. Basic mechanisms underlying the mutual dependencies of heart and kidney functions. CO, cardiac output; RAAS, renin-angiotensin-aldosterone system. A figure prepared by the authors on the basis of pathophysiological issues described by Rangaswami et al. [8]. The figure shows the influence of heart and kidney function on the afterload and preload values. The decrease in cardiac output due to heart failure causes renal hypoperfusion. The sympathetic nervous system, the renin-angiotensin-aldosterone system and the release of vasopressin are activated in order to increase systemic vascular resistance and circulating blood volume. Increased venous pressure causes renal congestion, which additionally impairs their function. A decrease in glomerular filtration causes not only hypervolemia (increased preload), but also unfavorable changes in ion concentrations, which affects the contractility of cardiomyocytes. In addition, along with the deteriorating kidney function, disturbances in calcium-phosphate metabolism increase and the synthesis of erythropoietin is impaired, which also adversely affects the function of blood vessels and the heart muscle.

Figure 2. Difficulties in implementing the current diagnostic algorithm for HF for patients with CKD [1,10,11,12,13,14,15,16,17]. The HF diagnostic algorithm (left) includes symptoms that are common in patients with CKD, with or without HF (center). Ruling out HF in patients with CKD may require further differentiation; (right) some potential differentiation factors are proposed; For example, arterial hypertension and diabetes are the primary risk factors for both CKD and HF. In a patient with a significantly reduced eGFR, dyspnea and oedema may be caused by both CKD and concomitant or occurring de novo HF. With the deteriorating renal function, the unequivocal interpretation of the elevated concentration of natriuretic peptides becomes troublesome and electrolyte disturbances may affect the ECG. In such a setting, it is difficult to conclude whether HF coexists with CKD or whether the deterioration of cardiac function is secondary to renal failure and therefore potentially reversible. This issue is discussed in detail later in the article; HF: heart failure; CKD: chronic kidney disease; ECG: electrocardiogram; BNP: brain natriuretic peptide; LV: left ventricular; eGFR: estimated…