Pharmacological Modulation of the Renin–Angiotensin–Aldosterone System and Natriuretic Peptides in Cardiorenal Syndrome

Cardiorenal syndrome encompasses a heterogeneous group of acute and chronic disorders in which dysfunction of the heart and kidneys develops through bidirectional hemodynamic, neurohormonal, inflammatory, and metabolic interactions. Persistent activation of the renin–angiotensin–aldosterone system is a central mechanism linking impaired renal perfusion, venous congestion, sodium retention, endothelial dysfunction, myocardial remodeling, and progressive renal injury. The natriuretic peptide system provides an endogenous counter-regulatory pathway by promoting natriuresis, vasodilation, glomerular hemodynamic adaptation, and inhibition of renin, aldosterone, sympathetic activity, inflammation, and fibrosis. However, patients with advanced heart failure and chronic kidney disease frequently develop relative natriuretic peptide insufficiency or resistance despite markedly elevated circulating peptide concentrations. This apparent paradox reflects altered peptide processing, impaired receptor signaling, enhanced enzymatic degradation, reduced renal responsiveness, and the overwhelming activity of sodium-retaining pathways. Pharmacological interventions directed at these interconnected systems include angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, mineralocorticoid receptor antagonists, angiotensin receptor–neprilysin inhibitors, exogenous natriuretic peptide analogues, and emerging agents targeting specific components of cyclic guanosine monophosphate signaling. Their clinical effects cannot be interpreted solely through changes in serum creatinine or estimated glomerular filtration rate, because transient hemodynamic reductions in filtration may coexist with long-term cardiac and renal protection. Conversely, treatment-related hypotension, hyperkalemia, acute kidney injury, and inadequate decongestion remain major barriers to implementation in patients with advanced cardiorenal disease. This narrative review examines the biological basis, clinical evidence, diagnostic implications, and therapeutic limitations of pharmacological modulation of the renin–angiotensin–aldosterone and natriuretic peptide systems in cardiorenal syndrome. https://doi.org/10.52783/jchr.v16.i4.15786