Cardiorenal syndrome in heart failure with preserved ejection fraction-an under-recognized clinical entity

Cardiorenal syndrome (CRS) results from the complex and bidirectional interaction between the failing heart and the kidneys. Limited information exists about the pathophysiology and treatment options for worsening kidney function in the setting of heart failure with preserved ejection fraction (HFpEF). This review summarizes the salient pathophysiological pathways in CRS in patients with HFpEF, with emphasis on type 1 and type 2 phenotypes, and outlines diagnostic and therapeutic strategies that are applicable in this population. Elevated central venous and intra-abdominal pressure, left ventricular hypertrophy, LV strain, RAAS activation, oxidative injury, pulmonary hypertension, and RV dysfunction play key roles in the pathogenesis of CRS in the backdrop of HFpEF. The availability of biomarkers of renal and cardiac injury offer a new dimension in accurately diagnosing and quantifying end organ damage in CRS and will improve the accuracy of goal-directed therapies in this population. Novel targeted therapies such as the development of angiotensin/neprilysin inhibitors and sodium-glucose cotransporter-2 (SGLT-2) inhibitors offer new territory in realizing potential benefits in reduction of cardio-renal adverse outcomes in this population. Future studies focusing exclusively on renal outcomes in patients with HFpEF are crucial in delivering optimal therapies in this subset of patients.