The close relationship between heart and kidney diseases was studied with respect to the 'Shrunken pore syndrome' that is characterized by a difference in renal filtration between cystatin C and creatinine. Patients were retrieved from the HeARt and brain failure inVESTigation trail (HARVEST) which is an ongoing study undertaken in individuals hospitalized for the diagnosis of heart failure. Ninety-five of 116 patients who underwent transthoracic echocardiograms (TTE) were eligible for this study. We used four different formulas for estimated glomerular filtration rate (eGFR); CKD-EPIcreatinine, CKD-EPIcystatin C, LMrev and CAPA. Presence of the syndrome was defined as eGFR cystatin C ≤ 60% of eGFR creatinine and absence of the syndrome as eGFR cystatin C >90% and <110% of eGFR creatinine. In a linear regression model, adjusted for age and sex, and the 'Shrunken pore syndrome' defined by the equation pair CAPA and LMrev and the equation pair CKD-EPIcystatin C and CKD-EPIcreatinine, echocardiographic parameters were studied. The 'Shrunken pore syndrome' showed statistically significant associations with measurements of right ventricular (RV) systolic function; (TAPSE and RV S') (according to the equation pair CKD-EPIcystatin C and CKD-EPIcreatinine). In conclusion, heart failure patients with the 'Shrunken pore syndrome' are at increased risk of having RV systolic dysfunction whilst heart failure patients without 'Shrunken pore syndrome' seem protected. These findings may indicate common pathophysiological events in the kidneys and the heart explaining the observed increased risk of mortality in subjects with the 'Shrunken pore syndrome'.
Keywords: Cardio-renal syndrome; creatinine; cystatin C; echocardiography; glomerular filtration rate.