Background and purpose: Chronic kidney disease is a risk factor for cardiovascular disease (CVD). Renal resistive index (RI) measured by Doppler ultrasonography is associated with renal impairment. We investigated the relationship between RI and cardiac function, and evaluated the utility of RI for predicting cardiac events in patients with CVD.
Methods and results: Renal Doppler ultrasonography and echocardiography were performed in a total of 452 patients with CVD. Correlations of RI with serum creatinine and estimated glomerular filtration rate (eGFR) were significant but not strong (r = 0.37, p < 0.001; r = -0.42, p < 0.001, respectively). RI correlated positively with age, left atrial volume index, left ventricular mass index, and early transmitral velocity to mitral annular early diastolic velocity (e') ratio (E/e'), and showed significant negative correlations with e' and diastolic blood pressure. Between two subgroups-112 patients hospitalized with cardiovascular events (Group A) and 200 age- and eGFR-matched controls (Group B)-RI was significantly higher in Group A than in Group B, although age and eGFR were similar.
Conclusions: RI reflects the impairment of intrarenal hemodynamics that cannot be adequately elucidated by eGFR alone. Assessment of renal RI may be useful in conjunction with prognostic estimates for patients with CVD.
Keywords: Cardiac events; Cardiovascular disease; Renal Doppler ultrasonography; Resistive index.