A new study published in The Annals of Thoracic Surgery investigated renal resistive index (RRI) variability related to aortic valve pathology. This was a retrospective review of cardiac surgery patients, wherein RRI and aortic valve pathology were assessed before cardiopulmonary bypass. Aortic valve status was categorized into four subgroups: normal – insufficiency and stenosis, none/trace/mild; insufficiency – insufficiency, moderate/severe, stenosis, none/trace/mild; combined insufficiency/stenosis – insufficiency and stenosis, moderate/severe; or stenosis – insufficiency, none/trace/mild, stenosis, moderate/severe. The findings showed that out of 175 patients, 60 had aortic valve pathology (16 insufficiency, 18 insufficiency/stenosis, 26 stenosis). When compared to the normal group, patients with aortic insufficiency had lower diastolic blood pressure and trough renal Doppler velocities, and higher RRI. Furthermore, patients with combined insufficiency/stenosis also had higher RRI. Hence, it was concluded that patients with aortic insufficiency and combined insufficiency/stenosis had higher median RRI values compared to normal patients. For these individuals, diastolic flow differences related to aortic insufficiency may explain why their pre-surgery RRI values often exceeded postoperative thresholds typically associated with AKI. It was suggested that strategies considering the potentially confounding effects of aortic insufficiency on renal flow patterns, independent of renal injury, may add to the value of RRI as an early AKI biomarker.