Exploring the Cerebro-Renovascular Link: Implications of Renal Haemodynamics on Intracranial Arterial Calcification

Evidence hints that the cerebro-renovascular pathway could offer promising approaches to enhancing renal health and reducing the associated risk and burden of intracranial arterial calcification (IAC), a crucial marker for ageing-related intracranial atherosclerosis. This study explored whether renal function and renovascular haemodynamic metrics could predict the severity and load of IAC and elucidate the clinical distinctiveness between intimal and medial IAC. Seventy-seven Chinese participants were enrolled in this cross-sectional study. Kidney functions were evaluated using the estimated glomerular filtration rate (eGFR). Renovascular haemodynamics (on resistance) was assessed using duplex ultrasound to record metrics such as the resistive index (RI) of renal and interlobar arteries. Non-enhanced computed tomography (CT) assessed the count, severity, and load of IAC and classified IAC into intimal and medial. Regression models were fitted for analyses. Among 69 patients with IAC, 29% exhibited predominantly intimal and 71% predominantly medial calcification. Of those with IAC, 26 (37.7%) had an eGFR below 60 ml/min/1.73m², 19 (27.5%) had values between 60-90 ml/min/1.73m², and 24 (34.8%) had scores above 90 ml/min/1.73m². Measures of eGFR <60 ml/min/1.73m² were independently associated with higher renal RI [adjusted OR=3.45 (95%CI: 1.38-8.59, p=.008)]. Patients with predominantly medial IAC had higher renovascular resistance. Higher renal RI independently predicted higher IAC load [adjusted OR=1.88 (95%CI: 1.06-3.35, p=0.032)]. In summary, renovascular haemodynamics significantly determine the load and severity of IAC, particularly in individuals with reduced renal function (eGFR <60 ml/min/1.73m²). The impact of renal impairment is more pronounced on medial IAC than on intimal IAC.