Impaired Renal Vein Flow in Atrial Fibrillation: A Potential Risk for Renal Dysfunction

BACKGROUND Atrial fibrillation (AF) is one of the most common heart rhythm disorders. Identification and early treatment of AF risk factors can improve mortality and morbidity rates. This study aimed to compare the renal venous stasis index (RVSI) and intra-renal venous flow (IRVF) patterns evaluated by intra-renal Doppler ultrasonography in patients with AF and sinus rhythm (SR). MATERIAL AND METHODS A total of 68 patients, 34 with AF (lasting >12 months AF) and 34 with SR (no previous diagnosis of AF and no AF attack in 24-h Holter monitoring) were included in the study. The RVSI was calculated, and the IRVF patterns were determined using intra-renal Doppler ultrasonography. High RVSI was defined as >0.12 RVSI. In addition, echocardiography and a 6-min walk test were performed. A model including diabetes mellitus, hypertension, creatine, Pro-BNP, left ventricular ejection fraction, presence of AF, and systolic pulmonary artery pressure was created to evaluate the effects of variables on high RVSI. RESULTS The RVSI value was significantly higher in patients with AF than in those with SR (P=0.004). The SR group exhibited a higher prevalence of the continuous flow pattern, which is one of the IRVF patterns (P=0.015). In contrast, the biphasic flow pattern was observed more frequently in patients with AF (P=0.003). The presence of AF was found to predict the high RVSI (P=0.002, OR=14.134, 95% CI 2.083-71.277). CONCLUSIONS The presence of AF may affect the IRVF and cause an increase in RVSI.