Changes in renal artery resistance after meal-induced splanchnic vasodilatation in cirrhotic patients.

Purpose: A relationship between vasomotor tone changes in mesenteric and renal vessels in cirrhotic patients has been suspected but remains controversial. The aim of this study was to assess by duplex Doppler sonography the changes in the circulatory resistance of the renal arteries and superior mesenteric artery (SMA) following meal-induced splanchnic vasodilatation.

Methods: Twenty-seven cirrhotic patients and 15 healthy volunteers with no hepatic or renal dysfunction were prospectively included in the study. The resistance index (RI) of the SMA and of the right and left renal arteries was measured by duplex Doppler sonography before and 30 minutes after ingestion of a standard 400-kcal balanced liquid meal. Values in controls and patients and values before and after the meal were compared, and correlations between RIs, Child-Pugh class (liver function), and creatinine clearance were assessed in cirrhotic patients.

Results: The fasting renal artery RI was greater in cirrhotic patients than in controls (p < 0.0001), but there was no difference in fasting SMA RIs. After the meal, there was a significant decrease in the SMA RI in controls (0.85 +/- 0.04 before versus 0.74 +/- 0.03 after meal, p = 0.0001) and in cirrhotic patients (0.85 +/- 0.04 before versus 0.77 +/- 0.04 after, p = 0.0001) and a significant increase in the renal artery RI (0.57 +/- 0.06 before versus 0.62 +/- 0.05 after in controls, p = 0.001; 0.68 +/- 0.07 before versus 0.70 +/- 0.07 after in cirrhotic patients, p = 0.001). No correlation was found in cirrhotic patients between the changes in renal artery RI and the postprandial SMA RI decrease, the Child-Pugh class, or the creatinine clearance.

Conclusions: Meal-induced SMA vasodilatation (RI decrease) is associated with a marked increase in the renal artery RI, worsening the renal vasoconstriction in cirrhotic patients.