Postprandial middle cerebral arterial vasoconstriction in cirrhotic patients. A placebo, controlled evaluation

The objective of this study was to determine whether cerebral arterial vasoconstriction occurs in relation to postprandial splanchnic blood pooling in cirrhotic patients.

The pulsatility and the resistive indexes and blood flow in the middle cerebral artery were measured by magnetic resonance imaging in 21 cirrhotics and 14 controls. These measurements were repeated 30 min after ingestion of a 400 kcal liquid meal or placebo. Seven controls and 14 patients received the meal, and seven controls and seven patients received placebo.

In the fasting conditions, cirrhotics had a greater pulsatility index (0.81 +/- 0.10 vs. 0.67 +/- 0.05, P < 0.001) and a greater resistive index (0.61 +/- 0.04 vs. 0.53 +/- 0.04, P < 0.001) and a lower blood flow (127 +/- 42 ml/min vs. 167 +/- 37 ml/min, P < 0.03) in the middle cerebral artery compared with controls. Meal ingestion significantly increased the pulsatility index (P < 0.03) and the resistive index (P < 0.01) and decreased blood flow (P < 0.03) in the middle cerebral artery in cirrhotics but not in controls. In contrast, placebo ingestion had no effect on the hemodynamic parameters in the middle cerebral artery in the two groups.

Results support the hypothesis that middle cerebral arterial vasoconstriction seen in cirrhotic patients is one of the cerebral artery's homeostatic responses to underfilling of the splanchnic arterial circulation.