Superior mesenteric artery impedance in chronic liver diseases: relationship with disease severity and portal circulation.

OBJECTIVE

The increase of splanchnic blood flow volume in liver cirrhosis is attributed to decreased arterial resistance. The aim of this study was to noninvasively investigate superior mesenteric artery impedance in patients with chronic liver diseases and to assess its relationship with portal hemodynamics and with clinical parameters.

METHODS

Superior mesenteric artery (SMA) pulsatility (SMA-PI) and resistance (SMA-RI) indices and portal vein flow parameters (velocity, volume, and congestion index) were measured by duplex-Doppler ultrasound in 14 patients with chronic hepatitis, in 73 cirrhotics, in 30 liver transplant recipients, and in 31 control subjects.

RESULTS

SMA-PI significantly differed among the five groups (p < 0.0001), being lower in cirrhotics (2.55+/-0.70) and transplanted patients (2.77+/-0.69) than in chronic hepatitis (3.28+/-0.57) and control subjects (3.42+/-0.92). SMA-PI was lower in ascitic cirrhosis (2.40+/-0.71) than in compensated cirrhosis (2.71+/-0.70) (p < 0.01) and in cirrhotics with large varices (2.30+/-0.67) than in those without varices (2.75+/-0.65) (p < 0.05). Moreover SMA-PI correlated with numeric Child-Pugh score (r=-0.28) and portal vein congestion index (r=-0.36).

CONCLUSION

Hyperdynamic splanchnic circulation, noninvasively assessed by a decrease of mesenteric artery impedance, occurs in cirrhosis since the early stage of the disease and tends to worsen in relation to liver failure and the severity of portal hypertension. Furthermore, the persistent SMA-PI decrease in transplant recipients suggests a consistent contribution to this circulatory alteration from a patent portosystemic collateral circulation.