SPLENIC DOPPLER IMPEDANCE INDEXES - INFLUENCE OF DIFFERENT PORTAL HEMODYNAMIC CONDITIONS

The spleen plays a pivotal role in the pathogenesis and maintenance of portal hypertension. Few data exist about splenic hemodynamics evalua ted by duplex sonography in this condition. Twenty-six normal subjects , 207 patients with portal hypertension of various causes, and in diff erent splenoportal hemodynamic conditions, and 31 patients with liver transplantation were evaluated. In each patient the splenic resistive index (RI = peak systolic - end diastolic velocity/peak systolic veloc ity) and pulsatility index (PI = peak systolic - end diastolic velocit y/mean velocity) were measured. In 17 cirrhotic patients, splenic indi ces were compared with portal hemodynamics as invasively evaluated by hepatic vein catheterization. In the various groups, RI and PI were re spectively: normal subjects, 0.51 +/- 0.05 and 0.72 +/- 0.11; cirrhoti c patients with hepatopetal portal blood now (n = 167), 0.64 +/- 0,08 and 1.03 +/- 0.24; cirrhotic patients with hepatofugal portal flow (n = 3), 0.74 +/- 0.08 and 1.27 +/- 0.08; cirrhotic patients with portal vein thrombosis (n = 9), 0.74 +/- 0.08 and 1.36 +/- 0.34; patients wit h noncirrhotic obstruction of the portal system (n = 7), 0.69 +/- 0,11 and 1.16 +/- 0.28; cirrhotic patients with surgical decompression of splenic vein system (n = 21), 0.54 +/- 0.07 and 0.76 +/- 0.15; patient s with liver transplantation (n = 31), 0.50 +/- 0.08 and 0.70 +/- 0.15 . Both RI and PI were significantly higher in cirrhotic patients with hepatopetal portal Bow compared with controls (P < .0001), and even hi gher in cirrhotic patients with portal vein thrombosis (P < .004 and P < .001 in comparison with RI and PI values of cirrhotic patients). In patients with noncirrhotic portal vein thrombosis, splenic impedance indices were higher than those in controls (RI and PIP < .0001). Cirrh otic patients who underwent surgery for the therapy of portal hyperten sion showed splenic impedance indices significantly decreased compared with other cirrhotic patients (RI and PI P < .0001), In patients who underwent liver transplantation, splenic impedance indices were the sa me as those in controls. In 23 of the 52 patients surgically treated ( surgical shunt or liver transplantation), impedance indices were evalu ated both before and after surgical treatment. All these patients show ed a decrease in splenic impedance indices (RI and PI, P < .0001) afte r surgical treatment. RI and PI values were higher in patients with la rge esophageal varices as compared with patients without or with small varices (P < .02 and P < .01). RI and PI values were not related to a ge, mean arterial pressure, sex, Child-Turcotte-Pugh score, presence o f ascites, or cause, A significant correlation was found between splen ic impedance indices and portal resistance as evaluated by hepatic vei n catheterization (r = .80, P < .001 for RI values; r = .87, P < .001 for PI values), In conclusion, this study shows that splenic impedance indices are increased in cirrhotic patients, and seems to demonstrate that in patients with cirrhosis these indices reflect portal vein blo od flow resistance.