Effects of splenectomy on portal pressure in short- and long-term portal hypertensive rats.

Different hemodynamic patterns were noted in short- and long-term portal hypertensive rats, induced by partial portal vein ligation (PVL) performed two weeks and six months earlier. In order to investigate the effect of splenectomy on the portal pressure of portal hypertensive rats with different hemodynamics, an operation was performed on these two groups of animals and the portal pressure measured thereafter at different time points. Splenectomy in the short-term group produced an immediate, but transient, drop in portal pressure from 14.1 +/- 2.7 to 11.0 +/- 3.0 mmHg, which bounced back to pre-splenectomy values in 20 seconds. Two weeks later, the portal pressure in these splenectomized rats was 15.2 +/- 4.2 mmHg, which was indistinguishable from that of the pre-splenectomy condition of the short-term group. However, after an additional two weeks, portal pressure in the splenectomized rats rose to 16.4 +/- 2.1 mmHg, which was significantly higher than that of the pre-splenectomy condition of the short-term group. This difference in portal pressure became even more pronounced at six months. Sustained portal hypertension was observed in the long-term group, but the pressure was significantly lower than that in the short-term group. Splenectomy in the long-term group produced neither an immediate drop nor a delayed rebound in portal pressure. We conclude that splenectomies in portal hypertensive rats at different stages of disease produce different effects.