Evaluation of the mortality rate caused by different periods of selective portal vein occlusion in rats

Mortality from acute selective portal vein occlusion (SPVO) is a matter of concern for surgeons during the management of traumatic portal vein injury. However, mortality rates related to different periods of SPVO remains undetermined. PURPOSE: To determine the mortality rates resulting from different periods of acute SPVO in rats. METHODS: Wistar male rats were randomized into 8 experimental, and 8 control groups. Experimental animals underwent SPVO during 15 to 75 minutes, and control groups underwent sham procedures. All surviving animals were followed up to 14 days for assessment of mortality rate. RESULTS: Death rates varied from 0% in the 15 min SPVO group, to 100% with 65 and 75 minutes of SPVO. A strongly positive correlation was observed between mortality rates and SPVO periods (p<0.001) with either linear or quadratic regression analysis tests. All deaths in the 20min and 25min SPVO groups occurred after 75 min from the moment of clamping (or after 60 min from unclamping); death from 30 or more min SPVO occurred predominantly within 75 min from clamping moment (or within 60 min from unclamping). (Exact Fisher test, p=0.009). CONCLUSIONS: The mortality from SPVO in rats increases with longer duration of SPVO; with deaths occurring later for short periods (< 25 min) of SPVO and earlier for longer periods (> 30 min) of SPVO.