Splenektomie reduziert den portalvenösen Blutfluss und damit das Risiko eines Hyperperfusions-Syndroms in small-for-size Lebern Splenectomy reduces risk for hyperperfusion syndrome in small-for-size livers by reduction of portal venous blood flow

The small-for-size syndrome reflects portal hyperperfusion in reduced-size livers such as cadaveric split livers or living-related donor grafts, presenting as a condition which might seriously impair postoperative liver regeneration. Using an experimental rat model, we investigated splenectomy as a measure to reduce portal hyperperfusion and its impact on postoperative recovery following extended partial hepatectomy. Male Wistar rats underwent partial (90 %) hepatectomy under isoflurane/oxygen inhalative anesthesia and temporary warm organ ischemia (30 min). One group of animals additionaly underwent splenectomy while the second group served as controls. In addition to 10-day survival rate, laser doppler flowmetry of hepatic blood flow and fluorescence microscopic analysis of the hepatic microcirculation were performed to assess the effect of splenectomy on initial microvascular reperfusion of liver remnants. While postoperative perfusion failure was comparable between both groups (9.5 vs 8.7 %), portal blood flow was reduced after simultaneous splenectomy, as was velocity (sinusoids: 247 ± 36 vs 271 ± 34 µm/s; venules: 321 ± 49 vs 375 ± 89 µm/s) and volumetric blood flow (sinusoids: 14 ± 1 vs 16 ± 1 pl/s; venules: 192 ± 47 vs 327 ± 112 pl/s), as compared to controls. Additionaly, splenectomized animals experienced lower AST levels (421 ± 36 vs 574 ± 73 U/l), and mean survival was significantly increased (p = 0.037), reaching 6.6 ± 1.3 vs 2.6 ± 0.8 days. Simultaneous splenectomy significantly reduced the risk for postoperative hyperperfusion syndrome in small-for-size livers. Shear stress induced liver injury was diminished due to reduction of portal venous blood flow, volumetric blood flow, and sinusoidal and venular velocity, while the sinusoidal perfusion rate was comparable. Thus, hepatic regeneration was positively influenced resulting in significantly higher survival in splenectomized animals.