左心辅助对右心功能影响的实验研究

目的　比较左心辅助对正常及急性缺血性功能不全右心室血流动力学的影响 ,初步探讨左心辅助后右心衰的发生原因。方法　以左心房 -主动脉旁路方式植入左心辅助装置于健康成年犬心脏 ,以 70 %辅助流率行左心辅助 ,在辅助前后记录中心静脉压 (CVP)、心输出量 (CO)、平均动脉压 (MAP)、肺动脉压 (PAP)、右心室最大收缩压(RVSPmax)、右心室最大收缩压一阶导数 (RVdp/dtmax)。停左心辅助并结扎右冠状动脉 ,5min后再行左心辅助 ,分别在辅助前后记录上述指标。结果　在右心功能正常时 ,左心辅助后肺动脉压下降 17% (P <0 0 1) ,其他血流动力学指标无明显变化 ;在右心功能不全时行左心辅助后 ,CVP上升 2 % (P>0 0 5 ) ,CO下降 4 % (P <0 0 5 ) ,MAP下降 7% (P <0 0 5 ) ,PAP下降 33% (P <0 0 1) ,RVSPmax及RVdp/dtmax分别下降18%和 14 % (P <0 0 1)。结论　在正常及急性缺血性功能不全右心室行左心辅助后血流动力学的不同变化趋势表明 ,原已存在功能损害的右心室能否承受LVAD应用后所产生的血流动力学的变化是左心辅助应用后发生右心衰的主要原因

Experimental study of the effects of left ventricular assist devices on right ventricular function

Objective To compare the effects of LVAD on normal and acute ischemic right ventricular dysfunction, study the cause of right ventricular failure following LVAD. Methods Eight median sternotomy sedated dogs were studied after placing LVAD (left atrium-aorta bypass), the assistance flow ratio was 70%. Hemodynamics data including central venous pressure (CVP), cardiac output (CO), mean artery pressure (MAP), pulmonary artery pressure (PAP), maximum right ventricular systolic pressure (RVSP max ), maximum rate of change of right ventricular pressure (RV d p /d t max ) were recorded before assistance and after assistance. Stoped LVAD and ligated right coronary artery, after five minute LVAD on again, the same hemodynamics data were recorded in the same time point.Results PAP decreased 17%( P<0 01 ) with LVAD during normal right heart function, while with LVAD during RCA ligation, the CO, MAP, RVSP max , RV d p /d t max and PAP were all decreased significantly, CVP increased ( P>0 05 ).Conclusion The different hemodynamics change with LVAD during normal right ventricular function and the acute ischemic right ventricular dysfunction suggested that the right ventricle with existed dysfunction couldn't tolerate the hemodynamics change during mechanical LV support was the main cause of right heart failure following LVAD.