外置主动脉旁反搏装置的慢性动物实验研究

Research of External Para-aortic Counterpulsation Device in a Chronic Animal Model

验证主动脉旁反搏辅助装置(paraaortic counterpulsation device,PACD)置于动物体外并进行短期辅助的可行性及该装置的生物学相容性。小尾寒羊5只,体重42.6±4.5 kg,全麻后左第4肋进胸,将PACD(每搏量为60ml)的人工血管与胸降主动脉吻合,气体管道连接IABP主机,利用体表心电或主动脉压力触发驱动装置反搏。PACD置于动物体外固定后关胸。记录反搏前后主动脉压力变化,定时测定凝血及肝、肾功能、血浆游离血红蛋白(PFH)等指标。4例顺利完成PACD短期(7 d)辅助实验,1例PACD辅助54 h后死亡。PACD辅助后主动脉收缩压(SAP)、主动脉舒张压(DAP)较辅助前显著下降(P<0.01),舒张期主动脉平均压(MADP)显著增加(P<0.01);肝、肾功能轻度损害。辅助期间PFH均在生理可接受范围内变化。PACD易植入,有良好的生物学相容性,可置于动物体外并进行短期(7 d)循环辅助。

To evaluate the feasibility of a new para-aortic counterpulsation device(PACD) implanted into descending aorta and be placed to the animal surface,meanwhile to investigate the hemodynamics characteristics and biocompatibility of PACD in chronic animal experiments.After five healthy sheep(weight,42.6±4.5kg) had been anesthetized,PACD consisting of a blood chamber(60ml) was anastomosed to descend thoracic aorta by a valveless graft through left thoracotomy.Then the chest was closed and PACD was placed to the animal surface of left chest.PACD was pneumatically driven with an intra-aortic balloon pump console that was gated by the electrocardiogram or aortic pressure.Anticoagulation therapy with heparin was used during perioperative stage and warfarin was used after the animal began to eat.Hemodynamics data were collected during the PACD assisting,and postoperative hematology and clinical chemistry tests were performed at regular time throughout the study.Four animals reached the scheduled endpoint of 7 d without device-related problems.One animal was dead after 54 h′s PACD assisting.Both of SAP and DAP decreased significantly(P<0.01) and MADP increased significantly(P<0.01)during PACD assisting.Renal and liver functions were slightly impaired perioperatively.The changes of other hematologic factors,such as total bilirubin and direct bilirubin were within normal limits.The PACD did not produce significant hemolysis as measured by plasma-free hemoglobin(PFH) levels.The PACD which is easy to implant and has high property of biocompatibility,runs successfully as a cardiac assist device for 7 d in sheep and has potential for long-term support.It may serve as an alternative circulatory assist device to current technologies.