Addonizio V P
Temple University Health Sciences Center, Department of Surgery, Philadelphia, Pennsylvania.
Hematol Oncol Clin North Am. 1990 Feb;4(1):145-55.
Extensive contact between blood and synthetic surfaces is associated with both quantitative and qualitative changes in platelet function. Cardiopulmonary bypass is associated with a decline in the circulating platelet count, release of platelet alpha granules and possibly platelet dense and lysosomal granule release, and a prolongation of the bleeding time. It is assumed that these platelet alterations contribute to postoperative blood loss and reoperation for bleeding. Improvements in technology have reduced but not eliminated the adverse platelet changes. Temporary inhibition of platelet function during surface contact has achieved additional improvement in the setting of heparin-induced thrombocytopenia but is not yet suitable for "routine" open heart surgery. Long-term cardiopulmonary bypass or extracorporeal circulation membrane oxygenation is receiving increased use during acute respiratory insufficiency. Systemic anticoagulation is required. Bleeding and platelet consumption continue as clinical problems and are treated by repeated platelet transfusion. Because no air interface is present in this setting and the synthetic surface is homogeneous this would appear to be the ideal area for application of platelet functional inhibition and synthetic surface passivation to reduce platelet consumption. Although still under review by the Food and Drug Administration, pulsatile devices, including the total artificial heart, increasingly are being used to provide temporary support for the failing heart. Furthermore, it is likely that totally implantable devices will become available in the very near future. Considering that thromboembolism is a major problem for recipients of mechanical valves, it is likely that thromboembolism will persist as a limiting factor in the further implementation of pulsatile devices. It is assumed that imaginative antithrombotic therapy will be required and that platelet activation will be fundamental to the thrombotic process. Platelet behavior in this setting, however, remains incompletely characterized. The analytical methodology that has been used to assess platelet behavior during cardiopulmonary bypass should be applied to the pulsatile devices as well and results correlated with clinical problems. This should permit standardization of antithrombotic therapy and rational use of platelet functional inhibition.
血液与合成材料表面的广泛接触与血小板功能的定量和定性变化均相关。体外循环与循环血小板计数下降、血小板α颗粒释放以及可能的血小板致密颗粒和溶酶体颗粒释放有关，还与出血时间延长有关。据推测，这些血小板改变会导致术后失血和因出血而再次手术。技术的改进减少了但并未消除不良的血小板变化。在肝素诱导的血小板减少症情况下，表面接触期间对血小板功能的临时抑制已取得了进一步改善，但尚不适合“常规”心脏直视手术。在急性呼吸功能不全期间，长期体外循环或体外膜肺氧合的使用越来越多。需要全身抗凝。出血和血小板消耗仍然是临床问题，并通过反复输注血小板进行治疗。由于在这种情况下不存在气液界面且合成材料表面是均匀的，这似乎是应用血小板功能抑制和合成材料表面钝化以减少血小板消耗的理想领域。尽管仍在接受美国食品药品监督管理局的审查，但包括全人工心脏在内的搏动装置越来越多地被用于为衰竭心脏提供临时支持。此外，完全可植入装置很可能在不久的将来问世。鉴于血栓栓塞是机械瓣膜接受者的主要问题，血栓栓塞很可能会继续作为搏动装置进一步应用的限制因素。据推测，将需要富有想象力的抗血栓治疗，并且血小板活化将是血栓形成过程的关键。然而，这种情况下的血小板行为仍未完全明确。用于评估体外循环期间血小板行为的分析方法也应应用于搏动装置，并将结果与临床问题相关联。这应能实现抗血栓治疗的标准化和血小板功能抑制的合理使用。
