Coagulación 2009: una visión moderna de la hemostasia

espanolTras una lesion vascular se pone en marcha el mecanismo hemostatico, un sistema de defensa del organismo para prevenir la hemorragia. Clasicamente se consideraba la coagulacion como una cascada enzimatica con 2 vias independientes, intrinseca y extrinseca, que convergian en una via fi nal comun. Dicho esquema no contemplaba la participacion de las plaquetas ni de otras superfi cies celulares. Segun la vision actual, la coagulacion se produce en tres etapas interrelacionadas: fases de iniciacion, amplifi cacion y propagacion, y tiene lugar sobre superfi cies celulares, lo que conlleva la formacion de sufi cientes cantidades de trombina para formar un coagulo estable capaz de detener la hemorragia. EnglishFolllowing vascular injury, blood loss is controlled by the mechanism of hemostasis. In a classic model of coagulation distinct intrinsic and extrinsic pathways converge on a common pathway. This scheme did not take into account the participation of platelets nor other cellular components. The concept has been challenged by a new one in which cells are important participants in the coagulation process. In a modern view, the cell-based model of coagulation actually occurs in an overlapping step-wise process: initiation, amplifi cation and propagation on the surface of activated cells, to produce the burst of thrombin that causes stabilization of the fi brin clot and stop bleeding.