Extracorporeal circulation, hemocompatibility, and biomaterials.
BACKGROUND
Performance of a majority of cardiac surgical procedures requires the use of extracorporeal circulation. Contact of the patients' blood with the nonendothelial surface of the cardiopulmonary bypass circuit is responsible for several, potentially harmful systemic reactions.


METHODS
The patients' response to extracorporeal circulation is reviewed briefly. The interactions between patient and circuit are discussed not only as they relate to blood-material contact, but also from a mechanical and rheologic standpoint. The theoretic benefits of the newer, more hemocompatible materials are presented, along with a review of published clinical experience with heparinized cardiopulmonary bypass circuits.


RESULTS
The response to extracorporeal circulation extends far beyond a simple derangement of hemostasis. This inflammatory response is strongly influenced by the rheologic design of the circuit and by the physical and chemical properties of the surface. Heparinized circuits decrease inflammation, but the clinical benefits of this reduction remain unclear, except for extended cardiopulmonary support. The safe use of these circuits requires full heparinization and does not reduce allogeneic transfusions.


CONCLUSIONS
Clinicians are still in the search of the ideal material and the ideal extracorporeal circuit design. Newer, heparinized materials offer real but limited clinical benefits.
Janvier
G
G
Biomaterial Research Unit (INSERM U.306), Centre Hospitalier Universitaire de Bordeaux, France.
Baquey
C
C
Roth
C
C
Benillan
N
N
Bélisle
S
S
Hardy
J F
JF
D001672:Biocompatible Materials; D001769:Blood; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000295:instrumentation; D005112:Extracorporeal Circulation / Q000009:adverse effects / Q000295:instrumentation*; D006493:Heparin; D006801:Humans; D007249:Inflammation / Q000209:etiology
D001672:Biocompatible Materials; D006493:Heparin