European Journal of Cardio-Thoracic Surgery, Vol 4, 40-44, Copyright © 1990 by European Association for Cardio-thoracic Surgery
A comparative study of prostacyclin infusion given before and during cardiopulmonary bypass to assess the first pass effect of the circuit on platelet number and function
HK Jestice, JE Humphreys, TA English, CE Hoggarth and FC Wells
Department of Haematology, Papworth Hospital, Cambridge, UK.
Platelet damage during cardiopulmonary bypass (CPB), although proportional
to the duration of bypass, may result in significant dysfunction after the
initial contact with an extracorporeal circuit, the so-called 'first pass'
phenomenon. The platelet sparing effect of prostacyclin (PGI2) infusion was
studied in a double-blind randomized trial on male patients undergoing
coronary artery bypass grafts to assess the effect of the 'first pass'
through the CPB circuit. Prostacyclin infusion was begun before the onset
of CPB or during CPB in two groups which were compared to a placebo control
group. A standardized anaesthetic, surgical and perfusion technique were
used. Preoperatively and during surgery at pre-set intervals, whole blood
platelet aggregation was studied using ADP and collagen agonists. Platelet
numbers and function measured by ADP aggregation were conserved in the two
PGI2 groups. There was no significant difference between the treated
groups. We conclude, therefore, that the initial contact of platelets with
the CPB circuit, in the absence of PGI2 did not irreversibly affect
platelet function. In addition, the hypotensive action of PGI2 was easier
to control once on bypass. It may therefore be preferable to delay PGI2
infusion until CPB has been established.
