EFFECTS OF CONSTANT INFUSION OF ILOPROST, A STABLE PROSTACYCLIN DERIVATIVE DURING CARDIOPULMONARY BYPASS
Prostacyclin (PGI2) is a potent inhibitor of platelet aggregation but it is highly unstable. Iloprost (Schering A.G.) is a stable carbacyclin derivative of PGI2 which is also a potent inhibitor of platelet aggregation. The effect of constant Iloprost infusion during cardiopulmonary bypass (CPB) on blood loss, platelet numbers, secretory proteins and platelet sequestration was studied in 50 adult males undergoing CPB for elective coronary vein bypass graft surgery.In a double-blind, randomised,
... blind, randomised, placebo-controlled study (25 patients in each group) intravenous infusion of Iloprost was commenced at 5ng/kg/min immediately after the induction of anaesthesia and increased to 10ng/kg/min when the patient was established on CPB. The infusion was discontinued on completion of CPB. Blood loss and units of blood transfused were not significantly different in the two treatment groups. During CPB, mean platelet numbers fell significantly in both groups but were significantly higher (P<.001) in the Iloprost group than in the placebo group at the end of CPB and until 18-24 hours post CPB (P<.05). Mean plasma thromboxane B2 and β thromboglobulin levels were marginally lower (P<.05 and P<.02) in the Iloprost group but the distribution of platelet factor 4 results were similar in both groups. Post operative spontaneous platelet aggregation was similar in both groups. Platelet sequestration in oxygenators and arterial line filters was assessed using Indium labelled patients' platelets reinjected immediately after commencing Iloprost infusion. Platelet sequestration was significantly greater in the placebo group than in the Iloprost group both in the oxygenators (placebo 9.2%, Iloprost 3.4% : P<.001) and in the arterial line filters (placebo 4.8%, Iloprost 0.6% : PC.05).Blood pressure was significantly lower in the Iloprost group than in the placebo group throughout the infusion period.Constant infusion of Iloprost during CPB is associated with significantly less platelet sequestration. The importance of this is not only in the conservation of platelet numbers but also the potential reduction in risk of platelet aggregate embolisation.