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The effect of prostaglandin E1 in patients undergoing clinical cardiopulmonary bypass
Insights
Prostaglandin E1 (PGE1) minimally protected platelets during cardiopulmonary bypass (CPB), but caused significant hypotension. Higher doses were precluded, limiting its protective effect on platelet damage.
Area of Science:
- Cardiovascular Surgery
- Hematology
- Pharmacology
Background:
- Cardiopulmonary bypass (CPB) can impair platelet function.
- Prostaglandin E1 (PGE1) has shown potential in animal models for platelet protection.
Purpose of the Study:
- To evaluate the efficacy and safety of PGE1 in protecting platelets during CPB in humans.
- To assess the hemodynamic side-effects of PGE1 infusion during coronary artery bypass grafting (CABG).
Main Methods:
- A prospective study comparing 9 patients receiving PGE1 with 10 control patients undergoing CABG.
- PGE1 was infused at 0.05 micrograms/kg/min, with dose adjustments due to hypotension.
- Platelet aggregation, number, and function were assessed, along with hemodynamic parameters and blood loss.
Main Results:
- PGE1 infusion caused significant hypotension (a 26% drop in mean arterial pressure initially, and below 50 mm Hg in 7/9 patients).
- Platelet aggregation was reduced but not completely inhibited during CPB; no preservation was observed post-bypass.
- No significant differences in platelet count, function, blood loss, or transfusion requirements were noted between groups.
Conclusions:
- Minimal PGE1 doses caused dose-limiting hypotension during CPB, preventing higher, potentially more effective doses.
- Hypotensive side-effects must be mitigated for PGE1 to achieve its demonstrated protective effects on platelet damage in clinical settings.
Abstract:
The effect of prostaglandin E1 (PGE1) on protection of platelets during cardiopulmonary bypass (CPB) was evaluated in 9 patients, who were compared with an identical control group of 10 patients undergoing coronary artery bypass grafting. To evaluate the hemodynamic side-effects, PGE1 (0.05 micrograms/kg/min) was infused prior to CPB, resulting in a 26% drop in mean systemic arterial pressure. With this dose, no inhibition of the adenosine diphosphate-induced aggregation could be measured in the pulmonary artery sample. During CPB, the same infusion dose resulted in a severe drop in systemic arterial pressure below 50 mm Hg in 7 of the 9 patients. In 5 of these patients, volume load and phenylephrine infusion could not compensate for the pressure drop, and PGE1 had to be reduced to 0.02 micrograms/kg/min. Platelet aggregation was reduced significantly in the PGE1-treated group compared with the control group, but not completely inhibited during CPB. However, in the postbypass period no platelet preservation was seen in the PGE1 group. In both groups, platelet number and function were equally low. No differences were measured in blood loss or blood transfusion requirements. Except for hypotension, no side-effects of the PGE1 treatment were seen. It is concluded that the hypotension caused by minimal doses of PGE1 during CPB precluded using higher doses, which might have had a greater effect on platelet inhibition. These hypotensive side-effects should be reduced or eliminated before PGE1 can be expected to have the same protective effect on platelet damage that has been demonstrated in animal experiments.