[Prostaglandin E1, as a vasodilator therapy, for low output syndrome after cardiac surgery]

Prostaglandin E1 (PGE1) has a direct vasodilating effect to smooth muscles of resistant vessel much more than that of capacitance one. In afterload mismatch, vasodilator which acts on resistant vessel mainly should be selected. We used PGE1 for vasodilator therapy to two patients with low cardiac output syndrome (LOS) in intensive care unit. One patient undergoing coronary artery bypass grafting developed LOS and disseminated intravascular coagulation which derived from post-transfusional anaphylactoid reaction. Another patient undergoing mitral valve replacement, tricuspid valve annuloplasty and coronary artery bypass grafting also developed LOS with massive thrombosis caused by cold agglutinin during cardio-pulmonary bypass. In both patients, PGE1 decreased systemic vascular resistance index and pulmonary arterial resistance index, and increased cardiac output. PGE1 inhibits release of lysosomal enzymes from polymorphonuclear leukocytes and increases splanchnic blood flow. These effects lead to inhibit production of myocardial depressant factor and might relate to the improvement of LOS partially. We suggest that PGE1 was effective for LOS after cardiac surgery, especially in afterload mismatch.