INFLUENCE OF CYCLIC GUANOSINE-MONOPHOSPHATE CHANGES ON HEMODYNAMICS AFTER REPERFUSION IN LIVER-TRANSPLANTATION

Orthotopic liver transplantation (OLT) is often associated with hemody namic instability upon reperfusion, recognized as postreperfusion synd rome. Changes in vascular tone due to humoral factors released upon re perfusion of the graft have been suggested as a possible mechanism. In this study, we looked at the perioperative changes in cyclic guanosin e monophosphate (cGMP), a mediator of vascular smooth muscle relaxatio n, and investigated its relationship with hemodynamic parameters. cGMP was measured in the plasma of 14 patients undergoing OLT by radioimmu noassay serially at the preanhepatic and anhepatic phases, and after r eperfusion at 30, 60, and 120 min, Hemodynamic data recorded were syst emic and pulmonary arterial pressures, cardiac output, and pulmonary a nd systemic vascular resistance. cGMP decreased markedly after reperfu sion from a baseline level of 5.33+/-0.7 ng/ml to 1.63+/-0.5 ng/ml (P< 0.01). Pulmonary arterial pressure increased from 17+/-1.21 mmHg to 23 .5+/-1.9 mmHg (P<0.05), and pulmonary vascular resistance increased fr om 62.8+/-12.9 dynes/sec/cm(5) to 135+/-42.7 dynes/sec/cm(5) (P<0.01). Changes in cardiac output and systemic vascular resistance were not s ignificant, The changes in cGMP correlated with pulmonary arterial pre ssure (r=0.74, P=0.005) and pulmonary vascular resistance (r=0.7, P=0. 01). These data confirm the occurrence of hemodynamic changes during O LT, and provide evidence to suggest that the reduction in cGMP after r eperfusion may mediate the vascular changes.