ACUTE HEMODYNAMIC-EFFECTS OF ENDOGENOUS ADENOSINE IN PATIENTS WITH CHRONIC HEART-FAILURE

Objective The objective of this study Was to assess the acute hemodyna mic effects of endogenous adenosine accumulation in patients with chro nic heart failure. Exogenously administered adenosine has been shown t o reduce pulmonary vascular resistance and to increase cardiac index i n normal subjects and in patients with pulmonary hypertension or end-s tage biventricular heart failure. Endogenous adenosine accumulation ca n be provoked by dipyridamole. Methods and Results Ultra-low-dose dipy ridamole (0.07 mg/kg/min for 4 minutes) was administered in 20 patient s with either symptomatic idiopathic (n = 12) or ischemic (n = 8) dila ted cardiomyopathy and reduced left ventricular ejection fraction (mea n 25% +/- 5%). Hemodynamic variables were measured before and within 1 minute from the end of dipyridamole infusion. After dipyridamole admi nistration, a mild but significant increase in heart rate (4.5%; p = 0 .03) and reduction in mean blood pressure (6.8%; p < 0.001) without ch anges in right atrial pressure (p = NS) were detected. Dipyridamole in creased cardiac output by 26.6% (p < 0.001), cardiac index by 24% (p < 0.001), and stroke volume by 19.8% (p < 0.001), with concomitant 24.6 % reduction of systemic vascular resistance (p < 0.001). Moreover, dip yridamole reduced mean pulmonary artery pressure by 8.3% (p < 0.07) an d pulmonary vascular resistance by 33.3% (p = 0.001), without changes in pulmonary wedge pressure (p = NS). A significant correlation betwee n percent decrease from baseline in pulmonary and systemic vascular re sistance (r = 0.66; p = 0.002) was Found after administration of dipyr idamole. Conclusions Endogenous adenosine accumulation induced by ultr a-low-dose dipyridamole infusion acutely improves the hemodynamic prof ile, decreasing pulmonary and, to a lower extent, systemic vascular re sistance and increasing cardiac index in patients with severe chronic heart failure.