We tested the hypothesis that plasma endothelin-1 (ET-1) and soluble intercellular adhesion molecule-1 (sICAM-1) in patients with congestive heart failure (CHF) are related to subsequent survival, and assessed whether the measurements of these substances provide additional prognostic information to that obtained from clinical and biochemical variables previously known to be associated with high mortality. Plasma levels of sICAM-1 and ET-1 were measured in 102 patients with CHF (left ventricular ejection fraction [LVEF] < 0.45), and patients were followed up for > 18 months. The plasma level of sICAM-1 increased with the severity of CHF (normal, 149 +/- 10 ng/ml, mild CHF [New York Heart Association functional class II], 207 +/- 9.4 ng/ml, severe CHF [functional class III or IV], 293 +/- 18 ng/ml). The plasma level of ET-1 also increased with the severity of CHF (normal, 1.5 +/- 0.2 pg/ml, mild CHF, 2.1 +/- 0.1 pg/ml, severe CHF, 4.0 +/- 0.4 pg/ml). Plasma levels of both sICAM-1 and ET-1 decreased after treatment in 14 patients, with improvements in symptoms (from functional class IV to II) during the follow-up period. There was a significant positive correlation between the plasma level of ET-1 and plasma sICAM-1 (r = 0.44, p < 0.001). A significant negative correlation was observed between LVEF and plasma ET-1 (r = -0.34, p < 0.001), and plasma sICAM-1 (r = -0.36, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)