Vasostatin-I, a chromogranin A-derived peptide, in non-selected critically ill patients: distribution, kinetics, and prognostic significance

Chromogranin A (CGA) is released in the plasma during life-threatening illnesses. Its N-terminal 1-76 peptide, vasostatin-I (VS-I), has never been assessed in critically ill patients. Our aim was to examine whether the admission VS-I concentration has prognostic significance without having to specify a primary diagnosis. VS-I concentrations were assessed with a new ELISA in 481 consecutive patients and 13 healthy controls. CGA and standard biological tests (including lactate) were performed; the simplified acute physiological score II (SAPS II) was calculated. Mortality was assessed at day 28. In a subgroup of 13 patients with shock, serial VS-I doses were given over 60 h. Critically ill patients had higher admission VS-I concentrations than controls [4.06 (2.78; 7.61) vs. 2.85 (2.47; 3.22) ng/ml, p < 0.001]. The plasma VS-I concentration was significantly lower in survivors than in non-survivors [3.70 (2.67; 6.12) vs. 5.75 (3.65; 11.20) ng/ml] and in the absence of shock [3.58 (2.59; 5.05) vs. 5.93 (3.30; 11.06) ng/ml, p < 0.001]. The survival rate was better in patients with VS-I concentrations under the median value of 3.97 ng/ml (p < 0.001). Admission VS-I and lactate values were independent predictors of mortality (p < 0.01). Moreover, taking them together, combined with age, provided a better indication for predicting mortality than taking each alone (p < 0.01). Significant amounts of VS-I are detected on admission in critically ill patients. A plasma VS-I concentration above 3.97 ng/ml is associated with poor outcome, and in routine practice simultaneous measurements of the three independent factors VS-I, lactate and age can affect the assessment of severity.