Usefulness of soluble endoglin as a noninvasive measure of left ventricular filling pressure in heart failure.

Progressive left ventricular (LV) dysfunction induces expression of the cytokine transforming growth factor-β1. Endoglin (CD105) is a transforming growth factor-β1 co-receptor that is released into the circulation as soluble endoglin (sEng). The objective of the present study was to assess the serum levels of sEng in patients with heart failure and to identify the predictive value of sEng for detecting elevated left ventricular end-diastolic pressures (LVEDPs). We measured the sEng levels in 82 consecutive patients with suspected LV dysfunction referred for determination of left heart filling pressures using cardiac catheterization. Among these subjects, the sEng levels correlated with the LVEDP (R = 0.689; p <0.0001), irrespective of the LV ejection fraction. Using a receiving operating characteristic curve, the sEng levels predicted an LVEDP of ≥16 mm Hg with an area under the curve of 0.85, exceeding the measured area under the curves for both atrial and brain natriuretic peptide, currently used biomarkers for heart failure diagnosis (atrial natriuretic peptide 0.68 and brain natriuretic peptide 0.65; p <0.01 vs sEng). In 10 subjects receiving medical therapy guided by invasive hemodynamic monitoring for heart failure, decreased a pulmonary capillary wedge pressure was associated with a reduced sEng level (R = 0.75, p = 0.008). Finally, compared to 25 healthy controls, the sEng levels were elevated in subjects with suspected LV dysfunction (3,589 ± 588 vs 4,257 ± 966 pg/ml, respectively, p <0.005) and correlated directly with the New York Heart Association class (R = 0.501, p<0.001). In conclusion, circulating levels of sEng are elevated in patients with increased LVEDP and New York Heart Association class, irrespective of the LV ejection fraction. sEng levels also decreased in association with a reduced cardiac filling pressure after diuresis. These findings have identified circulating sEng as a sensitive measure of elevated left heart filling pressures.