<prompt> Which of the following biomarkers has been shown to correlate best with pulmonary vascular resistance in patients with hea failure:Brain Natriuretic Peptide BNPAtrial Natriuretic Peptide ANPEndothelin- 1 ET-1Endothelin- 2 ET-2  <response>: Answer is C Endothelin-1 Endothelin-1 ET-I levels have been found to correlate best with pulmonary vascular resistance in patients with Hea Failure. Hea failure is associated with increase in plasma levels of Endothelin-1 ET-1. Endothelin-1 ET-I is amongst the most potent endogenous vasoconstrictors. The pulmonary circulation is the primary source of expression of this neurohormone and ET-1 Levels have been found to correlate with pulmonary vascular resistance. Plasma ET-1 Levels correlate directly with pulmonary vascular resistance and it is thought that this peptide may play a role in mediating pulmonary hypeension in persons with hea failure 