High-dose enoximone to evaluate reversibility of pulmonary hypertension: Is there a diagnostic value of neurohormonal measurements?

Background Heart transplantation is associated with a reduction of the neur ohumoral activation seen in patients with severe congestive heart failure. In this study, we investigated whether pharmacologically induced complex he modynamic improvement during assessment of reversibility of pulmonary hyper tension with a phosphodiesterase inhibitor is able to induce neurohormonal changed of diagnostic importance. Methods and Results Twenty-one patients with New York Heart Association cla ss III-IV heart failure underwent infusion of 3 mg/kg enoximone over a peri od of 30 minutes. Before and after drug infusion, we determined the plasma concentrations of atrial natriuretic peptide, endothelin-I, angiotensin-II, aldosterone, norepinephrine, epinephrine, and angiotensin-converting enzym e activity sampled from a peripheral vein and the pulmonary artery. In addi tion to the expected significant reduction of pulmonary hypertension and en hancement of cardiac output, increased levels of the vasoconstrictors endot helin-I, angiotensin-II, and norepinephrine were observed. Aldosterone Fell after enoximone infusion; a higher baseline aldosterone level correlated t o the degree of reduction of the pulmonary arteriolar resistance by enoximo ne. Baseline atrial natriuretic peptide levels correlated with parameters, indicating the severity of heart Failure. However, the plasma concentration of this peptide did not change significantly after enoximone infusion. Conclusions Acute hemodynamic improvement after enoximone bolus in candidat es For heart transplantation is not accompanied by a reduction of the enhan ced neurohumoral activity in these patients. The reaction of the investigat ed hormones cannot predict the individual degree of reversibility of pulmon ary hypertension.