Background: Vasoactive peptides are accepted indicators of the degree of heart failure and its progression or improvement following medical therapy. Normalization of cardiac hemodynamics by cardiac transplantation (HTx) may lead to normalization of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) plasma levels shortly after the procedure.
Methods: Long-term follow-up was done for 14 consecutive patients, 12 men and 2 women, 49 years of age (range 24 to 64 years). ANP and BNP were measured by radioimmunoassay (RIA) in central venous plasma samples (before breakfast, at steady state) at the following intervals after HTx: 7 to 30 (1), 31 to 60 (2), 61 to 90 (3), 120 to 180 (4) and 210 to 365 (5) days.
Results: During follow-up, ANP decreased significantly within 2 months after HTx and continued of this level, whereas BNP decreased continuously without reaching normal values. The mean ratio of ANP:BNP increased from 3.23 to 8.01 during follow-up. Whereas right atrial pressure (RAP), right ventricular pressure (RVP), right ventricular end-diastolic pressure (RVEDP) and pulmonary capillary wedge pressure (PCWP) did not change during follow-up, cardiac output (CO) improved slightly, but significantly from 5.21 liters/min to 5.9 liters/min (p = 0.035).
Conclusions: Normalization of left ventricular function after orthotopic HTx does not induce an early diminution of ANP and BNP plasma levels to normal concentrations. Although elevated ANP concentrations showed only minimal changes within 1 year, BNP decreased significantly as early as 2 months after HTx, without reaching normal values during the year of follow-up. Also, the ratio of ANP and BNP increased significantly from 3.23 to 8.01. These results demonstrate the contribution of other factors beyond cardiac function that determine the levels of these peptides.