Changes of urinary dopamine excretion early after balloon mitral commissurotomy in mitral stenosis

1. In order to investigate the changes of reduced urinary free dopamine excretion (uDA) in heart failure, 15 patients with symptomatic mitral stenosis were investigated on their uDA, endogenous creatinine (Cr) clearance, urinary excretion of sodium (UNaV), fractional excretion of sodium (FENa), plasma noradrenaline (pNA) and plasma L-dopa concentration before and early after percutaneous transvenous mitral commissurotomy (PTMC) by the clearance study. The delivery of L-dopa to renal proximal tubules (plasma L-dopa x Cr clearance), and the conversion ratio of plasma L-dopa to urinary dopamine in the kidney [uDA/(plasma L-dopa x Cr clearance)] were also estimated. 2. After successful PTMC, uDA, UNaV and FENa showed a significant but incomplete improvement and the changes of uDA were correlated positively with those of cardiac index (CI) (r = 0.665, P < 0.01), not with changes of pulmonary wedge pressure. While plasma L-dopa and plasma L-dopa x Cr clearance improved, uDA/(plasma L-dopa x Cr clearance) was not significantly changed early after PTMC. 3. From these results, it was suggested that reduced uDA tended to increase incompletely in relation with functional recovery of heart, and that increased plasma L-dopa and a delivery of L-dopa to renal proximal tubules have some positive role on urinary dopamine excretion, at least, early after PTMC.