Is atrial natriuretic polypeptide a cause of pathophysiology in total artificial heart animals?

The purpose of this study was to clarify whether plasma ANP levels (p-ANP) are abnormal in TAH animals, and if ANP plays an important role in circulatory failure in TAH animals. In five TAH goats that survived for 51-171 days, changes in hemodynamic parameters, plasma levels of renin, angiotensin I and II, aldosterone (p-RAA), and p-ANP were measured, and correlations between p-ANP and other parameters were studied, and histologic study of ANP and assay of the ANP content in atrial tissue was undertaken. Generally, p-ANP of TAH goats fell temporarily after surgery but then recovered to preoperative levels. Histopathologic studies of atrial tissue and ANP granules proved almost normal, although the coronary blood supply was occluded for more than 170 days; the ANP content in the atrium did not show significant changes after 51 days of TAH pumping. In one case prominent correlations between p-ANP and p-RAA were observed, and in another case significant correlation between p-ANP and arterial pressure was observed. However, these correlations were not observed in every case. In TAH goats the plasma ANP level did not increase in spite of high atrial pressures. Plasma ANP levels in TAH animals are almost normal. In TAH animals no role in the pathogenesis of hemodynamic abnormalities is played by abnormality of plasma ANP levels. However, TAH animals may display an abnormality in sensitivity to the p-ANP.