Physiological and clinical implications of proANP(1-98) circulating levels in the perioperative phase of liver transplantation.

Background: ProANP(1-126), the prohormone synthesized and secreted by atrial myocites, generates an ANP peptide family, the main forms of which are proANP(1-30), proANP(31-67), proANP(1-98) and proANP(99-126). These molecular circulating forms are involved in hemodynamic and electrolyte homeostasis. In cirrhotic patients, volume homeostasis is almost impaired due to abnormal sodium retention, which results in ascites formation and hemodynamic changes, including high cardiac output and low systemic vascular resistance. During liver transplantation, in the anhepatic phase, hemodynamic instability may occur because of decreased venous return due to surgical manipulation of inferior vena cava, considerable blood loss or cross-clamping. Moreover, marked hemodynamic instability is often observed at the reperfusion of the graft.
Aims: The aims of present study are to investigate the changes of ANP during the perioperative phases of Orthotopic Liver Transplantation (OLTx) in end-stage cirrhotic patients.
Patients and Methods: From July to September 1999, 11 cirrhotic patients undergoing to OLTx were included in the study: seven males and four females (average age 46+/-10.4 years) affected by post-alcoholic cirrhosis [Hypertension 15 (1990) 9], post-hepatitis cirrhosis [D.G. Gardner, M.C. Lapointe, B. Kovacic-Milivojevic, C.F. Deschepper, Molecular analisys and regulation of the atrial natriuretic factor gene, in: A.D. Struphers (Ed.), Frontiers in Farmacology and Therapeutics: Atrial Natriuretic Factor, Blackwell, Oxford, England, 1991, pp. 1-22], Wilson disease [Life Sci. 28 (1981) 89] and polycystic disease [Life Sci. 28 (1981) 89], autoimmune cirrhosis [Life Sci. 28 (1981) 89]. In each patient, a hemodynamic assessment was achieved using a Swan-Ganz catheter. Periferical venous samples were performed during and immediately after OLTx for the determination of ANP(1-98) and other biohumoral parameters.
Results: Mean ANP(1-98) (pmol/ml mean+/-SD) basal levels resulted higher than that recorded in the group of healthy subjects. A significant correlation between 24-h post-reperfusion ANP and intra-operative RBC and RIS requirement was found (p<0.05). The basal values resulted significantly higher than that observed at phase II degrees (p<0.04) and lower than that at phase VI degrees (p<0.05); the anesthetic induction values were significantly lower than that observed at phase VI degrees (p<0.03).
Conclusions: ANP(1-98) values may represent a useful marker of hemodynamic derangements during and after OLTx. Further clinical correlations will need a larger patient basis.