Refractory Ascitis Diagnosis by the Study of Labelled Albumin Pharmacokinetics

Overview

Refractory ascites is an indication for liver transplantation, and includes ascites that is resistant to, or intractable by diuretic therapy (International Ascites Club). This definition is partly subjective; it can be established only a posteriori, following diuretic therapy administration to all patients, including those in whom untoward effects are prominent; and requires prolonged follow-up. An early diagnosis of refractory ascites would avoid giving diuretic therapy to patients in whom it will fail and identify rapidly candidates to liver transplantation. Such diagnosis could be done with a pharmacokinetic (PK) study of radiolabeled albumin between the peritoneal cavity and serum.

Main objective: assess the performances of PK parameters (transfer of labelled albumin) between peritoneal and vascular compartments, for the diagnosis of refractory ascitis, in patients with cirrhosis and abundant ascitis. Design: proof of concept study. Interventional cross-sectional study in Beaujon Hospital (Clichy, France), 1 recruiting center and 1 non recruiting center. Patients are recruited in the Hepatology department (Pr Valla) and PK exploration is performed in the nuclear medicine department (Pr Lebtahi) of Beaujon Hospital. Description of intervention: diuretics treatment discontinuation 7 days before exploration for patients with sensitive ascitis, and more than 7 days for those with refractory ascitis. The day of exploration, the patients come to hospital and stay in lying position. One intra-veinous injection of 0,015 megabecquerel(MBq) /Kg labelled human serum albumin (Iode-125 (125-I), Séralb®CisBio), in compliance with market authorization, simultaneously to one intra-peritoneal injection of 200 MBq of labelled albumin (Technetium 99m (99m-Tc), Vasculocis®, Cisbio), off-label used. It follows 5 minutes mobilization of the patient (right and left lateral decubitus), then a scintigraphy will be performed using a gamma-camera Symbia T2 (Siemens®). Repeated blood (5 ml) and peritoneal ascitis (3 ml) samples are performed before injection and every 30 minutes for 6 hours (catheter in place). Diuretic treatment can be restarted the day after PK explorations. Patients are followed-up at 1 month by phone call (for the collection of adverse events). Measurements : radioactivity measurements of 99m-Tc and 125-I in the biological samples are performed by a counter device in the nuclear medicine department (Wizard 3000, Packard®). Unidirectional transfer of labelled albumin (125-I) from vascular compartment (plasma-P) to peritoneal compartment (ascitis-A) (TPA), Unidirectional transfer of labelled albumin (99m-Tc) from peritoneal (A) to vascular compartment (P) (TAP), and the ratio TPA/TAP are calculated from these measurements using Matlab®.The gold standard is defined by the diagnosis of refractory ascitis performed before inclusion. Statistical analyses: performances of the TAP, of the TPA, and of the ratio TPA/TAP for the diagnosis of refractory ascitis, will be computed using the Receiver Operating Characteristic (ROC) curve. Number of patients : 30 patients (15 patients with refractory ascitis and 15 patients with sensitive or untreatable ascitis) will be included during a 24 months period (1 or 2 patients per month), and followed-up for 2 months. The PK explorations will be performed in nuclear medicine department not more than 4 weeks after inclusion. Total length of study will be of 26 months.