MBT Versus HVPG in Identifying Responders to Portal Hypertension Therapy

Overview

The purpose of this study is to determine the effect on the (carbon 13 labelled(13C)-Methacetin Breath Test (MBT) of i.v. propranolol, a non-selective beta blocker (NSBB) following initial administration and after chronic use of each of these agents. The correlation of the MBT with Hepatic Venous Pressure Gradient (HVPG) measurement before and after treatment will be assessed. Additionally, the MBT measurements following 60 days of therapy will be compared to the first MBT measurement and to the second MBT measurement, post HVPG. Each patient's subsequent MBT measurement will be compared to his previous MBT results in order to determine his/her response to therapy.

Variceal bleeding is a life threatening complication of cirrhosis, which still carries a high mortality. Non selective beta-adrenergic blockers are effective at preventing first time variceal bleeding and re-bleeding. The efficacy of these drugs depends on the magnitude of reduction in portal pressure after administration, which varies widely between patients. Studies have shown that a reduction in portal pressure (as measured by HVPG) to 20% from baseline or to values ≤ 12 millimeters of mercury (mmHg) is associated with a low residual risk of bleeding . Patients with such a reduction are considered to be "responders" to beta blocker (BB) therapy. Unfortunately, a significant percentage of patients do not respond to therapy and need to be prescribed to an alternative therapy. The clinical application of this observation is limited since it requires a repeated HVPG measurement,which is not feasible in most cases. A non-invasive breath test that can assess portal pressure in correlation to HVPG and allow efficient management of patients at risk, could be very useful.