Endoscopic ultrasound guided portal pressure measurement to predict the outcome of liver resection

All subjects will have Endoscopic Ultrasound-guided Portal Pressure Gradient Measurement (EUS PPGM) and Transjugular Hepatic Venous Pressure Gradient (TJ-HVPG) assessment within 4 weeks of surgery. Procedural details as well as adverse events related to the procedures will be collected immediately after, 24 hours after and 7 days after the procedure. EUS-PPGM technique: The EUS-PPGM this will be performed by a gastroenterologist. Transjugular pressure gradient measurement will be performed by a radiologist. - the duration of EUS-PPGM- measurement of hepatic vein will take about 8 minutes, measurement of portal vein approximately 8 minutes, procedure time 15 minutes including insertion of echoendoscope The apparatus for EUS-PPGM will comprise of a linear echoendoscope, a 25G FNA needle, and a compact manometer with non-compressible tubing (Cook Medical, Bloomington, IN). The tubing will be connected by a luer lock to the distal port of the manometer, while the heparinised saline will be connected to the proximal port. The end of the tubing is connected through a luer lock to the inlet of the 25G needle. First a forward viewing endoscope will be inserted to document any endoscopic evidence of varices (including size and presence of red wale marks) as well as portal hypertensive gastropathy. Prior to echoendoscope insertion, the manometer will be zeroed at the midaxillary line of the patient. The hepatic vein (HV) measurement will be conducted first. Doppler flow will be used to confirm the typical multiphasic waveform of hepatic venous flow. Using the 25G FNA needle, a transgastric transhepatic approach is used to puncture the HV. Approximately 1 mL of heparinised saline will be used to flush the needle which is visible on EUS to confirm good position within the vessel. After the initial rise in pressure reading as a result of flushing, the manometer reading will equilibrate at a steady pressure, which will then be measured three times. The mean of these three pressures is then considered the HV pressure. The FNA needle is then withdrawn from the vein into the liver parenchyma, and then back into the needle sheath. The needle tract within the liver parenchyma will be observed with Doppler flow on to ensure there is no flow within the needle tract. The portal vein (PV) measurement will conducted next. The umbilical portion of the left portal vein will be targeted, and Doppler flow will then be used to confirm the typical venous hum of portal venous flow. Using the 25G FNA needle, a transgastric transhepatic approach is used to puncture the PV. The procedure that follows is the same as what would have been performed for the HV. Three readings will be taken, the mean of which is considered the PV pressure. The patient is recovered in a similar manner to a routine diagnostic EUS with FNA, and postprocedural antibiotics are usually given for 5 days postprocedure. TJ HVPG measurement technique: We will use the standard technique. Under local anaesthesia and light sedation, a venous catheter introducer sheath will be placed in the right jugular vein, antecubital vein or femoral vein under ultrasound guidance using the Seldinger technique. Under fluoroscopy, a balloon-tipped catheter will be advanced into a main HV. The Free Hepatic Venous Pressure (FHVP) will then be measured with the tip of the catheter in the HV at 2 – 4 cm from its opening into the inferior vena cava. The balloon of the catheter will be inflated to occlude the HV, and occlusion will be confirmed by injection of 5 mL of contrast dye. The measurement of the WHVP will then follow. Each of the WHVP and FHVP measurements will be taken in triplicate, and the mean FHVP will be subtracted from the WHVP to calculate the HVPG. In terms of monitoring adherence to the intervention, this is only required during the procedure to ensure that it was performed. Procedural details are documented and any adverse events related to the procedures will be collected after 24 hours and 7 days after the procedure.