Masazumi Fujimoto

Experiences of 120 microsurgical reconstructions of hepatic artery in living related liver transplantation

BACKGROUND We reviewed 120 microsurgical reconstructions of a hepatic artery in living related liver transplantation and discussed the problems encountered. METHODS From January 1991 to July 1994 we performed a series of 105 living related liver transplantations on children with end-stage liver disease. Arterial reconstruction was performed under the optical field of a continuous zoom magnification of approximately 10 times with an operating microscope. RESULTS Twenty-six percent of the graft arteries were less than 2 mm in diameter. The time required for an arterial reconstruction was 49.5 +/- 1.8 minutes. In 15 of the 31 cases in which there were two graft arteries, two arterial reconstructions were required. The caliber differences between the graft artery and the recipient artery in 30 instances was dealt with by cutting an undersized artery obliquely (17 instances), by fish-mouth method (10 instances), by end-to-side anastomosis (1 instance), or by funnelization method (2 instances). In one case we performed an intimal dissection of a recipient hepatic artery and substituted a splenic artery. Consequently, hepatic arterial thrombosis occurred in only two cases (1.7%). CONCLUSIONS Microsurgical technique has overcome the high risk of hepatic arterial thrombosis in cases of fine graft arteries, enabled the reconstruction of arteries with caliber difference, and decreased arterial complications with its delicate manipulation.

Vascular complications in living related liver transplantation detected with intraoperative and postoperative Doppler US

BACKGROUND/AIMS The purpose of this study was to clarify changes in the graft hemodynamics induced by vascular complications in living related liver transplantation. METHODS This study included 46 pediatric recipients who underwent partial liver transplantation from living related donors. The blood flow was evaluated in the portal system, the hepatic artery and the hepatic vein with serial intra- and post-operative Doppler ultrasound (US). RESULTS In 12 patients, intraoperative Doppler US showed a decrease in portal venous inflow (< 9 ml.min-1.kg-1) toward the liver graft and could act as a guide for ligation of collaterals in seven patients, portal re-construction in two, thrombectomy in one and relief of hepatic venous outflow obstruction in two for increasing the portal venous inflow. In five patients, intraoperative Doppler US showed poor arterial inflow, i.e. dampened arterial waveforms which involved both low pulsatility index (< 0.90) and low peak-systolic velocity (< 31 cm/s). In three of them, the waveform was more pulsatile after re-anastomosis or relief from stretching of the hepatic artery. The remaining two patients developed hepatic artery thrombosis. Most of the hepatic venous outflow obstruction (four of five patients) had flat waveforms, low flow velocity (< 10 cm/s) of the hepatic vein, and poor portal inflow (flow velocity < 14 cm/s). Postoperative Doppler US showed hepatic venous outflow obstruction in three patients, hepatic artery thrombosis in three (twice in one patient), portal vein stenosis in two and portal vein thrombosis in one. These complications were successfully managed with surgical procedures in three patients, transhepatic angioplasty in three and conservative treatments in four. Six patients died of non-vascular complications. CONCLUSIONS Serial intra- and post-operative Doppler US was a useful technique for making an early diagnosis of abnormal hemodynamics of the graft circulation. Furthermore, intraoperative Doppler US could assess reconstructed vessels objectively and would reduce the incidence of vascular complications following transplantation.

Influence of spontaneous portosystemic collateral pathways on portal hemodynamics in living-related liver transplantation in children: Doppler ultrasonographic study

We investigated the influence of spontaneous portosystemic collateral pathways on the portal hemodynamics and examined the necessity for ligating these vessels in pediatric liver transplantation from living donors. We assessed portal blood flow before, during, and after surgery in 82 pediatric recipients (mean age, 4.2 years), using Doppler ultrasonography. When blood flow in the reconstructed portal vein was decreased (< 10 ml/min/kg body weight) and portosystemic collaterals persisted during surgery, those vessels were ligated and Doppler flowmetry was examined again. Spontaneous portosystemic collaterals were detected at one or more sites in 67 patients before transplantation. These collaterals had been ligated in 17 patients before intraoperative flowmetry. Among the remaining 50 patients, initial Doppler studies revealed a decrease in portal blood flow in 22 patients. Nine patients had hepatofugal splenic venous flow and 6 had no significant flow signals from the intrahepatic portal vein. Ligation of collaterals resulted in a remarkable increase in portal blood flow in 20 patients, all of whom are alive. The remaining 2 patients died of graft failure due in part to portal hypoperfusion. On the other hand, the collaterals were not ligated in 24 patients because adequate portal blood flow was confirmed by intraoperative flowmetry. Postoperatively, flow signals from the unligated collateral vessels gradually diminished, but they still persisted in 3 patients at 12 months after transplantation. Hepatofugal blood flow through the portosystemic collateral pathways may persist after implantation of a normal graft. If the patent collaterals significantly reduce the effective portal blood flow, these vessels should be ligated in order to avoid graft failure.

Intraoperative measurement of the graft oxygenation state in living related liver transplantation by near infrared spectroscopy

Abstract Graft oxygenation plays an important role in successful liver transplantation. Intraoperative changes in the oxygenation state of the liver graft were measured by near infrared spectroscopy in 28 cases of living related liver transplantation. Oxygen saturation of hemoglobin in the liver (hepatic SO2) changed from 81.2%± 1.5% (mean ± SEM) before donation (in the donor) to 49.7%± 4.2% after portal reflow, to 58.4%± 5.0% after arterial reflow, and then to 71.4%± 3.9% before closure. Mean hepatic SO2 was positively correlated with portal flow rate as measured by duplex Doppler sonography. Cases with low portal flow rate showed a high coefficient of variation (SD/mean) of hepatic SO2, indicating heterogeneous tissue oxygenation. Though graft size was expected to affect the graft oxygenation state, hepatic SO2 was fairly independent of the graft‐to‐recipient weight ratio. In two cases with markedly low hepatic SO2, postoperative graft dysfunction occurred. This study suggest that the method of near infrared spectroscopy is reliable and useful for assessing the graft oxygenation state in liver transplantation.

Recovery of graft circulation following percutaneous transluminal angioplasty for stenotic venous complications in pediatric liver transplantation: assessment with Doppler ultrasound

Percutaneous transluminal angioplasty was performed for venous stenosis after living related liver transplantation in three children. Two of them had hepatic vein stenosis and one had stenosis of both the hepatic and portal veins. Progressive development of ascites and deterioration of liver function were found in all cases. Serial Doppler ultrasound studies showed that the flow velocity in the hepatic vein gradually decreased with a flattened velocity waveform, followed by a decrease in portal blood flow. After a successful hepatic vein angioplasty, the velocity in the hepatic and portal veins increased and the Doppler waveform in the hepatic vein became pulsatile in two cases. In the remaining case, a remarkable recovery of both graft perfusion and clinical findings was achieved via combined hepatic vein and portal vein angioplasty. We conclude that balloon angioplasty is an effective alternative to surgery for post-transplant vascular stenosis and that Doppler ultrasound is useful in monitoring graft circulation.

Change in hepatic arterial hemodynamics induced by hepatocellular carcinoma detected with Doppler sonography

To understand the hemodynamic differences between the hepatic arterial branches that supply hepatocellular carcinomas (HCCs) and those that do not, we compared the velocity waveforms of both types of arteries.