1 2 3 4 5 6 7 9 10 17 18 17 MATERIALS AND METHODS Patient Selection Criteria 17 Perfusion Circuit Perfusion sets (PfM, GmbH, Cologne, Germany) consisted of a tubing set with a volume of 220 mL, containing a bubble trap. All IHHPs were performed with inflow via the hepatic artery and outflow via portal vein. In the perfusion circuit, flow was maintained by a roller pump and pressure was measured via a sideline. Drugs A dosage of 1 mg/kg melphalan (L-Pam, Alkeran, Wellcome Ltd. London, UK) was used in 20 of the 24 patients and infused through a sideline into the perfusion circuit. Two times 1.5 mg/kg melphalan and two times 2.0 mg/kg was used. In the first eight patients, a bolus infusion was used. In the last 16 patients, a 10-minute pump infusion was used. The total perfusion (10-minute infusion included) with melphalan was conducted for 20 to 30 minutes. Surgical Procedure of the Retrograde Flow IHHP 1 FIG. 1. The retrograde perfusion setup.  The perfusate was circulated by a constant flow. Stable perfusion was monitored by pressure measurement and the perfusate level in the bubble trap. Hereafter, melphalan was infused into the circuit and the perfusion was conducted for 20 to 30 minutes. Thereafter, a washout procedure was performed by 1 L of Haemaccel collecting the venous effluent. Total liver ischemia time never exceeded 60 minutes. The isolation was terminated by relief of the clamps on the caval vein followed by the relief of the aortic clamp, controlling systemic blood pressure. The catheter in the hepatic artery could be removed and the gastroduodenal artery could be ligated followed by decanulation and closing the venotomy of the portal vein. In case of an aberrant left hepatic artery, this artery was ligated after removal of the catheter. Leakage Monitoring 131 14 Blood Sampling 19 Measurement of Melphalan Concentrations 20 Assessment of Tumor Response 19 RESULTS 1 TABLE 1. Characteristics of 24 patients with irresectable liver metastases treated by IHHP with retrograde outflow via portal vein with melphalan PT Tumor primary Progressive on chemotherapy Toxicity Response after perfusion Time to progr. (months) Status Months after perfusion Hepato Blood Renal 1 CRC No 1 0 0 CR 10 Alive 46 2 CRC No 1 0 0 PR 24 Dead 38 3 CRC Yes 1 4 0 SD 12 Dead 42 4 CRC No 1 0 0 PR 6 Dead 29 5 CRC No 1 3 0 PR 20 Dead 32 6 EM No 1 0 0 PR 5 Dead 9 7 SARC No 1 3 0 PR 13 Dead 17 8 CRC No 2 0 0 PR 9 Dead 9 9 CRC Yes 1 0 0 SD 12 Dead 37 10 CRC Yes 1 0 0 PD 2 Dead 10 11 CRC No 1 0 0 PR 9 Dead 29 12 CRC No 1 0 0 PD 9 Dead 18 13 CRC No 1 0 0 PD 2 Dead 8 14 CRC Yes 1 0 0 PR 4 Dead 18 15 EM No 1 0 0 PR 5 Dead 6 16 CRC No 1 2 0 PR 9 Alive 29 17 UP Yes 1 3 0 PD 2 Dead 5 18 EM No 1 0 0 PR 9 Dead 20 19 CRC No 2 2 0 PR 4 Dead 6 20 CRC No 1 0 1 PR 5 Dead 5 21 EM No 1 2 0 PR 13 Dead 15 22 CRC Yes 1 0 0 PD 4 Dead 6 23 CRC Yes 1 0 0 SD 5 Dead 6 24 CRC Yes 1 0 0 PD 9 Alive 11 PT, patient number; CRC, colorectal cancer; CR, complete response; SARC, sarcoma; PR, partial response; EM, eye melanoma; SD, stable disease; UP, unknown primary; PD, progressive disease. Operation Characteristics . Leakage Control All IHHPs were leakage free during the perfusion except in one patient, where 2% systemic leakage was measured. When this perfusion was finished, it appeared that in this patient there was an insufficient clamping of the suprahepatic caval vein. After washout of the isolated circuit with Haemaccell, a median of 7% (4–10%) leakage into the systemic circuit was demonstrated by continued monitoring until the end of the operation. 1 Hepatic toxicity consisted mainly of a transient rise of liver enzymes during the first week after IHHP. WHO grade I occurred in 92% of the patients (22 of 24) and WHO grade II in 8% of the patients (2 of 24). Three patients experienced bile duct necrosis (discussed in detail in the section “Complications”). No other hepatic toxicities occurred (no coagulopathy was observed). Systemic toxicity was mainly leucopenia, WHO grade I–III in 25% (6 of 24), and severe grade IV leucopenia in one patient (4%) after perfusion. Two of these patients received G-CSF (Neupogen, Amgen B.V., Breda, The Netherlands). One patient received prophylactic G-CSF. Eighteen patients (71%) did not develop leucopenia. No renal (except for one patient grade 1) or gastrointestinal toxicity was observed. Melphalan Pharmacokinetics 2 FIG. 2. Drug-concentration versus time curve.  Complications 3 FIG. 3. Intra-hepatic bile duct necrosis after IHHP  1 n n DISCUSSION Isolated liver perfusions are only performed by a few centers worldwide, demonstrating promising antitumor effects; however, the technique is a major, complex, expensive, and time-consuming operation. In the present study we describe an alternative technique using a retrograde hepatic flow in an isolated hypoxic hepatic perfusion (IHHP) system. The technique was performed in 24 patients and demonstrated to be safe, with minimal morbidity and no morbidity. Overall response rate was 62% with no progression in 75%, and median time to progression of disease was 9 months. 11 15 11 15 n n 11 15 1 21 The maximum period of 60-minute hypoxia did not seem to result in extrahepatic and/or systemic toxicity. Moreover, clamping of the aorta just underneath the diaphragm for a maximum of 60 minutes did not lead to renal and/or gastrointestinal morbidity. 22 23 24 25 11 15 16 24 26 27 11 28 29 30 31 32 33 34 35 37 n CONCLUSIONS Isolated hypoxic hepatic perfusion with retrograde outflow via portal vein is a promising technique that is a relatively simple procedure with reduced blood loss, no mortality, very limited toxicity, and response rates comparable to classic, extensive IHP. The operation time is reduced to 4 hours, without the need of a heart-lung machine and perfusionists, which reduces the costs.