Anterograde versus retrograde isolated lung perfusion with melphalan in the WAG-Rij rat.

Objective: Isolated lung perfusion (ILuP) is an experimental technique currently tested to increase the 5-year survival of 40% after surgical resection of pulmonary metastases from certain solid tumors. The standard technique of anterograde perfusion was compared with retrograde isolated lung perfusion in which the drug is introduced through the pulmonary veins while the effluent is collected from the pulmonary artery. Since the lung has a dual arterial circulation through the pulmonary artery and bronchial circulation, perfusion through the pulmonary veins can result in a more homogeneous distribution throughout the lung with subsequent higher melphalan concentration.
Methods: We randomized 20 rats into two groups. Group one underwent anterograde isolated left lung perfusion while group two underwent retrograde isolated left lung perfusion. A dose of 2 mg/kg melphalan (MN) was administered to the lung at a flow of 0.5 mL/min during 30 min, followed by a 5-min washout with buffered hetastarch (BHE). The final melphalan lung concentration (FMLC) was determined in the hilum, at the apex, the mid-periphery and the base of the lung. Statistical analysis was done with an unpaired student's t-test.
Results: Retrograde left ILuP resulted in a higher FMLC in the hilum (P<0.0001) and in the base of the lung (P=0.03), while anterograde ILuP induced a higher concentration at the apex of the lung (P=0.04). No difference was seen in the mid-peripheral area of the lung (P=0.92).
Conclusions: In this experimental study, retrograde perfusion seems to increase final melphalan lung concentration in hilar and basal regions of the lung compared to anterograde perfusion.