Ultrasonography-guided Suction Thrombectomy for an Isolated Portal Vein Thrombus in Liver Surgery

Discussion

Perhaps every liver surgeon removes isolated PV thrombi applying their preferred method, or the method appropriate for the particular case. In Figure 3, the various possible techniques for the removal of an isolated PV thrombus in liver surgery are depicted. The simplest technique may be the so-called back-flow technique (Figure 3A). This method is useful when the distance between the hole of the PV and the isolated PV thrombus is short. In all three of our cases, back-flow was recognized when we made the PV hole; however, no isolated PV thrombus was excised only by back-flow of the PV.

In this report, we present the technique called suction thrombectomy (Figure 3B). It was possible to excise all three isolated PV thrombi successfully by this method. Compared to the back-flow technique, injury to PV endothelial cells poses a possible problem in this method. To avoid this complication, we tried to minimize the contact of the Yankauer tip with the inner membrane of PV and minimized the power and duration of suction. In all three cases, no PV thrombus was found on enhanced CT at 7 and 90 POD.

The final possible method is the Fogarty catheter technique (Figure 3C) (7). This technique is useful when the isolated PV is too hard to be suctioned out. However, an intraoperatively isolated PV thrombus would likely be fresh and not so hard. In addition, this technique introduces the possibility of a fragment of the PV thrombus migrating into a peripheral branch of the PV. In our own experience, we have had no good occasion to use a Fogarty catheter for the removal of a PV thrombus.

From our experiences, we would present two especially important tips for the use of suction thrombectomy to remove an isolated PV thrombus. Firstly, the timing of the start of suction is important. The proper insertion of a Yankauer into the PV while suction is on is very difficult. The suction should be switched on only after navigating the Yankauer tip close to the isolated PV thrombus. Secondly, the visibility of a Yankauer tip is relatively poor in intraoperative US. In all three of our cases, constant movement of the Yankauer tip helped its visibility in US. We used a plastic Yankauer tip in all three cases. We believe the use of a metallic Yankauer tip might improve its visibility in intraoperative US.

We should also refer to the management of acute PV thrombosis, including conservative management, anticoagulation, and thrombolysis/thrombectomy (8). In recent years, the techniques of endovascular thrombus fragmentation and thrombectomy have rapidly progressed, and these would be alternative options for removal of an intraoperatively isolated PV thrombus (9).

Of course, the clinical utility of suction thrombectomy for isolated PV thrombus should be confirmed in a larger number of patients; however, cases with intraoperatively identified isolated PV thrombus in liver surgery are extremely rare. Therefore, comparisons of clinical efficacies of suction thrombectomy for PV thrombus among patients who either did not undergo suction thrombectomy or who had alternative thrombectomy are difficult and this remains to be investigated.