Introduction
Renal cell carcinoma (RCC) extending into the inferior vena cava (IVC) is observed in 4–19 % of RCC cases [
1‐
9]. Tumor thrombectomy in the IVC with the tumor thrombus or nephrectomy improves the prognosis in patients with this condition, including those in whom the tumor thrombus extends into the vessel [
5,
7,
10]. Both resection of the IVC and IVC replacement are required in cases where liver tumors have invaded the IVC [
11,
12].
RCC and low-grade malignant tumors extending into the IVC have been resected without cardiopulmonary bypass (CPB) or venous bypass, by achieving hemodynamic stability with aortic cross-clamping [
13,
14]. Good surgical results were obtained for different gastroenterological and urological diseases with IVC extension and IVC invasion. Therefore, this report presents the treatment strategies and the indications for IVC replacement, and reviews the pertinent literature.
Discussion
The surgical treatment of RCC with a tumor thrombus extending to the IVC is dependent on the disease site, thrombus extension level and the degree of IVC patency. Tumors are classified into four categories before surgery (level I: patients with tumor thrombus extending from the renal vein into the infrahepatic IVC for 1–2 cm and requiring only local control of the IVC for extraction, level II: patients with tumor thrombi that extend no further than the subhepatic IVC, level III: patients with thrombi that extend into the intrahepatic IVC or that extend to the suprahepatic IVC but not into the atrium, level IV: patients with intraatrial thrombi) according to the level of cephalad extension of the tumor thrombus into the IVC, as described by Naves and Zincke [
1].
Level I patients with a cephalad extension of the tumor thrombus can have the segment of the infrahepatic IVC clamped without depending on any specific technique. The segment of the infrahepatic IVC can be clamped in level II patients as well, but careful mobilization and IVC exposure are important to prevent the development of a pulmonary embolism (PE). A temporary IVC filter should therefore be put in place on the day of surgery or the day before surgery, or an initial plication can be performed in patients with level II or III disease to prevent perioperative PE. A plication involves loosely ligating the IVC two or three times, using 3-0 polypropylene sutures in the IVC of the suprahepatic or retrohepatic segment to ensure that the IVC maintains its round shape. The plication or the temporary IVC filter is especially effective for preventing massive PE. An IVC filter can be placed cephalad to the thrombus or plication can be performed when the tumor extends to the portion just below the hepatic vein segment of the IVC. In addition, a plication can be performed when the tumor extends up to the suprahepatic vein segment of the IVC, or when there is not enough space to place an IVC filter even though the tumor might extend up to the portion below hepatic vein segment of the IVC before the liver can be mobilized [
2,
14]. Cardiopulmonary bypass (CPB) without cardiac arrest is generally used in this institution, but other institutions have used CPB with cardiac arrest and deep hypothermia in patients with a level IV thrombus [
4,
15,
16].
The systemic blood pressure sometimes falls to less than 80 mmHg during the cross-clamping of the IVC in patients with a patent IVC, because of the decrease in venous return. Therefore, sufficient fluid replacement and control of the hemodynamic circulation should be confirmed. The infrarenal abdominal aorta can be clamped partially or totally to maintain the blood pressure and hemodynamic circulation if the systemic blood pressure falls during cross-clamping of the IVC, and then tumor resection can be performed [
13,
17]. Aortic cross-clamping and the Pringle maneuver are applied to minimize bleeding from the hepatic vein and to prevent hepatic congestion when the segment of the suprahepatic IVC is clamped. Venovenous bypass is sometimes used instead of aortic cross-clamping by other groups to maintain the hemodynamic stability [
18‐
20].
The tumor thrombus of the RCC can be peeled off the IVC wall easily because the tumor thrombus extends into the IVC but does not usually invade the IVC [
13]. However, it may be so difficult to exfoliate a tumor near the renal vein, and therefore both tumor thrombectomy with a wedge resection of the IVC need to be performed in order to completely resect a tumor [
13]. Therefore, the excision of a tumor extending into the IVC and running sutures are usually performed in such cases without IVC resection. IVC resection is advisable when the IVC is occluded by a tumor thrombus. This technique may also be applied to patients with another tumor thrombus.
The left renal vein (RV) can be separated from the IVC in cases where there is an RCC originating from the right kidney that extends into the IVC, because the left RV has several branch veins (adrenal, ovarian, lumbar) draining into the hemiazygos system [
13]. The renal function will be maintained when a left renal vein stump pressure of less than 35 mmHg is obtained, because the left RV can be divided if its stump pressure is about 50–60 cm of water (37–44 mmHg) or lower [
21]. On the other hand, the connection between the right RV and caudal IVC should be preserved if the RCC from the left kidney extends into the IVC, or the right RV should be reconstructed to the caudal IVC because of the inadequate number of draining veins from the right kidney [
13].
There are various surgical techniques, such as a partial IVC resection and direct closure or patch plasty, that can be used in cases of the direct invasion of liver tumors [
11,
22‐
24]. However, it is sometimes necessary to interpose the IVC using an ePTFE graft with removable rings, although it is disadvantageous to replace the IVC using a graft because of the risk of the complications such as leakage of bile or pancreatic juice. The graft and the site of the anastomosis may be covered with the omentum. The superior mesenteric artery should be clamped or a venovenous shunt will be applied using a biopump or Anthron bypass tube™ (Toray, Tokyo, Japan) if the portal vein must be clamped for very long [
25,
26].
IVC resection was performed to enhance the curability in case 1, but IVC replacement was not done, because the systemic blood pressure and hemodynamics were stable during cross-clamping of the infrahepatic IVC and the left RV stump pressure was 27 mmHg. Right hepatic trisegmentectomy with a resection of the invaded IVC was performed in case 2 to enhance the curability. It was necessary to perform the IVC reconstruction because the patient’s systemic systolic blood pressure fell below 80 mmHg during the IVC cross-clamping even after providing sufficient fluid replacement. Surgeons should decide whether to perform IVC replacement by considering intraoperative hemodynamics.
In conclusion, either partial or total abdominal aortic cross-clamping is considered to be a safe and simple technique and can be used to conveniently maintain hemodynamic stability without a shunt, even if the systemic blood pressure decreases during IVC cross-clamping when IVC replacement is performed for patients with gastroenterological, urological and gynecological diseases with IVC invasion or extension. Moreover, it is not necessary to reconstruct the IVC when the systemic blood pressure and hemodynamics are stable during cross-clamping the IVC without using a vasopressor after providing sufficient fluid replacement.