Editing Open Kidney Surgery (section)

==== Level III-IV vena caval thrombectomy: combined intra-abdominal and intrathoracic approach ====

* Level III thrombi that cannot be removed intra-abdominally and most level IV thrombi are managed with a combined intraabdominal and intrathoracic approach. 
*Pre-operative planning
**A cardiothoracic surgeon needs to participate with the planned operation.
*Surgical plan:
**Thoracoabdominal, chevron laparotomy with sternotomy, and anterior midline laparotomy with sternotomy incisions can be used to provide access to the chest and abdomen
**Abdominal portion of the case is identical to the intraabdominal approach described above. 
**Once the abdominal phase is completed, the cardiothoracic surgeon is called to the operating room and a median sternotomy is performed. The pericardium is opened and the right heart exposed. Often, mobilization of the liver and IVC is easier once the sternotomy is completed.
**Obtain bypass using one of the techniques described below. 
**Once on bypass, the ostium of the renal vein is circumferentially excised, the incision is extended cranially on the IVC, and the thrombus is extracted. 
**A right atriotomy is usually performed to help remove the suprahepatic thrombus. 
**The atrium and IVC are then closed. 
**The patient is taken off bypass and thoracotomy tubes and closed suction abdominal drains are placed. 
**The hepatic ligaments are tacked back into place to prevent torsion of the liver and regional lymphadenectomy is performed.

* '''Bypass techniques for IVC surgery'''
** '''Bypass should be considered in patients in whom the IVC cross-clamping trial causes significant hypotension, as well as in patients in whom there is preoperative cardiac or hepatic dysfunction, contralateral renal dysfunction, or portal venous hypertension, and when there is major intraoperative bleeding that is difficult to control.'''
** '''Venovenous bypass'''
*** '''Involves shunting the venous blood from below the renal veins to the venous return of the heart with the aid of a pump'''
*** '''Advantage'''
****'''Least invasive bypass technique for IVC thrombi;''' can be done without opening the chest, unlike traditional cardiopulmonary bypass.
*** 2 main options are available for infrarenal cannulation: 
****Percutaneous approach through the femoral vein
****Direct intraoperative approach through the IVC just above its bifurcation. 
*****When cannulating the IVC, it is important to position the tip of the cannula as far from the tumor thrombus as possible to avoid dislodging it, which can cause a massive pulmonary embolism, and to avoid aspirating and recirculating tumor cells.
*** Several options are available for delivering the shunted blood back to the heart: a percutaneous approach via the internal jugular vein, a cutdown approach to the brachial/axillary vein, and a direct intraoperative approach through the right atrium.
** '''Cardiopulmonary bypass +/- deep hypothermic arrest'''
*** '''Cardiopulmonary bypass can be performed with or without deep hypothermic arrest.''' 
****'''Cardiopulmonary bypass with deep hypothermic arrest involves stopping the heart and starting bypass, cooling the patient to 16° C to 18° C, and draining all of the blood from the patient.''' 
*****Advantages
******Can be used in cases in which the thrombus cannot be milked below an intrapericardial IVC clamp
******No need to clamp the aorta or porta hepatis or to ligate as many lumbar and hepatic veins since blood flow to these structures is no longer present. However, all vessels that have been traumatized or transected must be controlled since they will bleed once the patient is taken off bypass. 
******Absence of active blood flow allows for complete inspection of the IVC and hepatic veins, thereby aiding in achieving a complete thrombectomy. 
******Risk of embolization during thrombectomy is lower.
******'''Purpose of deep hypothermic arrest is to reduce organ metabolism, allowing for greater duration of absence of blood flow'''
*******At normothermia, brain injury occurs after approximately 4 minutes of circulatory arrest. Most patients tolerate 30 minutes of deep hypothermic circulatory arrest without significant neurological dysfunction. Above 60 minutes, the majority of patients will suffer irreversible brain injury.[https://academic.oup.com/bjaed/article/10/5/138/274654]
*****Disadvantage
******Very invasive
***** Surgical plan:
******Mobilize the kidney and dissect IVC. 
******The cardiothoracic surgeon performs the sternotomy, opens the pericardium, and exposes the heart and its vessels. 
******Heparin-bonded cannulae are placed in the infrarenal IVC and the right atrium to collect venous blood and a cannula is placed into the aortic arch for outflow. 
******The patient is heparinized and bypass is started. 
******The aorta is clamped and cardioplegia solution is administered. 
******The temperature of the recirculated blood is dropped to 10° C to 14° C and the patient is cooled for 15 to 30 minutes until a core temperature of 16° C to 18° C is reached. 
*******Intraoperative electroencephalography should be performed to determine when the brain has been adequately cooled. 
******When sufficient cooling has been achieved, the perfusion pump is stopped and 95% of the patient’s blood volume is drained into the pump reservoir. 
******Tumor thrombectomy should be performed as fast as possible, taking great care to ligate all potential bleeders. 
*******If the resection is taking longer than anticipated, the surgeon should consider allowing a 10-mL/kg/min trickle of blood to flow to the organs or using retrograde cerebral perfusion.
******If the patient has known coronary artery disease, coronary artery bypass can be performed at the same time. 
****** Once the IVC and right atrium are repaired, warm blood is reinfused from the pump reservoir and cardiopulmonary bypass is restarted. 
******Hemostasis is performed while the patient warms to 37° C over the next 30 to 45 minutes. 
******Once the heart has restarted pumping, bypass is stopped, the cannulae are removed, and protamine sulfate is administered.
******'''<span style="color:#ff0000">Most common difficulty associated with hypothermia and circulatory arrest is hemorrhage associated with platelet and clotting factor dysfunction</span>'''
*******Fresh frozen plasma, platelets, and packed red blood cells should be available to administer. 
******Thoracostomy tubes and closed suction abdominal drains are inserted.
*** Alternatives to CPB may include venovenous bypass and extensive liver mobilization
* '''<span style="color:#ff0000">Patching, replacing, and interrupting the IVC</span>'''
** '''<span style="color:#ff0000">Patch Cavoplasty</span>'''
*** '''<span style="color:#ff0000">If the IVC lumen is expected to be < 50% of its original size, a patch cavoplasty is necessary to prevent IVC stenosis and thrombosis-related events</span>'''
*** Autologous and bovine pericardium, polytetrafluoroethylene (PTFE), collagen-impregnated Dacron (DuPont, Wilmington, DE), and autologous saphenous vein are materials that can be used for patch cavoplasty.
** '''Vena caval replacement'''
*** In situations when a circumferential section of IVC has been removed or if a vena cava defect is too large for simple patching, vena caval replacement is necessary
*** Typically, PTFE grafts are used to replace the IVC, although others have described spiraled saphenous vein, superficial femoral vein, and tubularized pericardium as options
*** '''Postoperatively, low-dose intravenous heparin or a reduced dosage of low-molecular-weight heparin is given.''' Once the patient’s bowel function has recovered, lifelong oral warfarin is used with a target INR of 2 to 3.
* '''IVC filtration and permanent interruption for bland thrombus'''
** Occasionally, a patient with an infrarenal bland thrombus requires management at the time of tumor thrombectomy.
** For bland thrombus that is limited to the pelvic veins, intraoperative placement of an infrarenal vena cava filter is indicated.
** For bland thrombus that diffusely involves the infrarenal IVC, the optimal management is permanent interruption of the IVC. 
***Necessary intraoperative care is required to preserve the collateral lumbar venous drainage, since these vessels provide a “release valve” for the impaired caval blood flow. 
***Options for permanent interruption of the IVC include serrated vena cava clips (e.g., Adams-DeWeese clip, Moretz clip), cross stapling with a vascular GIA stapler (Covidien Ltd., Mansfield, MA), suture plication, and suture ligation.
* '''<span style="color:#ff0000">Perioperative complications</span>'''
** '''Air embolism'''
*** Potentially lethal
*** Risk of air embolism can be significantly reduced by releasing the caudal IVC clamp first and allowing air and some blood (5 to 10 mL) to escape from the IVC repair site prior to removing the cranial clamp.
** '''Acute PE'''
*** Tumor and bland thrombus can embolize during and after surgery. Minimizing intraoperative manipulation of the kidney and IVC before vascular control helps reduce the likelihood of acute thrombotic pulmonary embolism.
*** If respiratory distress is encountered during surgery, strong consideration should be given to prompt thoracotomy, pulmonary arteriotomy, and extraction of the thrombus.
** '''Massive hemorrhage'''
*** Major bleeding can occur during and after the surgery. If uncontrolled major bleeding occurs in a patient who is not on bypass, the surgeon should consider clamping the aorta above the celiac trunk or initiating deep hypothermic CPB
** '''Hepatic dysfunction'''
*** Temporary hepatic dysfunction, characterized by elevated transaminases and alkaline phosphatase, is common in patients with levels III and IV thrombi that require suprahepatic IVC clamping and/or bypass.
*** Liver enzymes typically peak 2 to 3 days postoperatively and slowly resolve thereafter.
** '''Organ ischemia'''
*** Cardiac ischemia is most common in patients undergoing suprahepatic IVC clamping without bypass.