Rapid Procurement

Use of the standard technique in stable donors has allowed the training of relatively inexperienced surgeons in the performance of a donor hepatectomy. When the technique is mastered, faster methods can be applied electively or, if required, by urgent clinical circumstances. With the rapid techniques, little or no preliminary dissection is done except for encirclement of the supraceliac aorta and cannulation of the inferior mesenteric vein and terminal aorta (Fig. 99.8). If the heart is to be removed, the cardiac surgeon proceeds as if other organs are not to be harvested but gives warning before the circulation is stopped.

FIGURE 99.8 Rapid technique of organ retrieval in which the initial dissection is limited to the exposure needed for the insertion of perfusion cannulae in the inferior mesenteric vein and distal aorta. If only the abdominal organs are to be used, the aorta is cross-clamped above or below the diaphragm.

At the moment heart function ceases, the abdominal aorta is cross-clamped above or just below the diaphragm, and an infusion of cold HTK solution is started in the inferior mesenteric vein and distal aorta (see Fig. 99.8). The amount of preservation fluid with the rapid technique is approximately the same as that used for the standard method (i.e., 2 L into the inferior mesenteric vein (IMV)/splenic vein and 10 L through the aorta). When the liver becomes cold, the infusions are slowed. In the now bloodless field, the main vessels of the celiac axis can be quickly dissected, and the hilar dissection can be completed in a matter of minutes.

The portal vein is cleaned inferiorly to the junction of the splenic and superior mesenteric veins, and these two tributaries are divided. As in the standard method, the surgeon must promptly exclude the possibility of a retroportal right hepatic artery originating from the superior mesenteric artery as well as other arterial vascular anomalies. The hepatectomy is then completed. The kidneys, which are excised only after the liver has been removed from the field, are kept cold throughout by continued, slow, intraaortic infusion of the preservation solution. By performing all dissections in the bloodless field, it is possible to remove multiple organs in about half an hour, including the heart, liver, and both kidneys. Procurement of the intestine adds only a few additional minutes.

Super-Rapid Procurement

In arrested or non–heart-beating donors, an even quicker procedure can be used to procure satisfactory organs. This method also can be applied in countries that do not have “brain death” laws or under special legal or religious circumstances. Here, cooling requires urgent cannulation and cold fluid infusion into the distal aorta (Fig. 99.9A). Sternum splitting, thoracic aortic cross-clamping, and severance of the suprahepatic inferior vena cava for venous decompression are performed (Fig. 99.9B), deferring cannulation and perfusion of the portal venous system until after the various organs are at least partly cooled intraarterially (Fig. 99.9C). The various dissections are done in the same way as with the standard and rapid techniques. Effective application of this method requires an extremely high level of skill.

FIGURE 99.9 The super-rapid technique used for unstable donors for whom time is insufficient for exposure; placement of perfusion cannulae is shown. A, A midline abdominal incision is used to cannulate the aorta and begin infusion. B, The sternum is split to expose the pericardium and thoracic aorta. The suprahepatic inferior vena cava (IVC) is incised and is bled into the chest, while the descending thoracic aorta is cross-clamped (inset). C, The inferior mesenteric vein is cannulated and perfused only after the steps taken in A and B.

Liver, Pancreas, and Intestine Procurement from the Same Donor

The pancreas and intestine can be retrieved independently or together with the liver. Before starting the procurement, the operation should be discussed among the surgeons involved. Considerations include organ priority, type and amount of preservation solution to be used, presence of aberrant hepatic arteries, length of portal vein, and a decision about which organ retains the celiac axis or superior mesenteric artery.

An important step in any cadaveric donor operation is the removal and storage of long segments of the donor iliac arteries and veins as well as other arteries and veins. These vessels can be used as vascular grafts to reconstruct the blood supply of the individual organs. With increased experience, it is rare to see any of the abdominal visceral organs discarded for purely technical reasons.

Venovenous Bypass

The most critical stage of the recipient operation is the anhepatic phase, during which the diseased liver is removed and replaced with the allograft. Obstruction of the portal vein and vena cava during this period results in splanchnic and lower body systemic venous hypertension. This situation can have devastating consequences in some patients. During the early 1980s, a pump-driven venovenous bypass, used without recipient heparinization, was developed in Pittsburgh to allow splanchnic and systemic blood to return to the heart by way of an inflow cannula placed in the axillary vein (Fig. 99.13). This technique permitted the hepatectomy and implantation to be done with significant reductions in blood loss, intestinal edema, and postoperative renal failure.

FIGURE 99.13 Pump-driven venovenous bypass used to decompress the systemic and splanchnic venous beds during the anhepatic phase of liver transplantation. The groin and venous return cannulae, when used, are usually placed percutaneously in the left groin and right neck.

Infants and small children weighing less than 15 kg tolerate venous occlusion reasonably well. Currently in adults, experienced surgeons use bypass selectively, avoiding it until it becomes apparent that its use cannot be avoided. When required, the cannulae are often now placed percutaneously in the groin and neck, thereby obviating the need for cut-downs as previously required. If bypass is not routine, the decision for or against its use should be made as early as possible in the course of the operation. The decision can be aided by testing the cardiocirculatory effects of test occlusion of the inferior vena cava and portal triad. If the test is conducted after preliminary dissection of the portal triad, and after the triangular and coronary ligaments are cut with entry into the right and left bare areas, it also is possible to evaluate the extent to which bleeding from raw surfaces can be anticipated without bypass. Alternatively, a temporary end-to-side portocaval shunt can also be constructed to prevent mesenteric congestion during the anhepatic phase. This is often created using a small segment of donor iliac vein in order to retain the full length of the recipient portal vein and for ease of creating the shunt. The portocaval shunt should be placed on the vena cava as inferiorly as possible, so its location does not interfere with placement of the vena caval clamp.

Hilar Dissection

In “easy” cases, the individual hilar structures can be readily skeletonized. The hepatic artery and common duct are ligated as close to the liver as possible, and the hepatic artery is dissected proximal to the origin of its gastroduodenal branch, facilitating exposure of the proximal portal vein (Fig. 99.14). If needed, venovenous bypass can be initiated with cannulation of the transected portal vein at this time or later.

FIGURE 99.14 Hilar dissection in the liver recipient.

Host Hepatectomy with or Without Vena Cava Removal

If the hilar dissection has been accomplished uneventfully, the liver is devascularized and now can be excluded from the circulation by cross-clamping the vena cava above and below the liver (Fig. 99.15A). The diseased organ with or without a segment of retrohepatic vena cava can be “peeled” out, working from the hilum up or from the diaphragm down. If the vena cava is part of the specimen, the obligatory ligation of the right adrenal vein (Fig. 99.15C) imposes a risk of adrenal infarction. If this occurs with venous hypertension and bleeding, the right adrenal gland should be removed immediately. Other systemic venous tributaries to the vena cava segment from the lumbar regions also must be scrupulously ligated. Because of regional venous hypertension in the right-sided bare area, it may be necessary then or later to obtain hemostasis by closing or oversewing the edges of the exposed bare areas with a continuous suture or by the use of such devices as the LigaSure (Covidien, Mansfield, MA) or the Monopolar or Bipolar sealer (Fig. 99.15D).

FIGURE 99.15 Completed recipient hepatectomy on venovenous bypass. A, With preservation of host retrohepatic vena cava. Note the hepatic vein cuffs. B, As in A, but with an injury to the right adrenal vein, which is being ligated. C, The retrohepatic vena cava has been included in the hepatectomy, necessitating ligation of its tributary lumbar veins and the right adrenal vein. D, Closure of the bare area to provide hemostasis. Bleeding from the bare area is more severe if the retrohepatic cava is removed or thrombosed because of the loss of venous drainage.

Many of these problems can be circumvented if the host retrohepatic vena cava can be conserved (see Fig. 99.15A). Separation of the diseased liver from the vena cava is done in the same way as in the classic experimental procedure of total canine hepatectomy. With this kind of hepatectomy, stumps of one or more of the main host hepatic veins are retained (Fig. 99.16A) for eventual receipt of the allograft’s venous outflow (Fig. 99.16B and C); this is known as the piggyback method of liver transplantation. To the extent vena cava flow can be maintained during the sometimes tedious and difficult denudation of the retrohepatic vena cava, the need for venovenous bypass is potentially eliminated, and the extent of retroperitoneal dissection is considerably reduced. Finally, the risk of right adrenal infarction is eliminated, unless the right adrenal vein is injured (see Fig. 99.15B).

FIGURE 99.16 The piggyback method of graft implantation with a conserved retrohepatic vena cava. A and B, Creation of an outflow cloaca from two or more hepatic veins. C, Completed anastomosis between the host hepatic veins and the suprahepatic vena cava of the graft. The inferior end of the graft vena cava is ligated.

Alternative Approaches to Hepatectomy

In many if not most cases, hepatectomy with or without inclusion of the retrohepatic vena cava is uncomplicated; however, dissection of the liver hilum sometimes is difficult or impossible because of scarring or the presence of varices. In these situations, the suprahepatic vena cava can be approached first. After transecting the suprahepatic vena cava, removal of the liver can be done from the top down, approaching the hilar structures from behind the liver (Fig. 99.17). If it is not possible to occlude the hepatic veins on the liver side, bleeding can be minimized by placing the fingers into the hepatic veins and retrohepatic vena cava or by squeezing shut the venous outflow of the liver. Alternatively, the inferior vena cava below the liver can be used as a “handle” to extract the liver from bottom to top, with cross-clamping or transection of the hilar structures at the earliest possible opportunity (Fig. 99.18). Finally, if adhesions are present that block access to the upper and lower vena cava and to the portal triad, the liver can be split in a superior-inferior direction, exposing the anterior surface of the retrohepatic vena cava from inside the liver (Fig. 99.19). Once bleeding from the raw surfaces is controlled, the two hepatic halves are stripped away from the surrounding structures. All these hepatectomy variations are made easier by venovenous bypass.

FIGURE 99.17 Removal of the recipient liver from the top down.

FIGURE 99.18 Removal of the recipient liver from the bottom up.

FIGURE 99.19 Splitting technique of hepatectomy. The split is facilitated by inserting a finger along the relatively vein-free anterior midsurface of the vena cava. The correct plane must be determined carefully by finger probing before any pressure is applied.

Vascular Anastomoses

It is important to have the surgical field completely prepared for implantation before the new liver is brought from the back table. The first graft vessel to be anastomosed is always the segment of donor vena cava into which all the hepatic veins of the transplanted liver drain. If host hepatectomy has included removal of the retrohepatic vena cava, the anastomosis is an end-to-end, suprahepatic to suprahepatic vena cava connection at the diaphragm (Fig. 99.20A). With the piggyback operation, in which the host vena cava is conserved, the suprahepatic vena cava is emptied into a cuff of host hepatic veins (see Fig. 99.16) or by a side-to-side anastomosis between the two vena cava segments (not shown).

FIGURE 99.20 Implantation steps. A, Suprahepatic vena cava anastomosis. B, Infrahepatic vena cava anastomosis. Before completing the anastomosis, the portal vein is infused with cold albumin or electrolyte solution when University of Wisconsin solution is used as the preservation solution. This allows air and the potassium-rich preservation fluid to be removed. (Alternatively, the liver can be flushed on the back table, and heparized saline can be used to remove air before completion of the portal vein anastomosis.) C, The portal vein anastomosis after removal of the bypass cannula. IVC, inferior vena cava.

The order of the other vascular anastomoses may vary. With the caval-sparing piggyback operation, the infrahepatic vena cava of the graft is ligated or stapled (see Fig. 99.16). When the host caval segment is excised (standard technique), a common practice is to anastomose the infrahepatic vena cava (Fig. 99.20B), followed by removal of the recipient from the portal (but not systemic) bypass and subsequent portal vein anastomosis (Fig. 99.20C). These anastomoses may be done in reverse order (i.e., portal vein first). An experienced surgeon may prefer to perform the arterial anastomosis before the portal vein reconstruction or may complete all four anastomoses before unclamping. These decisions are influenced by the anatomic and physiologic circumstances in the individual case, including the efficiency with which the bypass system has functioned or the degree of venous hypertension when bypass is not used.

In all cases if the preservation solution used is UW solution, it is important before liver reperfusion to flush the allograft with Ringer’s lactate solution, although some surgeons prefer albumin or blood. Flushing is done through the cannula placed in the graft portal circulation at the time of procurement (see Fig. 99.20A), either on the back table before beginning implantation or in situ before beginning the portal vein anastomosis. After its passage through the microvasculature of the allograft, the infusate is vented from the vena cava (see Fig. 99.20B). The objectives are to remove air and to rid the graft of any high-potassium solutions (UW solution) used for organ preservation (see Fig. 99.20B). Failure to perform this flush can result in air embolism or hyperkalemic cardiac arrest or dysrhythmias, although this step is not necessary if HTK is used.

All of the venous vascular anastomoses are routinely performed with continuous suture. To avoid anastomotic strictures, particularly of the portal anastomosis, special techniques are developed that are made feasible by the ability of polypropylene (Prolene) suture to glide freely through tissue. A growth factor is left by tying the sutures at a considerable distance above the vessel wall. After flow is restored through the anastomosis, the excess polypropylene recedes back into the vessel and redistributes itself throughout the circumference of the suture line (Fig. 99.21). If leaks develop, these are readily controlled with additional single sutures.

FIGURE 99.21 Technique of venous anastomosis. A, Traction sutures are placed at each corner. One end of the far suture is brought to the inside and run in continuous fashion to approximate the back wall. B, The other end of the far suture is used from the outside to approximate the anterior wall. C, The continuous suture is tied away from the vein wall to allow for a “growth factor.” The near corner suture is tied next to the running suture to prevent separation of the vessel. D, The excess suture is drawn into the vessel, allowing the circumference to expand when blood flow is restored.

Rather than being whimsical, variations of the order and details of revascularization frequently are mandated by anatomic anomalies or by pathologic factors, including thrombosis of the portal vein that once contraindicated liver transplantation, until techniques were developed to deal with them. Declotting a thrombosed portal vein may be possible (Fig. 99.22A); if not, iliac or other veins from the donor may be used as interposition grafts (Fig. 99.22B) or as mesoportal jump grafts (Fig. 99.22C). A mesoportal graft may be anastomosed end-to-side to the superior mesenteric vein and tunneled through the transverse mesocolon in a relatively avascular plane anterior to the pancreas to reach the hepatic hilum for end-to-end anastomosis to the donor portal vein (see Fig. 99.22C).

FIGURE 99.22 Management of recipient portal vein abnormalities. A, Removal of thrombus. B, Use of an interposition graft of donor vein to bridge the gap between donor portal vein and the confluence of the mesenteric and splenic veins. C, Donor vein jump graft from the host superior mesenteric vein to the graft portal vein. The jump graft is tunneled through the transverse mesocolon in front of the pancreas to the hepatic hilum. The graft can be anterior or posterior (inset) to the stomach.

Numerous techniques also have been used to restore the hepatic arterial supply. The ideal reconstruction, when the allograft and recipient have normal arterial anatomy, is shown in Figure 99.23A. If anomalies, vascular injuries, or pathologic changes are present in the donor or recipient blood vessels, such as from radiation for cholangiocarcinoma, that preclude effective rearterialization, grafts obtained from the donor can be used (Fig. 99.24; see also Fig. 99.23B and C).

FIGURE 99.23 Hepatic artery reconstruction. A, The most common reconstruction, in which the graft celiac trunk is anastomosed to the recipient common hepatic artery. With discrepant sizes, the circumference of the recipient vessel can be increased as shown in the inset. B, Jump graft of donor iliac artery based on the infrarenal aorta and tunneled anterior to the pancreas. C, Rarely used alternative retroperitoneal tunnel posterior to the pancreas and superior mesenteric artery.

FIGURE 99.24 Other originating sites for an arterial jump graft. A, Host iliac artery. B, Supraceliac aorta.

Biliary Tract Reconstruction

Good hemostasis must be achieved before the biliary reconstruction is performed. If the recipient duct is disease-free, and if there is a reasonable size match between the donor and recipient ducts, an end-to-end anastomosis is performed with or without a T-tube stent (Fig. 99.25). The anastomosis usually is performed with 8 to 10 interrupted absorbable sutures, such as 5-0 or 6-0 polyglycolic acid, or with a continuous suture, if the ducts are large enough. Because the integrity of the anastomosis depends primarily on an adequate blood supply of donor and recipient ducts, minimal dissection is performed in the periductal tissues. A small purse-string suture is usually placed around the T-tube exit site to prevent leakage, and the T-limb is brought out through a stab incision on the lateral side of the recipient duct.

FIGURE 99.25 Biliary tract reconstruction with end-to-end anastomosis over a T-tube. If duct reconstruction is not feasible or is contraindicated, the graft duct is anastomosed to a Roux-en-Y limb of host jejunum (inset).

If the recipient duct is diseased or otherwise inadequate for anastomosis, a choledochojejunostomy is performed. A 45-cm Roux-en-Y limb of proximal jejunum is brought, usually antecolic, to the hepatic hilum; the donor duct is then anastomosed end-to-side to the jejunal limb with a running or interrupted 5-0 or 6-0 absorbable polyglycolic acid suture with or without a stent (see Fig. 99.25, inset). When used, the stent is secured in place with a rapidly absorbed suture with the assumption that the stent will later pass spontaneously through the intestinal tract; however, occasionally the stent is retained and must be pushed into the bowel by an interventional radiologist, or it can be removed by push enteroscopy. Rarely does the stent require removal at laparotomy.