- Email: [email protected]
Pediatric Biliary Interventions
Pediatric Biliary Interventions John M. Racadio, MD, and Kamlesh Kukreja, MD The most common indication for percutaneous biliary evaluation and intervention in children is for the diagnosis and treatment of liver transplant complications, including strictures and bile leaks. Because liver transplants in children are commonly performed using a Roux-en-Y biliary-enteric anastomosis, endoscopic retrograde cholangiopancreatography is not technically possible; therefore, the first-line procedure for evaluation and treatment of biliary obstruction in this population is percutaneous transhepatic cholangiography (PTC). Percutaneous biliary intervention can be challenging in these patients, because ductal dilation may be minimal or altogether absent in pediatric transplant livers even in the setting of severe obstruction. However, with proper technique, including the use of ultrasound guidance, technical success rates for PTC and biliary drainage can be similar to those in adults. Biliary drainage and biliary stenosis management is a long-term commitment that usually takes several months to more than a year and may require multiple repeat cholangioplasties and biliary drainage catheter exchanges. Due to its minimally invasive nature and relatively low morbidity and mortality compared with open surgical alternatives, percutaneous biliary intervention should be considered the first-line treatment option in children with biliary stenosis who have had previous liver transplant, and for those nontransplant patients who cannot be treated endoscopically. Tech Vasc Interventional Rad 13:244-249 © 2010 Elsevier Inc. All rights reserved. KEYWORDS pediatric, biliary, interventional radiology, percutaneous transhepatic cholangiography
P
ediatric percutaneous biliary interventions are performed primarily for the diagnosis and treatment of biliary obstruction. In adults, biliary obstruction is most often related to cholethiasis or malignancy; in children, the vast majority of cases requiring percutaneous intervention occur as a complication of liver transplant. The most common biliary complications of pediatric liver transplantation are strictures and bile leaks, for which placement of a biliary drainage catheter is usually the initial treatment.1 Whereas biliary stenoses in liver transplants most commonly involve the biliary-enteric anastomosis, transplants that have received ischemic insult due to hepatic artery compromise or those with severe cholangitis may have multiple intrahepatic stenoses. Most cases requiring biliary investigation and intervention in native (nontransplanted) livers can be performed through endoscopic retrograde cholangiopancreatography (ERCP). Because liver transplants in children are commonly performed
Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH. Address reprint requests to John M. Racadio, Cincinnati Children’s Hospital Medical Center, Department of Radiology, 3333 Burnet Avenue, Cincinnati, OH 45229-3039. E-mail: [email protected]
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using a Roux-en-Y biliary-enteric anastomosis, ERCP is not technically possible; therefore, the first-line procedure for evaluation and treatment of biliary obstruction in this population is percutaneous transhepatic cholangiography (PTC). Bile leaks are typically only seen in liver transplant patients within the first few weeks after transplantation, either from the cut surface of a reduced-size graft or at the surgical anastomosis.2 Peritoneal bilomas are drained with standard percutaneous techniques. Occasionally, percutaneous biliary ductal drainage can divert bile allowing the leaking site to heal. With proper technique, including the use of ultrasound guidance, technical success rates for PTC and biliary drainage can be similar to those in adults.1
Indications for the Procedure Patients with biliary obstruction may present gradually with nonspecific symptoms, or with jaundice, pruritis, and elevated liver enzymes, or they may be acutely ill with fever and sepsis; clinical presentation dictates whether intervention needs to be performed electively, urgently, or emergently. Contraindications to percutaneous biliary intervention are relative and include uncorrectable coagulopathy, allergy to iodinated contrast, and large-volume ascites.
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Clinical Evaluation of the Patient Preprocedure patient evaluation is important to decrease the potential morbidity and mortality associated with percutaneous biliary intervention. Review of laboratory values pertinent to risk of bleeding is mandatory. To safely perform the procedure, the patient should have an INR of 1.5 or less, platelet count of 50,000/dL or greater, and a normal partial thromboplastin time (PTT). A focused physical examination should be performed to identify any potential access limitations, including nearby enteric stomas, open surgical wounds, and surgical drains. All prior imaging should be reviewed; ductal dilation may be minimal or altogether absent in pediatric transplant livers even in the setting of severe obstruction.3,4 In the case of transplant patients, it is imperative that the operative notes, especially those regarding the type of biliary enteric anastamosis, are read and understood. There should be a low threshold for contacting the surgeon to clarify the anatomy. In small children, split adult livers are commonly used for transplant, so that only a left lobe is present.
Percutaneous Transhepatic Cholangiography Prior to the procedure, the patient should receive prophylactic broad spectrum IV antibiotics, such as cefazolin 30 mg/kg (maximum single dose 1-2 g). The patient is placed under general anesthesia. Before the patient is prepped, transabdominal ultrasound is performed to fully evaluate the biliary system as well as the relationship between any biliary radicles that are potential targets for access and the central hepatic arteries, portal veins, and hepatic veins. An ultrasound probe, such as a 10-4 MHz vector probe with a small footprint that can fit into small subcostal or intercostal windows can be helpful for this evaluation. Ultrasound is also used to evaluate the inferior extent of the diaphragm and pleura while anesthesia gives a full inspiration to the patient, and to localize any nearby bowel or ascites. The bile ducts are imaged and accessed in the longitudinal plane parallel to the bile duct so that both the advancing needle and bile duct can be seen along their entire courses (Fig. 1). There are several factors to consider when choosing an appropriate target duct. First, as a general rule, there is less risk of pleural transgression when accessing left sided ducts as opposed to right sided ducts. Second, it is preferable to access a peripheral duct, because there is more risk of bleeding with central access attempts near the liver hilum.5 However, peripheral duct access may be difficult, particularly in liver transplant patients whose ducts tend to be more rigid and resistant to dilation even in the setting of obstruction.1 Third, the access angle of the needle into the duct should be as shallow as possible (ideally ⬍45 degrees). The needle should be directed antegrade in the direction of biliary flow with as direct a course as possible to the hilum, so that a guidewire passed through the needle will advance in the intended direction toward the central bile ducts and the biliary-enteric anastamosis. After an appropriate target access duct is identified, the patient’s position on the table can be adjusted to optimize operator comfort. If possible, the pa-
Figure 1 A 5-month-old male presents with elevated liver function tests and biliary ductal dilation 3 months after whole organ liver transplant. A 22-gauge echo tip Chiba needle is advanced under real time ultrasound while imaging the needle (arrow) and the targeted bile duct (*) along their longitudinal axes.
tient’s arms are raised away from their sides so that lateral fluoroscopic imaging is possible without the image being obscured by the patient’s arms. However, care must be taken to avoid positions with the arms extended greater than 90 degrees so as not to induce a brachial plexus neuropathy. The patient is then prepped and draped in sterile fashion using chlorhexidine scrub. The skin and deeper soft tissues are anesthetized with 1% lidocaine using a 27-gauge needle. Meticulous care must be taken not to introduce any air or microbubbles during this step, because it will hinder the ability to visualize advancement of the access needle. The lidocaine can be injected under direct ultrasound guidance, not only to assure optimal anesthetic placement, but also to gauge the proper angle of trajectory for subsequent advancement of the access needle. In this way, the small numbing needle is used for a “test” pass to the level of the liver capsule. If the angle is deemed not optimal, the skin entry site can be adjusted. Under direct ultrasound guidance, a 22-gauge Chiba needle is advanced percutaneously through the liver capsule and liver parenchyma toward the targeted duct. Anesthesia-provided breath hold is highly recommended during needle advancement. While maintaining real-time visualization of the entire length of the needle and longitudinal course of the bile duct, the needle tip is advanced to the duct wall such that it can be seen indenting the duct. At this point a decisive, short acceleration of the needle is often needed to puncture the anterior wall of the duct. A “pop” may be felt similar to that felt when accessing a vein with a needle. Liver transplant ducts are often more rigid and difficult to puncture. Because the bile ducts are usually very small, it can be difficult to avoid a “double wall” puncture.
J.M. Racadio and K. Kukreja
246 The stylet of the Chiba needle is then removed. If the needle tip is positioned perfectly in the duct, bile will often slowly flow back and fill the needle hub in conjunction with patient respirations. If bile does not fill the needle hub, the hub can be filled with contrast by performing a “wet hookup” with contrast from a 10-mL syringe and primed connecting tubing, making sure that no bubbles are in the system. However, to prevent infiltrated air from obscuring future needle passes, test contrast injection should only be performed if indentation or deflection of the bile duct was verified sonographically during needle advancement. Under live fluoroscopy, the contrast material is gently injected while slowly retracting the needle until a bile duct is opacified. If no ducts are opacified with this initial puncture, the needle tip is withdrawn to a subcapsular position and redirected under ultrasound guidance. With each needle pass, it may become more difficult to visualize the needle and duct due to inadvertent air infiltration into the parenchyma, bleeding, and parenchymal disruption from test contrast injections. If this occurs, it may be necessary to attempt to access a different portion of the duct or to choose an alternate duct. Once contrast fills a bile duct, it should continue to be slowly injected to opacify the biliary tree, taking care not to displace the needle tip position (Fig. 2). Contrast should be injected gently during cholangiography, because over distension of an infected system can cause rapid bacteremia and may lead to sepsis.6 The C-arm is rotated in various obliquities to fully evaluate the biliary tree, looking for stenoses, stones, and sludge, as well as any segments of liver whose ducts do not opacify, which may indicate a separate stenosis within that nonopacified segment. In the setting of a nonopacified segment containing dilated ducts on ultrasound, a second needle access and PTC is necessary to diagnose and potentially treat this “trapped” duct system. In keeping with the principles of the Image Gently, Step Lightly campaign,7 images should be stored using “last image hold” rather than taking “single shot” exposures to decrease ionizing radiation exposure to the patient. Many modern angio suite C-arm
Figure 2 A 6-year-old female status post left segmental liver transplant 4 years prior presents with jaundice and pruritis. After accessing a peripheral bile duct under ultrasound guidance with a 22gauge Chiba needle (arrow) contrast injection demonstrates a tight intrahepatic stenosis (arrowhead) with only a thin wisp of contrast progressing into a more central duct.
systems have the capability of storing a cine clip of a few seconds of fluoroscopy (“fluoro store”), which can provide and document dynamic information during duct opacification. In some complex cases involving multiple strictures and overlapping anatomy, C-arm “3D rotational cholangiography” (using typical C-arm 3D rotational angiography techniques available on most modern C-arm angio-interventional systems) may be helpful diagnostically as well as in planning biliary intervention (Fig. 3). However, if cholangiography is normal, the needle is removed and pressure is applied to the puncture site.
Cholangioplasty If the initial needle access is in a relatively peripheral duct, cholangioplasty and drainage catheter placement may proceed through this access site. If the needle puncture site is central (near the hilum), a second needle puncture into a more peripheral opacified duct can be performed under ultrasound and fluoroscopic guidance. A 0.018-inch guidewire, such as the Cope mandril guidewire included in the Neff Introducer Set (Cook Medical, Bloomington, IN), is passed through the 22-gauge Chiba access needle into the duct. Ideally, this guidewire is then advanced across the stenosis, across the biliary-enteric anastamosis, and into the roux loop of small bowel. If the wire cannot be advanced that far, one should at least gain enough purchase so the stiff stainless steel portion of the guidewire is positioned within the duct (Fig. 4). If purchase can only be achieved with the distal, floppy platinum portion of the guidewire, subsequent dilation may be difficult. Following a small dermatotomy at the access site, the Neff triaxial dilator and 6-Fr sheath combination are then advanced over the Cope guidewire. The triaxial sheath contains a stiff inner dilator and inner sheath that will accommodate the 0.018inch wire, whereas the outer sheath is large enough to accommodate both a 0.018-inch and a 0.035-inch guidewire after the removal of the inner dilator and sheath. The hydrophilic coating and smooth taper of the Neff sheath dilator facilitate advancement through the liver capsule and duct. The end of the outer sheath, which is marked with a radiopaque band, should be advanced into the duct (Fig. 5). The inner stiffener, inner sheath, and dilator can be removed over the wire while still maintaining guidewire access; to confirm that the outer sheath has indeed been advanced into the duct, a hemostasis valve with side arm is advanced over the wire, the luer lock is connected to the outer sheath, and contrast is injected through the side arm. With the sheath securely in the bile duct, any additional diagnostic cholangiography can be performed. Although the outer sheath of the Neff set can easily accommodate a 0.035-inch guidewire, typical pediatric biliary stenoses are often too narrow for a guidewire of this size. If the 0.018-inch Cope guidewire cannot cross the stenosis, a 0.018- or 0.014-inch hydrophilic wire can be used with our without support from a 3- or 4-Fr directional catheter, such as a JB1 (Cook Medical). Once the stenosis is crossed with either the 0.014-inch or 0.018-inch wire, balloon dilation can be performed. Monorail type balloons, such as Sterling (Boston Scien-
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tific, Natick, MA), have low profiles and their soft nature allows for successful navigation of sharp turns in the biliary anatomy (Fig. 6). Balloons up to 10 mm in diameter can be used through the outer sheath of the Neff set. Once the balloon is positioned across the stenosis, the duct is overdilated to approximately 1.5 times its normal caliber
Figure 4 (Same patient as Figure 2.) The 0.018-inch Cope guidewire is advanced into the duct. Accessing as peripheral a duct as possible allows more distance for the guidewire to be advanced, so the junction (*) between the proximal stiff stainless steel portion of the wire and the distal floppy platinum part of the wire is within the duct. With the junction in the duct and more central than the point of needle access (arrow), subsequent dilation through the duct wall is easier and less likely to kink the guidewire.
at the level of the stenosis. After dilation, a sturdier 0.035inch or 0.038-inch wire, such as an Amplatz (Boston Scientific), can be advanced through the Neff sheath along side the 0.018-inch wire and gently manipulated across the freshly plastied stenosis. Care must be taken not to create a dissection of the bile duct wall. If there is any resistance to advancement of the larger wire across the stenosis, the larger wire is removed and the flexible 0.018inch tapered dilator portion of the Neff is reintroduced over the 0.018-inch wire, luer locked with the outer Neff sheath, and the dilator and Neff sheath are advanced as a unit across the stenosis. The Neff dilator and 0.018-inch
Figure 3 (Same patient as Figure 1.) (A) Flat detector C-arm rotational cholangiography 3D reconstruction demonstrates needle in duct (arrow), central stenoses at the confluence of 4 central ducts (circle), and long segment stenosis of the “common duct” (arrowhead) at the biliary enteric anastamosis with the roux loop. (B) Abdominal film 1 day post cholangioplasty and biliary drainage demonstrating placement of 3 different 8-Fr drainage catheters: one through the initially accessed duct, across the biliary enteric anastamosis, and into the roux loop of bowel (arrow); another through the more inferior left duct, across the biliary anatamosis, and into the roux (arrowhead); and a third crossing from the inferior left duct into the superior right duct (*). Three of the four stenoses that contributed to the central confluence stenosis (circle) were able to be successfully plastied and drained. The inferior right duct stenosis could not be crossed with a guidewire and had to be drained via a separate right sided puncture at a later date.
Figure 5 (Same patient as Figure 2.) The tip of the outer sheath of the Neff set (arrow) has been advanced over the 0.018-inch Cope wire well into the bile duct. The floppy distal portion of the guidewire has been advanced across the stenosis.
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pigtail end of the catheter is positioned across the biliaryenteric anastamosis and locked in the small bowel. Side holes span the length of the catheter and a radiopaque band marks the most proximal sidehole. This marker is pulled back under fluoroscopy to the point at which the catheter enters the biliary tree to provide the most adequate drainage. Appropriate catheter position can be confirmed with contrast injection. The catheter is sutured to the skin and securely dressed.
Recognizing and Treating Complications
Figure 6 (Same patient as Figure 2.) Monorail balloon has been advanced over a wire through the superior Neff sheath. Typical “waist” is seen in the balloon (arrow) as the stenosis is dilated. Note a separate Neff sheath and guidewire that have been percutaneously placed via a second more inferior duct.
guidewire can then be removed (or remain in place as a safety wire) and a sturdier 0.035- or 0.038-inch wire advanced through the Neff outer sheath, across the biliaryenteric anastamosis, and into small bowel. Alternatively, a 4-Fr straight Glide catheter (Terumo Medical, Somerset, NJ) can usually be advanced coaxially through the outer Neff sheath, over the 0.018-inch wire, and across the stenosis; the wire can then be upsized for the 0.035-inch Amplatz wire. Finally, the Neff outer sheath is removed over the wire and an internal/external biliary drainage catheter can be placed.
Biliary Drainage Catheter Placement For most pediatric patients, either an 8.5- or a 10.2-Fr internal/external biliary drainage catheter (Cook Medical) is placed after serial dilation with appropriately sized hydrophilic dilators. Very small infants may require a 5- or 6-Fr drainage catheter modified by punching multiple side holes. The hydrophilic dilators pass more easily across liver capsule, parenchyma, and bile ducts than standard dilators, making it much less likely that the wire will kink. Internal/external drainage catheters allow bile to drain both externally into a bag and internally into small bowel, thus preserving normal enterohepatic bile ciruculation. In cases of complete biliary obstruction in which a guidewire cannot be advanced into small bowel, external drainage is the only option. Sometimes, however, after several days of drainage and IV antibiotics, ductal inflammation and edema can resolve such that repeat cholangiography through the external drainage catheter will reveal a severe but incomplete stenosis through which a guidewire can be passed, allowing subsequent cholangioplasty and eventual placement of an internal/external drainage catheter. The
The most common potential complications from biliary percutaneous interventions include bleeding, fever and bacteremia, and sepsis; minor complications occur in approximately 11% of cases and major complications in less than 2%.1 Accessing peripheral bile ducts away from the hilum and correcting any coagulopathies can reduce the risk of bleeding,1 whereas prophylactic pre- and post-procedure antibiotics and avoiding overdistension of bile ducts during cholangiography1 can reduce the risk of sepsis. Bleeding can present as intraperitoneal hemorrhage, intraparenchymal hematoma, or hemobilia. Most bleeding is transient and self-limiting. In cases of persistent or worsening hemobilia or sudden onset hemobilia 1-2 weeks or more postprocedure, hepatic arterial injury should be suspected and hepatic arteriography and embolization should be performed.8
Clinical Follow Up Patients should remain on IV antibiotics for at least 24 hours after the procedure. If a biliary drain has been placed, it should be left open to internal and external drainage for several days while the patient recovers from the effects of biliary obstruction and/or cholangitis. When the patient has clinically improved, the drainage tube can be closed to external drainage and allowed to drain only internally for 24-48 hours before discharge. Follow up includes cholangiography at 3 months postprocedure. An IV dose of prophylactic antibiotics, such as cefazolin 30 mg/kg, should be given whenever injecting or manipulating a biliary drainage catheter. The patient is placed under general anesthesia and contrast is injected into the existing biliary drainage tube to assess whether there has been interval decompression of any previously dilated ducts and to identify any new strictures. Any previous stricture that had been dilated cannot be fully evaluated for patency if the biliary drainage catheter is stenting it open. Therefore, the biliary drainage catheter is removed over a 0.035-inch Newton guidewire (Cook Medical) and a vascular type sheath with side arm (sized appropriately to the size of the biliary drain) is placed with the tip of the sheath positioned peripheral to the previous stenosis. Through the side arm of the sheath, cholangiography is again performed to evaluate for residual stenosis. If significant re-stenosis has occurred, cholangioplasty is per-
Pediatric biliary interventions formed and a new biliary drainage catheter placed and left for an additional 3 months. If no significant stenosis is identified, a new down-sized biliary drainage catheter is often placed, thereby maintaining access across the stenosis in case delayed re-stenosis occurs. Repeat cholangiography is performed approximately 1-2 months later; if no re-stenosis has occurred, the drainage catheter is removed and the patient is followed clinically for any signs or symptoms of recurrent biliary obstruction. Biliary drainage and biliary stenosis management is a long-term commitment that usually takes several months to more than a year and may require multiple repeat cholangioplasties and biliary drainage catheter exchanges.9 Long-term stenosis recurrence following percutaneous cholangioplasty and drainage catheter placement is not uncommon; in one study, 34% of patients with isolated biliary-enteric anstamotic stricures were documented to have had a recurrence at mean 2.2 year follow up.9 Due to its minimally invasive nature and relatively low morbidity and mortality compared with open surgical alternatives, percutaneous biliary intervention should be considered the first-line treatment option in children with biliary stenosis who have had previous liver transplant, and for those nontransplant patients who cannot be treated endoscopically.
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References 1. Lorenz JM, Funaki B, Leef JA, et al: Percutaneous transhepatic cholangiography and biliary drainage in pediatric liver transplant patients. AJR Am J Roentgenol 176:761-765, 2001 2. Heffron TG, Emond JC, Whitington PF, et al: Biliary complications in pediatric liver transplantation. A comparison of reduced-size and whole grafts. Transplantation 53:391-395, 1992 3. Zajko AB, Zemel G, Skolnick ML, et al: Percutaneous transhepatic cholangiography rather than ultrasound as a screening test for postoperative biliary complications in liver transplant patients. Transplant Proc 20:678-681, 1988 (suppl 1) 4. Zemel G, Zajko AB, Skolnick ML, et al: The role of sonography and transhepatic cholangiography in the diagnosis of biliary complications after liver transplantation. AJR Am J Roentgenol 151:943-946, 1988 5. Pomerantz BJ: Biliary tract interventions. Tech Vasc Interv Radiol 12: 162-170, 2009 6. Ferrucci JT Jr, Mueller PR, Harbin WP: Percutaneous transhepatic biliary drainage: Technique, results, and applications. Radiology 135:1-13, 1980 7. Sidhu MK, Goske MJ, Coley BJ, et al: Image gently, step lightly: Increasing radiation dose awareness in pediatric interventions through an international social marketing campaign. J Vasc Interv Radiol 20:11151119, 2009 8. Winick AB, Waybill PN, Venbrux AC: Complications of percutaneous transhepatic biliary interventions. Tech Vasc Interv Radiol 4:200-206, 2001 9. Moreira AM, Carnevale FC, Tannuri U, et al: Long-term results of percutaneous bilioenteric anastomotic stricture treatment in Liver-transplanted children. Cardiovasc Interv Radiol 33:90-96, 2010
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ediatric percutaneous biliary interventions are performed primarily for the diagnosis and treatment of biliary obstruction. In adults, biliary obstruction is most often related to cholethiasis or malignancy; in children, the vast majority of cases requiring percutaneous intervention occur as a complication of liver transplant. The most common biliary complications of pediatric liver transplantation are strictures and bile leaks, for which placement of a biliary drainage catheter is usually the initial treatment.1 Whereas biliary stenoses in liver transplants most commonly involve the biliary-enteric anastomosis, transplants that have received ischemic insult due to hepatic artery compromise or those with severe cholangitis may have multiple intrahepatic stenoses. Most cases requiring biliary investigation and intervention in native (nontransplanted) livers can be performed through endoscopic retrograde cholangiopancreatography (ERCP). Because liver transplants in children are commonly performed
Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH. Address reprint requests to John M. Racadio, Cincinnati Children’s Hospital Medical Center, Department of Radiology, 3333 Burnet Avenue, Cincinnati, OH 45229-3039. E-mail: [email protected]
244
1089-2516/10/$-see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1053/j.tvir.2010.04.007
using a Roux-en-Y biliary-enteric anastomosis, ERCP is not technically possible; therefore, the first-line procedure for evaluation and treatment of biliary obstruction in this population is percutaneous transhepatic cholangiography (PTC). Bile leaks are typically only seen in liver transplant patients within the first few weeks after transplantation, either from the cut surface of a reduced-size graft or at the surgical anastomosis.2 Peritoneal bilomas are drained with standard percutaneous techniques. Occasionally, percutaneous biliary ductal drainage can divert bile allowing the leaking site to heal. With proper technique, including the use of ultrasound guidance, technical success rates for PTC and biliary drainage can be similar to those in adults.1
Indications for the Procedure Patients with biliary obstruction may present gradually with nonspecific symptoms, or with jaundice, pruritis, and elevated liver enzymes, or they may be acutely ill with fever and sepsis; clinical presentation dictates whether intervention needs to be performed electively, urgently, or emergently. Contraindications to percutaneous biliary intervention are relative and include uncorrectable coagulopathy, allergy to iodinated contrast, and large-volume ascites.
Pediatric biliary interventions
245
Clinical Evaluation of the Patient Preprocedure patient evaluation is important to decrease the potential morbidity and mortality associated with percutaneous biliary intervention. Review of laboratory values pertinent to risk of bleeding is mandatory. To safely perform the procedure, the patient should have an INR of 1.5 or less, platelet count of 50,000/dL or greater, and a normal partial thromboplastin time (PTT). A focused physical examination should be performed to identify any potential access limitations, including nearby enteric stomas, open surgical wounds, and surgical drains. All prior imaging should be reviewed; ductal dilation may be minimal or altogether absent in pediatric transplant livers even in the setting of severe obstruction.3,4 In the case of transplant patients, it is imperative that the operative notes, especially those regarding the type of biliary enteric anastamosis, are read and understood. There should be a low threshold for contacting the surgeon to clarify the anatomy. In small children, split adult livers are commonly used for transplant, so that only a left lobe is present.
Percutaneous Transhepatic Cholangiography Prior to the procedure, the patient should receive prophylactic broad spectrum IV antibiotics, such as cefazolin 30 mg/kg (maximum single dose 1-2 g). The patient is placed under general anesthesia. Before the patient is prepped, transabdominal ultrasound is performed to fully evaluate the biliary system as well as the relationship between any biliary radicles that are potential targets for access and the central hepatic arteries, portal veins, and hepatic veins. An ultrasound probe, such as a 10-4 MHz vector probe with a small footprint that can fit into small subcostal or intercostal windows can be helpful for this evaluation. Ultrasound is also used to evaluate the inferior extent of the diaphragm and pleura while anesthesia gives a full inspiration to the patient, and to localize any nearby bowel or ascites. The bile ducts are imaged and accessed in the longitudinal plane parallel to the bile duct so that both the advancing needle and bile duct can be seen along their entire courses (Fig. 1). There are several factors to consider when choosing an appropriate target duct. First, as a general rule, there is less risk of pleural transgression when accessing left sided ducts as opposed to right sided ducts. Second, it is preferable to access a peripheral duct, because there is more risk of bleeding with central access attempts near the liver hilum.5 However, peripheral duct access may be difficult, particularly in liver transplant patients whose ducts tend to be more rigid and resistant to dilation even in the setting of obstruction.1 Third, the access angle of the needle into the duct should be as shallow as possible (ideally ⬍45 degrees). The needle should be directed antegrade in the direction of biliary flow with as direct a course as possible to the hilum, so that a guidewire passed through the needle will advance in the intended direction toward the central bile ducts and the biliary-enteric anastamosis. After an appropriate target access duct is identified, the patient’s position on the table can be adjusted to optimize operator comfort. If possible, the pa-
Figure 1 A 5-month-old male presents with elevated liver function tests and biliary ductal dilation 3 months after whole organ liver transplant. A 22-gauge echo tip Chiba needle is advanced under real time ultrasound while imaging the needle (arrow) and the targeted bile duct (*) along their longitudinal axes.
tient’s arms are raised away from their sides so that lateral fluoroscopic imaging is possible without the image being obscured by the patient’s arms. However, care must be taken to avoid positions with the arms extended greater than 90 degrees so as not to induce a brachial plexus neuropathy. The patient is then prepped and draped in sterile fashion using chlorhexidine scrub. The skin and deeper soft tissues are anesthetized with 1% lidocaine using a 27-gauge needle. Meticulous care must be taken not to introduce any air or microbubbles during this step, because it will hinder the ability to visualize advancement of the access needle. The lidocaine can be injected under direct ultrasound guidance, not only to assure optimal anesthetic placement, but also to gauge the proper angle of trajectory for subsequent advancement of the access needle. In this way, the small numbing needle is used for a “test” pass to the level of the liver capsule. If the angle is deemed not optimal, the skin entry site can be adjusted. Under direct ultrasound guidance, a 22-gauge Chiba needle is advanced percutaneously through the liver capsule and liver parenchyma toward the targeted duct. Anesthesia-provided breath hold is highly recommended during needle advancement. While maintaining real-time visualization of the entire length of the needle and longitudinal course of the bile duct, the needle tip is advanced to the duct wall such that it can be seen indenting the duct. At this point a decisive, short acceleration of the needle is often needed to puncture the anterior wall of the duct. A “pop” may be felt similar to that felt when accessing a vein with a needle. Liver transplant ducts are often more rigid and difficult to puncture. Because the bile ducts are usually very small, it can be difficult to avoid a “double wall” puncture.
J.M. Racadio and K. Kukreja
246 The stylet of the Chiba needle is then removed. If the needle tip is positioned perfectly in the duct, bile will often slowly flow back and fill the needle hub in conjunction with patient respirations. If bile does not fill the needle hub, the hub can be filled with contrast by performing a “wet hookup” with contrast from a 10-mL syringe and primed connecting tubing, making sure that no bubbles are in the system. However, to prevent infiltrated air from obscuring future needle passes, test contrast injection should only be performed if indentation or deflection of the bile duct was verified sonographically during needle advancement. Under live fluoroscopy, the contrast material is gently injected while slowly retracting the needle until a bile duct is opacified. If no ducts are opacified with this initial puncture, the needle tip is withdrawn to a subcapsular position and redirected under ultrasound guidance. With each needle pass, it may become more difficult to visualize the needle and duct due to inadvertent air infiltration into the parenchyma, bleeding, and parenchymal disruption from test contrast injections. If this occurs, it may be necessary to attempt to access a different portion of the duct or to choose an alternate duct. Once contrast fills a bile duct, it should continue to be slowly injected to opacify the biliary tree, taking care not to displace the needle tip position (Fig. 2). Contrast should be injected gently during cholangiography, because over distension of an infected system can cause rapid bacteremia and may lead to sepsis.6 The C-arm is rotated in various obliquities to fully evaluate the biliary tree, looking for stenoses, stones, and sludge, as well as any segments of liver whose ducts do not opacify, which may indicate a separate stenosis within that nonopacified segment. In the setting of a nonopacified segment containing dilated ducts on ultrasound, a second needle access and PTC is necessary to diagnose and potentially treat this “trapped” duct system. In keeping with the principles of the Image Gently, Step Lightly campaign,7 images should be stored using “last image hold” rather than taking “single shot” exposures to decrease ionizing radiation exposure to the patient. Many modern angio suite C-arm
Figure 2 A 6-year-old female status post left segmental liver transplant 4 years prior presents with jaundice and pruritis. After accessing a peripheral bile duct under ultrasound guidance with a 22gauge Chiba needle (arrow) contrast injection demonstrates a tight intrahepatic stenosis (arrowhead) with only a thin wisp of contrast progressing into a more central duct.
systems have the capability of storing a cine clip of a few seconds of fluoroscopy (“fluoro store”), which can provide and document dynamic information during duct opacification. In some complex cases involving multiple strictures and overlapping anatomy, C-arm “3D rotational cholangiography” (using typical C-arm 3D rotational angiography techniques available on most modern C-arm angio-interventional systems) may be helpful diagnostically as well as in planning biliary intervention (Fig. 3). However, if cholangiography is normal, the needle is removed and pressure is applied to the puncture site.
Cholangioplasty If the initial needle access is in a relatively peripheral duct, cholangioplasty and drainage catheter placement may proceed through this access site. If the needle puncture site is central (near the hilum), a second needle puncture into a more peripheral opacified duct can be performed under ultrasound and fluoroscopic guidance. A 0.018-inch guidewire, such as the Cope mandril guidewire included in the Neff Introducer Set (Cook Medical, Bloomington, IN), is passed through the 22-gauge Chiba access needle into the duct. Ideally, this guidewire is then advanced across the stenosis, across the biliary-enteric anastamosis, and into the roux loop of small bowel. If the wire cannot be advanced that far, one should at least gain enough purchase so the stiff stainless steel portion of the guidewire is positioned within the duct (Fig. 4). If purchase can only be achieved with the distal, floppy platinum portion of the guidewire, subsequent dilation may be difficult. Following a small dermatotomy at the access site, the Neff triaxial dilator and 6-Fr sheath combination are then advanced over the Cope guidewire. The triaxial sheath contains a stiff inner dilator and inner sheath that will accommodate the 0.018inch wire, whereas the outer sheath is large enough to accommodate both a 0.018-inch and a 0.035-inch guidewire after the removal of the inner dilator and sheath. The hydrophilic coating and smooth taper of the Neff sheath dilator facilitate advancement through the liver capsule and duct. The end of the outer sheath, which is marked with a radiopaque band, should be advanced into the duct (Fig. 5). The inner stiffener, inner sheath, and dilator can be removed over the wire while still maintaining guidewire access; to confirm that the outer sheath has indeed been advanced into the duct, a hemostasis valve with side arm is advanced over the wire, the luer lock is connected to the outer sheath, and contrast is injected through the side arm. With the sheath securely in the bile duct, any additional diagnostic cholangiography can be performed. Although the outer sheath of the Neff set can easily accommodate a 0.035-inch guidewire, typical pediatric biliary stenoses are often too narrow for a guidewire of this size. If the 0.018-inch Cope guidewire cannot cross the stenosis, a 0.018- or 0.014-inch hydrophilic wire can be used with our without support from a 3- or 4-Fr directional catheter, such as a JB1 (Cook Medical). Once the stenosis is crossed with either the 0.014-inch or 0.018-inch wire, balloon dilation can be performed. Monorail type balloons, such as Sterling (Boston Scien-
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tific, Natick, MA), have low profiles and their soft nature allows for successful navigation of sharp turns in the biliary anatomy (Fig. 6). Balloons up to 10 mm in diameter can be used through the outer sheath of the Neff set. Once the balloon is positioned across the stenosis, the duct is overdilated to approximately 1.5 times its normal caliber
Figure 4 (Same patient as Figure 2.) The 0.018-inch Cope guidewire is advanced into the duct. Accessing as peripheral a duct as possible allows more distance for the guidewire to be advanced, so the junction (*) between the proximal stiff stainless steel portion of the wire and the distal floppy platinum part of the wire is within the duct. With the junction in the duct and more central than the point of needle access (arrow), subsequent dilation through the duct wall is easier and less likely to kink the guidewire.
at the level of the stenosis. After dilation, a sturdier 0.035inch or 0.038-inch wire, such as an Amplatz (Boston Scientific), can be advanced through the Neff sheath along side the 0.018-inch wire and gently manipulated across the freshly plastied stenosis. Care must be taken not to create a dissection of the bile duct wall. If there is any resistance to advancement of the larger wire across the stenosis, the larger wire is removed and the flexible 0.018inch tapered dilator portion of the Neff is reintroduced over the 0.018-inch wire, luer locked with the outer Neff sheath, and the dilator and Neff sheath are advanced as a unit across the stenosis. The Neff dilator and 0.018-inch
Figure 3 (Same patient as Figure 1.) (A) Flat detector C-arm rotational cholangiography 3D reconstruction demonstrates needle in duct (arrow), central stenoses at the confluence of 4 central ducts (circle), and long segment stenosis of the “common duct” (arrowhead) at the biliary enteric anastamosis with the roux loop. (B) Abdominal film 1 day post cholangioplasty and biliary drainage demonstrating placement of 3 different 8-Fr drainage catheters: one through the initially accessed duct, across the biliary enteric anastamosis, and into the roux loop of bowel (arrow); another through the more inferior left duct, across the biliary anatamosis, and into the roux (arrowhead); and a third crossing from the inferior left duct into the superior right duct (*). Three of the four stenoses that contributed to the central confluence stenosis (circle) were able to be successfully plastied and drained. The inferior right duct stenosis could not be crossed with a guidewire and had to be drained via a separate right sided puncture at a later date.
Figure 5 (Same patient as Figure 2.) The tip of the outer sheath of the Neff set (arrow) has been advanced over the 0.018-inch Cope wire well into the bile duct. The floppy distal portion of the guidewire has been advanced across the stenosis.
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pigtail end of the catheter is positioned across the biliaryenteric anastamosis and locked in the small bowel. Side holes span the length of the catheter and a radiopaque band marks the most proximal sidehole. This marker is pulled back under fluoroscopy to the point at which the catheter enters the biliary tree to provide the most adequate drainage. Appropriate catheter position can be confirmed with contrast injection. The catheter is sutured to the skin and securely dressed.
Recognizing and Treating Complications
Figure 6 (Same patient as Figure 2.) Monorail balloon has been advanced over a wire through the superior Neff sheath. Typical “waist” is seen in the balloon (arrow) as the stenosis is dilated. Note a separate Neff sheath and guidewire that have been percutaneously placed via a second more inferior duct.
guidewire can then be removed (or remain in place as a safety wire) and a sturdier 0.035- or 0.038-inch wire advanced through the Neff outer sheath, across the biliaryenteric anastamosis, and into small bowel. Alternatively, a 4-Fr straight Glide catheter (Terumo Medical, Somerset, NJ) can usually be advanced coaxially through the outer Neff sheath, over the 0.018-inch wire, and across the stenosis; the wire can then be upsized for the 0.035-inch Amplatz wire. Finally, the Neff outer sheath is removed over the wire and an internal/external biliary drainage catheter can be placed.
Biliary Drainage Catheter Placement For most pediatric patients, either an 8.5- or a 10.2-Fr internal/external biliary drainage catheter (Cook Medical) is placed after serial dilation with appropriately sized hydrophilic dilators. Very small infants may require a 5- or 6-Fr drainage catheter modified by punching multiple side holes. The hydrophilic dilators pass more easily across liver capsule, parenchyma, and bile ducts than standard dilators, making it much less likely that the wire will kink. Internal/external drainage catheters allow bile to drain both externally into a bag and internally into small bowel, thus preserving normal enterohepatic bile ciruculation. In cases of complete biliary obstruction in which a guidewire cannot be advanced into small bowel, external drainage is the only option. Sometimes, however, after several days of drainage and IV antibiotics, ductal inflammation and edema can resolve such that repeat cholangiography through the external drainage catheter will reveal a severe but incomplete stenosis through which a guidewire can be passed, allowing subsequent cholangioplasty and eventual placement of an internal/external drainage catheter. The
The most common potential complications from biliary percutaneous interventions include bleeding, fever and bacteremia, and sepsis; minor complications occur in approximately 11% of cases and major complications in less than 2%.1 Accessing peripheral bile ducts away from the hilum and correcting any coagulopathies can reduce the risk of bleeding,1 whereas prophylactic pre- and post-procedure antibiotics and avoiding overdistension of bile ducts during cholangiography1 can reduce the risk of sepsis. Bleeding can present as intraperitoneal hemorrhage, intraparenchymal hematoma, or hemobilia. Most bleeding is transient and self-limiting. In cases of persistent or worsening hemobilia or sudden onset hemobilia 1-2 weeks or more postprocedure, hepatic arterial injury should be suspected and hepatic arteriography and embolization should be performed.8
Clinical Follow Up Patients should remain on IV antibiotics for at least 24 hours after the procedure. If a biliary drain has been placed, it should be left open to internal and external drainage for several days while the patient recovers from the effects of biliary obstruction and/or cholangitis. When the patient has clinically improved, the drainage tube can be closed to external drainage and allowed to drain only internally for 24-48 hours before discharge. Follow up includes cholangiography at 3 months postprocedure. An IV dose of prophylactic antibiotics, such as cefazolin 30 mg/kg, should be given whenever injecting or manipulating a biliary drainage catheter. The patient is placed under general anesthesia and contrast is injected into the existing biliary drainage tube to assess whether there has been interval decompression of any previously dilated ducts and to identify any new strictures. Any previous stricture that had been dilated cannot be fully evaluated for patency if the biliary drainage catheter is stenting it open. Therefore, the biliary drainage catheter is removed over a 0.035-inch Newton guidewire (Cook Medical) and a vascular type sheath with side arm (sized appropriately to the size of the biliary drain) is placed with the tip of the sheath positioned peripheral to the previous stenosis. Through the side arm of the sheath, cholangiography is again performed to evaluate for residual stenosis. If significant re-stenosis has occurred, cholangioplasty is per-
Pediatric biliary interventions formed and a new biliary drainage catheter placed and left for an additional 3 months. If no significant stenosis is identified, a new down-sized biliary drainage catheter is often placed, thereby maintaining access across the stenosis in case delayed re-stenosis occurs. Repeat cholangiography is performed approximately 1-2 months later; if no re-stenosis has occurred, the drainage catheter is removed and the patient is followed clinically for any signs or symptoms of recurrent biliary obstruction. Biliary drainage and biliary stenosis management is a long-term commitment that usually takes several months to more than a year and may require multiple repeat cholangioplasties and biliary drainage catheter exchanges.9 Long-term stenosis recurrence following percutaneous cholangioplasty and drainage catheter placement is not uncommon; in one study, 34% of patients with isolated biliary-enteric anstamotic stricures were documented to have had a recurrence at mean 2.2 year follow up.9 Due to its minimally invasive nature and relatively low morbidity and mortality compared with open surgical alternatives, percutaneous biliary intervention should be considered the first-line treatment option in children with biliary stenosis who have had previous liver transplant, and for those nontransplant patients who cannot be treated endoscopically.
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References 1. Lorenz JM, Funaki B, Leef JA, et al: Percutaneous transhepatic cholangiography and biliary drainage in pediatric liver transplant patients. AJR Am J Roentgenol 176:761-765, 2001 2. Heffron TG, Emond JC, Whitington PF, et al: Biliary complications in pediatric liver transplantation. A comparison of reduced-size and whole grafts. Transplantation 53:391-395, 1992 3. Zajko AB, Zemel G, Skolnick ML, et al: Percutaneous transhepatic cholangiography rather than ultrasound as a screening test for postoperative biliary complications in liver transplant patients. Transplant Proc 20:678-681, 1988 (suppl 1) 4. Zemel G, Zajko AB, Skolnick ML, et al: The role of sonography and transhepatic cholangiography in the diagnosis of biliary complications after liver transplantation. AJR Am J Roentgenol 151:943-946, 1988 5. Pomerantz BJ: Biliary tract interventions. Tech Vasc Interv Radiol 12: 162-170, 2009 6. Ferrucci JT Jr, Mueller PR, Harbin WP: Percutaneous transhepatic biliary drainage: Technique, results, and applications. Radiology 135:1-13, 1980 7. Sidhu MK, Goske MJ, Coley BJ, et al: Image gently, step lightly: Increasing radiation dose awareness in pediatric interventions through an international social marketing campaign. J Vasc Interv Radiol 20:11151119, 2009 8. Winick AB, Waybill PN, Venbrux AC: Complications of percutaneous transhepatic biliary interventions. Tech Vasc Interv Radiol 4:200-206, 2001 9. Moreira AM, Carnevale FC, Tannuri U, et al: Long-term results of percutaneous bilioenteric anastomotic stricture treatment in Liver-transplanted children. Cardiovasc Interv Radiol 33:90-96, 2010