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Urgent revascularization for hepatic artery thrombosis: Maybe good for the few, definitely good for the many

2010; Lippincott Williams & Wilkins; Volume: 16; Issue: 7 Linguagem: Inglês

10.1002/lt.22115

1527-6473

Heung Bae Kim,

Congenital Anomalies and Fetal Surgery

Liver TransplantationVolume 16, Issue 7 p. 812-814 EditorialFree Access Urgent revascularization for hepatic artery thrombosis: Maybe good for the few, definitely good for the many† Heung Bae Kim, Corresponding Author Heung Bae Kim heung.kim@childrens.harvard.edu Director, Pediatric Transplant Center, Children's Hospital Boston, Boston, MA Telephone: 617-355-8544; FAX: 617-730-0475Pediatric Transplant Center, Children's Hospital Boston, 300 Longwood Avenue, Fegan 3, Boston, MA 02115Search for more papers by this author Heung Bae Kim, Corresponding Author Heung Bae Kim heung.kim@childrens.harvard.edu Director, Pediatric Transplant Center, Children's Hospital Boston, Boston, MA Telephone: 617-355-8544; FAX: 617-730-0475Pediatric Transplant Center, Children's Hospital Boston, 300 Longwood Avenue, Fegan 3, Boston, MA 02115Search for more papers by this author First published: 25 June 2010 https://doi.org/10.1002/lt.22115Citations: 5 † See Article on Page 847 AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Early hepatic artery thrombosis (HAT) is one of the most dreaded complications after pediatric liver transplantation. The clinical course following early HAT can be quite variable, ranging from a clinically silent event to acute hepatic necrosis, liver failure, and death if left untreated. In pediatric patients, in the early days of liver transplantation, the classic teaching was that early HAT required immediate retransplantation for survival.1 However, more recent evidence suggests that there may be a subset of patients who might benefit from an attempt at revascularization and graft salvage following early HAT.2, 3 Even in cases where rearterialization fails or is not possible, both children4 and adults5 have been shown to develop hepatic artery collaterals if the graft is able to survive long enough on portal vein flow alone. However, based on the small number of reported cases, it is difficult to state with certainty that children have a greater potential for collateral formation than adults. Although many studies have shown that early HAT is more common in children than adults, the outcomes following early HAT are more difficult to define due to variability in definitions and management. In the recent literature review by Bekker et al.,6, the overall incidence of early HAT (most often defined as HAT within 30 days of transplant) was significantly higher in children (8.3%) than adults (2.9%). Attempted revascularization was more common in adults (75%) than children (54.1%), although the success rate was similar in both groups (approximately 56% overall). Retransplantation was the treatment of choice in 50% of adults and 61.9% of children, with an overall mortality of 55.1% when this approach was used and no significant difference between adults and children. The overall mortality of early HAT regardless of approach was significantly higher in adults (34.3%) than in children (25%). The mortality risk increases in situations where immediate retransplantation is not available, such as in countries where living donation is the primary source of donor organs. These poor overall results following early HAT have resulted in renewed efforts to improve early detection of HAT, which should result in increased graft salvage rates and improved patient survival. In the article by Warnaar et al.,7 immediate surgical thrombectomy following HAT in pediatric liver transplant recipients led to long-term allograft survival in 38% of patients. This large, single-center experience with this approach supports other recent reports of graft salvage rates ranging from 10% to 55% following attempted revascularization in children and adults with early HAT.6, 8 However, because 16 (50%) of the children with early HAT reported in this article underwent immediate retransplantation, the overall graft salvage rate was actually only 19% (6 of 32 patients) which is more consistent with the 10% long-term graft salvage rate reported by Duffy et al.8 Despite this low overall graft salvage rate, the 5-year patient survival of 67% following attempted revascularization compared favorably to the 71% 5-year patient survival following immediate retransplantation. Although these data might appear to support revascularization following early HAT in children, one must remember that 50% of the patients in this series were deemed too sick to undergo the procedure and 2 of them died before retransplantation could be performed. So, why should a surgeon take the risk of delaying retransplantation for a child with HAT by attempting revascularization when immediate retransplantation yields similar results? Abbreviations: HAT, hepatic artery thrombosis; MELD, Model for End-Stage Liver Disease; UNOS, United Network for Organ Sharing. On August 14, 2005, the United Network for Organ Sharing (UNOS) liver allocation policy definitions for Status 1 were revised to assure that patients who were listed as a Status 1 were truly in need of urgent liver transplantation. Two categories of Status 1 were created: Status 1A replaced the former Status 1 for adults and children, and the new category of Status 1B was created specifically for children with decompensated chronic liver disease and other diagnoses requiring urgent transplantation. For adult patients with HAT, there was a significant increase in the stringency of the criteria for listing as a Status 1A. The prior policy stated that an adult or child with HAT within 7 days of transplantation could be listed as a Status 1 without regard for physiologic parameters suggesting significant liver dysfunction. According to the revised UNOS liver allocation policy, early HAT may make a patient eligible for retransplantation at Status 1A if they meet certain criteria, but these criteria differ between children and adults. For pediatric candidates, hepatic artery thrombosis diagnosed in a transplanted liver within 14 days of implantation (UNOS Policy 3.6.4.2) qualifies a patient to be listed as a Status 1A. This pediatric criteria is less stringent than the prior limit of 7 days and has no required physiologic criteria. However, the criteria for adult patients to be listed as a Status 1A recipient are more stringent and include (UNOS Policy 3.6.4.1): 1 HAT in a transplanted liver within 7 days of implantation 2 Evidence of severe liver injury as defined as: a Aspartate aminotransferase ≥ 3000 and one or both of the following: i International normalized ratio ≥ 2.5 ii Acidosis, defined as having an arterial pH ≤ 7.30 or venous pH of 7.25 and/or lactate ≥ 4 mM/L b Anhepatic candidate 3 Candidates with HAT in a transplanted liver within 14 days of implantation not meeting the above criteria will be listed at a Model for End-Stage Liver Disease (MELD) of 40. The intent of this policy change for adults was to select out patients who truly met the spirit of Status 1A, ie, those who had <7 days to live without retransplantation. For the more stable patients and those who might have a later presentation of HAT within 14 days of transplant, retransplantation is still an option, but they should be listed with a MELD score of 40. A transplant center still retains the option of listing any candidate as a Status 1A through the exception process, even when they do not meet criteria. However, the system for review of nonstandard Status 1A exceptions has also changed. Prior to the implementation of the new policy for Status 1A in 2005, these exception cases were reviewed by the individual Regional Review Boards and, if deemed inappropriate, were sent on to the UNOS Liver-Intestine Committee for review. Since August of 2005, ALL exception Status 1A and 1B cases are retrospectively reviewed by the Status 1A/1B Subcommittee of the Liver-Intestine Committee. If a center is found to have multiple inappropriate listings, they are referred to the Membership and Professional Standards Committee for further evaluation. The result of these changes in allocation policy seems to have resulted in fewer patients who underwent transplantation at Status 1A than the prior Status 1. In 2004, the year before the policy changes, there were 535 patients who underwent transplantation at Status 1, which accounted for 9.1% of all deceased donor liver transplants. By 2007, the number of Status 1A transplants had decreased to 368, which represented 5.9% of all deceased donor transplants that year. Even if one includes the 66 (1.1%) Status 1B patients who underwent transplantation in 2007, the result of the new policies is that fewer patients underwent transplantation at the highest priority status. Because organ allocation within Status 1A or Status 1B is based on waiting time, this shift of patients undergoing transplantation based on MELD and PELD (pediatric MELD) scores results in an increase in patients undergoing transplantation based on severity of illness. Thus, while individual patient selection should remain the most important factor in the decision to revascularize or retransplant following HAT, we must also put this decision into the larger context of organ allocation policy and the organ shortage. If approximately 20% of grafts can be salvaged by revascularization without a significant penalty for attempting the procedure, then the liver transplant community should endorse this approach in the appropriate clinical setting to the possible benefit of the individual patient and the definite benefit to the liver transplant community as a whole. REFERENCES 1 Tzakis AG, Gordon RD, Shaw BW Jr, Iwatsuki S, Starzl TE. Clinical presentation of hepatic artery thrombosis after liver transplantation in the cyclosporine era. Transplantation 1985; 40: 667- 671. CrossrefCASPubMedWeb of Science®Google Scholar 2 Garcia-Gallont R, Bar-Nathan N, Shaharabani E, Yussim A, Shapira R, Zahavi I, et al. Hepatic artery thrombosis in pediatric liver transplantation: graft salvage after thrombectomy. Pediatr Transplant 1999; 3: 74- 78. Wiley Online LibraryCASPubMedGoogle Scholar 3 Nishida S, Kato T, Levi D, Naveen M, Thierry B, Vianna R, et al. Effect of protocol Doppler ultrasonography and urgent revascularization on early hepatic artery thrombosis after pediatric liver transplantation. Arch Surg 2002; 137: 1279- 1283. CrossrefPubMedWeb of Science®Google Scholar 4 Hall TR, McDiarmid SV, Grant EG, Boechat MI, Busuttil RW. False-negative duplex Doppler studies in children with hepatic artery thrombosis after liver transplantation. AJR Am J Roentgenol 1990; 154: 573- 575. CrossrefCASPubMedWeb of Science®Google Scholar 5 Horrow MM, Blumenthal BM, Reich DJ, Manzarbeitia C. Sonographic diagnosis and outcome of hepatic artery thrombosis after orthotopic liver transplantation in adults. AJR Am J Roentgenol 2007; 189: 346- 351. CrossrefPubMedWeb of Science®Google Scholar 6 Bekker J, Ploem S, de Jong KP. Early hepatic artery thrombosis after liver transplantation: a systematic review of the incidence, outcome and risk factors. Am J Transplant 2009; 9: 746- 757. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar 7 Warnaar N, Polak WG, de Jong KP, de Boer MT, Verkade HJ, Sieders E, et al. Long-term results of urgent revascularization for hepatic artery thrombosis after pediatric liver transplantation. Liver Transpl 2010; 16: 847- 855. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar 8 Duffy JP, Hong JC, Farmer DG, Ghobrial RM, Yersiz H, Hiatt JR, et al. Vascular complications of orthotopic liver transplantation: experience in more than 4,200 patients. J Am Coll Surg 2009; 208: 896- 903; discussion, 903-905. CrossrefPubMedWeb of Science®Google Scholar Citing Literature Volume16, Issue7July 2010Pages 812-814 ReferencesRelatedInformation