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Keywords:

  • Hepatitis C recurrence;
  • living donor liver;
  • protocol biopsy;
  • regeneration;
  • risk factors;
  • split livers

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

Concern exists that partial liver transplants (either a living donor [LD] or deceased donor [DD] in hepatitis C virus (HCV)-positive recipients may be associated with an increased risk for recurrence. From 1999 to 2003, at our institution, 51 HCV-positive recipients underwent liver transplants: 32 whole-liver (WL) transplants, 12 LD transplants and 7 DD split transplants. Donor characteristics differed in that WL donors were older, and LD livers had lower ischemic times. Recipient characteristics were similar except that mean MELD scores in LD recipients were lower (p < 0.05). With a mean follow-up of 28.3 months, 46 (90%) recipients are alive: three died from HCV recurrent liver disease and two from tumor recurrence. Based on 1-year protocol biopsies, the incidence of histologic recurrence in the three groups is as follows: WL, 81%; LD, 50% and DD split, 86% (p = 0.06 for LD versus WL). The mean grade of inflammation on the biopsy specimens was: WL, 1.31; LD, 0.33 and DD split, 1.2 (p = 0.002 for LD versus WL; p = 0.03 for LD versus DD split). Mean stage of fibrosis was: WL, 0.96; LD, 0.22 and DD split, 0.60 (p = 0.07 for LD versus WL). Liver regeneration does not seem to affect hepatitis C recurrence as much, perhaps, as factors such as DD status, donor age and cold ischemic time.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

Recurrence of liver disease induced by hepatitis C virus (HCV) in liver recipients who initially undergo a transplant for this reason is an increasingly common problem. This increase is even more important bacause HCV infection is now the most common indication for liver transplants, medical prophylaxis or treatment is inadequate and retransplants for recurrence are associated with poor results (1–6).

Recently, reports from some centers have suggested that living donor (LD) transplant recipients may be at a higher risk for recurrence of HCV; moreover, recurrence reportedly occurs earlier posttransplant in these cases and is more severe in nature (7,8). One proposed explanation is that the intense hepatocyte proliferation occurring in partial liver grafts may lead to increased viral translation and replication (9). If so, then one may expect split-liver recipients with deceased donors (DDs) to have an equal or greater likelihood of recurrence, as compared with LD recipients; to date, however, no compelling evidence suggests this. In fact, even the evidence regarding an increased likelihood of recurrence in LD recipients is not compelling, because the studies often lack good histologic data.

Hence, the objective of our study was to look at patterns of HCV recurrence in whole-liver (WL) and partial liver recipients. We attempted to assess several different markers of recurrence, including transaminase levels, viral loads, clinical course and histologic scoring of biopsy specimens.

Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

Study Groups

For our analysis, we considered all adult recipients at our institution who received a liver transplant for HCV-induced liver disease from January 1, 1999, through December 31, 2003. The 1999 start date was chosen as this was when our LD and split programs were initiated. This was also used as the start date for selecting WL recipients to ensure that there would be no selection bias based on time of transplant. We included only recipients surviving beyond the first posttransplant month with a minimum of 6 months of follow-up time. Recipients who may have been diagnosed with early recurrence of hepatitis C (by biopsy analysis), but who may have had less than 6 months of follow-up, were also included in the analysis. Indications for a transplant were (1) decompensated liver disease or (2) cirrhosis with an underlying hepatocellular cancer (HCC) that met the Milan criteria.

Surgical Technique

The surgical technique for WL transplants is well documented and was performed in a standard manner, with either preservation or replacement of the recipient's inferior vena cava. All LD transplants involved a donor right-lobe hepatectomy (segment V, VI, VII and VIII) with preservation of the middle hepatic vein in the donor and reconstruction of important segment V or VIII outflow vessels in the recipient, using reversed saphenous vein grafts. DD split-liver transplants involved in situ splitting of the liver in its midplane, generating a right lobe graft and a left lobe graft that could be used for two adult recipients (10). We attempted to keep the graft weight/recipient weight (GW/RW) ratio at greater than 0.8% for all partial (LD and DD split) transplants.

Immunosuppression

Immunosuppression (at time of transplant and maintenance) was similar in all HCV-positive recipients and did not differ by donor source or type of transplant. A 250-mg bolus dose of methylprednisolone was given intraoperatively during the anhepatic phase. Posttransplant, recipients began a triple immunosuppressive regimen consisting of tacrolimus, mycophenolate mofetil (MMF) and prednisone. In recipients with early kidney dysfunction, the tacrolimus was delayed for 1 to 2 weeks; in addition, 2 doses of an IL-2R inhibitor were used. The target levels for tacrolimus were 10–14 μg/L for the first 3 months, 8–10 μg/L for the next 3 months and 5–8 μg/L after 6 months posttransplant. Both the MMF and prednisone were withdrawn by protocol; this was the same for all three groups. The MMF was generally reduced to half dose (1000 mg/day) at 6 weeks posttransplant and then discontinued at 3 months. The prednisone dose was decreased to 5 mg/day by 3 months posttransplant and then withdrawn completely at 6 months posttransplant. All rejection episodes were biopsy-proven and treated initially with a steroid bolus.

HCV Monitoring

Pretransplant, all recipients had measurement of HCV viral load and determination of genotype. Two LD recipients were treated pretransplant with interferon and ribavirin. To evaluate and track HCV recurrence posttransplant, we extensively monitored all recipients for a number of different parameters. Biochemical laboratory values, including alanine transferase (ALT) and serum bilirubin, were measured regularly. Quantitative HCV titers were measured on a 6-month basis (and even more frequently in recipients undergoing treatment for HCV recurrence). Protocol biopsies were performed in all recipients at 6 months, 1 year and 2 years posttransplant (and, in addition, when clinically indicated by serum transaminase levels). At least one posttransplant biopsy specimen was available for all recipients included in the study. All biopsy specimens had been interpreted by a pathologist who was unaware of the history or diagnosis.

Histologic recurrence of HCV was diagnosed when biopsy results demonstrated the typical features of recurrence: lobular activity (eosinophilic bodies, lymphocytic infiltrate in the lobule and hepatocellular damage) and portal inflammation that lacked the diagnostic features of rejection. Biopsies were graded using the Batts and Ludwig grading system to quantify the degree of inflammation and fibrosis (11). Clinical HCV recurrence was defined by elevation of serum transaminase values, detectable HCV RNA and biopsy results consistent with recurrence. Recipients were treated with ribavirin and interferon therapy when biopsy results demonstrated evidence of fibrosis. Severe recurrence was defined by the presence of fibrosing cholestatic hepatitis (FCH), or by graft loss due to HCV recurrence leading to death or retransplantation. Fibrosing cholestatic hepatitis was diagnosed if clinically there was significant jaundice in the absence of an identified biliary tract problem, and if a biopsy showed ductular proliferation, portal expansion and bile stasis, with or without hepatocyte ballooning. This definition was uniform and applicable to all the recipients in the study period

Statistical Analysis

Categorical variables were analyzed using the chi-square test, and when applicable, Fisher's exact test. Continuous variables were analyzed parametrically using the Student's t-test. A p-value of ≤0.05 was considered significant.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

For the study period (January 1, 1999, through to December 31, 2003), a total of 53 recipients underwent transplant with a diagnosis of HCV liver disease. Of these two were excluded from analysis because of early death due to a surgical complication. Therefore, a total of 51 recipients were available for analysis. Of these, 32 underwent a WL transplant; 12, LD and 7, DD split. The mean length of follow-up for all three groups was 28.3 months, which was similar for each of the three groups (p = ns).

Donor and Recipient Characteristics

We observed some notable differences in donor characteristics between the three groups (Table 1). The mean donor age was significantly higher in the WL group (42.8, range = 14–61 years) than in either of the LD (37.7, range = 21–52 years, p = 0.03) or DD split groups (24.7, range = 17–34 years, p = 0.01). Cold ischemic time was significantly lower in the LD group versus the WL or DD split group (p < 0.01), as expected.

Table 1.  Donor characteristics for the three groups
  Whole liver N = 32 Living donor N = 12Deceased donor split N = 7
Median age (years)42.8 ± 16.237.7 ± 9.224.7 ± 6.5
Age range (years)14–6121–5217–34
Cold ischemic time (h)10.2 ± 4.2<17.2 ± 2.4
% Male544293
% Related58%

The most important difference with regard to recipient characteristics (Table 2) was the significantly lower model for end-stage liver disease (MELD) scores seen in the LD group (mean MELD = 17, range = 14–27), as compared with the WL group (mean MELD = 24, range 17–40, p = 0.01 versus LD recipients) or the DD split group (MELD = 23, 17–38, p = 0.03 versus LD recipients). Recipient age was similar in the three groups. So was the viral genotype of the HCV: about 90% of recipients were infected with viral genotype 1. Pretransplant viral loads were numerically lower in the LD group, but this difference was not statistically different (Table 3). Only two recipients had pretransplant treatment for HCV soon before their transplant. Both were LD transplant recipients, and both had undetectable viral titres at the time of their transplant.

Table 2.  Recipient characteristics for the three groups
  Whole liver N = 32 Living donor N = 12Deceased donor split N = 7
Median age (years)51.8 ± 15.352.3 ± 12.453.7 ± 14.8
% Male55%58%57%
Viral genotype (% Type 1)90%83%100%
Median MELD241723
MELD range17–4014–2717–38
Median follow-up (months)28.128.928.4
Table 3.  Viral loads and posttransplant liver function tests for the three recipient groups
  Whole liver N = 32 Living donor N = 12Deceased donor split N = 7
Viral load (pretransplant) (IU/mL)0.67 × 106 ±1.3 × 1060.38 × 106 ±1.1 × 1060.78 × 106 ±1.6 × 106
Viral load (6 months posttransplant) (IU/mL)1.86 × 106 ±2.5 × 1060.52 × 106 ±1.8 × 1061.98 × 106 ±1.3 × 106
Viral load (1 year posttransplant) (IU/mL)2.70 × 106 ±4.0 × 1060.63 × 106 ±1.0 × 1060.86 × 106 ±1.1 × 106
Mean serum ALT (6 months posttransplant) (IU/L)157 ± 106105 ± 45141 ± 116
Mean serum bilirubin (6 months posttransplant) (mg/dL)1.6 ± 3.50.8 ± 0.61.8 ± 3.2
Incidence acute rejection6.3%0%14.3%
Steroid-resistant acute rejection3.1%0%0%

Acute Rejection

The overall incidence of acute rejection (AR) was low in all three recipient groups. No acute rejection episodes occurred in the LD group during the follow-up period. The incidence of AR in the other two groups was also low: 9.4% in the WL group and 14.3% in the DD split groups. Only one of the rejection episodes was steroid-resistant—this was in a recipient of a WL transplant.

HCV Recurrence

Virtually all recipients had a detectable viral load when it was routinely measured at 6 and 12 months posttransplant. The mean viral load at 6 months was numerically lowest in the LD group (524000 IU/mL), as compared with the WL group (1840000 IU/mL) or the DD split group (1628000 IU/mL), but this difference was not statistically significant. ALT levels at 6 months were also lowest in the LD group (105 mg/dL), as compared with the WL group (157 mg/dL) or the DD split group (141 mg/dl), but again this difference was not statistically significant.

We compared recipients with severe recurrence versus those with minimal or no recurrence (Table 4). We also divided recurrence into the categories of histologic, treated and severe (all previously defined); see Figure 1 for the incidence at 6 months and Figure 2 for 12 months. The patterns for the two follow-up times were similar. Most (>60%) DD recipients (either WL or split) had evidence of histologic recurrence on biopsy specimens at both 6 and 12 months. However, only 35% of LD recipients had evidence of histologic recurrence on biopsy specimens at 6 months, significantly lower than the WL (70%) group (p = 0.02). None of the LD recipients have had either treated or severe recurrence. The WL and DD split groups have had similar patterns of recurrence: about 20% of recipients in each group have had treated recurrence and 10% severe recurrence by 12 months posttransplant (p = ns).

image

Figure 1. Hepatitis C recurrence at 6 months posttransplant. Note: p values shown represent comparison of that specific group versus living donor (LD) group.

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image

Figure 2. Hepatitis C recurrence at 12 months posttransplant. Note: p values shown represent comparison of that specific group versus living donor (LD) group.

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Results from the grading of biopsy specimens at 6 and 12 months posttransplant demonstrate the same clinical trend (Figure 3). The grade of inflammation and the stage of fibrosis were significantly lower in the LD group than in the WL group or the DD split group. The pattern remained the same when we compared the biopsy results at 6 and 12 months, though the actual grade and stage score for all recipients increased by 12 months (Figure 3).

Patient Survival

With a mean follow-up of 28.3 months, 46 (90%) of the recipients are alive. In the LD group, one recipient died from recurrence of hepatocellular carcinoma. In the WL group, two recipients died, both from HCV recurrence with liver failure. In the DD split group, two recipients also died: one from HCV recurrence with liver failure, and one from hepatocellular carcinoma recurrence and distant metastases.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

HCV recurrence after liver transplants is an important issue: virtually all recipients are reinfected. Furthermore, unlike with hepatitis B, no prophylaxis regimen has been shown to reliably prevent this reinfection. Two additional facts are also alarming: the progression of liver disease from HCV is significantly more rapid in transplanted (versus native) livers and retransplants for HCV-induced liver failure are associated with poor outcomes. Thus, HCV recurrence is an extremely difficult and important problem (12).

It is crucial to determine risk factors for, and patterns of, HCV recurrence posttransplant, in the hope that altering such risk factors may lead to lower rates of recurrence. Risk factors for recurrence can be divided into those related to the virus itself, to the donor and to the recipient. Viral factors include high viral loads pretransplant and certain viral genotypes (13, 14). Donor factors include increased donor age, female gender or graft steatosis (15,16). Recipient factors include AR and the amount of immunosuppression (17,18). Recently, some studies have suggested that partial liver grafts (such as with LD transplants) may be associated with an increased risk for HCV recurrence (19, 20). The exact reason is unclear, but it may be related to hepatic regeneration and rapidly proliferating hepatocytes acting as a stimulus for viral replication.

However, not all liver transplant centers have noted that association; some, in contrast, have shown essentially equivalent rates of HCV recurrence in LD and DD split recipients (21,22). In light of the risk factors for recurrence in DD split recipients, LD recipients should have lower rates of recurrence, because LD donors are generally young, LD grafts are not steatotic and LD graft cold ischemic times are minimal. Indeed, such lower rates of recurrence in LD recipients are borne out by our study: almost all parameters we monitored suggested lower rates of recurrence in our LD recipients. Viral loads and serum transaminase levels were numerically lower in the LD group. The ability to treat LD recipients with antiviral therapy pretransplant may account for the lower viral load seen in this group. Only two LD recipients were treated in this manner pretransplant, and both had undetectable viral load levels by the time of their transplant. More data with a larger number of such recipients will be required, however, to determine if this will prove to be an effective form of therapy.

The incidence of histologic recurrence was also lower and the recurrence that was seen was less severe. None of our LD recipients have required treatment with interferon, and none have had severe recurrence as defined by graft loss, FCH or stage 4 fibrosis. This was not the case for our WL recipients: by 12 months posttransplant, 22% of them were on antiviral therapy for recurrence. The difference (versus LD recipients) was statistically significant (p = 0.02).

Our biopsy findings were consistent with our clinical findings. The routine use of protocol biopsies and the availability of at least one biopsy specimen for all recipients represent two strengths of our study, and may explain, in part, the difference in our findings versus previous reports by others. Very few of those reports looked at histology, but rather used endpoints such as viral load, transaminase levels and graft survival. But some of those endpoints correlate poorly with graft damage. Histologic analysis, especially of protocol biopsies, gives clear objective evidence to the degree of graft damage.

Our biopsy findings for LD recipients demonstrated significantly lower grades of inflammation and less fibrosis in their grafts, as compared with the DD recipients (either WL or split). We noted this trend on biopsy results at 6 months and found it to be even more prominent by12 months.

The pattern of recurrence for our DD split recipients was a little more difficult to discern, because our numbers were relatively small. We would have expected them to have less likelihood for recurrence than WL recipients, since DD age was significantly lower and DD graft cold ischemic times were lower as well. However, our DD split recipients had significantly more recurrence (versus LD recipients), as measured either by treated recurrence or by the degree of inflammation and fibrosis on protocol biopsies. The rate of recurrence at 6 months was somewhat lower for DD split (versus WL) recipients, though by 12 months, the two groups had very similar clinical outcomes and histologic data. More data must be accrued with larger patient numbers. Nonetheless, based on our preliminary data, DD recipients should have outcomes very similar to those for WL recipients. Why DD split outcomes are more similar to WL outcomes (versus LD outcomes) is unclear. Cold ischemic times are significantly longer in split versus LD transplants, and this may be playing a significant role here (more so than the impact of donor age). There may be other, as yet unidentified, factors associated with the process of brain death that may be predisposing to recurrence. Lastly, it is possible that regeneration may represent a significant risk factor for recurrence when combined with other risk factors such as cold ischemia.

In conclusion, LD recipients do not seem to be at higher risk for HCV recurrence than their DD (either WL or split) counterparts. In fact, our study suggests that they may be at a lower risk for recurrence. Factors such as donor age, cold ischemic time and AR seem to play more of a role in determining risk for HCV recurrence. Liver regeneration (at least in LD recipients) does not seem to be a risk factor for HCV recurrence.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References