ICVTS Click here for other ICVTS advertising opportunities
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Interact CardioVasc Thorac Surg 2009;8:339-343. doi:10.1510/icvts.2008.192567
© 2009 European Association of Cardio-Thoracic Surgery
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Kestutis Rucinskas
Vytautas Sirvydis
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Malickaite, R.
Right arrow Articles by Sirvydis, V.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Malickaite, R.
Right arrow Articles by Sirvydis, V.

Institutional report - Assisted circulation

Sensitisation and post-transplant course after the implantation of ventricular assist device{star}

Radvile Malickaitea,b,*, Kestutis Rucinskasa,b, Aldona Stanevicieneb, Saulius Miniauskasa,b, Vyte Maneikieneb, Gitana Zuozienea,b and Vytautas Sirvydisa,b

a Vilnius University, Santariskiu 2, LT-08661, Vilnius, Lithuania
b Vilnius University Hospital Santariskiu Klinikos, Vilnius, Lithuania

Received 31 August 2008; received in revised form 25 November 2008; accepted 26 November 2008

{star} Presented at the 22nd Annual Meeting of the European Association for Cardio-thoracic Surgery, Lisbon, Portugal, September 14–17, 2008.

*Corresponding author. Tel.: +370 5 2365186; fax: +370 5 2365242.

E-mail address: radvile.malickaite{at}santa.lt (R. Malickaite).


   Abstract
Top
 Abstract
1. Introduction
 2. Patients and methods
 3. Results
 4. Discussion
 Conference discussion
 References
 
The purpose of this study was to evaluate sensitisation, occurring because of bridging with VAD, and development of rejection episodes after transplantation in selected groups of patients using triple drug immunosuppression, without induction or desensitisation therapy. Sensitisation using standard complement dependent cytotoxicity was tested in 16 patients awaiting cardiac transplantation before VAD placement, one month post-implantation and on a six-monthly basis later on. Long-term (955±998 days) post-transplant course of six transplanted post-VAD patients was compared with 19 non-bridged recipients (follow-up time 1425±1273 days) of the same age. One-third of VAD recipients had developed anti-HLA antibodies one month post-implantation; 4/16 patients were sensitised six months after implantation. No de novo sensitisation development was revealed in VAD group post-transplantation. All sensitised patients independent of VAD placement underwent graft rejection episodes. Only 1 of 6 VAD recipient was treated because of grade 2R rejection, compared to 6/19 in the non-bridged group, P=0.63. None of the patients had failed because of early graft rejection. In conclusion, VAD devices used in our centre cause low level risk for anti-HLA antibodies development. There were no differences in survival due to immunologic reasons between VAD bridged and non-bridged patients.

Key Words: Ventricular assist devices; Transplantation; Sensitisation


   1. Introduction
Top
 Abstract
 1. Introduction
2. Patients and methods
 3. Results
 4. Discussion
 Conference discussion
 References
 
As a result of widespread ventricular assist devices (VADs) use there has been an increase of sensitised heart transplant candidates [1]. Antibodies directed against donor major histocompatibility complex antigens, constitutively expressed by allograft endothelium, predict risk for early graft failure and, possibly, poorer graft survival. The purpose of this study was to evaluate the relationship between sensitisation, occurring because of bridging with VAD prior to heart transplantation, and development of rejection episodes after transplantation in selected groups of patients using standard triple drug immunosuppression, without induction or desensitisation therapy.


   2. Patients and methods
Top
 Abstract
 1. Introduction
 2. Patients and methods
3. Results
 4. Discussion
 Conference discussion
 References
 
2.1. Patient population

From 1999 to 2007, 44 patients (34 males and 10 females) with a mean age of 40 years (range 5–71 years) were assisted with VADs in our centre, of which 22 were bridged to transplantation. Pulsatile ExCor (Berlin Heart AG, Berlin, Germany) or continuous flow ventricular assist devices Incor (Berlin Heart AG, Berlin, Germany) and HeartMate II (Thoratec Inc, Pleasanton, USA) were used. Twelve patients received a cardiac transplant at 358±283 days (range 11–1097 days).

During the same period, 29 non-bridged patients (25 males, 4 females) underwent a primary cardiac transplantation at Vilnius University hospital Santariskiu klinikos for end-stage heart failure; mean patient age 40 years (range 1.17–70 years).

2.2. Study design

The study objectives were two-fold: to evaluate sensitisation after VAD implantation, and to investigate the relationship between pre- and post-transplant sensitisation and development of rejection episodes after transplantation in a single centre using standard triple drug immunosuppression.

Sensitisation of six Berlin Heart ExCor and ten Berlin Heart Incor recipients awaiting cardiac transplantation (12 males, 4 females) was evaluated. Eligibility: patients had to be supported on VAD for a minimum of one month to allow for possible sensitisation to occur.

For the second part of the study, we compared results of long-term post-transplant follow-up. From twelve VAD patients receiving a transplant, five died shortly (1–4 days) after transplantation due to multi-organ failure, and one died at 30 days due to infection. Post-transplant course of six VAD patients was compared with 19 non-bridged cardiac recipients of the same age. Inclusion criteria: surviving at least one month after the transplantation and triple drug immunosuppression regimen without induction or desensitisation. In all cases prospective cross-matches were performed and found to be negative with donor blood obtained prior to organ recovery.

The records of heart transplant waiting list and post-transplant management were reviewed retrospectively after institutional Ethics Board approval.

2.3. Immunosuppression and rejection surveillance

All heart transplant recipients received immunosuppressive therapy, consisting of cyclosporine, steroids (wean of at six months in the absence of treated rejection episodes), and azathioprine or mycophenolate mofetil. Rejection surveillance was conducted by echocardiography and endomyocardial biopsies, performed one week after the transplantation, on a biweekly basis until the end of the hospital stay, and approximately bimonthly until the end of the first year after cardiac transplantation. Histological grades were assigned according to the Billingham criteria [2]. Cellular rejection episodes of biopsy grade 2R (3A) or greater were treated with intravenous steroid pulses, Grade 1R (2) rejections were treated at clinician's discretion.

2.4. Detection of anti-HLA antibodies, cross-matching and HLA typing

For the first part of the study, sera were obtained before VAD implantation or initial listing for transplantation, after one month and approximately six-monthly thereafter during the period of support (all patients were on home care, blood sampling was performed upon the arrival at the hospital). After the transplantation blood samples were routinely obtained at the time of endomyocardial biopsy.

Sera were screened for the presence of lymphocytotoxic anti-HLA antibodies using complement dependent cytotoxicity (CDC) assay (the same method was used for cross-matching). HLA-typed lymphocytes from 40 non-related individuals, selected to represent most of the defined HLA specificities in the population, were mixed with recipients' sera. After subsequent steps (wash and incubation with complement) presence of anti-HLA antibodies was assessed by fluorescent microscopy (staining with ethidium bromide and acridine orange). Results were expressed as the percent reactive antibody (PRA, %), which is the percent of donor lymphocytes that reacted positively with the patient serum from the total number of lymphocytes tested. A patient was considered to be sensitised, when his PRA against the cell reference panel was 10%. Positive patients' sera were additionally tested in duplicate wells in the presence and absence of 0.01 M dithiothreitol (DTT): persistent serum reactivity following DTT treatment identified IgG alloantibodies, whereas loss of reactivity identified IgM alloantibodies. Serological HLA typing was performed using commercial (BIOTEST, Germany and One Lambda, USA) reagents. Sequence-specific primer (SSP) amplification (BIOTEST, Germany) was performed in cases of non-conclusive results.

2.5. Statistical methods

Continuous values were summarized by using the mean±1 S.D. and analysed with unpaired Student's t-test. Categorical variables were analysed by the Fisher's exact test. A P<0.05 was considered as statistically significant.


   3. Results
Top
 Abstract
 1. Introduction
 2. Patients and methods
 3. Results
4. Discussion
 Conference discussion
 References
 
3.1. Humoral sensitisation in VAD recipients

Fifteen patients had no detectable antibodies before VAD implantation, one patient was presensitised (>30% PRA, IgM isotype), Table 1.


View this table:
[in this window]
[in a new window]

  		Table 1 Demographic characteristics of the VAD group

 
One month after device implantation, five patients (3 men and 2 women) had newly developed anti-HLA antibodies of IgM isotype (PRA 55±24%). These anti-HLA antibodies were transient; six months after device implantation only four patients were still producing antibodies, in two of them immunoglobulin isotype had changed to IgG (PRA >75%); neither of these patients was included in the next part of the study while one of them died on support, the other was transplanted using induction therapy. Ten out of 16 (62.5%) VAD recipients with long-term support had not produced anti-HLA antibodies despite the usage of blood products.

3.2. One-year follow-up after the transplantation

Post-transplant course of six VAD patients was compared with 19 non-bridged recipients of the same age. The mean post-transplant follow-up time of VAD group was 955± 998 days (range 271–2945 days), and for the non-bridged group was 1425±1273 days (range 63–3987 days).

Donor to recipient mismatches for sex, blood group typing, cytomegalovirus serology, as well as cardiac diagnosis and ischemic time were comparable between groups (Table 2).


View this table:
[in this window]
[in a new window]

  		Table 2 Comparative statistics between VAD and non-bridged groups

 
Four out of six VAD group patients were presensitised during VAD implantation, peak PRA 43±24%, pre-transplant PRA 24±11% (all IgM isotype). Previous cardiac surgical operations had been performed in three non-bridged patients; three patients had pre-transplant sensitisation (PRA 10%, IgM isotype).

Post-transplant de novo development of anti-HLA antibodies was identified in four previously non-sensitized non-bridged group patients; in two cases sensitisation on 78 and 582 post-transplant days was clearly related to systemic infections (CMV and fungal) and followed by cellular rejection episodes. In VAD group no de novo sensitisation was revealed; however, in two previously sensitised patients short-time PRA rise related to rejection episodes was observed.

All sensitised patients independent of VAD placement underwent moderate, ISHLT grade 1R (2) or 2R (3A) cellular graft rejection. Nevertheless, no patient experienced serious haemodynamic compromise or compromise of systolic function by echocardiography related to any of these episodes and none of the patients failed because of early graft rejection.

During the first post-transplant year, early biopsy-proven moderate cellular rejection episodes occurred in 5/6 (83%) VAD and 8/19 (42%) non-bridged patients (P=0.16). Only one (17%) sensitised VAD recipient was treated because of grade 2R rejection, compared to six (26%) in non-bridged group, P=0.63. Sixteen moderate rejection episodes during the first post-transplant year occurred in non-bridged group (0.8 episode per patient), compared with seven rejection episodes in VAD group patients (1.2 episode per patient).

As is shown in Fig. 1, the majority of VAD group patients experienced moderate rejection episodes during the first post-transplant year. A trend towards earlier time to first rejection was revealed in the presensitised patients group: 49±45 days vs. 97±125 days in non-sensitised patients (P=0.34). All the patients but one survived the first post-transplant year. At two years, 33.3% of VAD patients and 36.8% non-bridged patients had experienced at least one episode of ≥2R rejection. On long-term follow-up almost all late rejecters had significant recent infections, e.g. in most cases late rejection was a consequence of immune response to an acute illness.


Figure 1
View larger version (16K):
[in this window]
[in a new window]

  		Fig. 1. Early biopsy proven cellular rejection episodes.

 

   4. Discussion
Top
 Abstract
 1. Introduction
 2. Patients and methods
 3. Results
 4. Discussion
Conference discussion
 References
 
The role of anti-HLA sensitisation after VAD implantation and in cardiac transplantation is still controversial. Some groups reported [3], that their appearance, especially in case of positive cross match, has been associated with poor outcomes after cardiac transplantation, whereas others consider them to be of no or negligible clinical significance [4, 5].

Our data were coincident with the report of Joyce et al. [5], showing the rate of sensitisation in LVAD-supported patients lies at the lower end of previously estimated spectrum – 40 to 66% sensitised patients [4, 6]. In our group of patients after the implantation of Berlin Heart devices (ExCor and Incor) with smooth silicon and titanium surfaces not allowing to the pseudo-intima formation, only 2 of 16 (12%) patients had developed IgG anti-HLA antibodies. Recent data show that the texture of the inner surface, not allowing the pseudo-intima formation could have an impact on lowering sensitisation rates post-VAD implantation [7].

A survey of adult heart transplant programmes [8] showed a variety of definitions and approaches used to sensitisation among centres, including reactivity with T and B-lymphocytes, only T- or only B-lymphocytes. The CDC assay still is the most commonly applied method for PRA determination, but several more sensitive techniques using solid-phase assays with purified HLA antigens, including multiplex technologies (Luminex), flow cytometry, enzyme-linked immunoassays (ELISA) are also practiced. After the re-evalution of our samples by ELISA (BIOTEST, Germany), IgG anti-HLA antibodies were found in the same two samples, defined as IgG positive by CDC.

Isotype of anti-HLA antibodies is not always discriminated, or at least not always reported to registries, which make the interpretation of published data extremely difficult. Our study has indicated that de novo anti-HLA antibodies developed in less than one-third of VAD bridged patients. Newly developed anti-HLA antibodies in the majority of cases were of IgM isotype, the later reduction at sensitisation levels has been observed. Massad et al. also reported that sensitisation after VAD implantation detected in 66% of the LVAD recipients decreased up to 22% at the time of transplantation [6].

No prospective, multicentre studies have been conducted to address the significance of various immunologic criteria, the impact of sensitisation and its management on post-transplant course, but the two biggest retrospective cohort studies, UNOS [9] and CTS (www.ctstransplant.org) show that PRA is still a significant risk factor in the outcomes of heart transplantation.

However, after analysing data from our programme, we identified only modest impact of sensitisation on the overall post-transplantation course. Despite the fact that all sensitised patients irrespectively of VAD placement underwent moderate cellular graft rejection, none of them experienced compromise of systolic function detected by echocardiography. As well, none of the patients of any group had failed because of early graft rejection.

Recent studies indicate that most of VAD patients were fit enough to tolerate immunosuppressive interventions (plasmapheresis, intraoperative plasma exchange cyclophosphamide, etc.) [10], whereas others reported that the application of aggressive immunosuppressive protocols for patients awaiting transplantation has been shown to be associated with an increased risk of immunosuppression associated complications, especially in association with a greater risk of infections associated with VAD use [6, 11]. Most probably in every single case risk and benefit balance should be estimated.

Our study demonstrates that early post-transplantation course of VAD bridged patients without desensitisation treatment or induction was similar to that of non-bridged control; unfortunately the group of sensitised patients was much too small, and follow-up time of three years was too short in order to evaluate the incidence of allograft vasculopathy. Besides, results of the present study should be interpreted with caution because of its retrospective nature.

In conclusion, physical properties of VAD biomaterials used in our centre causes low level risk for anti-HLA antibodies development. In spite of the fact that the majority of VAD group patients experienced moderate rejection episodes during the first post-transplant year, there were no differences in survival due to immunologic reasons between VAD bridged and non-bridged patients.


   Conference discussion
Top
 Abstract
 1. Introduction
 2. Patients and methods
 3. Results
 4. Discussion
 Conference discussion
References
 
Dr. G. Laufer (Innsbruck, Austria): You address a very important clinical problem after heart transplantation, and in transplantation medicine in general it has been shown for years in kidney transplantation that humoral sensitization against HLA-antigens expressed by panel reactive antibodies is associated with a lower graft survival.

In heart transplantation and in the particular setting of a previous assist device implantation, the situation is by far not so clear. The reason is that there are a relatively small number of patients analyzed in all the studies, different methods used to detect antibodies at different intervals after VAD implantation. There are many different types of devices used with different surfaces, and that might lead to different levels of sensitization. And finally, an increasing spectrum of immunosuppressive drugs is in use in these patients especially over the last years.

So I think your present work is also limited by these considerations, especially the number of patients is very small finally coming up with only 50% of patients surviving after the transplantation having a previous successful VAD implantation.

So I have three questions for you. First, what was the cause of death in the 50% of patients that died early after transplantation? Was early graft failure by immunological causes ruled out?

Second question, did you try to correlate the degree of sensitization to the type of VAD used? However, you have only 16 patients, which is, by the way, not meaningful, but it would be interesting to know the numbers anyhow.

And thirdly, the analysis concerned only acute cellular rejection and thus the T-cell response. Sensitization, however, was measured by PRA levels as expressing the humoral response. Could you give us the information about humoral rejection and chronic rejection in your patients?

Dr. Malickaite: I think to your first question, actually, there were no immunologic deaths in the group which was ruled out. And some of the patients were ruled out because induction therapy was used, and it was not inclusion criteria into our study.

I'm sorry, what was the next point?

Dr. Laufer: Humoral rejection.

Dr. Malickaite: We discussed with our pathologists several times, and actually we didn't see any humoral rejection with the exception of two cases. In all cases, whereby our patients, clear cellular rejection was seen or no rejection at all.

Dr. Laufer: Okay. And the second question was about different levels of sensitization in relation to the VADs used.

Dr. Malickaite: We are trying to study, but I was not presenting it because we didn't see a very big difference. Actually, with pulsatile devices, we saw a little bit more apoptotic cells and a little bit more sensitization, but it was not significant, for sure not significant.


   References
Top
 Abstract
 1. Introduction
 2. Patients and methods
 3. Results
 4. Discussion
 Conference discussion
 References
 

  1. Pollock-BarZiv SM, den Hollander N, Ngang B-Y, Kantor P, McMcrindle B, Dipchand AI. Pediatric heart transplantation in human leukocyte antigen-sensitized patients: evolving management and assessment of intermediate-term outcomes in high-risk population. Circulation 2007;116(Suppl_I):I-172–I-178.[Medline]
  2. Stewart S, Winters GL, Fishbein MC, Tazelaar HD, Koashigawa J, Abrams J, Anderson CB, Angelini A, Berry GJ, Burke MM, Demetris AJ, Hammond E, Itescu S, Marboe Ch C, Mc Manus B, Reed EF, Reinsmoen NL, Rodriguez ER, Rose AG, Rose M, Suciu-Focia N, Zeevi A, Billingham ME. Revision of the 1990 working formulation for the standardization of nomenclature in the diagnosis of heart rejection. J Heart Lung Transplant 2005;24:1700–1720.[CrossRef][Medline]
  3. Mahle WT, Naftel DC, Rusconi P, Edens RE, Shaddy RE, Group PHTS. Panel-reactive antibody cross-reactivity and outcomes in the Pediatric Heart Transplant Study Group. J Heart Lung Transplant 2004;23(Suppl 2):S167.
  4. John R, Lietz K, Schuster M, Naka Y, Vivek R, Mancini DM, Rose EA, Smith CR, Oz MC, Edwards NM, Itescu S. Immunologic sensitisation in recipients of left ventricular assist devices. J Thorac Cardiovasc Surg 2003;125:578–591.[Abstract/Free Full Text]
  5. Joyce DL, Southard RE, Torre-Amione G, Noon GP, Land GA, Loebe M. Impact of left ventricular assist device (LVAD)-mediated humoral sensitisation on post-transplant outcomes. J Heart Lung Transplant 2005;24:2054–2059.[CrossRef][Medline]
  6. Massad MG, Cook DJ, Stiven K, Schmitt SK, Smedira NG, McCarthy JF, Vargo RL, McCarthy PM. Factors influencing HLA sensitisation in implantable LVAD recipients. Ann Thorac Surg 1997;64:1120–1125.[Abstract/Free Full Text]
  7. Kirsch L, Timmermans T, Van Caenegem O, Gurne O, Noirhomme P, Jacquet L-M, Latinne D, Poncelet AJ. Allosensitization in bridge to trasplant Novacor left ventricular assist device patients: analysis of long-term outcomes with regard to acute rejection and chronic allograft vasculopathy. Eur J Cardiothorac Surg 2008;34:26874.
  8. Betkowski AS, Graff R, Chen JJ, Hauptman PJ. Panel-reactive antibody screening practises prior to heart transplantation. J Heart Lung Transplant 2002;21:644–650.[CrossRef][Medline]
  9. Nwakanma LU, Williams JA, Weis ES, Russell SD, Baumgartner WA, Conte JV. Influence of pretransplant panel-reactive antibody on outcomes in 8,160 heart transplant recipients in recent era. Ann Thorac Surg 2007;84:1556–1563.[Abstract/Free Full Text]
  10. Gonzalez-Strawinski GV, Cook DJ, Smedira NG, Navia JL, Taylor DO, Yamani MH, Hoercher K, Starling RC, Banbury MK. Attrition from heart transplantat waiting list for patients on ventricular assist devices is not affected by desensitisation strategies. Transplantation Proceedings 2007;39:1571–1572.[CrossRef][Medline]
  11. Gonzalez-Strawinski GV, Cook DJ, Chang ASY, Banbury MK, Navia JL, Hoercher K, Lober C, Atik FA, Taylor DO, Yamani MH, Young JB, Starling RC, Smedira NG. Ventricular assist devices and aggressive immunosuppression: looking beyond overall survival. J Heart Lung Transplant 2006;25:613–618.[CrossRef][Medline]




This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Kestutis Rucinskas
Vytautas Sirvydis
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Malickaite, R.
Right arrow Articles by Sirvydis, V.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Malickaite, R.
Right arrow Articles by Sirvydis, V.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ANN THORAC SURG ASIAN CARDIOVASC THORAC ANN EUR J CARDIOTHORAC SURG
J THORAC CARDIOVASC SURG ICVTS ALL CTSNet JOURNALS