A joint Congress by ERA-EDTA and ISN

THE PRO AND CON OF PROTOCOL BIOPSIES

Hermann Haller, Hannover, Germany

Chair: Michael J. Mihatsch, Basel, Switzerland

Mai Ots, Tartu, Estonia

Prof Hermann Haller Division of Nephrology Department of Medicine, School of Medicine University of Hannover Hannover, Germany

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…that still despite the discussion we had in the first talk, the rate of decline in renal function is unacceptably high in transplanted patients. The real issue is to put in a kidney and then the kidney should stay the same for the rest of the life of the patient. That’s the goal.

Slide 6

So when we talk about protocol biopsy programs and pros and cons, this is the Hannover experience.

So these are large numbers, these are almost 3000 protocol biopsies by now. These are more than 1000 patients and we have these three biopsies in these patients and we are planning to do this now every year in a regular way. So we are talking about a large database and the real question is what are we going to do with that database? It’s important that we have biopsies 1-3, so we have actually series of biopsies in each patient and we can follow the graft and the patient.

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Now first the arguments against protocol biopsies and the first is it is time consuming and expensive and yes this is absolutely true.

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This is the structure of the biopsy program in Hanover; you have to have a patient information which takes time for every patient. We biopsy at 6, 12 and 24 weeks after.

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We have clinical data, we have biopsy samples, we have to do histology, this goes into banks, we have RNA analysis, we have blood samples, we have urine analysis and I think for a real biopsy program you need more than one needle and one nephrologist in a patient and sometimes a pathologist, you need all this because if you don’t have the additional data, it’s not useless but then you can’t work with it. When you put this down into man hours or woman hours and numbers it tells you that this is an expensive program. So protocol biopsy program is expensive.

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The second argument and that’s now a real and serious issue it is invasive and patients don’t like it. Now first do patients like biopsies? Yes they do.

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If you explain the biopsy program to the patients, they actually love it because they understand more about their kidney and they understand more about what’s going on and our patient adherence is more than 90%. It’s only if you explain to let’s say 20% of the patients that they will be enrolled in a biopsy study then they hate that. So this is actually an argument for the centre, yes you can do this.

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But the second argument is now more important and this is about safety, is it safe to do protocol biopsies? We do protocol biopsies in an out patient fashion because we couldn’t afford it to do it on the ward, the insurance companies and the hospitals just wouldn’t pay for it. So this was the first real serious issue, is it safe? We published this, this is in 2500 biopsies, almost 400 complications, almost 16%.

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These are when you break down protocol biopsies in indication biopsies, gross hematuria: 3.1, hospitalisation necessary in 14 cases, catheter necessary in 10, cystoscopy in 1, blood transfusions in 2 patients in the protocol biopsies.

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When you look at AV-fistula, you have lots of them but they spontaneously go away. No problem with hemodynamics and we had one thrombosis.

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So, altogether we had no complications beyond the time of observation but those of you who want to go into a protocol biopsy program, I’ve put in here 3 more slides, this is all about calculation.

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When we break our numbers down for patients, when with low dose aspirin you see we have many more complications here

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and the serious complications you are seeing, this is not good clinical practice, is when patients over night after protocol biopsy develop chest pain and were given heparin infusion by the night shift, tremendous bleeding.

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The next patient the same; clopidogrel 5 days before only was stopped and then we had serious bleeding. So this is the major problem as in all biopsies when you talk about a protocol biopsy program.

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Now why do we do protocol biopsies? What is the advantage here? We have looked at several of these themes and I’m going to discuss a couple of them but the basic information here is that we are interested in finding out and sub classifying patients to get more information on what’s going on. First, about what we’re mostly interested in as nephrologists is rejection.

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These are the numbers from 1100 protocol biopsies in almost 500 patients. This is the percentage. You see here acute rejection, silent acute rejection with no creatinine increase, borderline, with a rise in creatinine, acute tubular changes, CNI toxicity, vascular CsA toxicity, chronic changes, nephrosclerosis and nephrocalcinosis. The most important finding here is that in most of these kidneys there is something happening. There is almost nothing like a quiet kidney, there are different things going on in these kidneys, it is important to use protocol biopsies to classify and sub classify patients according to the biopsy findings.

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Now for the clinical arena this here, 15% of acute rejection and most of the discussion on protocol biopsy programs has focused around this number. Is it better to treat them early and do a protocol biopsy program? You know better than me that there were several studies borderline, significant, yes it is better to do that. I don’t think at the moment this is the real discussion. It’s not the issue to pick up the rejection earlier, a protocol biopsy program is about what’s happening here and do we understand better what’s going on and then have a basis for clinical studies.

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But yes we change our therapeutic behaviour when we have the results from the protocol biopsies that we get the same day sent to our pathology department and the people working there. Then when we have acute rejection, we are changing, we have discussions about borderline rejection, CNI toxicity etc.

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These are the therapeutic interventions in Hannover at the moment but this is all only one centre. No recommendation whatsoever because we lack at the moment all serious prospective studies on that. These can only be done on the basis of the protocol biopsy program.

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There is absolutely nothing about fibrosis. We have heard this wonderful talk using protocol biopsies before mine but the therapeutical relevance is totally unknown. Calcineurin inhibitor toxicity? Yes we can do something but here we need prospective studies, acute tubular lesions, calcification it’s all the same. Now I think and these are the issues we are concentrating on, the characterisation of infiltrates is important.

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To characterise and Michael Mengel has done here important studies, what’s going on in the kidney, in the inflamed kidney and is perhaps the word more complicated with regards to the composition of infiltrates and where these infiltrates sit.

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This is just one example, this is an infiltrate and when we stain here for CD20 positive cells, you see that a large number of these cells are CD20 positive. So with a protocol biopsy program you can address the question about the quality of the infiltrates and then draw conclusions for classification of patients.

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What about fibrosis?

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These are the same not numbers, but the same data you have seen before. This is in yellow 6 weeks, 12 weeks, 26 weeks. Acute tubular changes, tubular cyclosporine toxicity, borderline changes. This is acute rejection and here you see this dramatic increase. Between week 6 and week 26 we almost go up to 40% with chronic interstitial slide but nonetheless interstitial changes.

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Now here you can use a protocol biopsy program in order to define this more clearly and you saw an example before we have used our protocol biopsy program and you can’t do this, you can only do this retrospectively because we characterise kidneys or we looked at all the kidneys which were without any infiltrates, without any changes in the first biopsies. Then we looked at 10 of them which stayed over the next protocol biopsies clean and we compared them to 10 which developed fibrosis.

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No infiltrates and you can only do this in a large protocol biopsy program because otherwise you have to biopsy a lot of patients in order to get such well characterised biopsies. Then we did like in the last studies we looked for the gene expression and here is the same beauty of the protocol biopsy program when you have sequential biopsies because here each patient serves as his or her own control.

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So we can really look at fibrotic changes, we have no interstitial infiltrates as I’ve mentioned. We are looking in a sequential manner into these patients and these are all or part of the genes we have now and it’s a basis for future research, for clinical research.

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What about new mechanisms?

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While doing the protocol biopsies, while looking at hundreds of biopsies, we observed that in these biopsies and that have been described before but it was more of smaller interest, in quite a few of these biopsies we had interstitial calcifications. These are not vascular calcifications but interstitial calcifications. Without a protocol biopsy program, without hundreds of biopsies we would have noticed this perhaps but we wouldn’t have known that this is a major problem.

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When you look at rejection, this is also the three protocol biopsies we are doing here, 6 weeks, 3 months and 6 months, you can see here that interstitial calcifications are a serious problem. I mean there are about as many as CNI toxicity and it goes up.

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We try now to understand this process whether it’s different from fibrosis and Doctor Gwinner has analysed this. These were the first results patients with calcifications although the difference is small have less good function.

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When we look at their calcium and phosphate metabolism, we see that we have a change in parathyroid hormone and perhaps this axis is disturbed in a number of our transplanted patients and you need a protocol biopsy program to characterise this and then on the basis of that draw conclusions and start a study.

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So this is the summary slide. Pros and cons of protocol biopsies, they are well tolerated by patients. They are safe, you can look at several issues and I’ve shown you infiltrates, we have not talked about drug toxicity, we have not talked about ischemia where we have published data. We’ve talked about fibrosis and novel mechanisms such as the calcinosis.

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A protocol biopsy program at the moment is for clinical research and not for daily practice yet. So there is no discussion should we have a protocol biopsy program at our institution when we have a transplant centre? It’s only when you go into a research program. In Hannover we have a large program now on transplantation and both protocol biopsies are an important part of a clinical and/or translational research program. I think that’s the message I want you to leave with.

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Finally, not the names but just the people, this is part of the transplant group in Hannover before and after having done the protocol biopsies. Thank you very much.

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Chairman: Yes, please questions.

Question: I suppose when you ask the audience about whether or not they do biopsies, perhaps you should ask the audience whether or not they would like a biopsy. You give the impression that German patients quite like having biopsies but the ethical imperative is to be safe and 15% morbidity is not exactly being safe. If you observe patients, some of them do get very apprehensive and concerned and so I don’t think you should under ride that because of the ethical imperative. So the question I ask you, I do ask you this, is do they actually sign a consent form knowing that they’re part of a research protocol? My second question is that it hasn’t been mentioned yet today but probably the major factor for chronic allograft damage is probably non adherence to medication which has been well recognised now. Therefore have you seen that this actually has improved the adherence to medication in your program?

Prof. Haller: Yes answering the last question, no we haven’t but actually I haven’t thought of it and it’s a very good idea and we should do this. Yes they sign a protocol, yes we talk to them, perhaps I’ve given the wrong impression, it’s not that Germans love to be biopsied it’s that we explain all the issues not only the safety issue but the implications for them. We are not trying to convince them but after having explained to the patient as part of the research program ongoing at the medical school they participate.

Chairman: I’m very sorry but we have to stop here. I think this is a very important issue and there will be a lot of discussion about these protocol biopsies in the future and I hope we come to a definite conclusion also with respect to daily practice. Thank you again Doctor Haller.