Abstract
The coronary Bypass operation at the beating heart ("off-pump surgery") is a new procedure which promises advantages in comparison to the established procedure with uses a heart-lung machine ("on-pump-surgery").
In the presented HTA report cardiac surgery the question is investigated, whether there are advantages of the off-pump-surgery in comparison to the on-pump-surgery regarding medical effectiveness, safety as well as cost effectiveness.
At the beginning a systematic literature search was done, the articles were classified according to the hierarchy of evidence.
There are partly considerable different groups of patients included in the different studies as well as quite different outcome parameters. The quality of the studies in detail, where at least two groups are compared was generally very good.
The studies results show more or less equivalent results in the comparison of the two operation techniques. Concluding neither a clinical superiority nor an inferiority on the basis of the present available studies can therefore be proven (off-pump Coronary Artery Bypass; OPCAB) or the conventional bypass operation with use of the heart-lung machine (Coronary Artery Bypass Graft; CABG can).
The diagnostic criteria of a patient who is allocated to the one or other operating technique are important. Due to technical reasons the majority of patients with the necessity of a bypass operation con only be treated by CABG, (on-pump-surgery). These criteria for the allocation of operation techniques should be the important components of optimization considerations.
Abstract
Die Bypassoperation am schlagenden Herzen (Off-Pump-Surgery) ist ein „neueres“ Verfahren, das Vorteile gegenüber der etablierten Vorgehensweise mit Einsatz einer Herz-Lungen-Maschine (HLM; On-Pump-Surgery) verspricht.
In vorliegendem HTA-Bericht wird daher der Frage nachgegangen, welche Vorteile hinsichtlich der medizinischen Wirksamkeit und Sicherheit sowie der Kosteneffektivität die Operation am schlagenden Herzen unter Verwendung einer speziellen Technik (Off-Pump-Surgery) im Vergleich zur konventionellen Herzchirurgie mit Verwendung der HLM (On-Pump-Surgery) hat.
Zu Beginn wurde eine systematische Literaturrecherche vorgenommen, die gefundenen wissenschaftlichen Artikel klassifiziert, im Sinn der Evidenzhierarchie bewertet und entsprechend ihrer Aussagekraft in die Gesamtaussage einbaut.
Zunächst fiel auf, dass sich die Kollektive zwischen den Studien teils beträchtlich unterscheiden, was den Risikostatus und die verwendeten Outcomeparameter angeht. Innerhalb der Studien ist je nach Evidenzgrad von einer unterschiedlich guten Vergleichbarkeit der Kollektive auszugehen.
Die Studienergebnisse zeigen in der Regel mehr oder weniger gleichwertige Resultate beim Vergleich der beiden Operationstechniken. Als Schlussfolgerung kann daher festgehalten werden, dass auf der Basis der gegenwärtig zur Verfügung stehenden Studien weder eine klinische Überlegen- noch eine Unterlegenheit der Bypassoperation am schlagenden Herzen (Off Pump Coronary Artery Bypass; OPCAB) bzw. der konventionellen Bypassoperation mit Verwendung der HLM (Coronary Artery Bypass Graft; CABG) belegt werden kann.
Eine große Bedeutung haben die differenzialdiagnostischen Kriterien, nach denen ein Patient als potenzieller Patient für einen „Off-Pump“-Eingriff betrachtet wird. Festzuhalten ist, dass ein Großteil der Herzoperationen, bei denen ein Bypass gelegt werden muss, aus operationstechnischen Gründen nicht mittels der „Off-Pump“-Technologie durchgeführt werden kann. Diese Kriterien unterscheiden sich geringfügig und sollten Bestandteil von operationstechnischen Optimierungsüberlegungen sein.
Executive Summary
1. Introduction
The Bypass operation at the beating heart “off-pump-surgery“ is a procedure which promises advantages over the established procedure with use of a heart-lung machine ("on-pumping-surgery"). These techniques are for about 18 years in the routine in use but only in the last few years there is an intensified research activity.
Altogether 97,870 heart surgical operations in 80 centres were carried out in the year 2000 in Germany. 4886 (5.0%) were carried out minimal invasively, 4095 (4.2%) were done by off-pump-technique (OPCAB) - the operation was carried out at the beating heart without use of the extracorporeal circulation (EKZ) or heart-lung machine (HLM).
With OPCAB-technique, the disadvantages of the HLM - a deterioration of the kidneys and respiratory function on the one hand and possible cerebrovasculary incidents on the other hand - should be avoidable. Both the myocardial damage and the inflammatory reactions to the heart operation or to the extracorporeal circulation appear to a presumably lower extent. The duration of the artificial respiration and the length of hospital stay shall be reduced significantly. Therefore OPCAB is interesting.
2. Question
The following questions arise in particular:
Is the bypass operation with the beating heart a medically effective and sure procedure and comparable to the technique of the operation with a heart-lung machine (CABG)?
Which cost efficiency does the Bypass operation with the beating heart gain in comparison with the operation with the use of a heart-lung machine?
Are there ethical doubts against use of the bypass operation with the beating heart?
Which recommendations for the use of the Bypass operation with the beating heart can be given for the German health system?
Which advantages does the conventional cardiac surgery (CABG) have in comparison to the off-pump-surgery regarding medical effectiveness, safety as well as cost effectiveness?
3. Methodology
To answer these questions statement a systematic literature research was carried out. The identified publications were classified according to the hierarchy of evidence and synthesized to general conclusions.
4. Results
The following answers can be given very briefly on the formulated questions:
Is the bypass operation with the beating heart a medically effective and sure procedure and comparable to the technique of the operation with a heart-lung machine (CABG)?
The Bypass operation at the beating heart is a medically effective and safe procedure, and for those patients at whom this technique can be chosen comparable to the conventional bypasses surgery with the use of the heart-lung-machine regarding its side effects and complications. At present, there is no scientific study with such a generalizibility which would favour the one or other method.
Which cost efficiency does the Bypass operation with the beating heart gain in comparison with the operation with the help of a heart-lung machine?
Both the total costs (not however part cost blocks) and the medical effectiveness of this operation technique of the operation at the beating heart are comparable after a present studies. There is no study which convincingly contradicts that the general hypothesis that the costs are equivalent. You can assume equal relations of cost/efficiency of the two techniques.
Are there ethical doubts against use of the Bypass operation with the beating heart?
There are no publications which have expressed ethical doubts concerning the technique of surgery with the beating heart. The discussion could most likely be measured in terms of complications. On the other hand this operation technique is not appropriate for the large part of the patients which must undergo a bypass operation for technical reasons.
Which recommendations for the use of the Bypass operation with the beating heart can be given for the German health system?
The application of OPCAB requires a permanent occupation of surgeons with this method. It could happen that at smaller heart centres the number of patients which could be treated with this special technique gets very small, also due to the fact that there are more different surgeons.
This minimum number is not fixed, but concerning quality assurance there is no doubt, that such a minimum exists. A recommendation could therefore be, that only a certain (small) number of surgeons should deal with this operation technique within a cardiac surgery centre or that small heart centres should cooperate with other centres possibly in questions of the applicability of this technique.
Which advantages does the conventional cardiac surgery (CABG) have in comparison to the off-pump-surgery regarding medical effectiveness, safety as well as cost effectiveness?
The broader applicability and greater universality of the on-pump-technique method can be regarded as advantages of the conventional cardiac surgery with use of the heart-lung machine. The conventional operation method also would be possible for all patients who need a bypass operation; this is reversely, however, in no way valid. About 10% of the patients which have to have a bypass operation would be suitable for the off-pump-technique. If there are uncertainties concerning the technique, the conventional method should be preferred to avoid a possible intraoperative chance of the operation technique.
5. Discussion
The method of off-pump-surgery at the beating heart has got more importance in the last few years. The question arose, whether it can be considered as superior in comparison to the connectional method CABG with the on-pump-technique.
It is that a large part of the heart operations at which a Bypass must be put cannot be carried out by off-pump-techniques due to technical reasons. These criteria for the technical applicability are different insignificantly and should be component of operation technical optimization considerations. The criterions are, however, relatively clear to the surgeons.
A classification exists with regard to the risk state which orientates itself due to enzymatic, hemodynamic and also other physical or biological criterions.
From the assumption, that the patients got the technique which is possible and applicable, there are subgroups, in which these two techniques can be compared.
There are partly considerable different groups of patients included in the different studies as well as quite different outcome parameters. The quality of the studies in detail, where at least two groups are compared was generally very good.
The outcome parameters vary also considerably within metaanalyses as well as between different randomized controlled trials.
The consideration is carried out from the perspective of the questions whether the OPCAB technique is a safe technique, and whether there are differences in economic respect.
As a rule, the studies results show more or less equivalent results in the comparison of the two operation techniques. If you assume a justified increased learning curve meanwhile that learning the operation technique is sufficiently possible, then the practically techniques are safe from the point of view of the innovation.
The central hypotheses, which states that under the assumption of a principal comparability of these two techniques, there is no difference between the outcomes, can not be refused.
6. Conclusion
The method of the "off-pump-surgery“ can be regarded as a safe method to provide the operation to those patients for which this type of heart surgically is possible from a technical point of view. No convincing publications could be found that one technique is superior to the other one.
The differential diagnostic criterions after which a patient is regarded as a potential patient for an „off-pump-surgery“ operation have a great importance. Here the individual heart centres seem to distinguish with regard to their experience, the drive of innovation or the risk to be willing to take.
An essential meaning also is the fact that the "off-pump-surgery“ is and will be rarer due to operation technical reasons. The question of the technical abilities of the surgeon has therefore to be mentioned since operations carried out rarely can lead to quality losses relatively quickly.
It has to be taken from scientific comments or the process of discussion that for a detailed judgement of the two procedures more and more also perioperative complications have to be drawn in consideration. These parameters are primarily fundamentally, however not so much for operation technical reasons for another optimization of the procedure from the perspective of the patient or the health supply system.
Concluding heart beating bypass operation is neither inferior nor superior in comparison to the conventional operating technique using the heart-lung machine (on-pump) on the basis of the systematically selected publications