Background to our research work
The right ventricle of the human heart pumps deoxygenated blood through the lungs, where it is supplied with oxygen. To prevent the blood from flowing from the lungs back into the right ventricle between the pumping phases, there is normally a valve at the exit of this ventricle: the pulmonary artery valve (pulmonary valve). In several thousand patients in Germany, this valve does not work, so it has to be replaced by a replacement pulmonary artery valve.
The replacement pulmonary artery valves currently available wear out over time. They then become leaky or narrow. In growing children, they become too small and then no longer function well enough - after a few years, they need to be replaced. These operations are stressful and not without risks. For this reason, the search is always on for a better replacement for the valves. In 1999, for example, a valve-bearing bovine neck vein (Contegra) was launched on the market. Since 2005, human pulmonary valves (CorLife) have been available, which are no longer rejected by the recipient's body thanks to a special preparation process. There are various names for this valve: Decellularized homograft, TE valve, tissue-engineered pulmonary valve, occasionally this valve is also referred to in layman's terms as a "valve that grows with the body". Whether new valves really function better and longer than conventional valves can only be determined by comparing the results.
The difficulty with such comparisons is that the recipients of the valves, the patients, are very different. Patient age, previous operations and the type of malformation have a very significant influence on durability. For a meaningful comparison with different types of replacement pulmonary artery valves, you need many well-fitting patients with comparable conditions. However, since even large Clinical Departments rarely use more than 50 such valves per year, data from many clinics is needed. And that is what we have been trying to do for many years.
Development of our pulmonary artery valve registry
The bovine vein replacement valve "Contegra" was introduced in 1999 as part of a European study involving several hospitals. The data of the 160 study patients, including their follow-up results, were recorded in Bad Oeynhausen in a database based on the study's data entry forms. Over time, the replacement pulmonary artery valves previously used there were also entered into the database for comparison purposes. After a few years, patients from Hannover Medical School were added to the database, as were the results of human replacement pulmonary artery valves implanted in Moldova but processed at the MHH using the CorLife method. In addition, there were results from Heidelberg, Stuttgart, Erlangen, Bordeaux and Chennai (India).
The CorLife valves, which are assumed to no longer be rejected and can therefore grow with the patient, are being used and monitored in many countries with the help of an EU-funded study. These results are also included in the registry.
One example of evaluations from the registry is the paper: "Decellularized fresh homografts for pulmonary valve replacement: a decade of clinical experience. Sarikouch S, Horke A, Tudorache I, Beerbaum P, Westhoff-Bleck M, Boethig D, Repin O, Maniuc L, Ciubotaru A, Haverich A, Cebotari S. Eur J Cardiothorac Surg. 2016 Mar 24. pii: ezw050. [Epub ahead of print]. PMID: 27013071.
Contents of the registry
Gender, age, diagnoses, previous operations and number of previously implanted replacement pulmonary artery valves; implantation data such as valve type and diameter, additional tissue used (expansion patch), use of tissue adhesive, suturing method; Follow-up data such as date of follow-up examination, degree of narrowing in different areas of the replacement pulmonary artery valve, valve leakage, ventricular size, calcifications, adverse events; follow-up operations, cardiac catheterization procedures; valve replacement and death with their respective causes. A special feature of the registry is that many evaluations are already prepared automatically: This considerably simplifies and accelerates the evaluation.
Experience and developments
The registry has been in existence since May 1999 and currently contains data on 2350 replacement pulmonary artery valves, 15356 follow-up examinations and 474 interventions/post-operations.
The registry is managed within the "Competence Network for Congenital Heart Defects". Around 50,000 affected patients are currently participating. The pulmonary artery was replaced in many thousands of these patients from all over Germany. Their results are compiled and evaluated on the basis of the experience with the register described above. The "Fördergemeinschaft Deutscher Kinderherzzentren" is making this project possible with its support. Results will be available in the course of 2017.
Every wearer of a replacement pulmonary artery valve is invited to participate in the registry of the competence network. Please use the links below for information and registration.