Artificial heart

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Left ventricular assist system

An artificial heart (artificial heart, cardiac support system, ventricular assist device VAD, ventricular support system) is inserted into the body of patients with incurable heart disease ( heart failure ) because the patient's heart is no longer able to maintain adequate circulation . That is why one speaks of the circulatory support system.

Types

There are different types of artificial hearts.

Subdivision according to anatomical criteria

Artificial heart system
Left Ventricular Assist System (LVAD)
This type of artificial heart is inserted into the left ventricle and pumps blood from there to the aorta . This type of great circulation support is the most common type of artificial heart.
Right Ventricular Assist System (RVAD)
An RVAD is implanted in the right ventricle and pumps blood to the pulmonary artery . Only the pulmonary circulation is supported here.
Biventricular Support System (BiVAD)
The simultaneous LVAD and RVAD support of the left and right heart chambers is used to support the entire heart until the therapy goal is achieved, whereby the human heart is preserved.
Total artificial heart (TAH)
The total artificial heart completely replaces the human heart. During the operation, the patient's heart is completely explanted and replaced with a mechanical pump. Here the small and the large cycle are supported.

Subdivision according to type of function

Pulsatile cardiac assist systems
With this type of artificial heart, the body's own pulse is usually simulated by using compressed air-operated clocked ( pulsatile ) blood pumps.
Non-pulsatile cardiac assist systems
With this type of artificial heart, the blood is usually conveyed by continuously conveying axial or centrifugal pumps.

surgery

X-ray after artificial heart implantation

Artificial heart implants have become a standard heart surgery operation in recent years due to many technical improvements in pump design and surgical improvements in implantation techniques. While operations in the past meant large incisions and many days in the intensive care unit, minimally invasive implantation techniques and short intensive care stays are already possible today.

Artificial hearts are used by cardiac surgeons. The operation is performed under anesthesia and takes about three hours. In most cases, the operation is performed on the heart-lung machine .

Standard implantation technique

The traditional artificial heart implantation takes place via a total, median sternotomy , i. H. through a complete transection of the sternum . This is followed by the connection of the patient to the heart-lung machine and the dissection of the heart. The inflow tract of the support system is attached to the heart with a retaining ring and the outflow tract is sewn to the aorta. The battery cable is led out of the lower abdomen through several small cuts. Then the artificial heart is tested, the heart-lung machine is weaned and at the end of the operation the sternum is closed again with wires.

Minimally invasive implantations

Minimally invasive LVAD implantation
Scar after minimally invasive artificial heart implantation

Newer methods largely dispense with the total opening of the sternum. The most common minimally invasive techniques use a side incision on the left chest wall through which the support system is inserted into the left ventricle. This approach is often supplemented by a partial transection of the upper third of the sternum. Other possible combinations are cuts below the left or right collarbone . Based on the incision, various attachment points for the outflow tract of the artificial heart are possible. The choice of which vessel the outflow tract is attached to depends on the patient's individual anatomy and disease situation.

The Hannover Medical School developed and significantly promoted the minimally invasive technology. The advantages of a minimally invasive VAD implantation are not only in the cosmetic field. The smaller cuts result in less scar tissue and less wound area. This reduces the risk of bleeding and infection. It can even be operated on without the use of blood transfusions. Even in the case of a re-operation, e.g. B. a subsequent heart transplant , adhesions are reduced.

Other centers such as the German Heart Center Berlin and the Medical University Clinic Vienna have developed methods in which the sternum does not have to be cut. The procedure is carried out through two small incisions on the left and right sides of the breastbone. However, this is not a standard approach in artificial heart surgery, as the outflow graft of the artificial heart does not connect to the aorta, but to other vessels such as e.g. B. the subclavian artery is attached below the collarbone. This creates unphysiological blood flows. A large number of variants of the conventional and minimally invasive implantation technique exist for special anatomical conditions.

The decision as to whether an artificial heart is implanted using a conventional or minimally invasive technique depends heavily on which artificial heart model is implanted and whether the patient has anatomical features such as B. has a calcified aorta .

Therapy goals

There are different therapy goals for artificial heart patients:

Bridge to transplant
The artificial heart is inserted and the patient's current state of health is stabilized or improved. As soon as a suitable donor organ is available, the artificial heart is explanted again and a human heart is transplanted.
Bridge to recovery
In a few cases, the heart muscle can recover after an artificial heart implantation so that the artificial heart can be explanted again.
Bridge to bridge
When bridging to bridging, the desired therapy goal is not a heart transplant, but rather long-term therapy using a cardiac support system. These are elderly patients who are no longer eligible for a heart transplant or patients who do not want to expose themselves to the risk of a heart transplant. In the event of complications in the support system, the damaged device is therefore replaced or a newer, improved pump is implanted.
Destination therapy
Here the artificial heart is seen as a permanent solution. This strategy is used in patients whose health does not allow a heart transplant. In addition, many artificial heart patients choose this strategy because they get along well with the system and do not want to take the risks of a heart transplant.
The bridge to bridge method is a modification of this strategy . If the artificial heart needs to be changed after a few years of therapy, a new artificial heart system can be installed with this strategy, which has technical improvements over the old system.

Living with an artificial heart

Artificial heart therapy is used to improve the performance of heart failure patients. The cardiac output should be increased. In addition to the resulting increased quality of life, there are also disadvantages of this therapy.

  • Limited battery life
    The battery     life of a cardiac assist system is around four to eight hours per battery, depending on the system and manufacturer. Two batteries are connected to the device at all times. The batteries must be changed after the battery life has expired.
  • Danger of infection
    Bacteria can enter the body through the artificial exit port below the navel. This can lead to infections. To avoid this disadvantage, methods were developed to transmit the energy and the control signals wirelessly through the skin with the aid of electromagnetic induction .
  • Necessity of anticoagulation
    The shear forces in the artificial heart can lead to the formation of thrombi in the blood. In order to reduce the risk of strokes and embolisms , anticoagulation is absolutely necessary during the support period . The therapy of choice are vitamin K antagonists . In addition, many artificial hearts require double anticoagulation using an additional platelet aggregation inhibitor .

Historical aspects

JARVIK-7, artificial heart
Research project "Artificial Heart" of the Wilhelm Pieck University, Rostock (1988)

The first artificial heart implantation was performed on April 4, 1969 at the Texas Heart Institute in Houston , USA by Denton A. Cooley . The 47-year-old patient Haskell Karp received an artificial heart developed by Domingo Liotta , which was replaced by a natural heart after 65 hours. Karp died shortly after the heart transplant .

The first permanent heart implant is the Jarvik-7 by Robert Jarvik , which was delivered to retired dentist Barney Clark (January 21, 1921 to March 23, 1983) at the University of Utah in Salt Lake City on December 2, 1982 in a seven-hour operation. The operation was carried out by William DeVries , a son of Dutch immigrants. Clark survived 112 days and suffered multiple thrombosis before he died. On November 25, 1984, the American William J. Schroeder was implanted an artificial heart, also of the Jarvik-7 type , with which he survived 620 days and died of a stroke on August 6, 1986.

In Berlin, the German scientist and heart surgeon Emil Bücherl has been researching the manufacture of artificial hearts since the 1960s. The survival time could be increased in several animal experiments. In 1981 a calf survived 268 days after an artificial heart implantation and a goat in 1984 around 345 days. In 1979 the organ, known as the Berlin artificial heart in Germany, was implanted in a person and served briefly to support his blood circulation .

In October 1990, at the German Heart Center Berlin (DHZB), a child's waiting time for a transplant was successfully bridged with an artificial heart for the first time.

After 160 days of relief from an artificial heart, the natural, so far seriously ill heart of a 38-year-old Thuringian recovered so well that the artificial heart could be explanted on April 10, 1994 in the German Heart Center Berlin and the patient was spared a transplant. This was the first case in the world.

Since then, over 100 artificial hearts have been explanted again at the DHZB because the patient's heart muscle had recovered during the support. The clinic has a special myocardial recovery program for artificial heart patients. In order not to damage the heart muscle too much during the explantation of the VAD, a special locking system was developed at the DHZB, which is made individually for each patient.

On November 13, 1998, a non-pulsatile axial VAD system was used for the first time at the German Heart Center Berlin with the “Micromed DeBakey VAD”.

Nowadays artificial heart patients can be cared for by the cardiac assist system for more than five years. The current European record holders were implanted at the Hannover Medical School .

On December 18, 2013, a surgical team under Christian Latrémouille implanted an artificial heart with biosynthetic skin in the Georges Pompidou Hospital in Paris . This has the advantage that the risk of rejection is minimized. The artificial heart is a bioprosthesis and can therefore replace the biological heart. It is about two fists tall; a smaller version is in development. According to developer Alain Carpentier , a transplant of a biological heart should be bridged for five years thanks to the built-in battery and sensors. The patient died after 75 days.

The investments for the development amounted to around 100 million euros. The support from the Matra Group under its then General Manager Jean-Luc Lagardère laid the foundation for the financing. Additional funding was provided through government research loans and investment funds. In particular, the Oseo fund invested 33 million euros. The price of this artificial heart is said to be around € 160,000 per copy.

Jan D. Schmitto, Uwe S., Axel Haverich, M. Strüber

In June 2014, the world's first HeartMate III artificial heart was implanted by Axel Haverich and Jan D. Schmitto at the Hannover Medical School .

With over 2,800 implantations to date, the German Heart Center Berlin operates the largest artificial heart program in the world.

On November 12, 2015, patient Uwe S. of the Hannover Medical School reached the milestone of ten years of artificial heart therapy with the HeartMate II device. He is considered the holder of the relevant European record as an artificial heart patient.

In the spring of 2016, cardiac surgeons Evgenij Potapov and Thomas Krabatsch at the German Heart Center Berlin successfully implanted an artificial heart of the type "HeartMate 3" on both halves of the heart for the first time worldwide in a patient from Thuringia.

In 2017, the surgeons at the Hannover Medical School published the first series of artificial heart upgrades to the currently most modern artificial heart HeartMate 3. This technology enables successful therapy of artificial heart patients who, for B. have to be operated on due to a driveline infection or a pump thrombosis. Simultaneously with the necessary replacement of the artificial heart, an artificial heart of the latest generation is implanted so that the patient benefits from the advantages of the new pump.

swell

  • Patent US4173796 : Total artificial hearts and cardiac assist devices powered and controlled by reversible electrohydraulic energy converters. ‌

Web links

Commons : Kunstherz  - collection of images, videos and audio files

Individual evidence

  1. ↑ Jasmin S. Hanke, Murat Avsar, Axel Haverich, Jan D. Schmitto: Heart-Failing Jehovah's Witness Patient Successfully Treated by Minimally Invasive LVAD Implantation without Any Blood Transfusions . In: The Thoracic and Cardiovascular Surgeon Reports . tape 4 , no. 1 , December 1, 2015, ISSN  2194-7635 , p. 21–24 , doi : 10.1055 / s-0035-1564614 , PMID 28078199 , PMC 5223739 (free full text) - (English).
  2. ↑ E. Potapov, T. Kranatsch: Minimally invasive continuous-flow left ventricular assist device implantation: Avoiding a median Sternotomy. In: The Journal of Heart and Lung Transplantation . 33, 2014, pp. 1199-120.
  3. ↑ Thomas Haberl, Julia Riebandt, Stephane Mahr, Guenther Laufer, Angela Rajek: Viennese approach to minimize the invasiveness of ventricular assist device implantation . In: European Journal of Cardio-Thoracic Surgery . tape 46 , no. 6 , December 1, 2014, ISSN  1010-7940 , p. 991–996 , doi : 10.1093 / ejcts / ezu051 (English, oup.com [accessed March 8, 2017]).
  4. ↑ Jasmin S. Hanke, Sebastian V. Rojas, Andreas Martens, Jan D. Schmitto: Minimally invasive left ventricular assist device implantation with outflow graft anastomosis to the innominate artery . In: The Journal of Thoracic and Cardiovascular Surgery . tape 149 , no. 4 , April 1, 2015, ISSN  1097-685X , p. e69–70 , doi : 10.1016 / j.jtcvs.2014.12.066 , PMID 25659850 (English).
  5. ↑ History of the DHZB ( Memento of the original from August 30, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.dhzb.de
  6. ↑ History of the DHZB ( Memento of the original from August 30, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.dhzb.de
  7. ↑ M. Dandel, C. Knosalla, R. Hetzer: Contribution of ventricular assist devices to the recovery of failing hearts: a review and the Berlin Heart Center Experience. In: European Journal of Heart Failure . 16, 2014, pp. 248-263. doi: 10.1002 / ejhf.18 .
  8. ^ EV Potapov et al.: A titanium plug simplifies left ventricular assist device removal after myocardial recovery . In: Journal of Heart and Lung Transplantation. 29, 2010, pp. 1316-1317.
  9. ↑ E. Potapov et al. Thoracic Transplantation and Ventricular Assist Devices Pulsatile Flow in Patients With a Novel Nonpulsatile Implantable Ventricular Assist Device . In: Circulation . 102, 2000, pp. III-183-III-187.
  10. ↑ a b c Cœur artificiel: une prouesse made in France. In: Le Monde . December 24, 2013, p. 1.
  11. ↑ a b Rudolf Balmer: Novel artificial heart as hope for tens of thousands of patients in the world. In: Neue Zürcher Zeitung . December 23, 2013, accessed December 24, 2013.
  12. ↑ Health: First owner of the new artificial heart died. In: FAZ. Retrieved March 8, 2014 .
  13. ↑ Recipient of an artificial heart: patient dies after only 75 days - N24.de. Retrieved March 8, 2014 .
  14. ↑ Thoratec Announces First HeartMate III ™ Human Implant. (No longer available online.) Archived from the original on October 7, 2014 ; accessed on October 7, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / phx.corporate-ir.net
  15. ↑ Largest artificial heart program in the world  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link / www.dhzb.de  
  16. ↑ https://www.dhzb.de/de/aktuell/grundinformationen/daten_und_ffekten/  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link / www.dhzb.de  
  17. ↑ Stefan Zorn: The pump belongs to me like a second heart.
  18. ↑ https://www.dhzb.de/de/aktuell/news/detailansicht_mektiven/ansicht/pressedetail/doppeles_kunstherz/  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link / www.dhzb.de  
  19. ^ JS Hanke, SV Rojas, G. Dogan, C. Feldmann, E. Beckmann: First Series of Left Ventricular Assist Device Upgrades to HeartMate 3 . In: The Thoracic and Cardiovascular Surgeon . tape 65 , S 01, January 1, 2017, ISSN  0171-6425 , p. S1 – S110 , doi : 10.1055 / s-0037-1598839 (English).
  20. ↑ Sebastian V. Rojas, Murat Avsar, Zain Khalpey, Jasmin S. Hanke, Axel Haverich: Minimally Invasive Off-Pump Left Ventricular Assist Device Exchange: Anterolateral Thoracotomy . In: Artificial Organs . tape 38 , no. 7 , July 1, 2014, ISSN  1525-1594 , p. 539-542 , doi : 10.1111 / aor.12226 (English).
  21. ↑ Jasmin S. Hanke, Axel Haverich, Jan D. Schmitto: Exchange of a HeartMate II left ventricular assist device with a HeartMate 3 pump . In: The Journal of Heart and Lung Transplantation: The Official Publication of the International Society for Heart Transplantation . tape 35 , no. 7 , July 1, 2016, ISSN  1557-3117 , p. 944-946 , doi : 10.1016 / j.healun.2016.03.013 , PMID 27160494 (English).
  22. ↑ Jasmin S. Hanke, Axel Haverich, Jan D. Schmitto: Exchange of a HeartWare HVAD to a HeartMate 3 left ventricular assist device . In: The Journal of Heart and Lung Transplantation . doi : 10.1016 / j.healun.2016.12.005 (English).