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Archive for the ‘Heart transplantation’ Category

Human body is intertwined collection of lives of Individual organs.We believe death occurs when brain dies , respiration stops and circulation ceases . Curiously ,when life ends , these organs  don’t die as a single unit . These three events can happen in any of the six possible permutations.Each organ takes different times to die after loss of life.It is like a crashed computer , where the mother board /RAM memory may be transferred to another and be functional . Out of these three , heart function appears to be supreme as it can function without the need of brain (Science of brain-death) and keep the body alive with intact circulation. Though the concept  called heart dead organ donors is catching up as well. (John Gill et all Use and Outcomes of Kidneys from Donation after Circulatory Death Donors in the United States    

The science of organ transplant has rapidly  evolved .We can transfer an organ from one who is dying or dead to another person who is also dying due to failure of a different organ. Though most organs can be transported and transplanted , we need to maintain life in a dead donor organ . A new and curious specialty  in medicine is emerging which could be named a  Critical Care of Dead or Critical Cadaveric Care Units !) till harvesting happens. Paradoxically ,after the harvest , the organ gains independent  life that has to be sustained.This is where the science of organ transport is waiting in to explode!

How to transport a dead man’s heart ?

There are two Ischemic times in organ donation.

  • Warm Ischemic time
  • Cold Ischemic time

Warm ischemic time refers to the amount of time that an organ remains at body temperature after its blood supply has been stopped or reduced. Cold ischemic time refers to the amount of time that an organ is chilled or cold and not receiving a blood supply. These times quiet vary with respect to different organs.

So far, we have been carrying organs in cold boxes with custodial solutions. (HTK*)

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This makes the transport time a big limitation of success of the procedure. *HTK -histidine, tryptophan ,a-ketoglutarate, solution 

Whats new in organ transplant science ?

Trans medics is an exclusive company , that has pioneered  in this unique science of organ transport .They have developed separate organ care system for heart ,lungs and liver.

donor heart

It is the first portable heart perfusion system , which increase the time between the harvest to transplant . It avoids cold ischemic time ,replaced by warm perfusion with metabolic activity monitored till  it is transplanted.Ideal far long distance transplant .Soon one can expect trans-continental transplant as well !

This technology could make the difference between warm and cold Ischemic times blurred and in future one may expect to prolong the warm ischemic  period and there is near zero cold Ischemic time.

A heart is perfused by transmedics system while being transported

 

                                              A  lung breathing in transit

A link to a video

Final message

Modern medical technology can be seen in action , in so many ways and brings both accolades and agonies in equal proportion. While, even flimsy ones tend to get due attention , Transmedics , probably deserves a  grandest reward  for uplifting the science of organ donation . I would think this is the most unique service (playing God )  . . . shipping dead man’s organ  with assured life on delivery  !

 

Link to Transmedics website

ocs heart transmedics heart transplantation

http://www.transplantation.de/fileadmin/transplantation/txmedizin/txmedizin_2011_3/04_yeter.pdf

 

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Heart transplantation  as a treatment modality was conceptualized  by Christian Barnard in 1967 . Still considered as an  “Act of God” this  surgery is regularly performed worldwide by dedicated  transplant team consisting of cardiac surgeon , physician , Anesthetist , pathologist and others .Unlike other organs , heart transplant cannot have a “live donor” .Though  started  half a century ago, the real  pace has  picked up only in last 2 decades .Currently it is  “globally accepted  standard” intervention in terminal cardiac failure (Including pediatric heart conditions)

How are the survival rates ?

HEART TRANSPLANT SURVIVAL

  • Now, many centers  are able to reach the  bench mark Stanford- statistical rates with a consistent  five  year survival rate crossing   75% .
  • The median survival rates is 10.5 years
  • One of the estimate indicate , If they cross first year, median survival reach 13.5 years
  • There has been many living survivors who have  crossed 30  years.

Looking at these numbers  , there is dramatic impact  in terms of global disease burden and the life gained.Statistically  speaking  successful treatment by heart transplant is equivalent to overwhelming  many  cancers in a human body !

Can these  results reproducible in all centers ?

These excellent outcome is  the reward to highly dedicated teams with  pioneering work culture . One should be cautious to start new transplant center without proper facility and expertise.Unregulated heart transplant  centers is vested with risk of pulling down the excellent  statistics of this unique form of human organ exchange.

Newer developments

Patient  selection criteria and  strategies to prevent rejection is being streamlined .The major  issue is availability of donor heart and how to optimize organ procurement and increase transport survival time .Transmedics has deviced a state of the art organ transport system . The other exciting thing expected to happen is potential (Ironical though !) heart donors from  even cardiac  /circulatory deaths . (Dhital KK, Iyer A, Connellan M Lancet. Adult heart transplantation with distant procurement and ex-vivo preservation of donor hearts after circulatory death: a case series.2015 Jun 27;385(9987)

What about artificial hearts ?

As of  now biological heart has definite edge over  artificial heart.Meanwhile rapid development of LV  assist  device and near total artificial  hearts may  end up with destination therapy rather than bridge to transplant. The “INTERMACS ” data are very promising and let us wait for the day artificial heart  can  score over the biological  ones.

Reference

1. The Registry of the International Society for Heart and Lung Transplantation: Twenty-eighth Adult Heart Transplant Report–2011.Stehlik J1, Edwards LB, Kucheryavaya  J Heart Lung Transplant. 2011 Oct;30(10):1078-94.


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heart transplantation
longest survival after heart transplanation
longest survivor of heart transplant

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