The Bridge To Heart Transplantation

| April 2, 2012 | 1 Comments

At this time, there are 3,181 persons on wait lists for heart transplantation at the country’s 250 plus transplant centers.

If you follow heart transplantation or heart disease, you are doubtless aware of the ventricular assist devices (VAD’s).  As defined by the Mayo Clinic, the VAD is “an implantable mechanical pump that helps to pump blood from the lower chamber of the left ventricles in the heart to the rest of the body.” This device is used by patents who suffer extreme end stage heart disease.  Many of these patients are awaiting heart transplant.

Heartware

Heartware

VAD’s are portable.  After surgery to implant the VAD, patients can rest or reside at home while waiting.  From my personal experience, there exist distinct differences between patient’s pre-VAD insertion and post-VAD surgery. In one case, a patient at Columbia Presbyterian, that I came to know, looked like a new man.  I barely recognized him after he received the LVAD. The color returned to his face and his energy level was significantly elevated, as was his outlook.

Typically, VAD’s are used by cardiologists to assist three classes of patients:

1.                Persons awaiting heart transplantation.

2.                Persons not considered good candidates for transplantation.

3.                Persons not wanting transplantation but who need a more functional heart.

There are advantages to VAD installation.  However, the procedure has always been considered dangerous because of its invasive characteristics.  The operation is similar to open heart surgery, which is not the easiest recovery.

Additionally, VAD have always been considered risky.  The major risks are: 

  • Blood clotting – Clots can occur as the blood goes through the VAD.  These clots ca back up the device.
  • Bleeding – Just as wit open-heart surgery excessive bleeding is commonplace.
  • Infection – Perhaps the greatest risk is infection, both during the surgery and afterwards.  Persons waiting for a heart transplant who encounter infection will not be candidates for transplantation until the infection is completely negated.
  • Device malfunctions – The VAD pump can become clogged or suffer any setbacks any highly used piece of equipment encounters.  Other issues can be caused by failure of the power connection.
  • Right heart failure – With a left ventricle assist device, the pump pushed blood through the right ventricle.  Sometimes, the right ventricle is not up to this excess flow and simply shuts down.

The good news is that HeartWare International Inc. has developed a much smaller and much less invasive VAD pump.   The pump has been clinically tested in two separate FDA initiatives through a Continued Access Protocol (CAP) begun in April 2010 and in December 2011. 

The newest FDA clinical test will be extended to 30 pre-approved transplant centers.  This initiative, called HeartWare ADVANCE, is described as “an Investigational Device Exemption (IDE).” 54 new patients will participate in this latest clinical trial overseen by the Institutional Review Board.

Heartware fittingly describes their ventricular assist system as a bridge to transplantation.  Specifically, Heartware develops “miniature assist devices.”  The newest and proudest accomplishment is tailored to benefit Class IIIB and Class IV patients suffering hear failure.  At this point, the patient, without a pump, is not expected to live long enough to receive a new heart.  Testing is also relevant for patients as “destination therapy” where prolonging life is the primary goal.

The system has already been approved for use in Australia and in the European Union.  The system is based upon the effectiveness of a very small implanted pump called the HVAD.  The pump has the capacity to move ten liters of blood flow per minute.  The pump only has one moving part, called the impeller.  The impeller is a proportionately wide blade that prevents damage to the cells and discourages blood clotting.

Procedurally, the implant is placed above the diaphragm, in the pericardial space adjacent to the heart.  The design is thoughtfully planned to simplify the surgery and expedite the recovery time.  The system is efficient, appears to have passed the initial testing famously and is probably the wait-listed patient’s best chance for bridging the gap between eroding heart function and heart transplantation. 

HeartWare International, Inc. is a publicly traded company with offices in Framingham Mass and Sydney Australia.

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1 Comment on "The Bridge To Heart Transplantation"

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  1. Davies Nsama says:

    Can ventricle transplanted in heart

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