| Weill
Cornell Medical College Advances
Edited
By Herman Rosen, M.D.
Study
of Cardiac Scarring That Leads to Heart Failure
A new study from Weill Cornell Medical College supplies ģimportant
missing linksī in our knowledge of ģthe causes, mechanism, and
compositionī of the scarring that occurs in heart muscle when
there is cardiac valvular disease, according to the lead author,
Dr. Jeffrey S. Borer, Professor of Medicine. The study, which
is published in a recent issue of Circulation, suggests
possible approaches to preventing scar formation and thus reducing
both the risk of heart failure and the need for valve operations.
Dr. Borer said that although physicians have long known that a
leaking aortic valve will lead to the formation of scar tissue
in the heart muscle, their knowledge has been incomplete as to
what causes this scarring and what might be done about it.
It had been thought, for example, that as the valve leaks and
allows blood to enter the heart, scarring occurs as a secondary
effect of the changes in other parts of heart. The new study shows,
instead, that the scar tissue results directly from the stretching
of the scar-forming cells of the heart that occurs as large volumes
of blood enter the organ through the leaking valve.
The study also identifies several of the genes responsible for
this abnormal scar formation. In addition, the study shows that
when the aortic valve leaks, the resulting scar tissue is unusually
rich in certain proteins that prevent a normal pumping of the
heart. This can lead to heart failure.
Scars are formed when the heart accumulates an abnormal amount
of the material that it produces as a scaffolding on which new
muscle cells are arranged. To prevent scar formation, new drugs
may be created, and the study identifies some of the specific
chemical reactions in heart cells, which can be targeted by the
new drugs. Dr. Borer adds that evaluation of these same chemical
reactions may be useful in determining the need for valve surgery
in asymptomatic patients.
"The
implications of these results are not limited to leaking heart
valves," Dr. Borer said."The same mechanical strains
that cause scarring when heart valves leak are present in the
hearts of patients who suffer heart attacks, and are likely to
be important causes of heart failure in these patients, too."
Thus, application of this knowledge may lead to treatments to
prevent many causes of heart failure.#
Herman
Rosen, M.D. is Clinical Professor of Medicine at Weill Medical
College of Cornell University.
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