Magnetic resonance quantitative myocardial perfusion reserve demonstrates improved myocardial blood flow after angiogenic implant therapy.
OBJECTIVE
The purpose of this study is to follow myocardial angiogenesis temporally using quantitative magnetic resonance first pass perfusion imaging and compare this with the "gold standard" of radioactive microspheres in a random subset of animals.


METHODS
Ameriod constrictors were placed around the left circumflex in 15 pigs to induce an ischemic area. Two groups were randomized to receive either a sham operation or treatment with angiogenic implants inserted into myocardium in the distribution of the left circumflex artery (LCX). These implants are designed to induce myocardial angiogenesis. Magnetic resonance first pass perfusion imaging was performed at baseline and also after treatment with either sham or implant therapy by using first pass perfusion imaging with a TurboFLASH sequence. Absolute myocardial blood flow was derived by applying a quantitative Fermi function model. Radioactive microspheres were also injected into a random subset of animals to measure myocardial blood flow.


RESULTS
Angiogenic implant therapy increased absolute myocardial blood flow in the left circumflex territory relative to baseline and sham treated groups during adenosine infusion. Myocardial blood flows measured with radioactive microspheres was increased significantly in both the LCX and LAD territories during stress. Myocardial Perfusion reserve was also significantly increased in both the LCX and left anterior descending territories relative to baseline. Ejection Fraction during stress with dobutamine infusion increased significantly in the implant therapy group while that in the sham group was not affected.


CONCLUSIONS
Quantitative MR myocardial first pass perfusion imaging can be used to track the development of angiogenesis as corroborated by radioactive microspheres. Angiogenic implant therapy is a new device based therapy that has potential to protect an ischemic region by accelerating angiogenesis although further research is necessary with this device.
Panse
Prasad
P
Health Science Center, University of Florida Jacksonville, Jacksonville, FL 32209, USA.
Klassen
Chris
C
Panse
Neeta
N
Siuciak
Alan
A
Rickers
Carsten
C
Jerosch-Herold
Michael
M
Wilke
Norbert M
NM
D020341:Absorbable Implants; D000818:Animals; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003326:Coronary Circulation; D004195:Disease Models, Animal; D005080:Exercise Test; D019786:Gadolinium DTPA; D018810:Magnetic Resonance Angiography; D019028:Magnetic Resonance Imaging, Cine; D008863:Microspheres; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy*; D018919:Neovascularization, Physiologic; D011897:Random Allocation; D013318:Stroke Volume; D013552:Swine; D013997:Time Factors
D003287:Contrast Media; D019786:Gadolinium DTPA