Myocardial contrast echocardiography can be used to assess the microvascular response to vascular endothelial growth factor-121.
BACKGROUND
Therapeutic angiogenesis is a new approach to treating ischemic heart disease, and the optimal method for assessing its efficacy is unclear. We used myocardial contrast echocardiography (MCE) to evaluate the therapeutic response to the angiogenic agent, vascular endothelial growth factor-121 (VEGF121).


RESULTS
After placement of an ameroid constrictor (day 0) around the left anterior descending artery (LAD), dogs were given intracoronary VEGF121 protein (108 microg, n=6) or placebo (n=6) on days 7 and 21, and subcutaneous VEGF121 (1 mg) or placebo on days 8 to 20 and 22 to 27. On day 48, MCE was performed during rest and dobutamine stress. Videointensity (y) and pulsing interval (t) were fit to an exponential model (y=A[1-e(-beta(t))]) used to derive indices of red cell velocity (beta) and capillary area (A), and parameters were compared with radiolabeled microsphere flow data. VEGF(121) treatment resulted in higher resting left anterior descending artery/left circumflex flow ratio compared with placebo (P<0.03) and improved collateral flow reserve. Beta was 0.94+/-0.37 in VEGF121 dogs versus 0.38+/-0.31 in controls (P<0.02), with the greatest difference in the endocardium. The parameter A was comparable in both groups, suggesting that microvascular changes did not alter capillary cross-sectional area, and histology indicated a trend toward higher arteriolar density in VEGF121-treated animals.


CONCLUSIONS
VEGF121 protein improves collateral flow and reserve. MCE can evaluate the transmural location and structural and functional responses of the microvasculature to angiogenic interventions.
Villanueva
Flordeliza S
FS
Cardiovascular Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pa 15213, USA. villanuevafs@msx.upmc.edu
Abraham
Judith A
JA
Schreiner
George F
GF
Csikari
Melissa
M
Fischer
David
D
Mills
James D
JD
Schellenberger
Ute
U
Koci
Bryan J
BJ
Lee
Joon S
JS
D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D003097:Collateral Circulation / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D004195:Disease Models, Animal; D004285:Dogs; D004452:Echocardiography; D004562:Electrocardiography; D016228:Endothelial Growth Factors / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects; D008222:Lymphokines / Q000494:pharmacology*; D008833:Microcirculation / Q000000981:diagnostic imaging* / Q000187:drug effects*; D009204:Myocardial Revascularization; D009206:Myocardium / Q000473:pathology; D011237:Predictive Value of Tests; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors