TY - JOUR
T1 - Mechanism of myocardial dysfunction in the presence of chronic coronary stenosis and normal resting myocardial blood flow
T2 - Clinical implications
AU - Pelberg, Robert A.
AU - Spotnitz, William D.
AU - Bin, Jian Ping
AU - Le, Elizabeth
AU - Goodman, N. Craig
AU - Kaul, Sanjiv
N1 - Funding Information:
Supported in part by a grant from the National Institutes of" Health (R01-HL-48890), Bethesda, Md. The radiolabeled microspheres were provided by Dupont Pharmaceuticals, North Billerica, Mass, and the ultrasound equipment was supplied by Advanced Technology Laboratories, Bothell, Wash. Dr Pelberg was supported by a Fellowship Training Grant from the Virginia Affiliate of the American Heart Association, Glen Alien, and Dr Elizabeth Le was supported bv a postdoctoral training grant (HL-07355) from the National Institutes of Health. Presented in part at the Young Investigator Award Competition at the 10th Annual Scientific Session of the American Society of Echocardiography, June 1999, in Washington, DC.
PY - 2001
Y1 - 2001
N2 - In chronic coronary artery disease, resting myocardial dysfunction can exist despite normal resting transmural myocardial blood flow (MBF). We hypothesized that this phenomenon occurs because of diminished endocardial MBF reserve. MBF (measured with radiolabeled microspheres) and wall thickening (WT) (measured with echocardiography) were assessed in 7 dogs after the development of severe left ventricular dysfunction caused by placement of ameroid constrictors on the left anterior descending (LAD) and left circumflex arteries and 3 weeks after selective bypass surgery to the LAD. Before surgery, the mean transmural MBF at rest and at peak dobutamine dose in the LAD bed were 1.1 ± 0.5 and 3.0 ± 1.5 mL/min per gram, respectively, and were not significantly changed after LAD bypass. The resting endocardial-to-epicardial MBF ratio (EER) was also normal before bypass (1.5 ± 0.6) and remained unchanged after surgery. The prebypass EER at peak dobutamine dose, however, was markedly diminished in the LAD bed (0.7 ± 0.3) and improved significantly (1.3 ± 0.8, P <.01) after surgery. Resting WT in the LAD bed also improved to normal levels (36% ± 4% versus 13% ± 6%, P =.0001) and no longer demonstrated a biphasic response to dobutamine. In comparison, the nonbypassed left circumflex bed continued to show reduced resting WT (12% ± 6%), a biphasic response to dobutamine, and abnormal EER during rest and dobutamine (0.7 ± 0.3). We conclude that persistent myocardial dysfunction in the presence of normal resting transmural MBF can occur as a result of diminished endocardial MBF reserve, with transmural MBF reserve remaining normal.
AB - In chronic coronary artery disease, resting myocardial dysfunction can exist despite normal resting transmural myocardial blood flow (MBF). We hypothesized that this phenomenon occurs because of diminished endocardial MBF reserve. MBF (measured with radiolabeled microspheres) and wall thickening (WT) (measured with echocardiography) were assessed in 7 dogs after the development of severe left ventricular dysfunction caused by placement of ameroid constrictors on the left anterior descending (LAD) and left circumflex arteries and 3 weeks after selective bypass surgery to the LAD. Before surgery, the mean transmural MBF at rest and at peak dobutamine dose in the LAD bed were 1.1 ± 0.5 and 3.0 ± 1.5 mL/min per gram, respectively, and were not significantly changed after LAD bypass. The resting endocardial-to-epicardial MBF ratio (EER) was also normal before bypass (1.5 ± 0.6) and remained unchanged after surgery. The prebypass EER at peak dobutamine dose, however, was markedly diminished in the LAD bed (0.7 ± 0.3) and improved significantly (1.3 ± 0.8, P <.01) after surgery. Resting WT in the LAD bed also improved to normal levels (36% ± 4% versus 13% ± 6%, P =.0001) and no longer demonstrated a biphasic response to dobutamine. In comparison, the nonbypassed left circumflex bed continued to show reduced resting WT (12% ± 6%), a biphasic response to dobutamine, and abnormal EER during rest and dobutamine (0.7 ± 0.3). We conclude that persistent myocardial dysfunction in the presence of normal resting transmural MBF can occur as a result of diminished endocardial MBF reserve, with transmural MBF reserve remaining normal.
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U2 - 10.1067/mje.2001.113232
DO - 10.1067/mje.2001.113232
M3 - Article
C2 - 11696827
AN - SCOPUS:0035182575
SN - 0894-7317
VL - 14
SP - 1047
EP - 1056
JO - Journal of the American Society of Echocardiography
JF - Journal of the American Society of Echocardiography
IS - 11
ER -