In situ microangiography using synchrotron radiation in dogs demonstrated that myocardial contraction reduced vascular short-axial diameters to 87% of end-diastolic values (P<0.001).
p-value: p=<0.001
In 8 dogs, in situ microangiography using synchrotron radiation visualized penetrating transmural arteries (PTAs) with a diameter of >60 micrometers and allowed quantitation of vessel diameters of >140 micrometers. Myocardial contraction reduced the vascular short-axial diameters to 87 +/- 17% (n = 62, P < 0.001, paired t-test) of the end-diastolic values and increased the longitudinal dimension to 129 +/- 5% (n = 45, P < 0.001). The diameter reduction in the subendocardial PTA segments was significantly more marked than that in the subepicardial PTA segments (60 +/- 12 vs. 88 +/- 12%, n=13, P < 0.001, paired t-test). Intracoronary administration of dobutamine (0.1 micrograms. kg-1. min-1) increased, and in contrast, partial clamping of the coronary artery (ischemia) decreased, the configurational changes. To-and-fro blood flow was clearly observed in PTAs with visual identification of capacitive backflow, resistive forward flow during ischemia on coronary arteriography, and even under baseline conditions in coronary venography. Thus this method advances our understanding of mechanical influences on the coronary circulation.
Mori et al. (Mon,) reported a other. In situ microangiography using synchrotron radiation was evaluated on Vascular short-axial diameters during myocardial contraction (p=<0.001). In situ microangiography using synchrotron radiation in dogs demonstrated that myocardial contraction reduced vascular short-axial diameters to 87% of end-diastolic values (P<0.001).
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