Myocardial blood volume and the amount of viable myocardium early after mechanical reperfusion of acute myocardial infarction: prospective study using venous contrast echocardiography

Abstract

Background: Myocardial capillary perfusion is a prerequisite of myocellular viability after reperfusion of acute myocardial infarction. It was hypothesised that the magnitude of myocardial capillary perfusion, assessed by transmural signal intensity in venous contrast echocardiography as a corollary of the blood volume of myocardial capillaries, and the amount of viable myocardium, represented by differential levels of contractile function two weeks after reperfusion, are correlated. Objectives: To evaluate the role of venous contrast echocardiography for the identification of viable myocardium in patients with acute myocardial infarction early after successful mechanical reperfusion. Methods: 60 patients with a first acute myocardial infarction underwent venous contrast echocardiography several hours after successful mechanical reperfusion (median time interval 190 min.). The relative transmural videointensity (median (25th, 75th percentiles)) of akinetic segments was determined. After two weeks, contractile function was re-evaluated at rest and during dobutamine infusion if segments without functional recovery were present. Results: Relative videointensity early after reperfusion differed significantly between functional groups after two weeks: normokinesia (88% (77%, 100%)), hypokinesia (74% (54%, 99%)), and akinesia with (61% (48%, 76%)) and without contractile reserve (31% (22%, 46%)). Relative videointensity and contractile function were significantly correlated (r = −0.67). The diagnostic accuracy of relative videointensity > 50% for prediction of contractility of initially akinetic segments at rest or during dobutamine was 82% (χ 2 = 76.2, p < 0.001). Conclusions: Early after successful mechanical reperfusion of acute myocardial infarction, the magnitude of capillary perfusion in the perfusion territory of an infarct related artery is correlated with the amount of viable myocardium. Quantitative venous contrast echocardiography can be used for accurate identification of viable myocardium.

Adenosine myocardial contrast echo in intermediate severity coronary stenoses: a prospective two-center study

“…Quantification of functional stenosis relevance is a step beyond this point and has been recently achieved with MCE by evaluation of myocardial blood flow velocity and flow [13,22,25]. If, with the technique used in the present study, differential grades of myocardial blood volume reduction can be recognized during adenosine in the setting of coronary artery stenosis on MCE, as has been recently demonstrated for patients with acute myocardial infarction [26] may be adressed in future studies. The prognostic significance of differential grades of functional stenosis severity, however, needs to be defined to render this information useful in clincial practice.…”

Assessment of myocardial perfusion and systolic function in patients with coronary artery disease after coronary artery bypass surgery by myocardial contrast echocardiography and two-dimensional strain echocardiography

“…Regions of interest are drawn and time intensity curves are fitted to a mono-exponential function, where A is plateau intensity reflecting the myocardial blood volume, which is strongly correlated with microvessel density on histochemical staining slice of human myocardial biopsy tissue, and the exponential k is the mean refilling velocity of myocardial microbubbles with intravascular kinetics comparable to that of red blood cells, and reflects myocardial blood velocity. Consequently, the product of A and k provides an objective estimate of myocardial blood flow [2,24] .…”

A fundamental study for quantitative measurement of ultrasound contrast concentration by low mechanical index contrast ultrasonography

“…3 Following this finding, attempts have been made to estimate relative bubble density on the basis of the ratio of dB value or that of VI. 2,[4][5][6][7][8] In myocardial contrast echocardiography in particular, myocardial CI (expressed in dB) or VI was measured, and relative myocardial blood volume was estimated on the basis of the ratio of these parameters between different regions of myocardium, yielding a number of clinically useful findings. 5,15,16 However, it is now necessary to determine the correct relationship between bubble density and CI for more accurate evaluation of tissue perfusion.…”

“…3 Following that finding, relative bubble density was estimated from the ratio of myocardial CI expressed in dB or that in VI. 2,[4][5][6][7][8] We previously examined the relationship between the concentration of the ultrasound contrast agent Levovist and the CI of harmonic power Doppler imaging, which is used for high mechanical index (MI) contrast ultrasonography under conditions of constant applied acoustic pressure. In that study, CI in dB had a good logarithmic correlation with Levovist concentration, indicating a good linearity between the concentration and the signal power, because the dB value is yielded from logarithmic conversion of signal power.…”