Effects of Dobutamine Stress on Myocardial Blood Flow, ^99m Tc Sestamibi Uptake, and Systolic Wall Thickening in the Presence of Coronary Artery Stenoses

Abstract

In the presence of stenoses that reduced or abolished regional flow reserve, (1) myocardial sestamibi uptake significantly underestimated the dobutamine-induced flow heterogeneity, (2) a "failure to increase systolic thickening" rather than a reduction in thickening was observed during dobutamine stress, and (3) myocardial stunning was observed during postdobutamine recovery.

Novel SPECT perfusion imaging agents with improved myocardial or liver kinetics: Experimental studies and the need for clinical evaluation

“…For a number of reasons that were addressed in the abovementioned editorial, and despite excellent myocardial extraction and encouraging clinical results, the neutral and lipophilic tracers TcN-NOET and Tc-TEBOROXIME have not reached routine clinical use. 1 On the other hand, the cationic and lipophilic tracer Tc-MIBI has been extensively studied experimentally [2][3][4][5][6][7][8][9][10] and has reached wide clinical acceptance for a number of years. However, in addition to suboptimal myocardial extraction in comparison to that of Tl-201 due to the roll-off phenomenon leading to underestimation of myocardial perfusion at high flow rates, 7 Tc-MIBI also presents a modest heartto-liver activity ratio which is comparable or lower than that of Tl-201 and which might be responsible for misinterpretation of myocardial perfusion in the inferior or inferoapical left ventricular wall.…”

Regional Mechanics of Demand Ischemia During Cardiac Stress Testing

“…110,111 The original model has been continuously improved and adapted to include more anatomic detail 36 for accurate measurement of regional strains, 40 and more realistic circulatory boundary conditions. 81 From this data we can conclude that E 33 and WT in the model are lower than measured experimentally, and this is likely because of the lack of sheet structure and shear in the model. Nevertheless, the model still shows depressed WT and E 33 with demand ischemia and supply ischemia, and replicates previously-observed results in which a WT abnormality is smaller than a perfusion abnormality at peak stress.…”

“…81 Strain and wall motion were compared to the perfusion defect size, location, and severity measured with radiolabeled microspheres. The goal of this study, detailed in Chapter 4, was to evaluate the effectiveness of 3DFS for detecting critical stenoses during DSE, and to compare 3DFS to strain in the ischemic region measured by sonomicrometry, a gold-standard measure of myocardial deformation.…”

“…77 Tissue mass and regional myocardial blood flow was determined for each block using standard methods for quantification of radioactive microspheres. 81 …”

“…After 45 minutes, data acquisition was performed and a critical LAD stenosis was set as described previously. 81 The LAD snare ligature was tightened as much as possible without reducing flow, and the hyperemic response was measured by occluding the LAD for 10 seconds and observing the peak hyperemic flow that followed.…”