Assessment of the effects of dobutamine on myocardial blood flow and oxidative metabolism in normal human subjects using nitrogen-13 ammonia and carbon-11 acetate

• Published in: The American journal of cardiology Vol. 71; no. 15; pp. 1351 - 1356
• Main Authors: Krivokapich, Janine, Huang, Sung-Cheng, Schelbert, Heinrich R.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.06.1993; Elsevier; Elsevier Limited
• Subjects: Adult; Biological and medical sciences; Blood Flow Velocity - drug effects; Carbon Radioisotopes; Cardiovascular disease; Cardiovascular system; Coronary Circulation - drug effects; Dobutamine - pharmacology; Feasibility Studies; Heart - diagnostic imaging; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical research; Medical sciences; Middle Aged; Myocardium - metabolism; Nitrogen Radioisotopes; Oxygen Consumption - drug effects; Radionuclide investigations; Tomography, Emission-Computed; Radionuclide study; Human; Pharmacologic test; Energy metabolism; Scintigraphic agent; Myocardium; Exploration; Hemodynamics; Positron emission tomography; Blood flow
• ISSN: 0002-9149; 1879-1913
• DOI: 10.1016/0002-9149(93)90554-P

The dual purposes of this study with positron emission tomography were to measure the effects of dobutamine on myocardial blood flow and oxidative metabolism, and to compare carbon-11 (C-11) acetate versus nitrogen-13 (N-13) ammonia in quantitating flow in normal subjects. Flow was quantitated with N-13 ammonia at rest and at peak dobutamine infusion (40 μg/kg/min) in 21 subjects. In 11 subjects, oxidative metabolism was also estimated at rest and peak dobutamine infusion using the clearance rate of C-11 acetate, k mono (min −1). A 2-compartment kinetic model was applied to the early phase of the C-11 acetate data to estimate flow. The rest and peak dobutamine rate-pressure products were 7,318 ± 1,102 and 19,937 ± 3,964 beats/min/mm Hg, respectively, and correlated well (r = 0.77) with rest and peak dobutamine flows of 0.77 ± 0.14 and 2.25 ml/min/g determined using N-13 ammonia as a flow tracer. Rest and dobutamine flows estimated with C-11 acetate were highly correlated with those determined with N-13 ammonia (r = 0.92). k mono increased from 0.05 ± 0.01 to 0.18 ± 0.02 min −1, and correlated highly with the increase in flows (r = 0.91) and rate-pressure products (r = 0.94). Thus, the increase in cardiac demand associated with dobutamine is highly correlated with an increase in supply and oxidative metabolism. C-11 acetate is a unique tracer that can be used to image both flow and metabolism simultaneously.