UNLABELLED: Beta-adrenergic blocking agents are widely used in coronary artery disease (CAD), although their impact on myocardial blood flow (MBF) and coronary flow reserve (CFR) remains unclear. We studied the effect of long-term beta-blocker treatment (carvedilol or metoprolol) on coronary microcirculation in CAD patients using PET. METHODS:Regional and global resting and adenosine-induced hyperemic MBF and CFR were measured with 13N-ammonia and PET in 36 CAD patients before and after 12 wk of oral therapy with either carvedilol, 50 mg/d, or metoprolol, 100 mg/d. RESULTS: Beta-blockade decreased global resting MBF in proportion to cardiac work (from 0.86 +/- 0.20 to 0.77 +/- 0.14 mL/min/g, P < 0.05) without affecting global hyperemic flow. Hyperemic MBF was significantly lower in stenosis-dependent segments than in remote segments (1.76 +/- 0.64 vs. 2.04 +/- 0.67 mL/min/g, P < 0.05) at baseline but was comparable in both after treatment (2.02 +/- 0.68 vs. 1.90 +/- 0.78 mL/min/g, P = not statistically significant [NS]), resulting in a significant CFR increase in stenotic segments (+15%, P < 0.05) but not in remote segments (+9%, P = NS). CONCLUSION: The beneficial effect of beta-adrenergic blockade can be explained by the reduction in oxygen consumption (= decreased demand) but also by a modest improvement in vasodilator capacity (= increased supply). The improvement in CFR is found predominantly in stenosis-dependent rather than remote segments.
RCT Entities:
UNLABELLED: Beta-adrenergic blocking agents are widely used in coronary artery disease (CAD), although their impact on myocardial blood flow (MBF) and coronary flow reserve (CFR) remains unclear. We studied the effect of long-term beta-blocker treatment (carvedilol or metoprolol) on coronary microcirculation in CAD patients using PET. METHODS: Regional and global resting and adenosine-induced hyperemic MBF and CFR were measured with 13N-ammonia and PET in 36 CAD patients before and after 12 wk of oral therapy with either carvedilol, 50 mg/d, or metoprolol, 100 mg/d. RESULTS: Beta-blockade decreased global resting MBF in proportion to cardiac work (from 0.86 +/- 0.20 to 0.77 +/- 0.14 mL/min/g, P < 0.05) without affecting global hyperemic flow. Hyperemic MBF was significantly lower in stenosis-dependent segments than in remote segments (1.76 +/- 0.64 vs. 2.04 +/- 0.67 mL/min/g, P < 0.05) at baseline but was comparable in both after treatment (2.02 +/- 0.68 vs. 1.90 +/- 0.78 mL/min/g, P = not statistically significant [NS]), resulting in a significant CFR increase in stenotic segments (+15%, P < 0.05) but not in remote segments (+9%, P = NS). CONCLUSION: The beneficial effect of beta-adrenergic blockade can be explained by the reduction in oxygen consumption (= decreased demand) but also by a modest improvement in vasodilator capacity (= increased supply). The improvement in CFR is found predominantly in stenosis-dependent rather than remote segments.
Authors: E Gordon Depuey; John J Mahmarian; Todd D Miller; Andrew J Einstein; Christopher L Hansen; Thomas A Holly; Edward J Miller; Donna M Polk; L Samuel Wann Journal: J Nucl Cardiol Date: 2012-04 Impact factor: 5.952
Authors: Arthur Nasis; Brian S Ko; Michael C Leung; Paul R Antonis; Dee Nandurkar; Dennis T Wong; Leo Kyi; James D Cameron; John M Troupis; Ian T Meredith; Sujith K Seneviratne Journal: Eur Radiol Date: 2013-02-21 Impact factor: 5.315
Authors: Richard T George; Armin Arbab-Zadeh; Rodrigo J Cerci; Andrea L Vavere; Kakuya Kitagawa; Marc Dewey; Carlos E Rochitte; Andrew E Arai; Narinder Paul; Frank J Rybicki; Albert C Lardo; Melvin E Clouse; Joao A C Lima Journal: AJR Am J Roentgenol Date: 2011-10 Impact factor: 3.959
Authors: Simone D Jenni; Tiziano Schepis; Rolf Jenni; Patrick T Siegrist; Philipp A Kaufmann; Tony M Glaus Journal: Eur J Nucl Med Mol Imaging Date: 2008-09-26 Impact factor: 9.236
Authors: Lars Husmann; Mischa Wiegand; Ines Valenta; Oliver Gaemperli; Tiziano Schepis; Patrick T Siegrist; Mehdi Namdar; Christophe A Wyss; Hatem Alkadhi; Philipp A Kaufmann Journal: Int J Cardiovasc Imaging Date: 2007-12-25 Impact factor: 2.357
Authors: Richard T George; Armin Arbab-Zadeh; Julie M Miller; Kakuya Kitagawa; Hyuk-Jae Chang; David A Bluemke; Lewis Becker; Omair Yousuf; John Texter; Albert C Lardo; João A C Lima Journal: Circ Cardiovasc Imaging Date: 2009-03-31 Impact factor: 7.792