THERAPY AND PREVENTION SURGERY Comparative long-term effects of coronary artery bypass graft surgery and percutaneous transluminal coronary angioplasty on regional coronary flow reserve

To evaluate the relative long-term improvement in coronary artery hemodynamics after revascularization by coronary artery bypass graft surgery (CABG) or percutaneous transluminal coronary angioplasty (PTCA), regional coronary flow reserve (CFR) was measured, by digital computer analysis of 35 mm cine film, in 50 men undergoing cardiac catheterization. CFR (mean ± SEM) in 12 atherosclerotic arteries before revascularization was 1.02 + 0.05. Mean CFR in 29 normal arteries of men with normal coronary arteriograms was significantly higher (2.59 + 0.11) than that in 16 atherosclerotic arteries of patients revascularized by CABG (2.02 + 0. 17, p < .01) or in 14 atherosclerotic arteries of those revascularized by PTCA (1.97 + 0.12, p < .01). No difference in CFR between the CABG and PTCA groups was found and variables known to influence CFR were similar between groups. Equivalent and significant long-term improvement in coronary artery hemodynamics is provided by CABG or PTCA. We postulate that the difference in CFR in the men with normal arteries and those who underwent revascularization was related to the effects of the general atherosclerotic process, which remain despite successful treatment by these techniques. Circulation 72, No. 4, 833-839, 1985. MYOCARDIAL REVASCULARIZATION can now be accomplished by either coronary artery bypass graft surgery (CABG) or percutaneous transluminal coronary angioplasty (PTCA).`Although symptomatic, metabolic, hemodynamic, and functional improvement has been demonstrated with each technique,5-'5 little data exist comparing the two. 6. 17 One difficulty in undertaking comparative studies resides in the clinical disparities in groups of patients undergoing these procedures. While patients who undergo CABG are more likely to have chronic symptoms, a history of myocardial infarction, and multivessel disease, those treated by PTCA characteristically have recent onset of symptoms, normal ventricular function, and singlevessel disease. More importantly, the lack of a generally available clinical test sensitive enough to evaluate From the Division of Cardiology, Veterans Administration Medical Center, Ann Arbor. Supported in part by grants from the Veterans Administration, the Merck Fellowship Foundation of the American College of Cardiology, and the Michigan Heart Association. Address for correspondence: Eric R. Bates, M.D., Division of Cardiology, Veterans Administration Medical Center, Ann Arbor, MI 48105. Received Feb. 7, 1985; revision accepted June 20, 1985 Vol. 72, No. 4. October 1985 subtle regional differences in coronary blood flow or myocardial function due to either technique has inhibited investigation. The coronary reactive hyperemic response is an important, reproducible physiologic parameter. l' 1' It can be measured by determining the ratio of maximal coronary blood flow to resting flow. Increasingly significant obstructive coronary artery disease progressively exhausts this coronary flow reserve (CFR) by reducing peak flow.20 2 Three techniques have recently been developed that allow the measurement of regional CFR in man. The first uses a pulsed Doppler coronary artery catheter, which can measure proximal coronary flow velocity in the catheterization laboratory.2-2 The second uses a Doppler velocity probe, which can be applied directly to selected epicardial coronary arteries at the time of open heart surgery to measure the reactive hyperemic response to transient arterial occlusion.25 The third is a digital radiographic technique performed during routihe cardiac catheterization that measures the myocardial reactive hyperemic response to intracoronary injection of contrast medium.24 25 The present study, in which we used the third tech833 by gest on July 5, 2017 http://ciajournals.org/ D ow nladed from