Anatomic and physiologic heterogeneity in patients with syndrome X: an intravascular ultrasound study

Interventional Cardiology Center, Columbia Presbyterian Medical Center, New York, New York 10032, USA.

OBJECTIVES. We used intravascular ultrasound imaging of the epicardial vessels to assess coronary morphology, vasomotor response to exercise and exercise-vasomotion after beta-adrenoceptor blockade in patients with syndrome X. BACKGROUND. Syndrome X is defined as chest pain, abnormal exercise test results and normal coronary angiographic findings. Because of the limitations of coronary angiography, intravascular ultrasound was used to define coronary pathophysiology. METHODS. Thirty patients with syndrome X were studied with intravascular ultrasound imaging (30 MHz, 4.3F catheter) of all three major epicardial vessels. Supine arm exercise was performed during coronary imaging. Lumen area was assessed at rest and during peak exercise. The exercise-imaging protocol was repeated after loading with 0.1 mg/kg body weight of intravenous propranolol. RESULTS. Three morphologic groups were identified using intravascular ultrasound: normal coronary arteries (no plaque, intimal thickness < 0.25 mm, n = 12), atheromatous disease (mean [+/- SD] area stenosis 37.9 +/- 7.2%, n = 10) and marked intimal thickening (0.73 +/- 0.11 mm, n = 8). Patients with normal coronary arteries displayed a vasodilatory response to exercise (+16.9% area increase); patients with abnormal coronary arteries displayed a vasoconstrictive response to exercise (-17.4% in the group with plaque; -17.6% in the group with intimal thickening). Propranolol loading attenuated the vasodilatory response in the group with normal coronary arteries (+6.4% area increase) and attenuated the vasoconstrictive response in the two groups with abnormal coronary arteries (-8.0% in the group with plaque; -8.8% in the group with intimal thickening). CONCLUSIONS. Most patients with syndrome X have abnormal coronary arteries by intravascular ultrasound. Intravascular ultrasound identifies three distinct morphologic groups: normal coronary arteries, atheromatous plaque and intimal thickening. Exercise-vasomotion is normal in patients with syndrome X who have normal coronary arteries by ultrasound; patients with abnormal arteries (plaque or intimal thickening) have an abnormal (constrictive) response to exercise. Propranolol loading attenuates vasoreactivity in all subgroups, suggesting divergent therapeutic utility.

This article has been cited by other articles:

				A.-H. Li, B.-C. Lee, K.-C. Chen, C.-S. Weng, and S.-H. Chu Brachial Artery Flow-Mediated Vasodilation in Patients With Cardiac Syndrome X Angiology, October 1, 2008; 59(5): 581 - 586. [Abstract] [PDF]

				G A Lanza Cardiac syndrome X: a critical overview and future perspectives Heart, February 1, 2007; 93(2): 159 - 166. [Abstract] [Full Text] [PDF]

				R. Arroyo-Espliguero, N. Mollichelli, P. Avanzas, E. Zouridakis, V. R Newey, D. K Nassiri, and J. C. Kaski Chronic inflammation and increased arterial stiffness in patients with cardiac syndrome X Eur. Heart J., November 2, 2003; 24(22): 2006 - 2011. [Abstract] [Full Text] [PDF]

				G. Theilmeier, P. Verhamme, S. Dymarkowski, H. Beck, H. Bernar, M. Lox, S. Janssens, M.-C. Herregods, E. Verbeken, D. Collen, et al. Hypercholesterolemia in Minipigs Impairs Left Ventricular Response to Stress: Association With Decreased Coronary Flow Reserve and Reduced Capillary Density Circulation, August 27, 2002; 106(9): 1140 - 1146. [Abstract] [Full Text] [PDF]

				L.-C. Chen, J.-W. Chen, M.-H. Wu, J.-C. Liu, G.-Y. Lan, P. Y.-A. Ding, and M.-S. Chang Differential Coronary Calcification on Electron-Beam CT Between Syndrome X and Coronary Artery Disease in Patients With Chronic Stable Angina Pectoris Chest, November 1, 2001; 120(5): 1525 - 1533. [Abstract] [Full Text] [PDF]

				L. Schwartz and M. G. Bourassa Evaluation of Patients With Chest Pain and Normal Coronary Angiograms Arch Intern Med, August 13, 2001; 161(15): 1825 - 1833. [Full Text] [PDF]

				S.-i. Saitoh, F. Onogi, K. Aikawa, M. Muto, T. Saito, K. Maehara, and Y. Maruyama Multiple endothelial injury in epicardial coronary artery induces downstream microvascular spasm as well as remodeling partly via thromboxane A2 J. Am. Coll. Cardiol., January 1, 2001; 37(1): 308 - 315. [Abstract] [Full Text] [PDF]

				E. Verna, L. Ceriani, L. Giovanella, G. Binaghi, and S. Garancini "False-Positive" Myocardial Perfusion Scintigraphy Findings in Patients with Angiographically Normal Coronary Arteries: Insights from Intravascular Sonography Studies J. Nucl. Med., December 1, 2000; 41(12): 1935 - 1940. [Abstract] [Full Text] [PDF]