Heterogeneous vasomotor responses of coronary conduit and resistance vessels in hypertension

Department of Medicine, Albany Medical College, New York, USA. jhoughton@ccgateway.amc.edu

OBJECTIVES: The purpose of our study was to investigate the relation between conductance and resistance coronary vasomotor responsiveness in hypertensive patients without atherosclerosis. BACKGROUND: Although similar in morphology, conduit and resistance coronary vessels differ importantly in size, function and local environment and appear to be differentially affected in certain disease processes, such as atherosclerosis and hypertension. However, little is known about the effect of hypertension on contiguous coronary conduit and resistance vessels in humans. METHODS: Changes in coronary blood flow (a measure of resistance vessel reactivity) and coronary artery diameter (a measure of conduit vessel reactivity) were investigated in response to graded infusion of the endothelium-dependent agonist acetylcholine (ACh) in 98 patients with normal coronary arteries. RESULTS: In 31 normotensive, euglycemic patients, conduit and resistance coronary artery responses to intracoronary infusion of ACh were significantly correlated (r = 0.73, p = 1 x 10[-6]), although eight patients (26%) had constriction of conduit but dilation of resistance arteries at peak effect. In 28 hypertensive patients without left ventricular hypertrophy (LVH), conduit and resistance artery responses to ACh remained significantly correlated (r = 0.5, p = 0.006), although 12 patients (43%) had discordant findings. Finally, in 39 hypertensive patients with LVH, conduit and resistance artery responses to ACh displayed the lowest correlation (r = 0.38, p = 0.02), with 22 patients (56%) demonstrating conduit artery constriction and resistance artery dilation. CONCLUSIONS: Despite angiographically normal coronary arteries, heterogeneous vasomotor responses (dilation and constriction) were demonstrated in contiguous conduit and resistance arteries in normotensive and hypertensive patients referred for cardiac catheterization because of chest pain. In addition to more severe endothelial dysfunction among conduit and resistance arteries, a greater frequency of discordant conduit and resistance artery responses and resistance vessel constriction was found with increasing severity of hypertension. Our study suggests differing mechanisms of endothelium responsiveness to ACh among conduit and resistance coronary arteries.

This article has been cited by other articles:

				A. L. Moens, I. Goovaerts, M. J. Claeys, and C. J. Vrints Flow-Mediated Vasodilation: A Diagnostic Instrument, or an Experimental Tool? Chest, June 1, 2005; 127(6): 2254 - 2263. [Abstract] [Full Text] [PDF]

				J. Gellman, J. M. Hare, C. J. Lowenstein, G. Gerstenblith, V. Coombs, P. Langenberg, J. A. Brinker, and J. R. Resar L-Arginine Ameliorates the Abnormal Sympathetic Response of the Dysfunctional Human Coronary Microvasculature Angiology, January 1, 2004; 55(1): 1 - 8. [Abstract] [PDF]

				J. L. Houghton, D. S. Strogatz, M. T. Torosoff, V. E. Smith, S. A. Fein, P. A. Kuhner, E. F. Philbin, and A. A. Carr African Americans With LVH Demonstrate Depressed Sensitivity of the Coronary Microcirculation to Stimulated Relaxation Hypertension, September 1, 2003; 42(3): 269 - 276. [Abstract] [Full Text] [PDF]

				J. L. Houghton, E. F. Philbin, D. S. Strogatz, M. T. Torosoff, S. A. Fein, P. A. Kuhner, V. E. Smith, and A. A. Carr The presence of African American race predicts improvement in coronary endothelial function after supplementary L-arginine J. Am. Coll. Cardiol., April 17, 2002; 39(8): 1314 - 1322. [Abstract] [Full Text] [PDF]

				M. Kelm Flow-mediated dilatation in human circulation: diagnostic and therapeutic aspects Am J Physiol Heart Circ Physiol, January 1, 2002; 282(1): H1 - H5. [Full Text] [PDF]

				D. E NEWBY Intracoronary infusions and the assessment of coronary blood flow in clinical studies Heart, August 1, 2000; 84(2): 118 - 120. [Full Text] [PDF]

				S. Hamasaki, J. Al Suwaidi, S. T. Higano, K. Miyauchi, D. R. Holmes Jr., and A. Lerman Attenuated coronary flow reserve and vascular remodeling in patients with hypertension and left ventricular hypertrophy J. Am. Coll. Cardiol., May 1, 2000; 35(6): 1654 - 1660. [Abstract] [Full Text] [PDF]

				E G Zouridakis, I D Cox, X Garcia-Moll, S Brown, P Nihoyannopoulos, and J C Kaski Negative stress echocardiographic responses in normotensive and hypertensive patients with angina pectoris, positive exercise stress testing, and normal coronary arteriograms Heart, February 1, 2000; 83(2): 141 - 146. [Abstract] [Full Text]