Association between coronary lesion severity and distal microvascular resistance in patients with coronary artery disease.
Homogeneity of microvascular resistance in different perfusion areas of the same heart is generally assumed. We investigated the effect of the severity of an epicardial stenosis on microvascular resistance in 27 patients with coronary artery disease and stable angina. All patients had an angiographically normal coronary artery, an artery with an intermediate lesion, and an artery with a severe lesion; the latter was treated with angioplasty. In each patient, distal blood flow velocity and pressure were measured during baseline and maximal hyperemia (induced by intracoronary adenosine) using a Doppler and pressure guide wire, respectively. The ratio of mean distal pressure to average peak blood flow velocity was used as an index for the microvascular resistance (MRv). Within patients, the hyperemic MRv was higher in arteries with more severe stenosis (P = 0.021). After percutaneous transluminal coronary angioplasty (PTCA), the hyperemic MRv decreased (pre-PTCA, 2.6 vs. post-PTCA, 1.9 mmHg.cm(-1)s(-1), P < 0.01) toward the value of the reference artery (1.7 mmHg.cm(-1)s(-1); P = 0.67). We conclude that there is a positive association between coronary lesion severity and variability of distal microvascular resistance that normalizes after angioplasty. This study challenges the concept of uniform distribution of hyperemic MRv that is relevant for the interpretation of both noninvasive and invasive diagnostic tests.
Chamuleau
Steven A J
SA
Department of Cardiology, Academic Medical Center, University of Amsterdam, B2-108, PO Box 22660, 1100 DD Amsterdam, The Netherlands.
Siebes
Maria
M
Meuwissen
Martijn
M
Koch
Karel T
KT
Spaan
Jos A E
JA
Piek
Jan J
JJ
D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000503:physiopathology*; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D012720:Severity of Illness Index; D014655:Vascular Resistance