title: Coronary flow--pressure relationship distal to epicardial stenosis.
abstract: To assess the coronary flow velocity - pressure relationship distal to a stenosis, and to evaluate the influence of microvascular abnormalities on this relationship, coronary flow velocity and coronary pressure were measured simultaneously in 38 patients (42 vessels). The instantaneous peak coronary flow velocity was plotted against the simultaneous measured distal coronary pressure, and the slope of the relation in the phase of diastolic flow decrease was calculated as the flow - pressure slope index (FPSI) and the X-intercept of the slope was calculated as zero-flow pressure (Pzf). The slope of the curve increased from 2.0+/-2.6 to 4.5+/-4.1 (p<0.001) and the X-intercept decreased from 42+/-16 to 27+/-13 mmHg (p<0.001) after papaverine injection. After successful coronary intervention, Pzf increased from 23+/-10 to 35+/-11 (p<0.01) and FPSI decreased from 6.8+/-5.1 to 3.5+/-1.8 (p<0.05). Pzf was higher in patients with an old myocardial infarction. It is feasible to assess the relationship between coronary flow and pressure distal to a stenosis in the clinical setting, and the relationship may provide additional information regarding coronary microcirculation. Microvascular abnormalities may play an important role in the coronary flow - pressure relationship distal to stenosis.
authors.affiliation: The Second Department of Internal Medicine, Tokyo Medical University, Japan. n-tanaka@tokyo-med.ac.jp
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tanaka
authors.forename: Kenji
authors.initials: K
authors.lastname: Takazawa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takeda
authors.forename: Masaru
authors.initials: M
authors.lastname: Aikawa
authors.forename: Naohisa
authors.initials: N
authors.lastname: Shindo
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Amaya
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kobori
authors.forename: Akira
authors.initials: A
authors.lastname: Yamashina
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D003326:Coronary Circulation; D023903:Coronary Restenosis / Q000503:physiopathology; D023921:Coronary Stenosis / Q000503:physiopathology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000503:physiopathology; D012307:Risk Factors