[Invasive examination of cardiovascular disease].
Invasive cardiovascular examination by coronary angioscopy and by using a Doppler guide wire, a pressure guide wire and intravascular ultrasound has extensively developed. A Doppler guide wire is used for measurement of flow velocity and evaluation of coronary blood flow. Previous studies demonstrated by assessing maximum coronary vasodilatory capacity that endothelium-dependent or independent vasodilation was impaired in hypertension and hypercholesterolemia or in syndrome X. Elevation of coronary vascular resistance during coronary microvascular spasm has been verified by using a Doppler wire. A pressure guide wire provides coronary transstenotic pressure and is available in calculating myocardial fractional flow reserve(FFRmyo). FFRmyo is an important parameter to assess the coronary functional stenosis that is culprit for myocardial ischemia. It is calculated from the ratio of the mean transstenotic pressure to the mean pressure proximal to the stenosis during maximum coronary hyperemia. The value of FFRmyo considered as necessary for coronary intervention is below 0.75. Intravascular ultrasound(IVUS) is applied as both a diagnostic tool and for intervention purpose. It enabled tissue characterization of the vascular wall as well as measurements of vascular diameter, vascular lumen area and plaque area. It also aided in optimal devise selection, decision of interventional endpoint and assessment of restenosis. IVUS promoted deployment of high-pressure stents to obtain a large post-procedural lumen area as well as abolition of anticoagulation in case of optimal stent deployment. Coronary angioscopy has been developed to investigate the pathogenesis of acute coronary syndrome, where disrupted yellow plaque and overlying thrombus play important roles. Angioscopy has also evidenced regression of intimal hyperplasia after coronary stenting.
Horimoto
M
M
Division of Cardiology, Sapporo National Hospital.
Takenaka
T
T
Igarashi
K
K
Inoue
H
H
Akino
M
M
D017546:Angioscopy; D001783:Blood Flow Velocity; D003327:Coronary Disease / Q000175:diagnosis* / Q000503:physiopathology; D003331:Coronary Vessels / Q000503:physiopathology; D006801:Humans; D018084:Ultrasonography, Interventional