title: Noninvasive evaluation of flow reserve in the left anterior descending coronary artery in patients with cardiac syndrome X.
abstract: Data on coronary flow reserve (CFR) in patients with syndrome X are still controversial. Further, noninvasive evaluation of epicardial and microvascular flow reserves in these patients has never been performed. In 17 patients with syndrome X and in 17 age- and gender-matched control subjects, CFR in the mid left anterior descending coronary artery (LAD) was evaluated by transthoracic color and pulse-wave Doppler using a 7-mHz probe (Sequoia, Siemens). Peak diastolic LAD flow was calculated at rest and at peak adenosine (140 microg/kg/min intravenously in 90 seconds). Myocardial contrast echocardiography (MCE) was performed at rest and during adenosine use by real-time cadence pulse sequencing and intravenous SonoVue (Bracco; 5 ml at 1 ml/min) and microvascular blood volume (A), velocity (beta), and flow (Axbeta) by replenishing curves (y = A[1 - e(betat)]). CFR was measured by Doppler echocardiography as an adenosine/rest velocity ratio and by MCE as a microvascular volume, velocity, and flow adenosine/rest ratio. Compared with controls, patients with syndrome X demonstrated lower LAD CFR and velocity and flow microvascular flow reserves (p <0.01, <0.005, and <0.005, respectively). In patients with syndrome X, those with angina and ST-segment depression during adenosine testing had even lower LAD CFR and velocity and flow microvascular flow reserves compared with those with no symptoms (p <0.0001, <0.0001, and <0.005, respectively). LAD CFR demonstrated a significant linear correlation with velocity microvascular flow reserve (r = 0.92, p <0.0001) and flow microvascular flow reserve (r = 0.77, p <0.0001). In conclusion, CFR in the LAD, successfully evaluated by transthoracic Doppler echocardiography and MCE, is significantly decreased in patients with syndrome X and even more in those with angina pectoris and ST-segment depression during adenosine testing. Thus, noninvasive evaluation of CFR by echocardiography is feasible and provides information on the severity of microvascular impairment.
authors.affiliation: Institute of Cardiology, Catholic University of the Sacred Heart, Rome, Italy. lgaliuto@rm.unicatt.it
authors.forename: Leonarda
authors.initials: L
authors.lastname: Galiuto
authors.forename: Alfonso
authors.initials: A
authors.lastname: Sestito
authors.forename: Sabrina
authors.initials: S
authors.lastname: Barchetta
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Sgueglia
authors.forename: Fabio
authors.initials: F
authors.lastname: Infusino
authors.forename: Claudio
authors.initials: C
authors.lastname: La Rosa
authors.forename: Gaetano
authors.initials: G
authors.lastname: Lanza
authors.forename: Filippo
authors.initials: F
authors.lastname: Crea
mesh_terms: D000241:Adenosine; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000187:drug effects; D001810:Blood Volume / Q000187:drug effects; D016022:Case-Control Studies; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004452:Echocardiography; D018618:Echocardiography, Doppler, Color; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D017566:Microvascular Angina / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008875:Middle Aged; D012146:Rest; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine