title: Coronary microvascular function and cortical pain processing in patients with silent positive exercise testing and normal coronary arteries.
abstract: ST-segment depression during exercise stress testing in asymptomatic subjects showing normal coronary arteries is considered a "false-positive" result. Coronary microvascular dysfunction, however, might be a possible cause of ST-segment depression in these cases. We assessed the coronary blood flow response to adenosine and to cold pressor test in the left anterior descending artery, using transthoracic Doppler echocardiography in 14 asymptomatic subjects with exercise-induced ST-segment depression and normal coronary arteries (group 1), 14 patients with microvascular angina (group 2), and 14 healthy subjects (group 3). Flow-mediated dilation was assessed in the brachial artery. Central pain processing was assessed using cortical laser evoked potentials during chest and right hand stimulation with 3 sequences of painful stimuli. The coronary blood flow response to adenosine was 1.8 ± 0.4, 1.9 ± 0.5, and 3.1 ± 0.9 in groups 1, 2, and 3, respectively (p <0.001). The corresponding coronary blood flow responses to the cold pressor test were 1.74 ± 0.4, 1.53 ± 0.3, and 2.3 ± 0.6 (p <0.001). The flow-mediated dilation was 5.5 ± 2.3%, 4.6 ± 2.4%, and 9.8 ± 1.2% in the 3 groups, respectively (p <0.001). The laser evoked potential N2/P2 wave amplitude decreased throughout the 3 sequences of stimulation in groups 1 and 3 but not in group 2 (chest, -19 ± 22%, +11 ± 42% and -36 ± 12%, p <0.001; right hand, -22 ± 25%, +12 ± 43% and -30 ± 20%, p = 0.009; in groups 1, 2, and 3). In conclusion, exercise stress test-induced ST-segment depression in asymptomatic subjects with normal coronary arteries cannot be considered as a simple false-positive result, because it can be related to coronary microvascular dysfunction. The different symptomatic state compared to patients with microvascular angina can, at least in part, be explained by differences in cortical processing of neural pain stimuli.
authors.affiliation: Institute of Cardiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Di Franco
authors.forename: Gaetano A
authors.initials: GA
authors.lastname: Lanza
authors.forename: Antonio
authors.initials: A
authors.lastname: Di Monaco
authors.forename: Alfonso
authors.initials: A
authors.lastname: Sestito
authors.forename: Priscilla
authors.initials: P
authors.lastname: Lamendola
authors.forename: Roberto
authors.initials: R
authors.lastname: Nerla
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Tarzia
authors.forename: Daniela
authors.initials: D
authors.lastname: Virdis
authors.forename: Catello
authors.initials: C
authors.lastname: Vollono
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Valeriani
authors.forename: Filippo
authors.initials: F
authors.lastname: Crea
mesh_terms: D000241:Adenosine; D000368:Aged; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D003080:Cold Temperature; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004452:Echocardiography; D015150:Echocardiography, Doppler; D005073:Evoked Potentials, Somatosensory; D005080:Exercise Test; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D017566:Microvascular Angina / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine