Coronary Microvascular Function and Cortical Pain Processing in Patients With Silent Positive Exercise Testing and Normal Coronary Arteries

• Published in: The American journal of cardiology Vol. 109; no. 12; pp. 1705 - 1710
• Main Authors: Di Franco, Antonino, Lanza, Gaetano A., Di Monaco, Antonio, Sestito, Alfonso, Lamendola, Priscilla, Nerla, Roberto, Tarzia, Pierpaolo, Virdis, Daniela, Vollono, Catello, Valeriani, Massimiliano, Crea, Filippo
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 15.06.2012; Elsevier; Elsevier Limited
• Subjects: Adenosine; Aged; Angina pectoris; Biological and medical sciences; Blood Flow Velocity; Blood pressure; Cardiology. Vascular system; Cardiovascular; Cardiovascular disease; Case-Control Studies; Cold Temperature; Coronary Angiography; Coronary Circulation - drug effects; Coronary heart disease; Coronary vessels; Coronary Vessels - diagnostic imaging; Coronary Vessels - physiopathology; Echocardiography; Echocardiography, Doppler; Electrocardiography; Evoked Potentials, Somatosensory; Exercise; Exercise Test; False Positive Reactions; Female; Heart; Humans; Male; Medical sciences; Microcirculation - drug effects; Microvascular Angina - diagnostic imaging; Microvascular Angina - physiopathology; Middle Aged; Pain - physiopathology; Vasodilator Agents; Physical exercise; Human; Pain; Coronary artery; Cardiovascular disease; Exercise tolerance test; Patient; Asymptomatic; Circulatory system; Cardiology; Normal; Coronary heart disease
• ISSN: 0002-9149; 1879-1913; 1879-1913
• DOI: 10.1016/j.amjcard.2012.02.012

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.