title: Measurements of coronary reactive hyperemia with a Doppler probe. Intraoperative guide to hemodynamically significant lesions.
abstract: The physiological significance of coronary obstructions of intermediate severity are difficult to assess from the angiogram alone. The hemodynamic significance of clinical coronary stenoses can be readily assessed, however, with a miniaturized Doppler probe developed at The University of Iowa Hospitals and Clinics to measure phasic coronary velocity. No dissection of the coronary vessel is required. The probe is held in place over the coronary vessel with a small suction cup. Reactive hyperemia responses obtained following a 20 second occlusion clearly demonstrate the hemodynamic significance of a coronary stenosis. We have employed this approach in 64 patients with coronary artery disease. In 12 (19%) in whom the degree of stenosis of the vessel was equivocal (diameter narrowing 25% to 70%), the use of the Doppler probe and a 20 second reactive hyperemia curve allowed accurate and immediate assessment of the need for a bypass. Five of these equivocal lesions did not produce any alterations in coronary reserve and, accordingly, the vessels were not bypassed. In seven of them, the reactive hyperemia response was markedly depressed and as a result the vessel in question was bypassed. Thus measurements of coronary reactive hyperemia in vessels with obstruction of intermediate severity can influence the operative plan by assessing the physiological significance of the obstruction.
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure; D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis* / Q000503:physiopathology; D004301:Doppler Effect; D006439:Hemodynamics; D006801:Humans; D006940:Hyperemia / Q000175:diagnosis* / Q000503:physiopathology; D008875:Middle Aged; D014465:Ultrasonics / Q000295:instrumentation; D014463:Ultrasonography