title: Hyperemic myocardial perfusion imaging for noninvasive detection of coronary disease in man: comparison of treadmill exercise and intravenous dipyridamole infusion.
abstract: To further understand hyperemic myocardial perfusion imaging, the effects of exercise and intravenous dipyridamole on coronary flow, coronary stenosis luminal area, stenosis flow resistance, and regional myocardial perfusion were evaluated in patients with arteriographically documented coronary artery disease. Coronary hemodynamics were assessed in 24 patients undergoing routine diagnostic catheterization. Coronary flow was measured by coronary sinus thermodilution. Computer assisted stenosis measurements were made. During isometric handgrip coronary sinus flow increased to 1.7 X baseline value, and epicardial coronary arteries constricted to increase predicted stenosis flow resistance by 40%. A 4-minute intravenous dipyridamole infusion (0.56 mg/kg) increased coronary sinus flow to 2.4 X baseline with, on average, no change in the stenotic coronary lumen diameter. During simultaneous isometric handgrip and dipyridamole infusion coronary sinus flow increased to 3.3 X baseline value and stenosis flow resistance increased an average of 36%. Regional myocardial perfusion was assessed in 33 patients by thallium201 myocardial perfusion imaging following maximal treadmill exercise and again following intravenous dipyridamole infusion. Regional thallium201 imaging effects were correlated with measurements of angiographic coronary disease. Sensitivity and specificity for detecting a greater than or equal to 50% stenosis were 85% and 64% (p less than .005), respectively, for dipyridamole and 84% and 68% (p less than .005) for exercise thallium201. In summary, coronary blood flow increases with isometric exercise and is near maximal following intravenous dipyridamole. Quantitative arteriographic techniques demonstrate isometric exercise-induced constriction of coronary stenoses and increased stenosis flow resistance. Stenosis flow resistance increases following intravenous dipyridamole only for severe (greater than or equal to 65%) lesions. Treadmill exercise and intravenous dipyridamole are comparably effective hyperemic stimuli for creating regional perfusion differences for the noninvasive detection of coronary disease.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging; D004176:Dipyridamole; D005080:Exercise Test; D006225:Hand; D006321:Heart / Q000000981:diagnostic imaging; D006439:Hemodynamics; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D011877:Radionuclide Imaging; D013815:Thermodilution
chemical_list: D004176:Dipyridamole