Effects of antihypertensive drugs on flow disturbances: nifedipine, captopril, and metoprolol evaluated by quantitative spectral analysis of Doppler flow patterns in patients with carotid stenosis.
Hemodynamic theories of atherogenesis suggest that flow disturbances (departures from laminar flow including high and low shear) and increases in heart rate may be important in the initiation, progression, and complications of atherosclerosis such as dissection and embolism. It is therefore desirable to evaluate the effects of antihypertensive drugs on the occurrence of such flow disturbances. Effects of metoprolol, nifedipine, and captopril were studied, by quantitative spectral analysis, in 20 patients with carotid stenosis to evaluate 3 indices of disturbed flow: peak velocity, spectral broadening index and window index (WI). Heart rate (HR), and the product of WI by HR, were improved (reduced) significantly by metoprolol (p < 0.05), and worsened by nifedipine (p < 0.05), but most of the effect was due to effects on heart rate. These findings suggest that most of the benefit of antihypertensive drugs on flow disturbances can be identified by counting heart rate. Further developments will require improved methods for quantitation of flow disturbances.
Spence
J D
JD
Department of Medicine, University of Western Ontario, London, Canada.
D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000627:therapeutic use*; D002302:Cardiac Output / Q000187:drug effects; D016893:Carotid Stenosis / Q000188:drug therapy / Q000503:physiopathology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use*; D009543:Nifedipine / Q000627:therapeutic use*; D012039:Regional Blood Flow; D014655:Vascular Resistance / Q000187:drug effects
D002216:Captopril; D008790:Metoprolol; D009543:Nifedipine