title: Acute type 5 phosphodiesterase inhibition with sildenafil enhances flow-mediated vasodilation in patients with chronic heart failure.
abstract: OBJECTIVE
  To determine the acute effects of type 5 phosphodiesterase inhibition with sildenafil on flow-mediated vasodilation in the brachial artery of patients with chronic heart failure.
  
  
  BACKGROUND
  Impaired endothelium-dependent, flow-mediated vasodilation in patients with heart failure is partly attributable to hyporesponsiveness of cyclic guanosine monophosphate (cGMP) mediated vasorelaxation effector mechanisms in vascular smooth muscle. The effect of inhibition of cGMP degradation with sildenafil, a specific type 5 cGMP phosphodiesterase inhibitor, on flow-mediated dilation in heart failure is unknown.
  
  
  METHODS
  Flow-mediated vasodilation after release of 1, 3 and 5 min of transient arterial occlusion was measured in the brachial artery with high resolution two-dimensional ultrasound imaging in 48 patients with chronic heart failure before and 1 h after randomized, double-blind assignment to a single oral dose of sildenafil 12.5, 25 or 50 mg or matching placebo.
  
  
  RESULTS
  In response to oral administration of a single dose of study drug, the change in flow-mediated vasodilation after release of 1, 3 and 5 min of arterial occlusion was significantly greater in patients receiving sildenafil 25 mg (3.3 +/- 1.9, 3.8 +/- 1.8 and 4.0 +/- 1.8%, respectively, p < 0.05) and patients receiving sildenafil 50 mg (3.7 +/- 1.3, 4.1 +/- 1.1, 3.9 +/- 1.3%, respectively, p < 0.05) than that of patients receiving placebo (0.7 +/- 1.1, 0.2 +/- 1.2, 0.6 +/- 0.8%, respectively).
  
  
  CONCLUSIONS
  Acute type 5 phosphodiesterase inhibition with sildenafil 25 and 50 mg increases endothelium-dependent, flow-mediated vasodilation in patients with chronic heart failure when compared with placebo.
authors.affiliation: Division of Circulatory Physiology, Columbia Presbyterian Medical Center, New York, New York 10032, USA. sdk8@columbia.edu
authors.forename: S D
authors.initials: SD
authors.lastname: Katz
authors.forename: K
authors.initials: K
authors.lastname: Balidemaj
authors.forename: S
authors.initials: S
authors.lastname: Homma
authors.forename: H
authors.initials: H
authors.lastname: Wu
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Maybaum
mesh_terms: D001775:Blood Circulation; D001783:Blood Flow Velocity / Q000187:drug effects; D002303:Cardiac Output, Low / Q000188:drug therapy* / Q000503:physiopathology*; D002908:Chronic Disease; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use*; D011687:Purines; D012016:Reference Values; D000068677:Sildenafil Citrate; D013450:Sulfones; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D007527:Isoenzymes; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D010727:Phosphoric Diester Hydrolases