title: Coronary vasoconstriction after angioplasty of total occlusions: relation to change in coronary perfusion pressure.
abstract: OBJECTIVE
  This study evaluated the coronary vasomotor response after successful angioplasty of chronic total coronary occlusions and tested the hypothesis that the degree of distal vasoconstriction is dependent on the change in perfusion pressure.
  
  
  BACKGROUND
  Although distal coronary vasoconstriction has been observed to occur frequently after successful percutaneous transluminal coronary angioplasty, little is known about this vasomotor response after angioplasty of chronic total occlusions.
  
  
  METHODS
  Thirty patients with successful angioplasty of chronic total occlusions of the left coronary artery were studied. Quantitative coronary measurements were made at 0, 15 and 30 min after angioplasty and again after intracoronary nitroglycerin administration in coronary artery segments distal to the dilated lesion and in a control vessel. The change in distal perfusion pressure was defined as mean systemic arterial pressure minus residual mean trans-stenotic pressure gradient minus mean coronary wedge pressure.
  
  
  RESULTS
  The distal segments showed greater vasoconstriction (vs. nitroglycerin) at 15 and 30 min compared with that at 0 min after angioplasty (32.3 +/- 2.2% and 35.2 +/- 2.5% vs. 12.5 +/- 1.8%, respectively, p < 0.005) and compared with control segments (32.3 +/- 2.2% vs. 12.1 +/- 2.0%, p < 0.005, and 35.2 +/- 2.5% vs. 12.5 +/- 2.0%, p < 0.005, respectively). The degree of vasoconstriction at 30 min in the distal segments was found to correlate closely with the change in distal perfusion pressure (r = 0.73, p < 0.001).
  
  
  CONCLUSIONS
  Coronary distal vasoconstriction occurs frequently after successful angioplasty of chronic total occlusions and correlates closely with the change in coronary perfusion pressure. These findings support the hypothesis of reset epicardial coronary autoregulation in chronic hypoperfusion such that restoration of normal perfusion pressure after successful angioplasty may provoke reflex vasoconstriction.
authors.affiliation: Department of Medicine, University of Hong Kong, Queen Mary Hospital.
authors.forename: W H
authors.initials: WH
authors.lastname: Leung
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D015906:Angioplasty, Balloon, Coronary; D001794:Blood Pressure / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology; D003327:Coronary Disease / Q000503:physiopathology* / Q000628:therapy; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D014661:Vasoconstriction / Q000502:physiology*