title: Coronary slow-flow causing transient myocardial hypoperfusion in patients with cardiac syndrome X: long-term clinical and functional prognosis.
abstract: BACKGROUND
  We investigated the possibility that transient coronary slow-flow as assessed during coronary angiography in patients with cardiac syndrome X may impair myocardial perfusion and the effects of this phenomenon on long-term prognosis.
  
  
  METHODS
  From 50 consecutive patients with cardiac syndrome X, we prospectively recruited 16 who exhibited coronary slow-flow during angiography. The remaining 34 patients served as controls. The slow-flow phenomenon was invariably worsened by nitrates and reversed by papaverine. During slow-flow, a dose of 99m-Tc-Methoxy-isobutyl-isonitrile (MIBI) was injected in 12 patients and SPECT imaging performed 1 h later. The perfusion study was repeated after 2 days at rest and, in 9 patients, at peak exercise after 10+/-4 days. Patients were then regularly followed-up.
  
  
  RESULTS
  All 12 patients had a significant MIBI defect in the regions served by the coronary artery that showed slow-flow just prior MIBI injection. After exercise, MIBI tomograms revealed a perfusion defect in 5 out of the 9 patients who underwent stress scanning. At 14+/-2 years follow-up, 1 patient with slow-flow had died and 4 developed significant coronary artery disease (CAD), while all patients of the control group were alive and none had developed significant CAD.
  
  
  CONCLUSIONS
  These results show that the slow-flow phenomenon might be the cause of transient myocardial underperfusion in patients with angina and normal coronary arteries. Apparently, this phenomenon is associated with a worse cardiac prognosis. Therefore, patients with coronary slow-flow should be carefully followed-up.
authors.affiliation: Division of Cardiology, Istituto Scientifico San Raffaele, Università Vita/Salute, Milano, Italy. fragasso.gabriele@hsr.it
authors.forename: Gabriele
authors.initials: G
authors.lastname: Fragasso
authors.forename: Sergio L
authors.initials: SL
authors.lastname: Chierchia
authors.forename: Francesco
authors.initials: F
authors.lastname: Arioli
authors.forename: Orazio
authors.initials: O
authors.lastname: Carandente
authors.forename: Stefano
authors.initials: S
authors.lastname: Gerosa
authors.forename: Mauro
authors.initials: M
authors.lastname: Carlino
authors.forename: Altin
authors.initials: A
authors.lastname: Palloshi
authors.forename: Luigi
authors.initials: L
authors.lastname: Gianolli
authors.forename: Giliola
authors.initials: G
authors.lastname: Calori
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Fazio
authors.forename: Alberto
authors.initials: A
authors.lastname: Margonato