title: Characterization of total occlusions with intracoronary ultrasound: the importance of the duration of occlusion.
abstract: OBJECTIVE
  To assess the impact of the occlusion duration on the characteristics of coronary occlusive plaques.
  
  
  BACKGROUND
  The percutaneous recanalization of chronic total coronary occlusions is a technically demanding and yet often unsuccessful procedure due to unfavorable morphological changes described by histology but not well defined in vivo.
  
  
  METHODS
  Thirty-five consecutive total occlusions of > or = 1 month duration in previously untreated native coronary arteries were studied using intracoronary ultrasound following dilatation with a 1.5 mm balloon. Plaque characteristics of lesions with an occlusive duration of > or = 3 months (old occlusions) and those of < 3 months (recent occlusions) were then compared. The ultrasound cross-section where there was maximal plaque accumulation at the site of occlusion was analyzed for its qualitative and quantitative characteristics. The lesion remodeling index was defined as the vessel area at occlusion divided by the vessel area at a proximal reference.
  
  
  RESULTS
  The old occlusion group comprised 11 lesions whereas 16 lesions were found in the recent occlusion group; the occlusion duration was undetermined in the remaining 8 lesions, and the mean occlusion duration was found to be 4.9 +/- 4.3 months, over a range of 1 36 months. The baseline clinical and angiographic characteristics were similar in the 2 groups. The lesion remodeling index was found to be significantly lower in older occlusions than in the more recent occlusions (0.75 +/- 0.14 vs. 1. 06 +/- 0.25; p = 0.007) and the duration of the occlusion also correlated with the length of calcified segment as determined by ultrasound (p = 0.040), and with a smaller angiographic proximal reference diameter (p = 0.043).
  
  
  CONCLUSIONS
  Long-standing occlusions undergo lesion shrinkage and exhibit more extensive calcification.
authors.affiliation: EMO Centro Cuore Columbus, Columbus Clinic and Catheterization Laboratory, San Raffaele Hospital, Via Buonarroti 48, 20145, Milan, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Nishida
authors.forename: C
authors.initials: C
authors.lastname: Di Mario
authors.forename: C
authors.initials: C
authors.lastname: Briguori
authors.forename: R
authors.initials: R
authors.lastname: Albiero
authors.forename: A
authors.initials: A
authors.lastname: Colombo
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D018084:Ultrasonography, Interventional