Vulnerable plaque features on coronary CT angiography as markers of inducible regional myocardial hypoperfusion from severe coronary artery stenoses

Haim Shmilovich, Victor Y. Cheng*, Balaji K. Tamarappoo, Damini Dey, Ryo Nakazato, Heidi Gransar, Louise E.J. Thomson, Sean W. Hayes, John D. Friedman, Guido Germano, Piotr J. Slomka, Daniel S. Berman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: We explored whether the presence of 3 known features of plaque vulnerability on coronary CT angiography (CCTA) - low attenuation plaque content (LAP), positive remodeling (PR), and spotty calcification (SC) - identifies plaques associated with greater inducible myocardial hypoperfusion measured by myocardial perfusion imaging (MPI). Methods: We analyzed 49 patients free of cardiac disease who underwent CCTA and MPI within a 6-month period and were found on CCTA to have focal 70-99% stenosis from predominantly non-calcified plaque in the proximal or mid segment of 1 major coronary artery. Presence of LAP (≤30 Hounsfield Units), PR (outer wall diameter exceeds proximal reference by ≥5%), and SC (≤3mm long and occupies ≤90° of cross-sectional artery circumference) was determined. On MPI, reversible hypoperfusion in the myocardial territory corresponding to the diseased artery was quantified both as percentage of total myocardium (RevTPD ART) by an automatic algorithm and as summed difference score (SDS ART) by two experienced readers. RevTPD ART≥3% and SDS ART≥3 defined significant inducible hypoperfusion in the territory of the diseased artery. Results: Plaques in patients with RevTPD ART≥3% more frequently exhibited LAP (70% vs. 14%, p<0.001) and PR (70% vs. 24%, p=0.001) but not SC (55% vs. 34%, p=0.154). RevTPD ART increased from 1.3±1.2% in arteries with LAP-/PR- plaques to 3.2±4.3% with LAP+/PR- or LAP-/PR+ plaques to 8.3±2.4% with LAP+/PR+ plaques (p<0.001); SDS ART showed a similar increase: 0.3±0.7 to 2.3±2.8 to 6.0±3.8 (p<0.001). Using the same LAP/PR categorization, there was a marked increase in the frequency of significant hypoperfusion as determined by both RevTPD ART≥3% (1/19 to 10/21 to 9/9, p<0.001) and SDS ART≥3 (1/19 to 8/21 to 8/9, p<0.001). LAP and PR, but not SC, were strong predictors of RevTPD ART and SDS ART in regression models adjusting for potential confounders. Conclusions: Presence of low attenuation plaque and positive remodeling in severely stenotic plaques on CCTA is strongly predictive of myocardial hypoperfusion and may be useful in assessing the hemodynamic significance of such lesions.

Original languageEnglish
Pages (from-to)588-595
Number of pages8
JournalAtherosclerosis
Volume219
Issue number2
DOIs
StatePublished - Dec 2011
Externally publishedYes

Keywords

  • Coronary artery stenosis
  • Low attenuation plaque
  • Myocardial perfusion
  • Positive remodeling
  • Spotty calcification

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