title: Atherosclerotic Plaque Analysis: A Pilot Study to Assess a Novel Tool to Predict Outcome Following Lower Limb Endovascular Intervention.
abstract: BACKGROUND
  Atherosclerotic plaque analysis using computed tomography angiography (CTA) has been found to be accurate and reproducible in the coronary and carotid arteries. The aim of our study was to assess the utility of this technique in predicting outcome following lower limb endovascular interventions.
  
  
  METHODS
  Pre-procedural CTA was retrospectively analysed in 50 patients who had undergone femoropopliteal (F-P) angioplasty (and/or stenting). Plaque analysis was performed using TeraRecon workstation by two observers blinded to the long-term outcome. Using the Hounsfield units (HU) scale atherosclerotic plaque composition was subdivided into volumes of soft (-100-100 HU) fibrocalcific (101-300 HU) or calcified (300-1000 HU) components. The relationship between plaque composition, clinical and procedural variables, and the study end points (vessel patency, binary restenosis rate, and Amputation-Free Survival [AFS]) were assessed using multivariate analysis.
  
  
  RESULTS
  The technical success rate of the endovascular procedure was 98%, with 48% of patients receiving F-P stents. The AFS was 90%, primary patency 84%, assisted primary patency 88%, and binary restenosis 44% all at 1 year. A significantly greater total volume of calcified plaque (1.1 [.01-3.2] cm(3) vs. .11 [0-1.86] cm(3), p < .001) was found in patients developing restenosis (>50%) compared with those who did not. Patients with a calcified plaque volume greater than 1.1 cm(3) had a significantly worse AFS than those with a volume less than 1.1 cm(3) (p = .0038). Multivariate analysis showed that the percentage calcified plaque (p = .003, HR 11.4, 95% CI 1.45-37.29) was an independent predictor of binary restenosis at 12 months, and that absolute volume of calcified plaque (p = .001, HR 3.56, 95% CI 1.64-7.7) was independently associated with AFS.
  
  
  CONCLUSIONS
  The burden of calcified plaque, but not soft or fibrocalcific plaque is related to restenosis, reintervention, and AFS. Computed tomography plaque analysis may form an important non-invasive tool for risk stratification in patients undergoing F-P endovascular procedures.
authors.affiliation: Department of Vascular Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: S D
authors.initials: SD
authors.lastname: Patel
authors.affiliation: Department of Vascular Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: V
authors.initials: V
authors.lastname: Zymvragoudakis
authors.affiliation: Department of Vascular Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: L
authors.initials: L
authors.lastname: Sheehan
authors.affiliation: Department of Vascular Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: T
authors.initials: T
authors.lastname: Lea
authors.affiliation: Department of Vascular Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: B
authors.initials: B
authors.lastname: Modarai
authors.affiliation: Department of Interventional Radiology, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: K
authors.initials: K
authors.lastname: Katsanos
authors.affiliation: Department of Vascular Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK. Electronic address: Hany.Zayed@gstt.nhs.uk.
authors.forename: H
authors.initials: H
authors.lastname: Zayed
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000671:Amputation, Surgical; D016009:Chi-Square Distribution; D003251:Constriction, Pathologic; D018572:Disease-Free Survival; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005355:Fibrosis; D006801:Humans; D053208:Kaplan-Meier Estimate; D023821:Limb Salvage; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D058729:Peripheral Arterial Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D010865:Pilot Projects; D058226:Plaque, Atherosclerotic; D011150:Popliteal Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012008:Recurrence; D019233:Retreatment; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents; D013997:Time Factors; D036542:Tomography, Spiral Computed; D016896:Treatment Outcome; D061205:Vascular Calcification / Q000000981:diagnostic imaging / Q000628:therapy; D014654:Vascular Patency
keywords: Computed tomography; Lower limb; Plaque analysis