title: Thoracic Aortic Strain is Irrelevant Regarding Endograft Sizing in Most Young Patients.
abstract: BACKGROUND
  The introduction of electrocardiogram gating in computed tomography (CT) angiography imaging of aortic disease raised questions whether diameters measured on diastolic images can lead to the undersizing of aortic endografts. As previous studies suggested that young patients may have the highest risk of an unintended undersize, the aim of our study was to analyze the strain of the thoracic aorta in a young patient cohort.
  
  
  METHODS
  We assessed the descending aorta of 52 patients (35 men, mean age 41.1 ± 7.3 years) who underwent coronary CT angiography (CCTA) with suspected coronary artery disease. To reduce radiation dose, native calcium score scans triggered on late systole were compared with diastolic phase CCTA images. Cross-section areas were measured, and effective diameters were derived at 3 levels of the visible segment of the descending aorta (P1, P2, and P3) in systole and diastole. Aortic pulsatility (mm, dsystolic-ddiastolic) and strain (%, [dsystolic-ddiastolic]/ddiastolic) were calculated at each level. All measurements were performed 3 times by 2 independent readers to evaluate interreader and intrareader reproducibility.
  
  
  RESULTS
  A total of 936 measurements were performed. Significant differences were found between systolic and diastolic diameters at each location (all P < 0.001). Average aortic pulsatility was 1.5 ± 0.6 mm at P1, 1.6 ± 0.7 mm at P2, and 1.7 ± 0.7 mm at P3, with a corresponding aortic strain of 6.7 ± 3.1% at P1, 7.4 ± 3.5% at P2, and 8.1 ± 3.6% at P3. The differences between the strain of the measurement levels were not significant (P = 0.344). Aortic strain and pulsatility did not show significant correlation with pulse pressure (P = 0.693), patient age (P = 0.649), or other anamnestic data. Intraclass correlation coefficient was in the range of 0.95-0.96 for interobserver and in the range of 0.95-0.97 for intraobserver analysis.
  
  
  CONCLUSIONS
  This study shows that descending aortic strain can be measured precisely and reliably on images of routine CCTA examinations with native scans acquired during systole. We demonstrated that young adults have an aortic strain of 6.7-8.1%. As the average thoracic aortic strain was still lower than the recommended prosthesis oversize of 10%, routine use of systolic phase imaging cannot be recommended: it has no clinical benefit for the vast majority of the patients but increases the risk of motion artefacts. We also demonstrated that large interindividual differences are present in the scale of thoracic aortic strain, a phenomenon that needs further investigations to be fully understood.
authors: Department of Vascular Surgery, Heart and Vascular Center, Semmelweis University, Budapest, Hungary. Electronic address: media@csobay.hu.
authors: Csaba
authors: C
authors: Csobay-Novák
authors: Department of Vascular Surgery, Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
authors: Daniele Mariastefano
authors: DM
authors: Fontanini
authors: Department of Geometry, Budapest University of Technology and Economics, Budapest, Hungary.
authors: Brigitta
authors: B
authors: Szilágyi
authors: Department of Vascular Surgery, Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
authors: Zoltán
authors: Z
authors: Szeberin
authors: MTA-SE Cardiovascular Imaging Research Group, Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
authors: Márton
authors: M
authors: Kolossváry
authors: MTA-SE Cardiovascular Imaging Research Group, Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
authors: Pál
authors: P
authors: Maurovich-Horvat
authors: Department of Vascular Surgery, Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
authors: Kálmán
authors: K
authors: Hüttl
authors: Department of Vascular Surgery, Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
authors: Péter
authors: P
authors: Sótonyi
mesh_terms: D000328:Adult; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D001018:Aortic Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D055424:Cardiac-Gated Imaging Techniques; D000072226:Computed Tomography Angiography; D017023:Coronary Angiography / Q000379:methods; D057510:Endovascular Procedures / Q000295:instrumentation*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015588:Observer Variation; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011673:Pulsatile Flow; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D013314:Stress, Mechanical