Intravascular Ultrasound (IVUS) in Complex Aortic Endovascular Interventions
Condition: Thoracic Aortic Aneurysm
MeSH terms: Aneurysm; Aortic Aneurysm; Aortic Aneurysm, Thoracic
Study type: Observational [Patient Registry]

Summary: 
      The study aims to investigate the applicability of intravascular ultrasound (IVUS) in the
      endovascular therapy of juxta-, supra- and thoracoabdominal aortic aneurysms.

      The focus of the study is on the intraoperative and postoperative evaluation of the geometric
      data of bridging stentgrafts in terms of patency, occurrence of stenosis and/or kinking.
    

Detailed description: 
      Intravascular ultrasound (IVUS) is an already validated diagnostic method increasingly use in
      endovascular interventions. In contrast to conventional digital subtraction angiography
      (DSA), the IVUS provides in vivo real-time vessel images. Furthermore, its accuracy has been
      examined in histological studies, which could report of a good correlation regarding the
      vessel diameters (Jin ZG et al. Int J Cardiovasc Imaging. 2017 Feb; 33 (2): 153-160.).

      Stenosis and/or kinkings of stents or stentgrafts as well as their fully expansion and
      morphology can be assessed with the use of IVUS.

      The IVUS has already been used successfully in the context of endovascular treatment of
      infrarenal aortic aneurysms (Endovascular Aortic Repair or EVAR). Here, the IVUS has proven
      to be a valuable diagnostic instrument to examine the anatomy of the inserted stent grafts
      intraoperatively and to detect any abnormalities. In addition, the use of IVUS led to a
      significant reduction in the use of iodine-containing contrast media and radiation exposure
      as part of these complex endovascular interventions (Pecoraro F et al. Ann Vasc Surg. 2019
      Apr; 56: 209-215.).

      In the endovascular therapy of thoracoabdominal as well as suprarenal and juxtarenal aortic
      aneurysms, stent grafts with recesses (windows - Fenestrated EVAR or FEVAR) or side arms
      (branches - Branched EVAR or BEVAR) for the renovisceral vessels (truncus coeliacus, superior
      mesenteric artery and renal arteries) are implanted. In exceptional cases, the renovisceral
      vessels are supplied with stent grafts that are implanted in parallel to the aortic stent
      grafts (Chimney-Technique). These branches or windows are then connected to the corresponding
      target vessels via a bridging stent graft. The patency and anatomy of the bridging stent
      grafts are usually checked intraoperatively by angiography. The dynamics of the contrast
      agent flow and the X-ray images of the framework of the stent graft help in assessing their
      patency as well as the absence of structural problems.

      The Computed Tomographic Angiography (CTA) is considered the gold standard as diagnostic
      method to assess the patency and anatomy of the stentgrafts postoperatively. This diagnostic
      method bares with it the exposure to relevant radiation dose as well as to contrast media.
      However, CTA scans do not provide in vivo real-time vessel images.

      Furthermore, in case of pathological findings a new intervention may be necessary. The IVUS
      technique overcomes these issues due to its low invasiveness and its possible use during the
      index procedure. This can lead to the immediate identification of eventual structural
      problems of the bridging stent grafts which can jeopardize their patency and to correct them
      already during the index procedure.

      The use of the IVUS during FEVAR, BEVAR and CHEVAR has already been implemented in our
      clinical routine. At our knowledge, a prospective collection of anatomical-geometric data by
      IVUS in complex endovascular treatments of complex aortic aneurysm has not been yet reported.

      The aim of the current study is the retrospective evaluation of the anatomical-geometric data
      already collected by IVUS as well as the prospective collection of new data regarding the
      patency and anatomy of bridging stent grafts.
    

Intervention name(s): IVUS control
Intervention type(s): Diagnostic Test
Intervention description(s): Intravascular Control of the bridging stentgrafts during branched EVAR
Other intervention name(s): Volcano Philips
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients treated by BEVAR/CHEVAR/FEVAR due to a thoracoabdominal aneurysm,
      
Keywords: Intravascular ultrasound; bridging stentgraft; BEVAR; EVAR; IVUS