Accuracy of Deep Inferior Epigastric Artery Perforator Mapping - Color Doppler Ultrasound Versus CT Angiography
Condition: Mammaplasty
Study type: Interventional

Summary: 
      The goal of this clinical trial is to compare the accuracy and contribution of Color Doppler
      Ultrasound (CDU) guided Deep Inferior Epigastric Artery (DIEA) perforator mapping with or
      without mapping using Computer Tomography angiography (CTA) in women over 18 years undergoing
      2021 unilateral or bilateral breast reconstruction with an abdominal free flap.

      Participants underwent scheduled reconstruction of one or both breasts with a free flap
      transferred from the lower abdomen. If there is a comparison group: Researchers compared
      interventional groups - examined using preoperative CTA of the abdominal wall supplemented
      with an examination of the perforators using CDU (active comparator group), and examined
      exclusively by using the CDU (experimental group), to see the comparison of the accuracy and
      contribution of CDU-guided DIEA perforator mapping with CTA mapping.

      The hypothesis is that CDU examination alone is not inferior to CTA examination supplemented
      with parameters that CTA does not show (flow velocity, vessel diameters), by measuring these
      parameters with CDU.

      The main questions it aims to answer are:

        -  To evaluate the comparison of the accuracy of surgeon-conducted CDU perforator mapping
           in defining the significant/dominant perforators and their exact location [XY
           coordinates] with the accuracy of CTA mapping.

        -  To compare the time duration of the CDU examination was measured.

        -  To measure the Fat Necrosis of the flap [3 months postoperative ]

        -  To measure the Flap Loss [1-week post-op, 2 weeks post-op, 6-8 weeks post-op and 3
           months post-op].
    

Detailed description: 
      A blinded, randomized, prospective clinical trial was performed involving women over 18 years
      undergoing 2021 unilateral or bilateral breast reconstruction with an abdominal free flap.
      The inclusion of the mapping of major perforators as a part of preoperative deep inferior
      epigastric perforator (DIEP) flap planning reduces the operating time and complication rate.
      According to recent meta-analyses computed tomographic angiography (CTA) brings the most
      advantages; however, only a few studies comprising colour Doppler ultrasonography (CDU) were
      included with several biases in addition. Especially, studies directly comparing CTA and CDU
      (surgeons conducted in one study only, in one case) are rare. Recently, CDU has seen
      significant advances in quality and imaging capabilities, and ultrasound devices are widely
      available.

      Women were originally randomized 1:1 to the groups one of which will undergo only CDU
      perforator mapping (experimental group) and the other using CTA+CDU (active comparator
      group). Every patient included in the CTA+CDU group preoperatively underwent CT angiography
      of the abdominal wall. Based on the CTA examination XY coordinates of DIEA perforators with a
      vessel calibre of 1 mm were determined.

      The velocity and vessel diameters of these perforators were additionally examined using a CDU
      device. Any additional perforators were marked, nor were CTA deducted XY coordinates of
      marked perforators changed, based on the CDU examination. The same sonography surgeon
      performed all CDU examinations.

      All patients included in the CDU group were examined with the same CDU device by the same
      sonography surgeon as patients included in CTA + CDU group. During the examination, DIEA
      perforators were mapped and those with a vessel calibre of 1 mm were marked and XY
      coordinates deducted. Calibres and velocities of perforator vessels and the abdominal
      subcutaneous tissue thickness were measured.

      In the CTA+CDU group, CDU was used only to determine the additional parameters necessary to
      define categories 1-3 (according to the number of perforators). Based on CDU, coordinates
      were not measured in the CTA+CDU group. The main aim of this clinical study is to compare the
      accuracy of perforator localization (coordinates) using CDU vs. CTA.

      Based on the preoperative mapping, all patients in both groups were assigned a category for
      each flap as follows:

      A) At least one perforator of the flap meets the criteria defined for a dominant perforator.
      In such a case, the tactic was to dissect a single perforator flap.

      B) Any perforator meets the criteria defined for a dominant perforator, but at least two
      perforators on the same DIEA branch meet the criteria for a significant perforator. In such a
      case, the tactic was to dissect the flap with the pedicle of two of those perforators.

      C) Any perforator meets the criteria defined for a dominant perforator or significant
      perforator. In such a case, the surgical tactic was to dissect the flap with a pedicle of
      three perforators or as an MS-TRAM flap.

      The operating surgeon was fully informed of the results of the preoperative examination and
      the recommended perforator or perforator selected for the flap's pedicle. However, these
      recommendations were not binding, and the surgeon chose the tactics of the operation taking
      into consideration his clinical experience. Participating in the project did not change the
      surgical technique and the surgery was performed as standard according to current knowledge
      of medicine and common practice of the department. The surgery itself was not the subject of
      the research. XY coordinates and diameters of the dissected perforators were measured during
      the surgery.

      R 4.1.3 software and Joinpoint Regression 4.9.0.0. were used to perform data management and
      exploratory statistical analysis (p = 0.05). A two-sided Wilcoxon test was used for
      verification of both patient groups' comparability. The same test was used to compare the
      length of the CDU examination in both groups. The breaking point on the curve showing the
      length of the CDU examination depending on the numerical order of the examined patient was
      searched using the Joinpoint Regression as a secondary outcome. Euclidean distance was used
      to determine the difference between the CDU/CTA and during the surgery measured coordinates
      of the dissected perforators. Statistical testing of the difference between the accuracy of
      CTA and CDU examinations was performed using the GLS method. The GEE model was used to
      determine the difference between the CDU/CTA+CDU recommended and finally dissected a number
      of perforators supplying the flap.
    

Intervention name(s): Colour Doppler Ultrasound
Intervention type(s): Procedure
Intervention description(s): The main perforators were examined using a LOGIQ S8/V1 CDU device (GE Healthcare, Chalfont St Giles, Great Britain) with a linear transducer of frequency 4-11 MHz. Measured parameters were: 1) calibre of artery and vein; 2) Peak systolic velocity (PSV) of blood in the artery [cm/s]; 3) blood velocity in the perforator vein [cm/s]; 2) the thickness of the subcutaneous tissue of the lower abdomen measured 4 cm caudal and lateral to the umbilicus. Any additional perforators were marked nor have CTA deducted XY coordinates of marked perforators changed based on the CDU examination. The same sonography surgeon performed all CDU examinations. The time duration of the CDU examination was measured.
Other intervention name(s): CDU
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomization was carried out using an envelope method, during which the patients were randomly assigned in a ratio 1:1 to an active comparator group: "CTA+CDU (preoperative examination of vascular anatomy by CTA supplemented with vessel calibre examination of the perforator using CDU)" or an experimental group: "CDU (preoperative examination of vascular anatomy by colour duplex sonography only)".
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: CT Angiography; Mammaplasty; Ultrasonography; Doppler