Predicting the Feasibility of Utilizing SIEA Flap for Breast Reconstruction with Preoperative BMI and Computed Tomography Angiography (CTA) Data

Diameters greater than 1.5 mm are considered one of the generally accepted criteria for utilizing superficial epigastric artery (SIEA) flaps for breast reconstruction. However, this standard fails to consider individual differences among patients or deep inferior epigastric perforator (DIEP) perfusion of the same angiosome as the SIEA. This study combined the SIEA system with the DIEP system and explored the relationship between the two systems and body mass index (BMI) to theoretically provide a reference for flap choice in the preoperative surgical plan.

This study analysed preoperative computed tomography angiography (CTA) data from patients who received systematically postoperative treatment for unilateral breast cancer and were scheduled for breast reconstruction from 2013 to 2018 in our centre. All patients included had no past medical history that might have influenced the diameter of the SIEA, and their CTA data showed the presence of SIEA.

Twenty-five females with a mean BMI of 23.6 ± 3.3 kg/m² were included. A total of 30 hemi-abdomens identified with the SIEA were assessed. The measured mean diameter of the SIEA was 1.63 ± 0.55 mm, showing a highly linear correlation with BMI (r = 0.73, p < 0.001), while the maximum diameter of the deep inferior epigastric perforator (DIEPmax) and the number of dominant perforators originating from the deep inferior epigastric artery (DIEA) were not related to BMI. It was analysed from the equation between the calibre of the SIEA and BMI that when the BMI was greater than or equal to 24 kg/m², the minimum diameter of the SIEA was at least 1.5 mm; when the BMI was 25 kg/m², the diameter of the SIEA was, at most, 2.0 mm. Based on the linear correlation described above, we proposed that if the diameter of the SIEA was greater than or equal to 2.0 mm, a BMI ≥ 25 kg/m² could be fully guaranteed. In terms of the advantageous single pedicle for reconstruction, the ratio of the SIEA diameter to DIEPmax (SIEA/DIEPmax) showed a significant linear correlation with BMI (r = 0.82, p < 0.001), and when the BMI was greater than or equal to 25 kg/m², the lower limit of its predicted value was above 1.0; in other words, the SIEA diameter was advantageous compared with DIEPmax for the use of a single pedicle. In terms of perfusion, the SIEA system was positively correlated with BMI (p < 0.001), while the DIEP system was not. The difference in perfusion level between the SIEA and DIEP systems showed a positive correlation with BMI (p = 0.001), while the sum of the two systems only tended to be correlated, without statistical significance (p = 0.06).

For patients with a BMI ≥ 25 kg/m² or an SIEA diameter ≥ 2.0 mm, application of an SIEA flap is theoretically a preferable choice in preoperative surgical planning for breast reconstruction. And the patients should meet two conditions: the first one is the absence of past medical history that might potentially influence the diameter of the SIEA; the second is the presence of the SIEA, which has already been shown by the preoperative imaging data. Through perfusion-related studies, we propose that the SIEA is likely a compensatory vessel that is inclined to present in people with larger BMIs.

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