Differences in Female and Male-to-Female Transgender Facial Skin Micro-Vessel Density.

ABSTRACT

Importance The risk of hematoma formation after rhytidectomy is gender associated and can lead to postoperative complications. The literature to help explain and elucidate the mechanism behind this gender-associated risk is poorly developed and requires further investigation. Objective: The objective of this study was to compare facial skin micro-vessel density of female and male-to-female (MTF) transgender patients undergoing rhytidectomy to better understand the mechanism of gender-correlated hematoma risk factors. The authors hypothesized that transgender patients would have higher micro-vessel density compared with female patients. Design, Setting, and Participants: This was a prospective histopathological analysis of pre- and post-auricular facial skin samples from patients undergoing primary rhytidectomy. Patient clinical data and skin samples were collected. Histopathological slides were prepared and stained with CD-31, a marker of vessel endothelium, followed by image analysis allowing for micro-vessel stained pixel counts and calculated pixel density comparisons at a single academic hospital. Female, MTF transgender, and male patients >18 years of age were studied. Exposure Patients undergoing primary rhytidectomy between 2015 and 2018. Main Outcomes: Gender-associated pre- and post-auricular micro-vessel pixel density. Results: Forty-one patients contributed skin samples for analysis. Post-auricular micro-vessel pixel density was greater than pre-auricular density (mean difference post-pre 0.359 percentage points [p.p.], standard error [SE] = 0.135, p = 0.009). The mean post-auricular micro-vessel pixel density was 1.60% (SE = 0.13 p.p.), 2.16% (SE = 0.19 p.p.), and 2.77% (SE = 0.34 p.p.) for female, transgender, and male patients, respectively (p = 0.016). Pre-auricular micro-vessel pixel density showed no difference among females, males, and transgender patients (p = 0.30). Gender was a strong predictor of increased post-auricular micro-vessel pixel density on stepwise linear regression, but it did not predict pre-auricular micro-vessel density. Both preoperative hair removal and a history of hypertension were associated with increased pre-auricular micro-vessel density. Conclusions and Relevance Facial skin micro-vessel density differs by gender, in addition to pre- and post-auricular locations in patients undergoing rhytidectomy.