Novel assessment of lip redness and microcirculation using optical coherence tomography after dermal filler injection

OBJECTIVES: Lip filler injections are one of the most popular procedures in esthetic dermatology. In this study, we used three-dimensional colorimetric photography to assess lip color and optical coherence tomography-angiography (OCT-A), a noninvasive alternative to histopathology, to evaluate microcirculation after hyaluronic acid (HA) injection. The pain of the injection procedure was also assessed. METHODS: An average of 0.85cc of the total volume of HA with lidocaine was injected into the upper and lower lip of eighteen young (<30yo) and nine postmenopausal healthy women. OCT-A, two-dimensional, and three-dimensional images were acquired immediately before (visit 1) and 15 days after injection (visit 2). Custom-made software was used to analyze the imaging data to detect vessel morphology and redness changes. The Wong-Baker FACES pain rating scale (0-10) was used to score the subject procedural pain. RESULTS: For young and old subjects, three-dimensional lip volume was greater than the injected volume. OCT-A images of the lips showed higher vessel density and thickness, reaching statistical significance in the younger cohort. The overall trend of increased redness assessed by three-dimensional colorimetric imaging and increased vascularity evaluated by OCT-A imaging were similar. However, the correlation was not statistically significant for standard two-dimensional digital photography. The average pain score after the first needle insertion and overall procedure were 2.9 and 3.5, respectively. CONCLUSIONS: The results suggest an increased microvasculature network observed in OCT-A images in young females. The increased blood vessel density and thickness observed by OCT-A after HA lip filler injection is associated with increased lip redness and volume as assessed by colorimetric three-dimensional photography; however, more research is needed to confirm these findings. This study presents OCT-A as a novel noninvasive tool to investigate changes in lip microvascularity after HA filler injection and indicates that HA filler procedures may affect lip vascularity.