Relative indexes of cutaneous blood perfusion measured by real-time laser Doppler imaging (LDI) in healthy volunteers

Heterogeneous Features of Keloids Assessed by Laser Speckle Contrast Imaging: A Cross-Sectional Study

BACKGROUND AND OBJECTIVES

Keloids are described as benign dermal fibroproliferative lesions, and vascularization may play a significant role in their pathogenesis. In this study, laser speckle contrast imaging (LSCI) was used to assess perfusion within keloids and surrounding skin, and perfusion of keloids at different stages was compared.

STUDY DESIGN/MATERIALS AND METHODS

A total of 59 patients with 110 untreated keloids on the anterior chest were enrolled in this study. Different keloid stages (progressive, stable, and regressive) were defined according to patients' descriptions of whether keloids became larger, stable, or smaller during the previous year. Vancouver Scar Scale (VSS) was assessed by a plastic surgeon, and patient reports on pain and itching were documented. LSCI was used to evaluate blood perfusion of keloids (K), skin adjacent to keloids (A), and nonadjacent skin (N). The mean perfusion of these regions was determined, and ratios (K/N, A/N) were calculated.

RESULTS

A heterogeneous perfusion map was observed among the keloid groups, as well as within each keloid. A positive correlation was found between keloid perfusion and VSS. There were 62 (56.4%) keloids in the progressive stage, 33 (30.0%) keloids in the stable stage, and 15 (13.6%) keloids in the regressive stage. The mean K/N ratios in the progressive, stable, and regressive stages were 2.3 ± 0.5, 1.8 ± 0.3, and 1.5 ± 0.5, respectively. The mean A/N ratios were 1.2 ± 0.4, 1.2 ± 0.2, and 1.0 ± 0.5, respectively. Within each keloid, significantly higher perfusion was noted in the keloid and adjacent skin compared with nonadjacent skin.

CONCLUSION

These results indicate that LSCI is a promising technique for evaluating keloid blood perfusion and distinguishing heterogeneous keloids. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

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

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.

Quantitative impact analysis of remote ischemic conditioning and capsaicin application on human skin microcirculation

BACKGROUND

Improvement of skin microcirculation would be beneficial in transplanted tissues and thus, there is a demand for effective, reliable and harmless angiogenic treatments. The aim of this study was to assess the effect of capsaicin application (CA), the remote effect of capsaicin application (REC), the impact of remote ischemic conditioning (RIC), and the impact of combined remote ischemic conditioning with capsaicin application (Comb) on human skin microcirculation.

METHODS

Perfusion changes were assessed using a laser Doppler device (easyLDI, Aimago Lausanne). 30 healthy volunteers were enrolled and divided into two groups: 1) CA and REC: perfusion was assessed on both forearms after application of capsaicin cream on one forearm with an exposure time of 40 minutes. 2) RIC and Comb: perfusion of one forearm was assessed after four cycles of 5 min blood occlusion and 5 min reperfusion using a tourniquet on the contralateral upper arm and application of capsaicin on the ipsilateral forearm. Baseline skin perfusion measurements of both forearms were carried out initially and were used as intra-individual reference.

RESULTS

1) Skin perfusion significantly increased after capsaicin application (CA = +328.3% , p > 0.05). There was no remote skin perfusion change due to capsaicin (REC). 2) RIC significantly improves skin perfusion (RIC = +20.0% , p < 0.05). The combination of RIC and CA does not improve skin perfusion compared to CA alone (Comb).

CONCLUSIONS

The conditioning techniques RIC and CA showed a significant increase in human skin perfusion, CA being superior to RIC. However, the combination of CA and RIC showed no additional improvement potential as compared to CA alone. Furthermore, a remote effect of capsaicin application could not be demonstrated. These results encourage to analyze if the conditioning treatments are also beneficial for transplanted tissue survival.

Fundamental supply of skin blood flow in the Chinese Han population: Measurements by a full-field laser perfusion imager

BACKGROUND

Skin blood flow is believed to link with many diseases, and shows a significant heterogeneity. There are several papers on basal cutaneous microcirculation perfusion in different races, while the data in Chinese is vacant.

OBJECTIVE

The aim was to establish the database of absolute fundamental supply of skin blood flow in the Chinese Han population.

METHODS

With a full-field laser perfusion imager (FLPI), the skin blood flow can be quantified. Cutaneous perfusion values were determined in 17 selected skin areas in 406 healthy participants aged between 20 and 80 years (mean 35.05 ± 11.33). Essential parameters such as weight, height were also measured and values of BMI were calculated. The perfusion values were reported in Arbitrary Perfusion Units (APU).

RESULTS

The highest cutaneous perfusion value fell on eyelid (931.20 ± 242.59 in male and 967.83 ± 225.49 in female), and pretibial had the lowest value (89.09 ± 30.28 in male and 85.08 ± 33.59 in female). The values were higher in men than women on the bank of fingertips, nose, forehead, cheek, neck and earlobe (P < .05). Perfusion values on stretch and flexion side of forearm had negative correlation with age (P = .01 and P = 4.88 × 10^-3 , respectively) in male. Abdomen was negatively correlated with BMI in both gender (P = .02, respectively).

CONCLUSIONS

Skin blood flow values vary with skin regions. There is a tendency to measure higher perfusion values in men than in women. And the values are irrelevant with age or BMI.

Laser doppler imaging as additional monitoring after digital replanting: A prospective study

BACKGROUND

Despite various exisiting monitoring methods, there is still a need for new technologies to improve the quality of post-operative evaluation of digital replantation. The purpose of the study is using a laser Doppler imaging device (Easy-LDI) as an additional tool to assess perfusion. In this method, the changes in the frequency of the laser ligth provide information regarding perfusion of the monitored tissue.

PATIENTS AND METHODS

This study included seven patients (10 fingers; age of patients: 21-57 years) who suffered from a total (n = 6) or subtotal amputation (n = 4) due to accidents. In addition to hourly standard monitoring with clinical evaluation and skin thermometry, revascularized fingers were hourly monitored with Easy LDI for 48 h.

RESULTS

LDI measurement values ranged between 0.8 and 223 (mean 90.62 ± 21.42) arbitrary perfusion units (APU). The mean LDI values before and after revascularization were 7.1 ± 2.85 and 65.30 ± 30.83 APU, respectively. For the successful revascularized fingers (8 of 10 fingers) values from 19 to 223 APU (mean 98.52 ± 15.48) were demonstrated. All of the replants survived, but due to venous occlusion two digits required revision 12 and 35 h after revascularization, respectively. In the two cases, Easy-LDI also showed a constant and slow decline of the perfusion values. Furthermore, Pearson normalized correlation coefficient showed a positive significant correlation between temperatures of the replants and LDI-values (P < .001, r = +0.392) and a negative significant correlation between Δtemperature and LDI-values (P < .001, r = -0.474).

CONCLUSION

The LDI-device might be a promising additional monitoring technique in detection of perfusion disturbance in monitoring digital replantations.