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Background: Propranolol, a nonselective β-adrenergic receptor antagonist, is approved by the U.S. Food and Drug Administration to treat problematic infantile hemangiomas, but a subset of patients experience treatment complications. Parents wary of long-term use and side effects consult plastic surgeons on surgical options or as a second opinion. Understanding the mechanism(s) of action of propranolol will allow plastic surgeons to better inform parents., Methods: A systemic literature search was performed to query published translational and basic science studies on propranolol effects on infantile hemangiomas and cells derived from these lesions., Results: In experimental studies, propranolol was antiproliferative and cytotoxic against hemangioma endothelial and stem cells and affected infantile hemangioma perivascular cell contractility. Propranolol inhibited migration, network formation, vascular endothelial growth factor A production, and vascular endothelial growth factor receptor 2 activation and down-regulated PI3K/AKT and mitogen-activated protein kinase signaling in hemangioma endothelial cells, but it increased ERK1/2 activity in hemangioma stem cells. At effective clinical doses, measured propranolol plasma concentration is 100 times higher than necessary for complete β-adrenergic receptor blockade, yet was 10 to 100 times less than required to induce hemangioma stem cell death., Conclusions: Propranolol targets multiple cell types in infantile hemangiomas by means of β-adrenergic receptor-dependent and -independent mechanisms. Plasma concentration played a significant role. At clinically relevant doses, incomplete infantile hemangioma suppression may explain the rebound phenomenon and worsening ulceration, and propranolol off target effects may lead to commonly reported adverse effects, such as sleep and gastrointestinal disturbances. Propranolol limitations and complications underscore the importance of surgical treatment options in cases of rebound and severe adverse effects. Surgical intervention remains an important treatment choice when parents are hesitant to use propranolol., (Copyright © 2021 by the American Society of Plastic Surgeons.)

Background: Infantile hemangiomas can cause significant morbidity during proliferation, yet there is no U.S. Food and Drug Administration-approved treatment. They are believed to form from hemangioma stem cells, which differentiate toward a hemangioma endothelial cell phenotype. Recently, propranolol has demonstrated effectiveness in treating complicated infantile hemangiomas. The authors hypothesize that propranolol facilitates their involution by altering cellular behavior in both hemangioma endothelial and stem cells., Methods: Hemangioma endothelial and stem cells were isolated from resected infantile hemangioma specimens. Cells were treated with 100 μM propranolol for 48 hours, and apoptosis was determined by the presence of annexin V antibody. Proliferation of stem and endothelial cells was assessed after treatment with 50 or 100 μM propranolol or vehicle, for 72 and 96 hours, respectively. Adipogenesis was induced in stem cells with and without propranolol. Pro-adipogenic genes PPARδ, PPARγ, C/EBPα, C/EBPβ, C/EBPδ, RXRα, and RXRγ were analyzed by quantitative polymerase chain reaction., Results: Annexin V levels were increased in propranolol-treated endothelial cells but not in stem cells. Proliferation of stem and endothelial cells was inhibited by propranolol in a dose-dependent manner. Propranolol-treated stem cells demonstrated accelerated adipogenesis when compared with untreated controls. Transcript levels of C/EBPβ (p < 0.05), RXRγ (p < 0.05), and PPARγ (p < 0.02) were significantly increased when treated with 50 or 100 μM propranolol; and C/EBPδ (p < 0.05), RXRα (p < 0.05), and PPARδ (p < 0.01) transcripts were increased when treated with 100 μM propranolol. C/EBPα transcript levels remained unchanged at either dose., Conclusions: Propranolol increased apoptosis of hemangioma endothelial cells, but not stem cells, and accelerated adipogenesis of hemangioma stem cells. Thus, propranolol likely accelerates involution to fibrofatty residuum.

Background: The external ear is the second most common site for extracranial arteriovenous malformation in the head and neck., Methods: This retrospective review of 41 patients with auricular arteriovenous malformation was based on medical records, imaging studies, and photographs. Data were collected on natural history, progression, and outcome; patients were questioned about quality of life after treatment., Results: The median age at initial presentation was 26 years (range, 1 to 55 years), and Schobinger stage was I in two patients, II in 19 patients, and III in 20 patients. No patients had a Schobinger stage of IV. Expansion occurred during childhood in seven patients, adolescence in 14 patients, pregnancy in 10 patients, and adulthood in 10 patients. Distribution of auricular and extra-auricular arteriovenous malformation was not limited to "watershed" areas between vascular territories (angiosomes). Twelve patients were untreated (follow-up, 0.5 to 6 years). Mean follow-up time for the 29 treated patients was 5.19 years (range, 1 to 18.75 years). Proximal ligation in nine patients caused progression: eight of them underwent amputation and one had embolization. Fifteen patients had embolization only: the arteriovenous malformation worsened and amputation was necessary in six patients; in the remaining nine patients, two improved, four persisted, and three worsened. Of 20 patients who had auricular amputation, 16 (80 percent) were controlled, three (15 percent) improved, and one had unresectable, residual cervicofacial arteriovenous malformation. Of 22 of 29 treated patients surveyed, 81 percent were satisfied with their management. Hearing was either unaffected (n = 15) or diminished (n = 5); two patients noted decreased sound localization., Conclusions: The authors recommend periodic evaluation for stage I to II auricular arteriovenous malformation and intervention if there is evolution to stage III. Preoperative embolization and partial or total amputation effectively control auricular and para-auricular arteriovenous malformation. Embolization can be palliative in children or in patients who are not psychologically prepared for amputation. Extensive extra-auricular arteriovenous malformation requires individualized endovascular therapy and resection.

Pulsed magnetic fields have been shown to stimulate neovascularization in the authors' laboratory. The rat groin composite flap was used to create a prospective randomized trial to test the effectiveness of these pulsed magnetic fields. The skin paddle to this flap is highly consistent, and the authors proposed using the flap to study how pulsed magnetic fields affect composite flap survival when the dominant vessel to the flap is divided and flap survival becomes dependent on a transferred vessel loop. Forty-three rats had the tail artery microsurgically anastomosed to the femoral artery and placed between the groin musculature and the abdominal skin. Pulsed magnetic energy of 1 gauss was applied for 8 (n = 14) or 12 (n = 8) weeks to the experimental groups. Control groups were treated in a comparable manner for 8 (n = 16) or 12 (n = 5) weeks. After the 8 or 12 weeks, all groups had an 8 x 4-cm skin flap raised, and the superficial epigastric artery, the main feeding vessel, was ligated. After 5 days, the total area of the flap and the area of necrosis were traced onto velum paper for each rat. The percent survival was calculated per rat, and a mean survival percentage was calculated per group. The experimental animals treated with pulsed magnetic fields for 8 weeks had statistically significant improved flap survival over the control animals. The study provides evidence that pulsed magnetic energy stimulates angiogenesis and suggests a possible use of this modality to create island vascular flaps in otherwise random vascular territories.