Initial Experience With Propranolol Treatment of Lymphatic Anomalies: A Case Series

Infantile hemangioma: the common and enigmatic vascular tumor

Infantile hemangioma (IH) is a benign vascular tumor that occurs in 5% of newborns. The tumor follows a life cycle of rapid proliferation in infancy, followed by slow involution in childhood. This unique life cycle has attracted the interest of basic and clinical scientists alike as a paradigm for vasculogenesis, angiogenesis, and vascular regression. Unanswered questions persist about the genetic and molecular drivers of the proliferating and involuting phases. The beta blocker propranolol usually accelerates regression of problematic IHs, yet its mechanism of action on vascular proliferation and differentiation is unclear. Some IHs fail to respond to beta blockers and regrow after discontinuation. Side effects occur and long-term sequelae of propranolol treatment are unknown. This poses clinical challenges and raises novel questions about the mechanisms of vascular overgrowth in IH.

Investigation into the genetics of fetal congenital lymphatic anomalies

OBJECTIVE

Congenital lymphatic anomalies (LAs) arise due to defects in lymphatic development and often present in utero as pleural effusion, chylothorax, nuchal and soft tissue edema, ascites, or hydrops. Many LAs are caused by single nucleotide variants, which are not detected on routine prenatal testing.

METHODS

Demographic data were compared between two subcohorts, those with clinically significant fetal edema (CSFE) and isolated fetal edema. A targeted variant analysis of LA genes was performed using American College of Medical Genetics criteria on whole exome sequencing (WES) data generated for 71 fetal edema cases who remained undiagnosed after standard workup.

RESULTS

CSFE cases had poor outcomes, including preterm delivery, demise, and maternal preeclampsia. Pathogenic and likely pathogenic variants were identified in 7% (5/71) of cases, including variants in RASopathy genes, RASA1, SOS1, PTPN11, and a novel PIEZO1 variant. Variants of uncertain significance (VOUS) were identified in 45% (32/71) of cases. In CSFEs, VOUS were found in CELSR1, EPHB4, TIE1, PIEZO1, ITGA9, RASopathy genes, SOS1, SOS2, and RAF1.

CONCLUSIONS

WES identified pathogenic and likely pathogenic variants and VOUS in LA genes in 51% of fetal edema cases, supporting WES and expanded hydrops panels in cases of idiopathic fetal hydrops and fluid collections.

Propranolol Therapy for Congenital Chylothorax

Congenital chylothorax is a rare and often severe anomaly without well-established medical therapies. Previously, propranolol use in patients with lymphatic malformations and secondary chylothorax was associated with improvement in clinical signs. We hypothesized that propranolol treatment would be beneficial for severe congenital chylothorax. We reviewed medical records of neonates born from 2015 to 2019 at our tertiary center with a prenatal diagnosis of congenital chylothorax for whom either prenatal or postnatal propranolol therapy was initiated. Inclusion was limited to fetuses diagnosed with severe congenital chylothorax without significant genetic, infectious, or cardiac anomalies, and who underwent prenatal interventions to mitigate consequences of the condition. Propranolol was administered orally to pregnant women at 20 mg 4 times daily and increased to a maximum dose of 40 mg 4 times daily, or to infants at 0.3 mg/kg/d and increased to 1 to 2 mg/kg/d. Primary outcomes were the time course of resolution of ultrasonographical, clinical, and/or radiologic signs of chylothorax after treatment with propranolol. Four neonates met the inclusion criteria. In 2 cases, prenatal initiation of propranolol led to resolution of the chylothoraxes before delivery (38 and 32 days after treatment) on a dose of 40 mg/day 4 times daily. Neonates had a normal postnatal course. Postnatal propranolol was initiated in 2 neonates with respiratory failure when chylothoraces were refractory to standard management. Stabilization and improvement of their pleural effusion was observed by imaging at 29 and 13 days after initiation of propranolol. There were no significant maternal or neonatal complications from prenatal or postnatal propranolol use. Propranolol may be efficacious in treating severe fetal congenital chylothorax.

Clinical and genetic analyses of patients with lateralized overgrowth

Background

The genetic features and treatment strategies of lateralized overgrowth have been elusive. We performed this study to analyze the genetic characteristics and treatment results of propranolol- or alpelisib-treated patients with lateralized overgrowth.

Methods

Fifteen patients with lateralized overgrowth were involved. Clinical characteristics and whole-body magnetic resonance imaging (WB-MRI) findings were evaluated. Targeted exome sequencing with a gene panel of affected tissue and peripheral white blood cells was performed. Propranolol was administered and treatment results were evaluated. The PIK3CA inhibitor alpelisib was prescribed via a managed access program.

Results

The identified mutations were PIK3CA (n = 7), KRAS (n = 2), PTEN (n = 1), MAP2K3 (n = 1), GNAQ (n = 1), TBC1D4 (n = 1), and TEK (n = 1). Propranolol was prescribed in 12 patients, and 7 experienced mild improvement of symptoms. Alpelisib was prescribed in two patients with a PIK3CA mutation, and the reduction of proliferated masses after 1 year of treatment was proved by WB-MRI.

Conclusions

Targeted exome sequencing identified various genetic features of lateralized overgrowth. Propranolol could be applied as an adjuvant therapy for reducing vascular symptoms, but a PIK3CA inhibitor would be the primary therapeutic strategy for PIK3CA-related overgrowth syndrome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01362-1.

Expression of β1 adrenergic receptor in vascular anomalies in children

OBJECTIVE

Controversial, heterogeneous, and inconsistent responses to beta-blockers have been reported in some cases of infantile proliferative hemangiomas. On the basis of these clinical observations, we aimed to examine the β1 adrenergic receptor (β1-AR) protein expression distribution among different types of pediatric vascular anomalies.

METHODS

Immunohistochemistry (IHC) was performed for β1-AR on 43 surgical specimens.

RESULTS

We found positive β1-AR IHC staining in all intramuscular hemangiomas, capillary-lymphatic, lymphatic, venous, and combined malformations, and Masson's tumor cases, as well as in 7 of 10 cases of proliferative infantile hemangiomas.

CONCLUSIONS

Our research demonstrates, for the first time, the degree of heterogeneous expression of β1-AR among pediatric vascular malformations. Our results support the need for β1-AR assessment in pediatric vascular anomalies to select cases with a robust response to β1-selective blockers. β1-AR assessment may have a strong impact on therapeutic refinement for pediatric vascular anomalies by selecting cases with a stronger response to beta-blockers.

Propranolol treatment for chylothorax after congenital cardiac surgery

OBJECTIVE

Postoperative chylothorax causes significant morbidities in pediatric patients with cardiac disease. New treatment approaches based on evolving understanding of underlying lymphatic dysfunction are being developed. We hypothesized that propranolol reduces morbidities and duration of chest tube requirement in high-output chylous effusion.

METHODS

The postoperative courses of 50 pediatric patients with cardiac disease and high-output chylous effusion (control, n = 25; propranolol-treated, n = 25) were reviewed, including morbidities, length of hospitalization, and duration of chest tube requirement. Statistical analysis was performed using Welch's t test, Kruskal-Wallis tests for continuous variables, and chi-square and Fisher exact tests for categorical variables. Univariable logistic regression was used to determine predictors of response.

RESULTS

Propranolol response was defined as 80% or more drainage reduction in 9 days or less. Treated patients were grouped into responders (<9 days) and nonresponders (>10 days). Neither initial amount of drainage (P = .12) nor day of propranolol initiation (P = .17) correlated with response. When compared with controls and nonresponders, responders had significantly fewer days with chest tube requirement (P < .01), infection (P < .0002), and thrombus (P = .005), and shorter hospitalization (P < .05). All patients had low serum albumin, although nonresponders had significantly decreased serum albumin when compared with responders and control patients (P < .002), and were more likely to receive albumin replacement (P < .01). Malnutrition was prevalent in all patient groups.

CONCLUSIONS

Responders to propranolol had significantly less morbidity and duration of chest tube requirement when compared with control patients and nonresponders. Nonresponders did not have worse outcomes than control patients. We conclude that propranolol may be an effective treatment of patients with refractory chylothorax.

Use of Propranolol in the Treatment of Chylous Effusions in Infants

Chylothorax and chyloperitoneum are rare in infants and challenging to definitively diagnose by using current criteria extrapolated from the adult population. They can be of primary or secondary etiologies, including congenital lymphatic malformations and postoperatively, after cardiothoracic or abdominal surgery. Current first-line management consists of bowel rest, parenteral nutrition, and a modified diet of medium-chain triglycerides but can often take weeks to be effective. Off-label use of octreotide has been reported in numerous case studies for the management of chylous effusions. However, there are no definitive neonatal data available regarding dosing, safety, and efficacy; moreover, octreotide has a side effect profile that been linked to serious morbidities, such as pulmonary hypertension and necrotizing enterocolitis. Propranolol, commonly used for the treatment of infantile hemangiomas, is currently gaining interest as a novel therapy for chylous effusions. In this case series review, we describe the use of propranolol in 4 infants with presumed chylous effusions: 1 with congenital pleural effusions and 3 infants who developed postoperative chylothorax and/or chylous ascites. Clinical improvement was noted within a few days of initiating oral propranolol, and the maximum dose used in our cases was 6 mg/kg per day. In previous case reports, researchers describe the use of oral propranolol in infants with chylous effusions, with the dose used ranging from 0.5 to 4 mg/kg per day. However, this is the first case series in which researchers report its use exclusively in infants with chylothorax and chyloperitoneum. Although further research is needed to establish safety and efficacy, our experiences suggest that propranolol could be an acceptable treatment option for chylous effusions in infants.

Management of lymphatic vascular malformations: A systematic review of the literature

OBJECTIVE

Lymphatic malformations (LM) are common congenital vascular lesions, most often diagnosed at birth. They deform local anatomy and can be life-threatening if they compress the aerodigestive tract or other vital structures. Significant progress has been made in the treatment of LMs in the past 20 years. We conducted a systematic review of the literature on the management of LMs.

METHODS

On September 21, 2020, we searched PubMed/MEDLINE for studies published from 2000 to 2020 reporting outcomes of invasive and pharmacologic treatment of LMs.

RESULTS

A total of 251 studies met the eligibility criteria. Surgery has continued to be a mainstay in the management of LMs, especially in the treatment of microcystic and mixed lesions. Sclerotherapy has emerged as a first-line treatment of macrocystic LMs and as an adjunctive therapy used in combination with surgery for other lesions. Sirolimus, a strong inhibitor of mTOR (mechanistic target of rapamycin), has shown tremendous promise in the treatment of LMs, as both an oral and a topical agent. Recent investigations have shown the potential of targeted small molecule modulators of cellular pathways in the treatment of LMs.

CONCLUSIONS

Multiple invasive and pharmacologic therapies have been shown to be effective in the treatment of LMs. Future research should focus on rigorous, prospective comparisons of these treatment modalities.

Recent Progress in Lymphangioma

Lymphangioma is a common type of congenital vascular disease in children with a broad spectrum of clinical manifestations. The current classification of lymphangioma by International Society for the Study of Vascular Anomalies is largely based on the clinical manifestations and complications and is not sufficient for selection of therapeutic strategies and prognosis prediction. The clinical management and outcome of lymphangioma largely depend on the clinical classification and the location of the disease, ranging from spontaneous regression with no treatment to severe sequelae even with comprehensive treatment. Recently, rapid progression has been made toward elucidating the molecular pathology of lymphangioma and the development of treatments. Several signaling pathways have been revealed to be involved in the progression and development of lymphangioma, and specific inhibitors targeting these pathways have been investigated for clinical applications and clinical trials. Some drugs already currently in clinical use for other diseases were found to be effective for lymphangioma, although the mechanisms underlying the anti-tumor effects remain unclear. Molecular classification based on molecular pathology and investigation of the molecular mechanisms of current clinical drugs is the next step toward developing more effective individualized treatment of children with lymphangioma with reduced side effects.

Propranolol for the Treatment of Lymphatic Malformations in a Neonate - A Case Report and Review of Literature

Lymphatic malformations in neonates often manifest as a chylothorax, and although rare, morbidity and mortality can be significant. First-line treatment with medium-chain triglyceride-enriched formulas, or enteric rest with total parenteral nutrition, are not always successful. We describe the case of a premature neonate with trisomy 21 who presented with bilateral pleural effusions and a pericardial effusion that worsened with the initiation of enteral nutrition. Clinical improvement was not seen until the initiation of treatment with oral propranolol at a maximum dosage of 0.5 mg/kg/day divided every 8 hours with extubation 8 days after propranolol initiation. Two case reports have described the use of propranolol in similar patients receiving 2 mg/kg/day; however, our experience is the first to report treatment success at a much lower dose. A review of the literature for alternative medication treatments uncovered numerous case reports and series documenting variable results with incongruent definitions of treatment success in a diverse patient population. The rarity of this disease state makes accrual of patients difficult and more robust treatment data unlikely. Therefore, selection of the optimal adjunctive treatment must be based on individual patient and disease state characteristics as well as safety and efficacy profile of the medication.

Chylous Manifestations and Management of Gorham-Stout Syndrome

Gorham-Stout disease (GSD) was first described by Gorham and colleagues in 1954, but its precise mechanism and cause remain to be elucidated. In this condition, voluminous and potentially fatal chylous effusions into the thorax can occur. Herein, we describe a case of GSD in which the patient presented with massive pleural effusions and mottled osteolytic bone lesions. We performed multiple operations, including thoracic duct ligation using video-assisted thoracoscopic surgery and thoracotomic decortication, but these procedures did not succeed in preventing recurrent pleural effusion and chest wall lymphedema. After administering sirolimus (0.8 mg/m², twice a day) and propranolol (40 mg, twice a day), the process of GSD in this patient has been controlled for more than 2 years.

Treatment of Lymphatic Malformations with the mTOR Inhibitor Sirolimus: A Systematic Review

BACKGROUND

Extensive lymphatic malformations are low-flow vascular malformations that can cause devastating complications. Treatment of these malformations is challenging. This systematic review presents current use of sirolimus in patients with extensive lymphatic malformations.

METHODS

MEDLINE and Google scholar search was conducted for studies on sirolimus treatment of lymphatic malformations up to July 2017. Search items included "lymphatic malformation," "lymphangioma," "cystic hygroma," "vascular malformation," "low-flow malformation," "sirolimus," "rapamycin," and "mTOR inhibitor."

RESULTS

Twenty studies, including 71 patients receiving sirolimus, were included into this review. Forty-five patients had lymphatic malformations, eight patients venolymphatic malformations, and 19 patients capillary-lymphatico-venous malformations. Sirolimus led to a partial remission of disease in 60 patients, three patients had a progressive disease, and the outcome of eight patients was not reported. Dosing, target trough level, and duration of treatment differed between the studies. Common adverse effects were hyperlipidemia and neutropenia.

CONCLUSIONS

Available literature indicated that sirolimus therapy might be effective for lymphatic malformations. However, further randomized controlled studies are required to analyze the efficacy and long-term adverse events and to clarify the potential role for sirolimus in the management of lymphatic malformations.

Successful management of extremely high-output refractory congenital chylothorax with chemical pleurodesis using 4% povidone-iodine and propranolol: a case report

First‐line therapy for congenital chylothorax is conservative treatment. However, surgical intervention or chemical pleurodesis is required for refractory cases. With all the concerns regarding its complications, povidone–iodin provided a successful management for a high‐output congenital chylothorax. However, renal and thyroid function must be monitored during treatment.

Long-Term Follow-Up of Lymphatic Malformations in Children Treated with Sildenafil

BACKGROUND/OBJECTIVES

Lymphatic malformations (LMs) are challenging to treat. Reports on the benefits of sildenafil for LM management have been mixed. This study evaluated long-term clinical outcomes of pediatric LM patients after sildenafil treatment.

METHODS

A retrospective chart review was performed on pediatric LM patients treated with sildenafil in the past 5 years. Patients were also contacted to complete a survey of comprehensive questions about their LM after sildenafil and subsequent interventions.

RESULTS

Of 12 patients identified, 10 (83.3%) participated in the follow-up survey. The average age was 8 years (range 4-16 yrs), median treatment duration was 9 months, and the average time of follow-up after sildenafil was 4 years; one patient is still taking sildenafil. Ten patients surveyed (83.3%) reported positive therapeutic response, with improvement in the size and compressibility of their LM during posttreatment clinical visits. Six received additional interventions (four sirolimus, one sclerotherapy, one surgery) after sildenafil was discontinued, with all but one reporting a positive response to subsequent interventions. Minor side effects at the time of sildenafil treatment included mild flushing, dizziness, and transient nausea, but no adverse effects were reported at the long-term follow-up.

CONCLUSION

This is the first report of long-term follow-up of pediatric LM patients treated with sildenafil. Our findings suggest that sildenafil is beneficial for the symptomatic treatment of LMs. Additional analysis on the role of sildenafil as adjuvant therapy is necessary to optimize the use of this medication in the management of complex LMs.