Genetic mutations and phenotype characteristics in peripheral vascular malformations: A systematic review

Vascular malformations (VMs) are clinically diverse with regard to the vessel type, anatomical location, tissue involvement and size. Consequently, symptoms and disease impact differ significantly. Diverse causative mutations in more and more genes are discovered and play a major role in the development of VMs. However, the relationship between the underlying causative mutations and the highly variable phenotype of VMs is not yet fully understood. In this systematic review, we aimed to provide an overview of known causative mutations in genes in VMs and discuss associations between the causative mutations and clinical phenotypes. PubMed and EMBASE libraries were systematically searched on November 9th, 2022 for randomized controlled trials and observational studies reporting causative mutations in at least five patients with peripheral venous, lymphatic, arteriovenous and combined malformations. Study quality was assessed with the Newcastle-Ottawa Scale. Data were extracted on patient and VM characteristics, molecular sequencing method and results of molecular analysis. In total, 5667 articles were found of which 69 studies were included, reporting molecular analysis in a total of 4261 patients and 1686 (40%) patients with peripheral VMs a causative mutation was detected. In conclusion, this systematic review provides a comprehensive overview of causative germline and somatic mutations in various genes and associated phenotypes in peripheral VMs. With these findings, we attempt to better understand how the underlying causative mutations in various genes contribute to the highly variable clinical characteristics of VMs. Our study shows that some causative mutations lead to a uniform phenotype, while other causal variants lead to more varying phenotypes. By contrast, distinct causative mutations may lead to similar phenotypes and result in almost indistinguishable VMs. VMs are currently classified based on clinical and histopathology features, however, the findings of this systematic review suggest a larger role for genotype in current diagnostics and classification.

Development of a condition-specific patient-reported outcome measure for measuring symptoms and appearance in vascular malformations: the OVAMA questionnaire

Background

The symptoms and appearance of vascular malformations can severely harm a patient’s quality of life. The aim of treatment of vascular malformations generally is to improve condition‐specific symptoms and/or appearance. Therefore, it is highly important to start testing treatment effects in clinical studies from the patient’s perspective.

Objectives

To develop a patient‐reported outcome measure for measuring symptoms and appearance in patients with vascular malformations.

Methods

A first draft of the patient‐reported outcome measure was based on the previously internationally developed core outcome set. The qualitative part of this study involved interviews with 14 patients, which led to a second draft. The second draft was field tested cross‐sectionally, after which groups of items were evaluated for adequate internal consistency (Cronbach’s alpha > 0·7) to form composite scores. Construct validity was evaluated by testing 13 predefined hypotheses on known‐group differences.

Results

The patient interviews ensured adequate content validity and resulted in a general symptom scale with six items, a head and neck symptom scale with eight items, and an appearance scale with nine items. Cronbach’s alpha was adequate for two composite scores: a general symptom score (0·88) and an appearance score (0·85). Ten out of 13 hypotheses on known‐group differences were confirmed, confirming adequate construct validity.

Conclusions

With the development of the OVAMA questionnaire, outcomes of patients with vascular malformations can now be evaluated from the patient’s perspective. This may help improve the development of evidence‐based treatments and the overall care for patients with vascular malformations.

What is already known about this topic?

The symptoms and appearance of vascular malformations may severely impact the patient’s physical, mental and social functioning.

Condition‐specific symptoms and appearance are the main drivers for treatment of vascular malformations.

Symptoms and appearance were determined to be core outcome domains and should be measured in all clinical research on vascular malformations.

No instrument exists for measuring patient‐reported symptoms and appearance problems in vascular malformations.

Vascular malformation research is hampered by heterogeneity in outcome measures.

What does this study add?

With this study, a condition‐specific patient‐reported outcome measure was developed for measuring symptoms and appearance in patients with vascular malformations: the OVAMA questionnaire.

This study confirms adequate content and construct validity.

What are the clinical implications of this work?

The problems that matter most to patients with vascular malformations can now be evaluated from the patient’s perspective.

Treatments can be evaluated and compared for effects on these core outcome domains.

This study is a big step in tackling current heterogeneity in outcome measures.

Clinically distinct groups can be determined based on disease severity.

The many applications of the OVAMA questionnaire may significantly improve research and, ultimately, the care for patients with vascular malformations.

Linked Comment: J. Tan. Br J Dermatol 2021; 185:695–696.

Responsiveness of quality of life measures in children with peripheral vascular malformations: The OVAMA project

Background

The OVAMA (Outcome Measures for VAscular MAlformations) project determined quality of life (QoL) as a core outcome domain for evaluating treatment effect in vascular malformations. To correctly evaluate treatment effect on QoL, patient-reported outcome measures (PROMs) are needed that are responsive to changes. In children with vascular malformations, we explored if two widely used PROMs were responsive to changes: the Pediatric Quality of Life Inventory (PedsQL) and the Children's Dermatology Life Quality Index (CDLQI).

Methods

In an international multicenter prospective study, conservatively and invasively treated children completed the PedsQL and CDLQI at baseline and after follow-up of 6-8 weeks. At follow-up, change in health was assessed by a global rating of change (GRC) scale. Responsiveness was assessed by testing hypotheses on expected correlation strength between change scores of the PROMs and the GRC scale, and by calculating the area under the receiver operating characteristics curve (AUC). The PROMs were considered responsive if ≥75% of the hypotheses were confirmed or if the AUC was ≥0.7.

Results

Twenty-nine children were recruited in three centers in the Netherlands and United States, of which 25 completed all baseline and follow-up measurements. For both the PedsQL and CDLQI, less than 75% of the hypotheses were confirmed and the AUC was <0.7.

Discussion

The results suggest that these PROMs are not sufficiently responsive for evaluating treatment effect in peripheral vascular malformations. Our study emphasizes the need for assessing responsiveness before using a PROM in evaluating treatment effect.

Responsiveness of quality-of-life measures in patients with peripheral vascular malformations: the OVAMA project

Background

The OVAMA (Outcome Measures for Vascular Malformations) project determined quality of life (QoL) as a core outcome domain for patients with vascular malformations. In order to measure how current therapeutic strategies alter QoL in these patients, a patient‐reported outcome measurement (PROM) responsive to changes in QoL is required.

Objectives

To assess the responsiveness of two widely used generic QoL PROMs, the Medical Outcomes Study Short Form 36 (SF‐36) and Skindex‐29, in adult patients with vascular malformations.

Methods

In an international multicentre prospective study, treated and untreated patients completed the SF‐36 and Skindex‐29 at baseline and after a follow‐up period of 6–8 weeks. Global rating of change (GRC) scales assessing various QoL‐related outcome domains were additionally completed. Per subscale, responsiveness was assessed using two methods: by testing hypotheses on expected correlation strength between change scores of the questionnaires and the GRC scales, and by calculating the area under the receiver operating characteristics curve (AUC). The questionnaires were considered responsive if ≥ 75% of the hypotheses were confirmed or if the AUC was ≥ 0·7.

Results

Eighty‐nine participants were recruited in three centres in the Netherlands and the U.S.A., of whom 67 completed all baseline and follow‐up questionnaires. For all subscales of the SF‐36 and Skindex‐29, < 75% of the hypotheses were confirmed and the AUC was < 0·7.

Conclusions

Our findings suggest that the SF‐36 and Skindex‐29 seemed unresponsive to change in QoL. This suggests that alternative PROMs are needed to measure – and ultimately improve – QoL in patients with vascular malformations.

What's already known about this topic?

Quality of life is often impaired in patients with vascular malformations.

Quality of life is considered a core outcome domain for evaluating treatment of vascular malformations.

To measure the effect of treatment on quality of life, a patient‐reported outcome measure is required that is responsive to changes in quality of life.

What does this study add?

This is the first study assessing the responsiveness of quality‐of‐life measures in patients with vascular malformations.

The results seem to indicate that the Medical Outcomes Study Short Form 36 (SF‐36) and Skindex‐29 are not responsive to changes in quality of life in patients with vascular malformations.

What are the clinical implications of this work?

Medical Outcomes Study Short Form 36 (SF‐36) and Skindex‐29 are not ideal to assess the effect on quality of life over time, of treatment strategies for peripheral vascular malformations.

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Complications of pregnancy and labour in women with Klippel-Trénaunay syndrome: a nationwide cross-sectional study

OBJECTIVE

To evaluate complications of pregnancy, including thromboembolism, in women with extensive vascular malformations associated with Klippel-Trénaunay syndrome (KTS).

DESIGN

Nationwide cross-sectional study.

SETTING

Two tertiary expert centres and the Dutch Klippel-Trénaunay patient organisation.

SAMPLE

Adult women with KTS.

METHODS

Patients with KTS were invited to participate in a comprehensive online survey about their obstetric history. Reference data on pregnancy outcomes and complications of non-diseased women were collected from population-based cohorts from the literature.

MAIN OUTCOME MEASURES

Prevalence of complications, specifically venous thromboembolism and postpartum haemorrhage.

RESULTS

Sixty women completed the survey. Seventeen patients did not conceive, of whom three refrained from pregnancy because of KTS. A total of 97 pregnancies and 86 deliveries were reported in 43 patients. KTS-related symptoms were aggravated during pregnancy in 43% of patients. Deep vein thrombosis was present in 5.8% and pulmonary embolism was present in 2.3% of pregnancies, which was extremely high compared with the reference population (P < 0.0001), with a relative risk of 108.9 (95% confidence interval, 95% CI 46.48-255.03) and 106.2 (95% CI 26.97-418.10), respectively. Severe postpartum haemorrhage (PPH) occurred in 11% of KTS pregnancies, compared with 5.8% of pregnancies in the reference population (relative risk, RR 1.81, 95% CI 0.97-3.37, P = 0.06).

CONCLUSIONS

Our data suggest that women with KTS have a significant risk of venous thromboembolic events, severe postpartum haemorrhage, and aggravation of KTS symptoms during pregnancy, and in early postpartum period. Obstetricians should counsel patients about these risks in the preconception phase. Antithrombotic prophylaxis should be considered in the obstetric management of patients with KTS.

TWEETABLE ABSTRACT

High risk of complications during pregnancy and labour in women with Klippel-Trénaunay syndrome.