Pulmonary arterial hypertension as the first manifestation in a patient with hereditary hemorrhagic telangiectasia

Pulmonary hypertension in hereditary hemorrhagic telangiectasia: A clinical review

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant hereditary disorder characterized by recurrent spontaneous epistaxis, mucocutaneous telangiectasias, and solid organ arteriovenous malformations (AVMs). Pulmonary hypertension (PH) is an increasingly recognized complication in patients with HHT, most often precipitated by high-output heart failure in the presence of hepatic AVMs as well as pulmonary arterial hypertension in the form of a proliferative vasculopathy. The presence of PH in patients with HHT is associated with significant elevations in rates of morbidity and mortality. Additionally, there is growing recognition of a thromboembolic propensity in this population that increases the risk of chronic thromboembolic PH, posing unique clinical considerations regarding the use of anticoagulation. Patients with HHT are also at risk of PH due to disorders commonly seen in the general population, including left-sided heart and lung disease. The etiology of PH in HHT is multifaceted and complex; the diagnostic approach and treatment strategies must consider the underlying pathophysiology of HHT. This comprehensive review summarizes current knowledge of PH in HHT, detailing the pathogenesis of known etiologies, diagnostic evaluation, and suggested treatment modalities as well as emerging therapies that may be of future interest.

Treatment of pulmonary hypertension in patients with Hereditary Hemorrhagic Telangiectasia - A case series and systematic review

RATIONALE

Pulmonary Arterial Hypertension (PAH), a rare complication of HHT is associated with poor outcome. There are no trials to date that have investigated whether pulmonary vasodilator therapy improves hemodynamics or survival in this disease.

OBJECTIVE

To determine whether pulmonary vasodilator therapy improves survival, exercise capacity, or hemodynamics in HHT patients with pre-capillary PH.

METHODS

We performed a before-and-after observational study on a multicenter cohort of subjects with HHT-PAH who received intravenous prostanoid therapy. We then conducted a systematic review, searching Medline and EMBASE through December 2019. Studies that enrolled HHT-PAH subjects and reported treatment outcomes were selected. PROSPERO #158179.

RESULTS

Twenty-one articles were selected. Studies were before-and-after observational studies, case reports, and case series. Among all subjects with HHT-PAH, both mPAP (65 ± 19 pre-treatment vs 51 ± 16 mmHg post-treatment p = 0.04) and PVR (12 ± 6 pre-treatment vs 8 ± 4 WU post-treatment p = 0.01) improved with treatment. The mPAP improved with either oral (57 ± 17 pre-treatment versus 44 ± 13 mmHg post-treatment, p = 0.03) or intravenous (80 ± 15 pre-treatment versus 64 ± 16 mmHg post-treatment, p = 0.017) therapy. PVR also improved with either oral (10 ± 4 pre-treatment versus 6 ± 3 WU post-treatment, p = 0.004) or intravenous (17 ± 5 pre-treatment versus 10 ± 4 WU post-treatment, p = 0.04) therapy. Survival among HHT-PAH patients who received oral or intravenous therapy was not different (p = 0.2). Unadjusted survival among HHT-PAH patients was longer than that of IPAH patients (p = 0.008). There was no difference in side effects among HHT-PAH patient who received oral or intravenous therapy (p = 0.1).

CONCLUSION

Pulmonary vasodilator therapy is effective in improving hemodynamics of subjects with HHT-PAH and was not associated with increased risk of side effects.

Recognizing genetic disease: A key aspect of pediatric pulmonary care

Advancement in technology has improved recognition of genetic etiologies of disease, which has impacted diagnosis and management of rare disease patients in the pediatric pulmonary clinic. This review provides an overview of genetic conditions that are likely to present with pulmonary features and require extensive care by the pediatric pulmonologist. Increased familiarity with these conditions allows for improved care of these patients by reducing time to diagnosis, tailoring management, and prompting further investigation into these disorders.

Urologic Surgery with Multisystem Comorbidities: A Case Report

BACKGROUND Originally implemented for colorectal surgery, enhanced perioperative protocols have been incorporated into many surgical fields in an effort to improve outcomes. The cornerstone of many strategies includes patient education, liberalized oral intake on the day of surgery, no routine bowel prep, targeted multimodal analgesia, cautious use of IV hydration, early extubation, avoidance of NG tubes and/or surgical drains, and encouraging early postoperative ambulation. CASE REPORT We report on the successful outcome of a single patient with a rare autosomal dominant disorder (hereditary hemorrhagic telangiectasia) with multisystem involvement including pulmonary, cardiac, hematologic, gastrointestinal, renal, oncologic, and hepatic comorbidities, scheduled for open nephrectomy. CONCLUSIONS Prospective and retrospective studies are needed to specifically elucidate the role of similar management in higher-risk surgical candidates.

Functional analysis of a novel ENG variant in a patient with hereditary hemorrhagic telangiectasia (HHT) identifies a new Sp1 binding-site

Hereditary Hemorrhagic Telangiectasia (HHT) is a rare disease, with an autosomal dominant inheritance and a worldwide incidence of about 1: 5000 individuals. In >80% of patients, HHT is caused by mutations in either ENG or ACVRL1, which code for ENDOGLIN and Activin A Receptor Type II-Like Kinase 1 (ALK1), belonging to the TGF-β/BMP signalling pathway. Typical HHT clinical features are mucocutaneous telangiectases, arteriovenous malformations, spontaneous and recurrent epistaxis, as well as gastrointestinal bleedings. An additional, but less frequent, clinical manifestation in some HHT patients is the presence of Pulmonary Arterial Hypertension (PAH). The aim of this work is to describe the functional role of a novel ENG intronic variant found in a patient affected by both HHT and PAH, in order to assess whether it has a pathogenic role. We proved that the variant lies in a novel binding-site for the transcription factor Sp1, known to be involved in the regulation of ENG and ACVRL1 transcription. We confirmed a pathogenic role for this intronic variant, as it significantly reduces ENG transcription by affecting this novel Sp1 binding-site.

Identification of multiple ACVRL1 mutations in patients with pulmonary arterial hypertension by targeted exome capture

Pulmonary artery hypertension (PAH) is characterized as sustained elevation of pressure in the pulmonary vascular system that is attributable to a variety of causes. More than a dozen genes have previously been proposed as being associated with PAH. To examine potential mutations of these genes in patients with PAH, we developed a targeted exome kit containing 22 PAH-associated genes for genetic screens of 80 unrelated patients with PAH. As a result, we identified 16 different mutations in the BMPR2 gene and four different mutations in ACVRL1, the gene for activin receptor-like kinase-1 (ACVRL1). However, no deleterious mutations were found in the remaining 20 genes. In the present study, we provided detailed characterization of the ACVRL1 mutations in four pedigrees, including two novel missense mutations (c.676G>A, p.V226M; c.955G>C, p.G319R) and two recurrent mutations (c.1231C>T, p.R411W; c.1450C>T, p.R484W). Furthermore, we showed that markedly reduced Smad1/5 phosphorylation levels and reduced activities of luciferase reporters in each of the four ACVRL1 mutant-transfected NIH-3T3 cells. Therefore, our findings demonstrated that missense mutations of ACVRL1 identified in the present study significantly affected the bone morphogenetic protein 9 (BMP-9) pathway, implicating PAH pathogenesis. Detailed genotype–phenotype correlation analysis revealed initial symptoms of hereditary haemorrhagic telangiectasia (HHT) in some of the patients, suggesting the importance of sequencing molecular markers for early identification and intervention of individuals at risk for PAH and potential HHT. We developed a customized exome sequencing system to identify mutations in these PAH-associated genes, and found two novel missense mutations and two recurrent mutations in the ACVRL1 gene in four unrelated Chinese families; we also determined hypomorphic alleles using functional studies.

Pulmonary Arterial Hypertension: A Current Perspective on Established and Emerging Molecular Genetic Defects

Pulmonary arterial hypertension (PAH) is an often fatal disorder resulting from several causes including heterogeneous genetic defects. While mutations in the bone morphogenetic protein receptor type II (BMPR2) gene are the single most common causal factor for hereditary cases, pathogenic mutations have been observed in approximately 25% of idiopathic PAH patients without a prior family history of disease. Additional defects of the transforming growth factor beta pathway have been implicated in disease pathogenesis. Specifically, studies have confirmed activin A receptor type II-like 1 (ACVRL1), endoglin (ENG), and members of the SMAD family as contributing to PAH both with and without associated clinical phenotypes. Most recently, next-generation sequencing has identified novel, rare genetic variation implicated in the PAH disease spectrum. Of importance, several identified genetic factors converge on related pathways and provide significant insight into the development, maintenance, and pathogenetic transformation of the pulmonary vascular bed. Together, these analyses represent the largest comprehensive compilation of BMPR2 and associated genetic risk factors for PAH, comprising known and novel variation. Additionally, with the inclusion of an allelic series of locus-specific variation in BMPR2, these data provide a key resource in data interpretation and development of contemporary therapeutic and diagnostic tools.