Neuroradiological Manifestations of Hereditary Hemorrhagic Telangiectasia in 139 Japanese Patients

A Case of Preoperative Diagnosis of Pulmonary Artery Aneurysm Resected by Segmentectomy

A pulmonary artery aneurysm (PAA) is a rare condition. It is treated in various ways, depending on its location and size. Herein, we describe the preoperative diagnosis of a PAA that was resected by segmentectomy. A 44-year-old female underwent CT, which revealed a 15-mm saccular protrusion in the right pulmonary artery and was diagnosed with PAA. The patient was initially observed without requiring further treatment, but a gradual increase in size led to therapeutic intervention. Because the PAA was located just peripheral to the right A8 bifurcation, embolization using interventional radiology was deemed too difficult. Therefore, a surgical intervention was planned. Subsequently, S8 segmentectomy, basal segmentectomy, and basilar pulmonary artery ligation were all considered. Ultimately, basal segmentectomy was selected because it allowed the resection of the pulmonary artery and did not result in invalid ventilation of the basal segment. A basal segmentectomy was performed, and the PAA was safely removed without hemorrhage. Histopathological examination revealed arterial and venous wall-like areas, and the patient was diagnosed with pulmonary artery malformation. A PAA is typically treated with coil embolization, ligation of the pulmonary artery, aneurysmectomy, and lung resection; however, no clear treatment guidelines exist. After discussion, we selected basal segmentectomy as a safe and minimally invasive procedure, and we resected the PAA without complications. The optimal treatment strategy for PAAs varies according to location and size, and a careful treatment plan should be established.

Brain arteriovenous malformation in hereditary hemorrhagic telangiectasia: Recent advances in cellular and molecular mechanisms

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder characterized by vessel dilatation, such as telangiectasia in skin and mucosa and arteriovenous malformations (AVM) in internal organs such as the gastrointestinal tract, lungs, and brain. AVMs are fragile and tortuous vascular anomalies that directly connect arteries and veins, bypassing healthy capillaries. Mutations in transforming growth factor β (TGFβ) signaling pathway components, such as ENG (ENDOGLIN), ACVRL1 (ALK1), and SMAD4 (SMAD4) genes, account for most of HHT cases. 10-20% of HHT patients develop brain AVMs (bAVMs), which can lead to vessel wall rupture and intracranial hemorrhages. Though the main mutations are known, mechanisms leading to AVM formation are unclear, partially due to lack of animal models. Recent mouse models allowed significant advances in our understanding of AVMs. Endothelial-specific deletion of either Acvrl1, Eng or Smad4 is sufficient to induce AVMs, identifying endothelial cells (ECs) as primary targets of BMP signaling to promote vascular integrity. Loss of ALK1/ENG/SMAD4 signaling is associated with NOTCH signaling defects and abnormal arteriovenous EC differentiation. Moreover, cumulative evidence suggests that AVMs originate from venous ECs with defective flow-migration coupling and excessive proliferation. Mutant ECs show an increase of PI3K/AKT signaling and inhibitors of this signaling pathway rescue AVMs in HHT mouse models, revealing new therapeutic avenues. In this review, we will summarize recent advances and current knowledge of mechanisms controlling the pathogenesis of bAVMs, and discuss unresolved questions.

Neurovascular Manifestations in Pediatric Patients With Hereditary Haemorrhagic Telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a multiorgan vascular dysplasia with limited data regarding its neurovascular manifestations and genotype-phenotype correlation in children. The objective of this study was to describe the neurovascular findings in a large cohort of children with HHT and correlate between phenotype and genotype.

METHODS

This retrospective study was conducted on 221 children (<18 years) with a definite or possible diagnosis of HHT based on Curacao criteria, or with positive genetics for the mutated genes of ENG, ACVRL-1, and SMAD-4, who also underwent brain MRI and/or conventional angiography. Demographic and clinical information, imaging findings, and follow up information were gathered.

RESULTS

Two hundred twenty-one children with HHT (70.6% genetically confirmed, and 99.5% positive family history) were included, with a median age of 7 years (interquartile range: 3 to 11 years) and 58.8% male predominance. Neurovascular lesions were found in 64 of 221 (28.9%), with 3.1% prevalence of intracranial hemorrhage. The most commonly observed vascular malformations were developmental venous anomalies (48.5%) and brain arteriovenous malformations (AVMs) (31.2%), followed by capillary malformations (14.1%). Multiple AVMs were seen in 10.0% of the cohort. We found no instances of de novo AVM (1281.8 patient-years).A significantly higher proportion of patients with ENG mutations (19.7%) had brain AVM than those with ACVRL-1 (4.9%) and SMAD-4 (0%) mutations (P < 0.01). There was no significant difference in the hemorrhagic risk of shunting lesions associated with ENG (35.3%) or ACVRL-1 (33.3%) positivity (P = 0.9).

CONCLUSIONS

We describe the neurovascular imaging and genetic findings from a large pediatric cohort of HHT, to enhance clinical awareness and guide management of patients with HHT.

Snake Technique in Osler's Disease-associated Thoracoabdominal Aortic Aneurysm

Osler's disease is an autosomal dominant disorder characterized by epistaxis, telangiectases, and arteriovenous malformations of the internal organs. We, herein, report the first published case of dissecting thoracoabdominal aortic aneurysm repair in a 66 year-old woman with hereditary hemorrhagic telangiectasia associated with activin receptor-like kinase 1 gene mutations. We maintained the activated clotting time around 400 seconds during cardiopulmonary bypass to avoid lethal hemorrhage from telangiectases or arteriovenous malformations. The Adamkiewicz artery could not be identified on imaging studies preoperatively. We, therefore, used the 'Snake technique' for intercostal revascularization, which was effective in preventing paraplegia.

[Hereditary hemorrhagic telangiectasia (Rendu-Osler syndrome)]

The analysis of publications is carried out and current data concerning the etiology, pathogenesis, diagnosis, and principles of treatment of hereditary hemorrhagic telangiectasia are presented.

Utility of modified Rankin Scale for brain vascular malformations in hereditary hemorrhagic telangiectasia

Background

Approximately 10% of hereditary hemorrhagic telangiectasia (HHT) patients harbour brain vascular malformations (VMs). Intracranial hemorrhage (ICH) from brain VMs can lead to death or morbidity, while treatment options for brain VMs also have associated morbidity. The modified Rankin Scale (mRS) may provide an approach to identifying HHT-brain VM patients with poor outcomes, and their predictors. We aimed to measure the relationship between mRS score and brain VM, brain VM number, as well as other aspects of HHT, at enrollment and during prospective follow-up.

Methods

1637 HHT patients (342 with brain VMs) were recruited from 14 HHT centres of the Brain Vascular Malformation Consortium since 2010 and followed prospectively (mean = 3.4 years). We tested whether the presence of brain VM, other HHT organ involvement, and HHT mutation genotype were associated with worse mRS scores at baseline and during follow-up, using linear mixed models, adjusting for age, sex, and year of visit.

Results

Presence of brain VMs was not associated with worse mRS score at baseline and there was no significant worsening of mRS with prospective follow-up in these patients; 92% had baseline mRS of 0–2. HHT-related gastrointestinal (GI) bleeding was associated with worse mRS scores at baseline (0.37, 95% CI 0.26–0.47, p < 0.001), as were history of anemia (0.35, 95% CI 0.27–0.43, p < 0.001) and liver VMs (0.19, 95% CI 0.09–0.30, p < 0.001). Presence of pulmonary arteriovenous malformations (AVMs) was not associated with worse mRS scores at baseline. mRS score was not associated with either HHT genotype (Endoglin vs ACVRL1). Only GI bleeding was associated with a significantly worsening mRS during prospective follow-up (0.64, 95% CI 0.21–1.08, p = 0.004).

Conclusion

Most HHT-brain VM patients had good functional capacity (mRS scores 0–2) at baseline that did not change significantly over 3.4 mean years of follow-up, suggesting that mRS may not be useful for predicting or measuring outcomes in these patients. However, HHT patients with GI bleeding, anemia history or liver VMs had worse mRS scores, suggesting significant impact of these manifestations on functional capacity. Our study demonstrates the insensitivity of the mRS as an outcomes measure in HHT brain VM patients and reinforces the continued need to develop outcomes measures, and their predictors, in this group.

Hereditary Hemorrhagic Telangiectasia: The Convergence of Genotype, Phenotype, and Imaging in Modern Diagnosis and Management of a Multisystem Disease

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease that manifests as vascular malformations in the brain, lung, liver, gastrointestinal tract, nasal mucosa, and skin. Diagnosis and management of HHT is guided in large part by imaging studies, making it a condition with which the radiology community needs familiarity. Proper screening and care lead to improved morbidity and mortality in patients with HHT. International guidelines were recently updated and form the basis for a detailed discussion of the role of imaging and image-guided therapy in HHT. © RSNA, 2021 Online supplemental material is available for this article.

Basal Ganglia T1 Hyperintensity in Hereditary Hemorrhagic Telangiectasia

BACKGROUND AND PURPOSE

The implications of basal ganglia T1 hyperintensity remain unclear in patients with hereditary hemorrhagic telangiectasia. This study was performed to assess the prevalence of this imaging finding in a large cohort of patients with hereditary hemorrhagic telangiectasia and to identify any association between this phenomenon and other disease manifestations.

MATERIALS AND METHODS

In this retrospective study, we identified all patients at our institution diagnosed with definite hereditary hemorrhagic telangiectasia from 2001 to 2017. Patients who did not undergo brain MR imaging were excluded. Patient demographics, laboratory results, and hereditary hemorrhagic telangiectasia disease characteristics were noted. Basal ganglia hyperintensity was evaluated both qualitatively and quantitatively relative to the signal intensity in the ipsilateral thalami. Statistical analysis was performed with commercially available software.

RESULTS

A total of 312 patients (41% men, 59% women; mean age, 51 ± 18 years) with definite hereditary hemorrhagic telangiectasia were identified. Basal ganglia T1 hyperintensity was present in 23.4% of patients and demonstrated a statistically significant association with older age (P < .001), increased hepatic AVMs (P < .001), high cardiac output state (P < .001), hepatic failure (P = .01), elevated peak serum alkaline phosphatase level (P = .03), and increased total bilirubin count (P = .03). There was no significant association with sex, hereditary hemorrhagic telangiectasia genetic mutation status, parkinsonism, or serum transaminase levels.

CONCLUSIONS

Basal ganglia T1 hyperintensity occurs in >23% of patients with hereditary hemorrhagic telangiectasia and is associated with hepatic vascular malformations, hepatic dysfunction, and elevated cardiac output. The presence of this finding on screening MR imaging in patients with hereditary hemorrhagic telangiectasia should prompt further evaluation for visceral lesions causing arteriovenous shunting.

A case of hereditary hemorrhagic telangiectasia with hepatic encephalopathy due to portal hepatic venous shunt

An 86-year-old male who was able to perform all activities of daily living (ADL) was diagnosed with hereditary hemorrhagic telangiectasia (HHT) at 70 years of age. Following his diagnosis, he had been receiving treatment at our hospital. After the sudden onset of a consciousness disorder, he was admitted to our hospital's emergency department with asterixis, a high serum ammonia level, and hepatic encephalopathy. After angiography, he was diagnosed with hepatic encephalopathy due to portal hepatic venous shunts. HHT is characterized by abnormal blood vessel construction and the formation of peripheral vasodilatation and shunt blood vessels. Although rare, portal hepatic venous shunts may sometimes cause hepatic encephalopathy. The extent of this shunt increases with age. As Japan is an increasingly aging society, the number of HHT patients with hepatic encephalopathy is likely to increase markedly in the future.