Clinical presentation and treatment paradigms of brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia

Stereotactic radiosurgery for brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia

OBJECTIVE

Brain arteriovenous malformations (AVMs) in patients with hereditary hemorrhagic telangiectasia (HHT) present different characteristics from sporadic AVMs, and they have lower initial bleeding rates. Conservative management is usually preferred for the treatment of these lesions. In this case study, we present the largest series of HHT patients treated with stereotactic radiosurgery to date.

METHODS

We identified eight patients with HHT and 14 AVMs. We retrospectively collected clinical, radiographic, and treatment characteristics of the patients and each AVM.

RESULTS

Most patients in our sample presented with small AVMs. The median volume of these AVMs was 0.22 cm3 (IQR 0.08-0.59). Three out of eight patients presented with initial intracerebral hemorrhage (ICH). The majority of lesions had low (12/14) Spetzler-Martin grades (I-II). Median maximum and margin doses used for treatment were 36.2 (IQR 35.25-44.4) and 20 (IQR 18-22.5) Gy, respectively. The overall obliteration rate after SRS was 11/14, and the median time to obliteration across all 11 obliterated AVMs was 35.83 months (IQR, 17-39.99). Neurological status was favorable with all patients having a mRS of 0 or 1 at the last follow-up. Symptomatic radiation-induced changes (RIC) after SRS were low (7.1%), and there were no permanent RIC.

CONCLUSIONS

Patients with HHT who present with multiple brain AVMs are generally well served by SRS. Obliteration can be achieved in the majority of HHT patients and with a low complication rate. In the current study, initial hemorrhage rates prior to SRS were noticeable which supports the decision to treat these AVMs. Future studies are needed to better address the role of SRS for HHT patients harboring ruptured and unruptured AVMs.

ANG2 Blockade Diminishes Proangiogenic Cerebrovascular Defects Associated With Models of Hereditary Hemorrhagic Telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a vascular disorder characterized by arteriovenous malformations and blood vessel enlargements. However, there are no effective drug therapies to combat arteriovenous malformation formation in patients with HHT. Here, we aimed to address whether elevated levels of ANG2 (angiopoietin-2) in the endothelium is a conserved feature in mouse models of the 3 major forms of HHT that could be neutralized to treat brain arteriovenous malformations and associated vascular defects. In addition, we sought to identify the angiogenic molecular signature linked to HHT.

METHODS

Cerebrovascular defects, including arteriovenous malformations and increased vessel calibers, were characterized in mouse models of the 3 common forms of HHT using transcriptomic and dye injection labeling methods.

RESULTS

Comparative RNA sequencing analyses of isolated brain endothelial cells revealed a common, but unique proangiogenic transcriptional program associated with HHT. This included a consistent upregulation in cerebrovascular expression of ANG2 and downregulation of its receptor Tyr kinase with Ig and EGF homology domains (TIE2/TEK) in HHT mice compared with controls. Furthermore, in vitro experiments revealed TEK signaling activity was hampered in an HHT setting. Pharmacological blockade of ANG2 improved brain vascular pathologies in all HHT models, albeit to varying degrees. Transcriptomic profiling further indicated that ANG2 inhibition normalized the brain vasculature by impacting a subset of genes involved in angiogenesis and cell migration processes.

CONCLUSIONS

Elevation of ANG2 in the brain vasculature is a shared trait among the mouse models of the common forms of HHT. Inhibition of ANG2 activity can significantly limit or prevent brain arteriovenous malformation formation and blood vessel enlargement in HHT mice. Thus, ANG2-targeted therapies may represent a compelling approach to treat arteriovenous malformations and vascular pathologies related to all forms of HHT.

Multiple brain arteriovenous malformations: systematic review and individual patient data meta-analysis

Multiple brain arteriovenous malformations (bAVM) are rare neurovascular lesions usually related to genetic syndromes. Its management is not well established given its rarity. The objective of this study was to describe the clinical and angiographic features of published cases and to explore their associations with treatment outcomes. We performed a literature search of published cases in Medline and the Regional Index Medici. Additional cases were searched in our single-center registry. Data on the proportions of patients and clinical and angiographic characteristics were extracted. The study outcomes were nidal instability in patients who underwent staged treatment and radiological cure in patients who underwent treatment using any treatment modality. Logistic regression models for the study outcomes were analyzed. Data on the proportions of multiple bAVM patients were summarized with meta-analyses of proportions. We included 118 patients (reported in 68 studies) from the literature and 6 cases identified in our registry. A total of 124 patients harboring 339 bAVM nidi were included in the analyses. Differences between syndromic and non-syndromic cases were observed. The logistic regression analyses showed that angiographically occult untreated bAVM was associated (OR 14.37; 95% CI 2.17 to 95.4) with nidal instability after staged treatment, and deep (OR 5.11; 95% CI 1.51 to 17.27) and eloquent (OR 3.91; 95% CI 1.22 to 12.52) locations were associated with residual disease after treatment. Inconsistent reporting of relevant data throughout the included studies undermined the planned analyses. Some prognostic factors were found to be related to the study outcomes. Study Registration: The protocol of the systematic review was registered in PROSPERO as CRD42021245814.

Intermixed arteriovenous malformation and hemangioblastoma: case report and literature review

We report the third presentation of an intermixed arteriovenous malformation and hemangioblastoma. The rare occurrence of the diagnostic histologic features of both a neoplasm and vascular malformation in a single lesion is more common in gliomas, as angioglioma, and is termed an 'intermixed' lesion. We review the literature concerning the developmental biology of each lesion, and potential interplay in the formation of an intermixed vascular neoplasm and vascular malformation. The roles of cellular origin, genetic susceptibility, favourable microenvironment, altered local gene expression and key regulatory pathways are reviewed. Our review supports angiography and genetic profiling in intermixed lesions to inform management strategies. Consideration should be given to multimodality therapeutic interventions as required, including microsurgical resection, stereotactic radiosurgery and further research to exploit emerging molecular targets.

Cerebral Arteriovenous Malformations in Pediatric Patients with Hereditary Hemorrhagic Telangiectasia: Re-evaluating Appearance, Bleeding Risk, and Treatment Necessity in a Selective Meta-analysis

Pediatric patients suffering from cerebral nidal arteriovenous malformations are a unique population due to the rare occurrence of the disease. Diagnosis of hereditary hemorrhagic telangiectasia (HHT) in children is a rare event and mainly restricted to coincidental detection from screening of possibly afflicted family members. In patients with HHT, it is well known that the incidence of cerebral vascular malformations (CVMs) is higher than expected when compared with the nonafflicted population. Even though CVMs comprise a variety of different distinct anatomical and radiographic entities (e.g., capillary telangiectasia, nidal arteriovenous malformation [AVM], cavernous malformation, dural or pial as well as mixed fistula, and vein of Galen malformation), they are mostly summarized and analyzed all in one category due to the low number of individual cases identified in single centers. Nevertheless, the best treatment algorithm will likely vary significantly between different CVMs as does the clinical presentation and the natural course of the CVM. It is therefore the objective of this article to focus on nidal AVMs in pediatric patients suffering from HHT. To this end, we performed a systematic selective literature research to estimate incidence, clinical and radiological appearance, as well as classification according to established grading system, and to evaluate the necessity of treatment of these lesions in light of their respective outcomes. Our line of arguments explains why we recommend to follow these lesions expectantly and suggest to keep pediatric patients under surveillance with sequential scans until they reach adulthood.

Gender differences in hereditary hemorrhagic telangiectasia severity

Background

Gender differences in organ involvement and clinical severity have been poorly described in hereditary hemorrhagic telangiectasia (HHT). The aim of this study was to describe differences in the severity of HHT manifestations according to gender.

Methods

Severity was measured according to Epistaxis Severity Score (ESS), Simple Clinical Scoring Index for hepatic involvement, a general HHT-score, needing for invasive treatment (pulmonary or brain arteriovenous malformations -AVMs- embolization, liver transplantation or Young’s surgery) or the presence of adverse outcomes (severe anemia, emergency department -ED- or hospital admissions and mortality).

Results

One hundred forty-two (58.7%) women and 100 (41.3%) men were included with a mean age of 48.9 ± 16.6 and 49 ± 16.5 years, respectively. Women presented hepatic manifestations (7.1% vs 0%) and hepatic involvement (59.8% vs 47%), hepatic AVMs (28.2% vs 13%) and bile duct dilatation (4.9% vs 0%) at abdominal CT, and pulmonary AVMs at thoracic CT (35.2% vs 23%) more often than men. The Simple Clinical Scoring Index was higher in women (3.38 ± 1.2 vs 2.03 ± 1.2), and more men were considered at low risk of harboring clinically significant liver disease than women (61% vs 25.3%). These differences were mantained when considering HHT1 and HHT2 patients separetely. Duodenal telangiectasia were more frequent in men than women (21% vs 9.8%). Invasive treatments were more frequently needed in women (28.2% vs 16%) but men needed attention at the ED more often than women (48% vs 28.2%), with no differences in ESS, HHT-score, anemia hospital admissions or mortality.

Conclusions

HHT women showed more severe hepatic involvement than men, also among HHT1 and HHT2 patients. Women had higher prevalence of pulmonary AVMs and needed invasive procedures more frequently, while men needed attention at the ED more often. These data might help physicians to individualize HHT patients follow-up.

Benefits of Treating Arteriovenous Malformations in Hereditary Hemorrhagic Telangiectasia: A Retrospective Analysis of 14 Patients

Background

Arteriovenous malformations (AVMs) are a cardinal feature of hereditary hemorrhagic telangiectasia (HHT). However, whether to treat brain AVMs in patients with HHT remains questionable because of the possible risks.

Methods

We performed a retrospective study of patients with HHT who had been treated for brain AVMs at our institution from January 1, 2003, to December 31, 2016. An institutional database was queried for the phrases “hereditary hemorrhagic telangiectasia” and “HHT,” and those patients who had been treated during the study period were identified. Data were extracted regarding presentation, AVM characteristics, treatment modality, and treatment outcomes.

Results

We identified 14 patients (10 males, 4 females) with HHT who had had AVMs (n = 27) from the institutional database. The mean age of the patients was 43 years (range, 2–64). Of the 27 brain AVMs, 13 were Spetzler-Martin grade I, 12 were grade II, and 2 were grade III; none were grade IV or V. Treatment was by microsurgery only (11 AVMs in 10 patients), embolization followed by microsurgery (2 AVMs in 2 patients), and radiosurgery only (12 AVMs in 2 patients). AVM obliteration was achieved in 100% of the patients. No new fixed neurologic deficits developed after treatment of unruptured HHT AVMs.

Conclusions

The risk of treatment of brain AVMs in patients with HHT is quite low for appropriately selected patients with treatment individualized to radiosurgery, microsurgery, or a combination of embolization and microsurgery.

Thyroplasty in unilateral vocal fold paresis with coexisting hereditary hemorrhagic telenagiectasia: A case report

RATIONALE

The coincidence of an idiopathic unilateral vocal fold paresis and hereditary hemorrhagic telenagiectasia (HHT) is extremely rare and has not been described in the available literature yet.

PATIENTS CONCERNS

A 55-year-old female was admitted to hospital due to acute onset of hoarseness, voice fatigue, and effort dyspnea. In the past, the patient was diagnosed with HHT and on admission presented characteristic vascular lesions in the oral cavity. She reported also experiencing a moderate epistaxis at least once per month.

DIAGNOSES

The otolaryngological examination (fiberolaryngoscopy, phoniatric examination) revealed unchanged mobility and morphology of the right vocal fold and paresis of the left vocal fold in intermediate position. Computed tomography and magnetic resonance imaging of head, neck, and chest were inconclusive and showed no pathologic findings.

INTERVENTIONS

The unilateral paresis was treated for 12 months as idiopathic, with extensive rehabilitation. However, no improvement was observed. As a patient suffering from HHT is a challenge for anesthesiologists in terms of general anesthesia, the decision to perform type I thyroplasty (medialization) in local anesthesia was made.

OUTCOMES

There were no complications intraoperatively or in postoperative period. The implemented treatment was successful, as the voice quality improved both in perceptual evaluation (GRBAS scale) and acoustic analysis (F0, jitter, shimmer, NHR).

LESSONS

A routine surgical treatment in patients with HHT is a challenge. However, in this case, it was uneventful and successful, thus it can be recommended in other patients with similar background.