Incidence of Spontaneous Pulmonary AVM Rupture in HHT Patients

Prevalence and Characteristics of Intracranial Aneurysms in Hereditary Hemorrhagic Telangiectasia

BACKGROUND AND PURPOSE

The association between hereditary hemorrhagic telangiectasia and intracranial aneurysms remains controversial. This study evaluated the prevalence and characteristics of intracranial aneurysms in patients with hereditary hemorrhagic telangiectasia with brain vascular malformations.

MATERIALS AND METHODS

Between 2007 and 2021, patients enrolled in the Brain Vascular Malformation Consortium with definite hereditary hemorrhagic telangiectasia, the presence of brain vascular malformations, and available angiographic studies of the brain were retrospectively reviewed. Angiographic features of intracranial aneurysms and their relationship to coexisting brain vascular malformations were analyzed. We also examined the association between baseline clinical features and the presence of intracranial aneurysms.

RESULTS

One hundred eighty patients were included. A total of 14 intracranial aneurysms were found in 9 (5%) patients, and 4 intracranial aneurysms were considered flow-related aneurysms. Patients with intracranial aneurysms were significantly older than patients without intracranial aneurysms (mean, 48.1 [SD, 18.2] years versus 33.5 [SD, 21.0] years; P = .042). If we excluded flow-related intracranial aneurysms, the prevalence of intracranial aneurysms was 3.3%. All intracranial aneurysms were in the anterior circulation, were unruptured, and had an average maximal diameter of 3.9 (SD, 1.5) mm. No intracranial aneurysms were found in pediatric patients with hereditary hemorrhagic telangiectasia. No statistically significant correlation was observed among other baseline demographics, hereditary hemorrhagic telangiectasia features, and the presence of intracranial aneurysms.

CONCLUSIONS

The prevalence of intracranial aneurysms in this large cohort study is comparable with that in the general population and might be increased slightly due to hemodynamic factors associated with shunting brain vascular malformations.

[Hereditary hemorrhagic telangiectasia]

Hereditary hemorrhagic telangiectasia, also known as Rendu-Osler - Weber disease, is a rare, autosomal dominant vascular disease, with prevalence of 1/5,000. The condition is characterized by muco-cutaneous telangiectasias, which are responsible for a hemorrhagic syndrome of variable severity, as well as arteriovenous malformations (AVMs) appearing in the lungs, the liver, and the nervous system. They can be the source of shunts, which may be associated with high morbidity (neurological ischemic stroke, brain abscess, high-output heart failure, biliary ischemia…). It is therefore crucial to establish a clinical diagnosis using the Curaçao criteria or molecular diagnosis based on genetic analysis of the ENG, ACVRL1, SMAD4 and GDF2 genes. In most cases, multidisciplinary management allows patients to have normal life expectancy. Advances in interventional radiology and better understanding of the pathophysiology of angiogenesis have resulted in improved therapeutic management. Anti-angiogenic treatments, such as bevacizumab (BVZ, an anti-VEGF antibody), have proven to be effective in cases involving bleeding complications and severe liver damage with cardiac repercussions. Other anti-angiogenic agents are currently being investigated, including tyrosine kinase inhibitors.

Twenty-Seven-Year Retrospective Review of Hemoptysis from Systemic Collaterals Following Pulmonary Arteriovenous Malformation Embolization

OBJECTIVE

To determine the prevalence of hemoptysis secondary to post-embolization systemic collaterals and review the recurrence rate and treatment outcomes.

METHODS

The records of 930 patients with PAVM (801 with known or possible HHT), from a single HHT center between July 2, 1996 and July 22, 2021, were searched for a single lifetime episode of hemoptysis secondary to post-embolization systemic collaterals. Embolization was performed with permanent particles or gelatin slurry. Clinical features and treatment outcomes of identified patients were reviewed.

RESULTS

Twenty-eight embolization procedures have been performed in 9 patients with post-PAVM embolization systemic artery collateral reperfusion. This included 8 patients with known HHT. Permanent particles were used in 5 cases and gelatine slurry was used in 19 cases. Due to the recurrence of hemoptysis, four patients required four embolizations each, two patients required three embolizations and two patients required two embolizations. Chronic unresolving hemoptysis was the presentation in 5 patients and massive hemoptysis requiring ICU admission in 4. The lifetime prevalence and incidence of hemoptysis secondary to systemic artery reperfusion in HHT patients was estimated to be 1.0% and 0.05%, respectively. Bronchial artery origin was most common (8 patients). In the first patient treated at this center, a major adverse event resulting in myocardial infarct and stroke occurred with the use of 300-500-micron permanent particles. This was presumed to be due to left-to-right shunting and subsequent systemic embolization. Subsequent patients were treated with gelatin sponge slurry without adverse events. This patient ultimately expired due to large volume hemoptysis, in the setting of bilateral diffuse PAVMs. A second patient, with history of childhood bronchial artery coil embolization, expired from large volume hemoptysis while awaiting lobectomy. In two cases, patients underwent surgery, including one lobectomy and one pneumonectomy, for recurrent hemoptysis (requiring at least five hospital admissions). The remaining five patients achieved prolonged resolution of hemoptysis with endovascular treatment alone.

CONCLUSION

Lifetime prevalence of hemoptysis secondary to PAVM post-embolization systemic collaterals is rare, but recurrence is high. In this limited series, embolization with gelatin sponge slurry appeared safe, although surgical resection may ultimately be required in refractory and multifocal disease.

Hereditary Hemorrhagic Telangiectasia and Arterio-Venous Malformations—From Diagnosis to Therapeutic Challenges

Hereditary hemorrhagic telangiectasia is a rare autosomal dominant vascular disease defined by the presence of mucosal and cutaneous telangiectasia and visceral arterio-venous malformations. The latter are abnormal capillary-free direct communications between the pulmonary and systemic circulations with the following consequences: arterial hypoxemia caused by right-to-left shunts; paradoxical embolism with transient ischemic attack or stroke and brain abscess caused by the absence of the normally filtering capillary bed; and hemoptysis or hemothorax due to the rupture of the thin-walled arterio-venous malformations (particularly during pregnancy). It is frequently underdiagnosed, commonly presenting as complications from shunting through arterio-venous malformations: dyspnea, chronic bleeding, or embolism. Arterio-venous malformations are present not only in the lungs, but can also be found in the liver, central nervous system (mainly in the brain), nasal mucosa, or the gastrointestinal tract. The first choice of therapy is embolization of the afferent arteries of the arterio-venous malformations, a minimally invasive procedure with a high efficacy, a low morbidity, and low mortality. Other therapeutic modalities are surgery (resection) or stereotactic radiosurgery (using radiation). Routine screening for arterio-venous malformations is indicated in patients diagnosed with this condition and can prevent severe complications such as acute hemorrhages, brain abscesses, or strokes. Clinicians should provide a long-term follow-up for patients with arterio-venous malformations, in an effort to detect their growth or reperfusion in case of previously treated malformations. In spite of two experts’ consensuses, it still possesses multiple therapeutic challenges for physicians, as several aspects regarding the screening and management of arterio-venous malformations still remain controversial. Multidisciplinary teams are especially useful in complex cases.