Embolisation therapy for pulmonary arteriovenous malformations

Review question

We reviewed the evidence about the effect of blocking the blood vessels which feed abnormal direct connections between arteries and veins in people who have these in their lungs.

Background

Pulmonary arteriovenous malformations are abnormal connections between arteries and veins in the lung which can cause serious complications such as stroke, brain abscess, bleeding in the lung and poor oxygenation. Embolisation is the mainstream treatment for pulmonary arteriovenous malformations. During the procedure, balloon or coil embolisation devices (or both combined) are used to block the feeding artery or arteries to the malformation. These malformations can often be small, multiple and widely spread out, so not all of them are suitable for embolisation treatment.

This is an update of a previously published review.

Search date

The evidence is current to: 10 April 2017.

Study characteristics

In this systematic review, we did not include any randomised controlled trials of embolisation versus surgery or comparing different embolisation devices. We have identified one ongoing trial comparing two different embolisation devices which might be eligible for inclusion in the review when it is completed.

Key results

While no randomised controlled trials of this treatment are included in this review, a number of observational studies have suggested embolisation therapy has benefits. However, randomised controlled trials are not always feasible on ethical grounds. In the absence of randomised controlled trials, a standardised approach to reporting, as well as long-term follow-up through registry studies can help to improve the safety and outcome of embolisation for pulmonary arteriovenous malformations.

Quality of the evidence

We have not been able to present any evidence from randomised controlled trials in this version of the review.

Authors' conclusions: 

There is no evidence from randomised controlled trials for embolisation of pulmonary arteriovenous malformations. However, randomised controlled trials are not always feasible on ethical grounds. Accumulated data from observational studies suggest that embolisation is a safe procedure which reduces morbidity and mortality. A standardised approach to reporting with long-term follow-up through registry studies can help to strengthen the evidence for embolisation in the absence of randomised controlled trials.

Read the full abstract...
Background: 

Pulmonary arteriovenous malformations are abnormal direct connections between the pulmonary artery and pulmonary vein which result in a right-to-left shunt. They are associated with substantial morbidity and mortality mainly from the effects of paradoxical emboli. Potential complications include stroke, cerebral abscess, pulmonary haemorrhage and hypoxaemia. Embolisation is an endovascular intervention based on the occlusion of the feeding arteries the pulmonary arteriovenous malformations thus eliminating the abnormal right-to-left-shunting. This is an update of a previously published review.

Objectives: 

To determine the efficacy and safety of embolisation in patients with pulmonary arteriovenous malformations including a comparison with surgical resection and different embolisation devices.

Search strategy: 

We searched the Cystic Fibrosis and Genetic Disorders Group's Trials Register; date of last search: 10 April 2017.

We also searched the following databases: the Australian New Zealand Clinical Trials Registry; ClinicalTrials.gov; International Standard Randomised Controlled Trial Number Register; International Clinical Trials Registry Platform Search Portal (last searched 27 August 2017). to be updated

We checked cross-references and searched references from review articles.

Selection criteria: 

Trials in which individuals with pulmonary arteriovenous malformations were randomly allocated to embolisation compared to no treatment, surgical resection or embolisation using a different embolisation device.

Data collection and analysis: 

Studies identified for potential inclusion were independently assessed for eligibility by two authors, with excluded studies further checked by a third author. No trials were identified for inclusion in the review and hence no analysis was performed.

Main results: 

There were no randomised controlled trials included in the review; one ongoing trial has been identified which may be eligible for inclusion in the future.

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