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Old 03-13-2003, 05:13 AM
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Default New AVM Classification System Predicts Safety of Sclerotherapy

New AVM Classification System Predicts Safety of Sclerotherapy

Laurie Barclay, MD

Feb. 28, 2003 ? A new classification system for arteriovenous malformations (AVMs), based on anatomic and hemodynamic features, is published in the February issue of Pediatric Radiology. The authors tested their system for empirical use in treated patients, and they found that sclerotherapy is safe in types I and II but may not be safe in types III and IV.

"When planning sclerotherapy, clinical results and possible complications must be weighed against each other," write Stefan Puig, from the University of Vienna in Austria, and colleagues. "Classification systems are useful for making a precise clinico-anatomical diagnosis, serve as a basis for treatment choice, and facilitate communication among different specialists.... The connection to the normal venous system varies and has not been taken into consideration by these systems. Therefore, we decided to develop a new classification system focusing on venous malformations and based on anatomical and hemodynamic features."

The authors describe four types of AVMs. Type I is an isolated malformation without peripheral drainage; type II is a malformation draining into normal veins; type III is a malformation draining into dilated veins; and type IV is a malformation representing dysplastic venous ectasia.

During a 10-month period, the authors tested the system prospectively in a sample of 43 children and adolescents with AVMs who were referred for treatment. Phlebography revealed that 13 patients (30%) had a type-I AVM, 16 patients (37%) had a type-II AVM, nine patients (21%) had a type-III AVM, and five patients (12%) had a type-IV AVM.

Sclerotherapy was safely performed in more than 90% of patients with a type-I or type-II lesion, but it had to be withheld in one-third of patients with a type-III AVM, and one patient with a type-III AVM (11%) developed a severe complication after therapy. Of the five patients with type-IV lesions, three (60%) had to be excluded from sclerotherapy.

Study limitations include lack of independent assessment of phlebography findings and inability to measure interobserver variability.

"Our initial results indicate that sclerotherapeutic intervention in patients with type-III and type-IV AVMs must be carefully considered, while it can be safely performed in low-risk patients with type-I and type-II lesions," the authors write. "In future research, this system may be useful for the evaluation of outcome or to compare different techniques. Further, it can serve as a guideline for the interventional radiologist."

Pediatr Radiol. 2003;33:99-103

Reviewed by Gary D, Vogin, MD
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