Pulmonary Arteriovenous Fistulas

Abstract

To the Editor: The 15-year experience with pulmonary arterio­ venous fistulas (PAVFs) at the Mayo Clinic' interested me as a neurologist because I investigated a family with hereditary hem­ orrhagic telangiectasia (HHT) in the mid 1960s and reviewed the then-existing literature.' The mother and younger daughter both proved to have coexistent PAVF and cerebral arteriovenous mal­ formation (CAVM).3 These are among the first authenticated cases reported. Only 2 patients with HHT with symptomatic gross central nervous system (CNS) vascular malformation were de­ scribed in the literature to that date. By 1978, however, Roman et al' found more than 200 such cases, nearly 15% of which showed CNS AVM. A prospective study' (published in abstract form) of 130 individuals with HHT, all of whom underwent brain magnetic resonance imaging, turned up AVMs in 23%. In light of the above, I was struck by a mere 4% occurrence of CAVM in the Mayo Clinic series. This discrepancy may be explained by the fact that only patients with neurologic mani­ festations were subjected to neurodiagnostic As to current practice, Swanson et al state, We do not feel that screening asymptomatic patients for cerebral arteriovenous malformation is indicated. I disagree with this opinion for the following reasons. First, the natural history of CAVM is far from benign. Both bleeding and epilepsy pose notable risk of death and disability over a lifetime. Second, eradication of CAVM carries substan­ tially less risk if it is repaired prior to rather than at the time of an episode of bleeding. Third, a smaller CAVM, which is easier to deal with surgically, is paradoxically more apt to bleed than a larger one. Finally, modem interventions (eg, embolotherapy alone or followed by surgery, stereotactic radiosurgery) have greatly improved surgical results and long-term favorable outcomes. Therefore, the question appears not to be whether HHT pa­ tients should undergo brain imaging but rather what is the op­ timum time for screening. Rengachary and Kalyan-Raman recently offered the following advice: Ifthere are CNS or pulmo­ nary manifestations among family members, the siblings should be screened before Otherwise screening may start after adolescence. They also state: Magnetic resonance imaging and magnetic resonance angiography are the best screening tests. When all the factors alluded to are considered, a seemingly favorable cost-benefit ratio also justifies such screening in every individual with HHT or PAVF.