EFFECT OF PERCUTANEOUS TRANSCATHETER EMBOLIZATION ON PULMONARY-FUNCTION, RIGHT-TO-LEFT SHUNT, AND ARTERIAL OXYGENATION IN PATIENTS WITH PULMONARY ARTERIOVENOUS-MALFORMATIONS

The effects of percutaneous transcatheter embolization on pulmonary function and exercise capacity were assessed in 15 patients with pulmonary arteriovenous malformations (PAVM). Vital capacity (VC), REV1, DL(CO), Sa(O2), exercise performance, and right-to-left shunt (100% oxygen method) were measured before and 2 to 6 months after treatment. Surgical correction had been attempted in 9 patients prior to referral, and 11 had associated hereditary hemorrhagic telangiectasia (HHT). Lung function test before intervention showed normal VC and FEV1/VC ratios, reduced DL(CO) (mean 71% predicted, range 36 to 123%), a resting supine Sa(O2) of 86% (range 67 to 95%) and mean shunt fraction of 33% (range 15 to 47%). Despite further marked falls in Sa(O2) on exertion, exercise capacity was well preserved. Following steel coil embolization of all PAVM with a feed vessel internal diameter >3 mm (one to four sessions per patient), mean shunt fraction improved from 33 to 19% and resting Sa(O2) from 86 to 92% with no change in VC. A consistent improvement in diffusing capacity was seen only in patients with coexisting HHT. Exercise capacity increased in the majority (unchanged in 6), and Sa(O2) during maximal exercise improved in all except one patient. There were no long-term complications following embolization. These findings indicate that embolization of all macroscopic PAVM, undertaken primarily to reduce the risk of paradoxical embolization, is safe and results in substantial improvements in resting and exercise Sa(O2) without evidence of loss of normal lung. The right-to-left shunts remaining following embolization may reflect the presence of numerous microscopic PAVM in these patients.