Research Abstracts

Contrast Echo During Cardiac Catheterization for the Diagnosis of Pulmonary AVMs in Patients with Fontan/Hemi-Fontan Connection

Anne G. Farrell MD, Marcus S. Schamberger MD, Timothy M. Cordes MD, Sanjay R. Parikh MD. Indiana University, Indianapolis, IN.

Pediatrics 1999, 104l(3)Supp:667-668

Background: Development of pulmonary arteriovenous malformations (AVMs) in patients after construction of Hemi-Fontan connection is a known problem. Small pulmonary AVMs, however, are difficult to diagnose by pulmonary angiography.

Methods: 9 Hemi-Fontan pts and 3 Fontan pts (mean duration after surgery: 1.52 ± 1.1 yrs) underwent elective cardiac catheterization. Pulmonary artery and SVC angiograms were performed to assess for the presence of pulmonary AVMs. Thereafter, agitated saline was injected through the catheter and subxiphoid echo pictures of the right and left atrium (LA) were obtained. Appearance of more than a trace of micro-bubbles in the LA was considered positive for pulmonary AVMs.

Results: Only 3 of the 12 pts (2 with Hemi-Fontan and 1 with Fontan) showed clear angiographic evidence of pulmonary AVMs. However, 6 of the 12 patients (including the 3 with positive findings on angiography) had appearance of micro-bubbles in the LA after saline-contrast injections. Careful restudy of the 9 negative pulmonary angiograms was suggestive of rapid clearance of contrast material from the pulmonary arterial phase with poor opacification of the capillary bed in the 3 with positive bubbles. In some saline injections where bubbles were noted in the LA, angiography confirmed a wedged catheter position. Confirmatory SVC injection was negative.

Conclusions: Pulmonary artery and SVC injection of saline contrast under echo during cardiac cath is highly sensitive for the presence of pulmonary AVMs. These small AVMs are not apparent on pulmonary angiography. The development of these malformations may be responsible for systemic arterial desaturation seen in pts with Hemi-Fontan. Positive studies should be confirmed by SVC injection to exclude false positive results due to peripherally wedged catheter position.