Abstract 21190: Does Pulmonary Vein Stenosis Occur with Aggressive Cryoablation?
Introduction: Balloon cryoablation of pulmonary veins (PVs) has emerged as a promising technique for the isolation of potentially arrhythmogenic substrate for AF. Whether or not cryoablation can lead to PV stenosis however remains unsettled.
Purpose: Therefore, the outcome of extensive cryoablation of PVs was assessed in 10 dogs.
Methods: The right(RI) and left inferior(LI) PVs were cryoablated, with 4 applications of 4 minutes of cryothermy each. Lasso guided PV isolation assessment and venography were performed pre-ablation and at study. Pathological inspection of the PVs was done upon necropsy.
Results: The RI PVs had a mean of 15.6 ± 1.3 min of cryothermy each while the LI PVs had 16 min each. All RI and LI PVs were isolated with the initial procedure. Subacute success was 85% at 39 ± 8 days at necropsy. The mean balloon temperature at RI and LI PVs were −65.4 ± 7.4°C and −50.5 ± 7.2°C (p< 0.001) respectively. Angiographic and gross pathologic vein stenosis (>75%) were observed in 3/10 RI and 2/10 LI PVs. Two dogs had stenosis of both inferior PVs. The mean temperature of PVs with stenosis was −67.2 ± 11.1°C versus −54.7 ± 8.1°C (p<0.001) without stenosis. Visual assessment of distal ablation position of the balloon occurred in 14/16 ablations in those with stenosis, and 40/56 ablations in those without stenosis. The mean diameter of the cryoballoon in the veins with stenosis versus those without was 22.1 ± 0.4 mm and 22.2 ± 0.9 mm (P=0.64). The ratio of PV diameter to balloon diameter for the veins with and those without stenosis was 0.67 ± 0.11 and 0.68 ± 0.17 (P=0.91). The mean length of the balloon in the veins with and those without stenosis was 19.5 ± 1.2 mm and 19.2 ± 1.5 mm (P=0.54) and the ratio of balloon diameter to length was 1.14 ± 0.08 and 1.16 ± 0.10 (P=0.41). Gross pathologic inspection revealed that the effect of cryoablation did extend into all ablated PVs.
Conclusions: PV stenosis can occur with cryoballoon ablation. Changes in balloon diameter or length are inaccurate for assessing the location of ablation. The location and degree of cryothermy induced temperature change, however, appear to be determinants in the development of inflammatory cascade leading to stenosis.
- © 2010 by American Heart Association, Inc.