Phrenic nerve injury during right inferior pulmonary vein ablation with the second-generation cryoballoon: clinical, procedural, and anatomical characteristics.

AIMS

There is still sparse information regarding phrenic nerve injury (PNI) during ablation of the right inferior pulmonary vein (RIPV) by means of the second-generation cryoballoon advance (CB-A). The aim of this study was to describe the procedural, anatomical, and clinical characteristics of patients who experienced PNI during the RIPV ablation.

METHODS AND RESULTS

Consecutive patients who had undergone pulmonary vein isolation (PVI) using CB-A and suffered PNI during RIPV ablation were retrospectively included in our study. A cohort of patients who did not suffer any PNI was randomly included in a 1:3 ratio as a control group. The incidence of PNI during RIPV cryoapplication was 3.5%, (34 of 979 patients). There were no significant differences in clinical characteristics between patients with and without PNI. The prevalence of right common ostium (RCO) was significantly higher in patients with a PNI [4 patients (11.8%) vs. 1 patient (1.0%); P < 0.01]. A temperature drop velocity from the basal temperature to - 20 °C of 2.38 °C/s rendered a sensitivity of 82.4% and a specificity of 51.0% with a negative predictive value of 89.7%. Temperature drop velocity from basal to - 20 °C and the presence of an RCO were predictors of PNI in the multivariate analysis [odds ratio (OR) 7.27, 95% confidence interval (CI) 2.54-20.80; P < 0.01 and OR 18.41, 95%CI 1.87-181.23; P = 0.01, respectively).

CONCLUSION

PNI during RIPV freeze might occur in around 3.5% of cases. The presence of an RCO and a fast temperature drop must prompt a careful monitoring of the phrenic nerve function during cryoapplications on the RIPV.