Anatomic predictors of phrenic nerve injury in the setting of pulmonary vein isolation using the 28-mm second-generation cryoballoon

BACKGROUND: Phrenic nerve injury (PNI) is the most frequently observed complication during pulmonary vein (PV) isolation using the second-generation cryoballoon.

OBJECTIVE: The purpose of this study was to analyze anatomic predictors based on preprocedural computed tomographic imaging data.

METHODS: Forty-one patients with PNI during the procedure and 123 age-, gender-, and body mass index-matched controls were included. A total of 343 right PVs were evaluated for axial/coronal orientation, ostial diameters with cross-sectional area, ovality index, and branching pattern. External angle between the right superior pulmonary vein (RSPV) and the anterolateral wall of the left atrium (LA) was measured (RSPV-LA angle). Distance from this vertex to the superior vena cava (SVC) was considered the RSPV-SVC distance.

RESULTS: For the RSPV, more anterosuperior orientation, larger dimensions, shorter RSPV-SVC distance, and more obtuse RSPV-LA angle (all P <.001) were associated with PNI on univariate analysis. Independent variables after multivariable analysis were RSPV-LA angle (odds ratio 1.03 per degree, 95% confidence interval 1.01-1.04, P <.001) and RSPV area (odds ratio 1.2 per mm², 95% confidence interval 1.1-1.3, P <.001), with a cutoff value ≥141° for RSPV-LA angle (91% sensitivity, 85% specificity) and ≥275 mm² for RSPV area (88% sensitivity, 85% specificity). RIPV area was an independent predictor for PNI at RIPV. A right-sided long common trunk was seen exclusively in 3 patients in the PNI group.

CONCLUSION: Preprocedural anatomic assessment of right PVs is useful in evaluating the risk of PNI. Ostial vein area and external RSPV-LA angle measurement showed excellent predictive value for PNI at the RSPV.