CT Pulmonary Parenchymal Changes Combined with Vascular Findings - A Highly Suggestive Complex for the Elusive Diagnosis of Post Ablation Pulmonary Vein Stenosis

Objectives: Post pulmonary vein isolation (PVI) pulmonary vein stenosis (PVS) is an easily missed diagnosis. The aim of this study was to describe the CT findings of post PVI PVS emphasizing the combination of parenchymal and vascular changes and their dynamic changes over time.

Material and methods: A retrospective review of PVI database (N=486). PVS grading: Grade 1 :< 50%, Grade 2: 50-75%, Grade 3: 76-99% and Grade 4: total occlusion. CT findings included parenchymal and vascular changes; documented and correlated with clinical course and sequential scans.

Results: Post PVI symptoms (shortness of breath cough and hemoptysis) occurred in 11% who underwent post PVI CT (N=56/486; 81% males; average age 52 ± 10 years). Grade 1 PVS (PVS< 50%) was documented in 71% (N=40/56) in which no parenchymal or vascular CT findings were demonstrated. Grade 2 and 3-4 PVS were demonstrated in 3% (N=2/56) and 25% respectively (N=14/56). The left PV’s were involved in all grade 3 and 4 PVS. Pulmonary consolidations, “ground glass” opacities and increased interlobular septal thickening were documented in 85.7%, 78% and 85.7% of patients with PVS grade 3-4, respectively. Sluggish flow (mimicking PE) in the left pulmonary artery, oligemia and collateral vessels were depicted in 71%, 36% and 50% of patients with PVS grade 3-4, respectively. Follow up CT scans demonstrated complete resolution, improvement and worsening in 18% 27% and 55%, respectively. Eleven stents were inserted in 43% of PVS grade 2-4 (N=7/16); stent patency, restenosis up to 50% and occlusion were seen in 45%, 36% and 18% of inserted stents, respectively. None of these patients demonstrated clinical improvement or resolution of CT findings.

Conclusions: Recognizing typical CT changes in post PVI PVS is mandatory for correct diagnosis. CT parenchymal and vascular changes with concomitant lack of resolution is the hallmark of this elusive diagnosis.