Teaching Case

A 60-year-old male presents to the emergency department with dyspnea, chest pain and hemoptysis lasting for 2 months.

Relevant medical history included atrial fibrillation, for which he had been submitted to two ablation procedures, the most recent one around 6 months ago. Physical examination and laboratory findings were unremarkable.

A Chest CT Angiography (CTA) was performed and revealed normal opacification of the pulmonary arteries, with no signs of pulmonary embolism. However, there was evidence of occlusion of the left inferior pulmonary vein. The lung window images showed multiple peripheral consolidations in the left inferior lobe, some of them with wedge morphology, that were interpreted as pulmonary infarcts.

A diagnosis of pulmonary vein occlusion with associated lung infarcts as a possible complication of ablation of atrial fibrillation was made.

A follow-up Chest CTA was performed 9 months after the initial one, that demonstrated persistence of the pulmonary vein occlusion and appearance of new areas of pulmonary infarcts.

The patient was then referred to Cardiothoracic Surgery consultation and is now waiting for endovascular treatment with angioplasty of the occluded pulmonary vein.

Pulmonary vein stenosis or obstruction is a rare complication that can be difficult to manage, with a considerable mortality rate. In adults, the most common causes are radiofrequency ablation complications, neoplastic infiltration, and fibrosing mediastinitis. Other potential causes include surgical complications (for example, from heart surgery or lung transplantation) and extrinsic compression by a benign inflammatory process, such as tuberculosis. [1]

Clinical manifestations are usually progressive dyspnea and hemoptysis (commonly called “pseudo–mitral stenosis syndrome”). After a long period of time, pulmonary vein stenosis can lead to pulmonary arterial hypertension and cor pulmonale. [1]

This complication can occur in up to 10% of patients who undergo radiofrequency ablation for atrial fibrillation, with severe stenosis occurring in less than 1.4% of the patients. It should always be suspected whenever a patient who has been submitted to these procedures develops respiratory symptoms (dyspnea or hemoptysis), either weeks or months after the procedure. [2]

Chest CTA is essential to the diagnosis and the choice of protocol will depend on the experience of each hospital center or institution. If there is enough experience with it, a choice of an electrocardiography gated cardiac CT protocol is recommended as it will provide higher-quality images for post-reconstruction techniques and better demonstrate the pulmonary vein ostia and the presence of pulmonary vein stenosis or occlusion. [1]

Typically, the main findings will be an absence/abrupt cut-off or narrowing of a pulmonary vein. [3,4]

Additionally, these patients tend to develop lung oedema and infarction of the region drained by the occluded vein, as a result of venous hypertension. This will present on CTA as ground glass opacities, consolidations, and smooth interlobular septal thickening, usually confined to the lobe/region that is drained by the affected vein. [3,4] These indirect findings tend to wax and wane in serial evaluations due to transitory changes in venous pressure. [4]

Untreated, eventually this venous hypertension can transmit retrogradely through the pulmonary capillaries and result in post-capillary pulmonary hypertension, for which right-heart catheterization can contribute to its detection (by showing mean pulmonary artery pressure (mPAP) ≥25 mm Hg, pulmonary capillary wedge pressure (PCWP) ≥15 mm Hg, and transpulmonic gradient (mPAP−PCWP) <10 mm Hg.) [5]

Treatment of this acquired postprocedural stenosis is usually interventional, relying on catheter-related techniques, such as balloon angioplasty. [2]

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