Pulmonary vein stenosis (PVS) may have various etiologies, classifiable into three categories: congenital, acquired, or iatrogenic. Its manifestation is insidious, complicating and delaying diagnosis. A high index of suspicion is necessary, along with knowledge of targeted noninvasive studies for accurate diagnosis. Once diagnosed, techniques are used to determine its clinical relevance for the patient. Etiological treatment and transcatheter procedures, including balloon angioplasty and stent implantation, are cornerstones in managing this condition. There are no established guidelines regarding diagnosis, treatment, or follow-up management. Institutions rely on their experience, and today’s review aims to highlight the latest trends in diagnosing and treating this rare pathology.

COMMENTARY:

PVS can result from extrinsic compression or luminal narrowing, though no universal definition of PVS exists. In adults, an average pulmonary vein diameter ranges from 10 to 15 mm; it must be reduced to 4-6 mm to cause symptoms. The 2017 atrial fibrillation consensus defined PVS severity as mild for caliber reductions <50%, moderate for 50-70%, and severe for >70%. In addition to stenosis degree, the number and location of affected veins are critical since involvement at the veno-atrial junction differs from bifurcations or intraparenchymal segments. There are three primary PVS patterns: focal “hourglass” constriction, tubular hypoplasia, and extensive bilateral extramural involvement.

Acquired PVS etiologies include mediastinal inflammatory diseases and iatrogenic injury from invasive procedures. Historically, PVS followed extrinsic compression by fibrosing mediastinitis, hypersensitivity to Histoplasma capsulatum, tuberculosis, or IgG4-related diseases. Other causes include malignancies or sarcoidosis with similar symptoms. Iatrogenic forms often result from pulmonary vein surgeries or atrial fibrillation (AF) ablation, now the leading PVS cause, with an incidence ranging from .3% to 4% depending on the series. Given nearly 10,000 AF ablations performed worldwide annually, hundreds of patients are at risk of developing this complication.

Symptoms are often insidious and nonspecific, commonly including dyspnea, pleuritis, chest pain post-exertion, fatigue, malaise, and hemoptysis. Misdiagnosis is frequent; one in three patients typically receives prior diagnoses of pneumonia, bronchitis, or malignancy. Early diagnosis impacts prognosis, especially if secondary to AF ablation, as stenoses can rapidly obstruct and cause pulmonary infarction.

Both noninvasive and invasive techniques are crucial for diagnosing and treating PVS. Among noninvasive methods:

• Contrast-enhanced computed tomography angiography (CTA) aids diagnosis and procedural planning, allowing dual-phase imaging to rule out left atrial appendage thrombus. CTA is valuable for pre- and postprocedural evaluation, though it may be less sensitive for subocclusive/occlusive PVS. Invasive procedures may be warranted even if CTA suggests occlusion.
• Magnetic resonance imaging (MRI), a non-ionizing modality, is ideal for renal insufficiency patients but limited by lower spatial resolution and signal loss with stents.
• Ventilation/perfusion tests using technetium-99 help assess physiological repercussions but need correlating anatomical imaging. Significant perfusion deficits appear in severe stenoses, but intermediate stages may go undetected.
• Transesophageal echocardiography (TEE) enables stenosis assessment in adults by measuring diameter reduction, peak diastolic velocity (>0.9-1.1 m/s) with Doppler, or turbulent flow. Visualization is challenging and lacks standardized criteria for PVS.

Invasive evaluation through cardiac catheterization assesses pulmonary venous hypertension across segments. The classic parameters include the diastolic gradient between the pulmonary artery wedge pressure or left atrium and the left ventricle. Cross-referencing with CTA allows precise segment evaluation and comparison to unaffected areas. Exercise testing can reveal true hemodynamic compromise in inconclusive segments.

Unlike congenital PVS, which is treated surgically, acquired cases are managed percutaneously through balloon angioplasty with or without stenting, though restenosis is common. Restenosis predictors include vessel thickness; veins <10 mm have a 70% restenosis rate versus 10% in veins >10 mm. Typically, stents are placed in vessels >10 mm, while angioplasty is used for those 7-8 mm, with possible stent placement later. No superiority between drug-eluting and bare-metal stents has been established, with both showing up to 30% restenosis.

Follow-up is individualized by stent size and stenosis complexity. Routine CTA is performed at 3 and 9 months, with double antiplatelet therapy for six months post-intervention, shifting to aspirin monotherapy if needed. Persistent symptoms after exhausting hemodynamic options may prompt surgical alternatives with uncertain outcomes.

In conclusion, today’s JACC article highlights a rarely discussed condition, providing key insights but warranting full reading for comprehensive management, including handling complete occlusions and restenosis strategies. The article’s contribution to general awareness is significant; it encourages clinicians to include PVS in differential diagnoses for respiratory symptoms in patients with an AF ablation history.

REFERENCE:

Simard T, Sarma D, Miranda WR, Jain CC, Anderson JH, et al. Pathogenesis, Evaluation, and Management of Pulmonary Vein Stenosis: JACC Review Topic of the Week. J Am Coll Cardiol. 2023 Jun 20;81(24):2361-2373. doi: 10.1016/j.jacc.2023.04.016.