Massive Hemoptysis Due to Pulmonary Vein Stenosis Following Catheter Ablation for Atrial Fibrillation

Discussion

Hemoptysis is a common symptom in clinical practice and accounts for 10–15% of all pulmonary consultations.⁶ Although hemoptysis generally has a good prognosis, massive hemoptysis, defined as expectoration of a large amount of blood (100–600 mL of blood/24 h), is life-threatening and is considered a medical emergency.⁷ Chronic inflammatory lung disease, bronchogenic carcinoma, and tuberculosis remain the most common causes of massive hemoptysis.⁸ Although there have been some case studies that reported pulmonary vein stenosis as a rare cause of hemoptysis,^4,5 to our knowledge, we present here the first case report of massive hemoptysis caused by pulmonary vein stenosis in a patient who had undergone radiofrequency catheter ablation for atrial fibrillation.

Pulmonary vein stenosis is a relatively rare condition that can be congenital or acquired. Although pulmonary vein stenosis due to neoplasm, sarcoidosis, or fibrosing mediastinitis has been reported, the most common cause of acquired pulmonary vein stenosis is a radiofrequency catheter ablation procedure for treatment of atrial fibrillation.² The frequency of pulmonary vein stenosis varies, with 1–10% of patients developing it following radiofrequency catheter ablation, although the frequency has been reported to be as low as 1.3% due to improvements in technique and experience.⁹

Some patients with isolated mild pulmonary vein stenosis are asymptomatic, but patients with extensive and severe pulmonary vein stenosis can present with dyspnea, cough, chest pain, or hemoptysis. Presentation varies depending on several factors: (1) number of pulmonary veins involved, (2) lesion severity, (3) response of the entire pulmonary vasculature to the lesion, (4) time course of the stenosis, (5) clinical setting, and (6) presence and extent of collaterals.¹⁰ As we had no strong clinical suspicion of pulmonary vein stenosis in our patient, the diagnosis was delayed until he presented with massive hemoptysis, although he had symptoms and signs suggestive of pulmonary vein stenosis, such as a small amount of hemoptysis. Early diagnosis based on clinical suspicion is important for these patients, with a previous study showing that early intervention is recommended in any symptomatic patients.¹⁰ Saad et al¹¹ also recommended pulmonary vein stenosis dilatation for patients with luminal narrowing of > 70% irrespective of the presence or absence of symptoms.

Assessment of the presence and degree of severity of pulmonary vein stenosis is essential for diagnosing and setting the treatment plan. Although chest x-rays may be abnormal, they are non-diagnostic. Although ventilation-perfusion scans can be employed to characterize the pattern of blood flow within the distribution of pulmonary vein stenosis,¹⁰ chest computed tomography and, to a lesser extent, magnetic resonance imaging are currently the best evaluation tests because they not only detect pulmonary vein stenosis but also measure the prestenotic pulmonary vein orifice dimension, site and length of the stenosis, and baseline vessel diameter.³ However, a standardized follow-up or routine screening strategy after radiofrequency catheter ablation to detect pulmonary vein stenosis in asymptomatic patients remains to be established and varies by institution.

The underlying molecular mechanisms of pulmonary vein stenosis remain unknown. One likely mechanism is that thermal injury in the vessel wall (abnormal wall stress) induces damage and abnormal biological processes, such as intense periadventitial inflammation or collagen deposition, which may compromise or even occlude the lumen.^12,13 This is predictable shortly after the procedure, but a 2-y follow-up human study¹⁴ and an animal study conducted by Taylor et al¹⁵ showed similar radiologic and laboratory (cascade of inflammatory protein precursors) evidence of progression of pulmonary vein stenosis severity with time. Additionally, because stenoses usually appear in the extraparenchymal segment of the pulmonary vein, not in the intraparenchymal veins, the axial wall stress, which is known as a basic pathologic process, could not explain the progression of stenosis, but could explain only the immediate damage to the pulmonary vein.¹⁶

Management of pulmonary vein stenosis is often unsuccessful. Although stenting is generally preferred to surgical resection, the rate of re-stenosis is estimated to be as high as 20–40%.⁵ Moreover, one study reported that this procedure was complicated by hemorrhage, venous tear requiring open repair, and stroke in 13% of patients.¹⁷ However, the experiences and long-term follow-up results of surgical resection are more limited because only some case studies have so far reported short-term successful outcomes.¹⁸ Given that massive hemoptysis is reported to result in 30–85% mortality in non-trauma patients, prompt treatment is essential. Although previous case reports detailed successful management with stent insertion in patients with pulmonary vein stenosis presenting with hemoptysis,^4,5 our patient required surgical resection because pulmonary venography revealed that he was unsuitable for stent insertion. This difference could be due to a different pulmonary vein stenosis chronicity, lesion severity, or stenotic lesion location.

In conclusion, our case suggests that pulmonary vein stenosis following radiofrequency catheter ablation for atrial fibrillation can cause massive hemoptysis. Physicians should thus be aware of the possibility of various complications, including massive hemoptysis, in these patients and suspect pulmonary vein stenosis when the associated symptoms are present. In addition, the optimal follow-up strategy after radiofrequency catheter ablation should be established for preventing these life-threatening complications.