Abstract & Commentary
Comments by John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville. Dr. DiMarco is on the Editorial Board of Clinical Cardiology Alert.
Synopsis: Pulmonary vein stenosis is a significant complication of atrial fibrillation ablation procedures that can occur insidiously late after the ablation.
Source: Packer DL, et.al. Clinical Presentation, Investigation, and Management of Pulmonary Vein Stenosis Complicating Ablation for Atrial Fibrillation. Circulation. 2005;111:546-554.
Catheter ablation for atrial fibrillation has become increasingly popular, but the techniques for this procedure are still evolving. In this paper, Packer and colleagues from the Mayo Clinic report on their experience with pulmonary vein stenosis, one of the most serious complications associated with catheter ablation for AF. Packer et al identified 23 patients who underwent catheter ablation for atrial fibrillation and later presented with pulmonary vein stenosis. A variety of techniques were used for catheter ablation. Most of them involved placement of lesions at the ostia or within 1 or more pulmonary veins. Twelve of the 23 patients had undergone 2 ablation procedures, and 5 had undergone 3. In the 23 patients, a total of 34 pulmonary veins developed stenosis. Symptoms were insidious in onset. They developed a mean of 103 ± 100 days after follow-up. Symptoms included dyspnea on exertion (19), dyspnea at rest (7), and recurring cough (9). Six patients complained of aching or burning chest pain. In 3 patients, flu-like symptoms were noted. These 3 had received a course of antibiotics without benefit. Three patients developed hemoptysis. In most patients, physical examination and plain chest radiography was unrevealing. A diagnosis was made with either CT imaging or transesophageal echocardiography. In patients with a baseline CT study, the diameter of the pulmonary vein at the subsequent site of stenosis was initially 13 ± 3mm and, at repeat study, had decreased to 3 ± 2mm. The stenoses began a mean of 1.4 ± 2.5 mm from the orifice, and ranged in length from 7-35mm. Transesophageal echo was utilized in 16 patients. Lesion narrowing could be detected in 11. Flow velocities, measured from the pulmonary veins, was increased in most patients.
Ventilation/perfusion scanning showed normal ventilation, but a perfusion defect that correlated with the lesion for all 34 stenotic veins. Since each patient presented with symptoms, interventional attempts were made to relieve the stenosis. Balloon venoplasty, with or without stent insertion, was immediately effective for symptom relief in all patients, but was associated with a significant complication rate. Among the 23 patients, the following procedural complications were noted: transient ST segmental elevation in the inferior leads and hypotension, guidewire perforation of the pulmonary vein, pulmonary vein dissection, and embolization of a stent to an iliac artery. Although these patients recovered without need for further surgical intervention, other than chest tube placements in 2, pulmonary vein venoplasty was clearly not a low-risk procedure. In addition, 14 of the 23 patients developed recurrent symptoms 3.2 ± 2.8 months after the initial intervention. In 13 patients, repeat interventions were performed. In 6 of these, progressive stenosis in an untreated segment was noted at the time of the repeat study. Eventually, however, 15 of the 23 patients became completely asymptomatic, but 8 patients continued with mild or moderate residual symptoms.
Packer et al conclude that pulmonary vein stenosis is a significant complication of atrial fibrillation ablation procedures that can occur insidiously late after the ablation. Recognition and therapy can acutely relieve patient symptoms but techniques to reopen the veins have significant complication rates, and may not be successful long-term.
Comments
The initial description of pulmonary vein ablation procedures for patients with atrial fibrillation involve attempts to ablate arrhythmogenic foci directly within the pulmonary veins. Subsequently, most operators have switched their technique to place lesions either just outside the orifice of the pulmonary veins or further back in the main body of the left atrium. However, pulmonary venous anatomy is often quite complex, and damage to the pulmonary veins can still occur.
This paper by Packer et al illustrates some of the problems that can occur in patients who develop pulmonary vein stenosis. Since they develop symptoms late after the procedure, diagnosis is often delayed. A high degree of suspicion is important when evaluating complaints of dyspnea, even late after an ablation. Even when pulmonary vein stenosis is correctly diagnosed, therapy to relieve the stenosis is not entirely satisfactory. Balloon venoplasty has a high rate of recurrent stenosis, and stent placement does not eliminate the risk for restenosis.
It seems clear that future ablation procedures of atrial fibrillation will hopefully leave the inner lumen of the pulmonary veins untouched. Where exactly to place the lesions in either the pulmonary vein antrum or further back in the left atrium for optimal results, still remains to be determined.
Pulmonary vein stenosis is a significant complication of atrial fibrillation ablation procedures that can occur insidiously late after the ablation.
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