Heat-induced necrosis after bronchial thermoplasty: a new concern?

Bronchial thermoplasty (BT) is an endoscopic procedure for the treatment of severe refractory asthma, based on the local airways delivery of radio-frequency at 65 °C. Several controlled clinical studies demonstrated the effectiveness of BT on clinical outcomes, particularly the reduction of asthma exacerbations. During procedure or shortly after, significant but transient respiratory adverse events have been reported.

We describe the case of a male, caucasian, 56-year-old, non-smoker patient with non-allergic severe asthma. A few days after the second BT session performed in the left lower lobe, persistent haemoptysis appeared requiring patient hospitalization. A chest CT scan showed mild varicoid bronchiectasis and distal parenchymal infiltrate in the basal anterior segment of the left lower lobe. At fibreoptic bronchoscopy two small nodular neoformations were observed in sub-segmental areas of the same lobe. Histological examination showed mild non-specific inflammation of bronchial mucosa, and some large fragments of peribronchial pulmonary parenchyma with an area of haemorrhagic necrosis. The patient was treated empirically with co-amoxiclav, azithromycin and prednisone. A new chest CT showed a complete resolution of the parenchymal opacity. Finally, the patient underwent the third session of BT, without recurrence of haemoptysis or radiological changes.

Bronchial thermoplasty is a generally safe procedure. To our knowledge this is the first report of necrosis of the treated bronchus and haemoptysis complicating BT after the second session. The pulmonary damage was most likely determined by a thermal shock induced by BT. One hypothesis could be a structural fragility of the treated bronchus, possibly related to bronchiectasis. A technical malfunction of the BT controller or the catheter, causing an excessive energy delivery could not be excluded. Adverse events following BT deserve particular attention but should not discourage clinicians from the application of this promising procedure.