Preoperative evaluation including indications and risk factors
| Indications for VATS |
| A history of guideline's recommended stage 4–5 (GINA) treatment and adherence to this treatment |
| Recurrent exacerbations (>2 per year) |
| Systemic corticosteroid treatment (at least 10 mg prednisone-equivalent per day over the past 12 months) |
| Attendance at an asthma centre or specialist for at least 6 months |
| Atypical presentation: |
| Parenchymal alterations in the HRCT (e.g. massive air trapping, ground-glass opacities) |
| Increased FeNO or eosinophils despite high doses of systemic corticosteroids |
| Need for oxygen treatment or low DLCO (<70% of reference) |
| Positive autoantibodies (thyroid, ANAs, ANCAs, lupus anticoagulants or rheumatoid factor) |
| Coexisting autoimmune disease |
| Positive family history for autoimmune disease |
| Unclear differential diagnosis (e.g. EGPA or HSP) (see table 2) |
| Risk factors for diagnostic VATS |
| DLCO <35% [83] |
| FEV1 <55% [83] |
| Immunosuppressive treatment |
| Current asthma exacerbation |
| Systolic PAP >40 mmHg (patients with signs of pulmonary hypertension should be evaluated by echocardiography) [84] |
VATS: video-assisted thoracoscopic surgery; GINA: Global Initiative for Asthma; HRCT: high-resolution computed tomography; FeNO: exhaled nitric oxide fraction; DLCO: diffusing capacity of the lung for carbon monoxide; ANA: anti-nuclear antibodies; ANCA: anti-neutrophil cytoplasmic antibodies; EGPA: eosinophilic granulomatosis with polyangiitis; HSP: hypersensitivity pneumonitis; FEV1: forced expiratory volume in 1 s; PAP: pulmonary arterial pressure.