From the Guidelines
Cryobiopsy is not recommended as the primary diagnostic method for Pulmonary Veno-Occlusive Disease (PVOD) or Pulmonary Capillary Hemangiomatosis (PCH) due to significant bleeding risks. The preferred diagnostic approach combines clinical evaluation, pulmonary function tests, high-resolution CT scans showing characteristic ground-glass opacities, septal lines, and lymph node enlargement, along with genetic testing for EIF2AK4 mutations which are present in hereditary forms 1. Bronchoalveolar lavage showing hemosiderin-laden macrophages can support the diagnosis. If tissue diagnosis is absolutely necessary, surgical lung biopsy under controlled conditions is safer than cryobiopsy, as open or thoracoscopic lung biopsy is not recommended in patients with PAH due to substantial risk of morbidity and mortality 1. The high pulmonary pressures in PVOD/PCH patients create substantial bleeding risks with any invasive procedure.
Diagnostic Approach
- Clinical evaluation
- Pulmonary function tests
- High-resolution CT scans
- Genetic testing for EIF2AK4 mutations
- Bronchoalveolar lavage
Treatment
- Careful use of pulmonary vasodilators (particularly prostacyclins) with close monitoring for pulmonary edema 1
- Lung transplantation remains the definitive treatment
- Management at specialized pulmonary hypertension centers is strongly advised for optimal outcomes 1
The 2015 ESC/ERS guidelines for the diagnosis and treatment of pulmonary hypertension recommend a step-wise approach to diagnosis, including echocardiography, ventilation/perfusion or perfusion lung scan, contrast CT angiography of the PA, and routine biochemistry, haematology, immunology, HIV testing, and thyroid function tests 1. However, cryobiopsy is not a recommended diagnostic method due to its associated risks, and the guidelines emphasize the importance of a comprehensive diagnostic evaluation to guide treatment decisions.
From the Research
Diagnosis of Pulmonary Veno-Occlusive Disease (PVOD) / Pulmonary Capillary Hemangiomatosis (PCH)
The diagnosis of PVOD/PCH is typically based on high clinical suspicion and confirmed by histology. The following are some key points to consider:
- A definite diagnosis of PVOD requires a lung biopsy or pathologic examination of pulmonary explants or postmortem lung samples 2, 3, 4.
- However, lung biopsy is hazardous in patients with severe pulmonary hypertension, and there is a need for noninvasive diagnostic tools in this patient population 2, 3.
- High-resolution computed tomography of the chest can suggest PVOD in the setting of pulmonary hypertension when it shows nodular ground-glass opacities, septal lines, lymph node enlargement, and pleural effusion 2, 4.
- Occult alveolar hemorrhage found on bronchoalveolar lavage in patients with pulmonary hypertension is associated with PVOD 2, 4.
Clinical and Radiologic Findings
Some clinical and radiologic findings that may suggest PVOD include:
- A higher male:female ratio and higher tobacco exposure 2, 4
- Lower body mass index 2
- Lower partial pressure of arterial oxygen (PaO2), diffusing lung capacity of carbon monoxide/alveolar volume (DLCO/VA), and oxygen saturation nadir during the 6-minute walk test 2, 4
- Nodular and ground-glass opacities, septal lines, and lymph node enlargement on computed tomography of the chest 2, 4
Cryobiopsy of the Lung
There is no direct evidence in the provided studies to support the use of cryobiopsy of the lung for the diagnosis of PVOD/PCH. However, lung biopsy is considered the gold standard for diagnosis, and cryobiopsy may be a potential method for obtaining lung tissue for histological examination. Further research is needed to determine the efficacy and safety of cryobiopsy for diagnosing PVOD/PCH.