Chronic thromboembolic pulmonary hypertension (CTEPH) is the result of single or recurrent
pulmonary thromboemboli that are thought to develop into organized pulmonary arterial
obstructions by recurrent embolism and in situ thrombosis. Radioisotopic ventilation-perfusion
scanning (V/Q scan) is a safe and highly sensitive test for pulmonary thromboembolic
disease. The aim was to assess the natural history of thrombus expansion. We performed
a prospective quantitative evaluation of ventilation/perfusion scintigrams (V/Q scans)
in 20 patients with severe unoperated CTEPH. The baseline V/Q scan of each patient
served as a reference for the second scan 21.7 ± 8.2 months later. Planar images with
intravenous 99mTc-labeled human albumin macroaggregates were reconstructed in six
standard projections. Perfusion scans were analyzed by a semiquantitative evaluation.
In parallel, hemodynamics and clinical condition were prospectively observed. Lung
perfusion scintigrams analyzed by a semi-quantitative method in patients with severe
unoperated CTEPH show an apparent decrease of segmental flow abnormalities over time,
paralleling right ventricular decline.
Keywords
Pulmonary embolism - perfusion lung scintigraphy - thrombosis - pulmonary hypertension