Novel evaluation of pulmonary hypertension associated with chronic lung disease using perfusion SPECT/CT: A pilot study

Abstract In pulmonary hypertension (PH) associated with chronic lung disease (CLD), identifying patients who would benefit from pulmonary vasodilators is a significant clinical challenge because the presence of PH is associated with poorer survival. This study evaluated the severity of pulmonary circulation impairment in patients with CLD‐PH using pulmonary perfusion single‐photon emission computed tomography/computed tomography (SPECT/CT). This single‐center, observational study enrolled patients with CLD‐PH who had a mean pulmonary arterial pressure (PAP) ≥ 25 mmHg, as confirmed by right heart catheterization. The primary outcome was to measure the percentage of pulmonary perfusion defect (%PPD), calculated by dividing the perfusion defect volume from perfusion SPECT images by the lung volume from CT scan images. The secondary outcome was to assess the correlation between %PPD and baseline characteristics. The median %PPD was 52.4% (interquartile range, 42.5%–72.3%) in 22 patients. In multivariate linear regression analysis, both forced vital capacity (β = 0.58, p = 0.008) and mean PAP (β = 0.68, p = 0.001) were significantly correlated with %PPD. In conclusion, significant correlation between mean PAP and %PPD in patients with CLD‐PH was observed. This noninvasive assessment of %PPD may be useful for evaluating the severity of pulmonary circulation impairment in CLD‐PH.