Background: Risk stratification in patients with chronic thromboembolic pulmonary hypertension (CTEPH) relies mainly on functional testing and imaging-based structural assessment. The aim of this study was to investigate the prognostic significance of automated regional attenuation analysis on computed tomography pulmonary angiography (CTPA) as a surrogate of perfusion abnormalities.
Methods: We analyzed 52 consecutive patients diagnosed with CTEPH. Patients underwent either surgical [pulmonary endarterectomy (PEA), n=21] or non-surgical treatments [balloon pulmonary angioplasty (BPA) and/or pharmacotherapy, n=31]. Parameters derived from CTPA, including automated lung attenuation analysis and clinical metrics, were correlated with survival outcomes over a median follow-up of 5.0 years.
Results: During follow-up, 19 patients (36.5%) died. In the non-surgical group, predictors of survival derived from CTPA included diameter of the ascending aorta [hazard ratio (HR) =1.37, P=0.013] and right atrial area (HR =1.17, P=0.007). Automated attenuation analysis demonstrated that a higher proportion of hyperemic parenchyma in the middle and peripheral regions of the right middle and both lower lobes was associated with increased mortality (HR from 1.38 to 1.69 and P from 0.002 to 0.027). Oligemic parenchyma in similar regions was protective (HR from 0.72 to 0.74 and P from 0.010 to 0.015). In the surgical group, no significant predictors were identified.
Conclusions: Automated, region-specific attenuation analysis of CTPA provides quantitative prognostic information in non-surgically treated CTEPH patients. Increased peripheral hyperperfusion in the right middle and lower lobes was associated with decreased survival. We hypothesize that hyperperfusion in these regions may reflect neovascularization and the development of peripheral collaterals.
Keywords: Chronic thromboembolic pulmonary hypertension (CTEPH); computed tomography; image processing; pulmonary embolism.
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