Imaging-based Assessment of Pulmonary Vascular Pruning and Ventricular Dimension Changes Related to Embolic Burden in...

Pulmonary embolism (PE) is a significant cause of morbidity and mortality, with long-term sequelae including pulmonary vascular pruning and right ventricular (RV) remodeling. This study aimed to investigate the relationship between baseline pulmonary arterial obstruction, quantified by the Qanadli index (QI), and the subsequent development of vascular pruning and associated cardiac changes over time.

This retrospective single-center study included patients diagnosed with PE between January 2022 and September 2025, who underwent two follow-up computed tomography pulmonary angiography (CTPA) scans at 3-6-month intervals. Pulmonary vascular and cardiac parameters were quantified using CTPA-derived metrics, including total vascular volume (TVV) and peripheral vascular volume (PVV). RV to left ventricle (LV) diameter ratios were measured, and interobserver reproducibility was assessed. Longitudinal changes in these parameters were evaluated using random intercept linear mixed effects models, with baseline QI, age, and sex as covariates.

A total of 162 patients were included, with a mean QI of 22.13 ± 21.25%. Significant decreases in PVV (p = 0.004) and the PVV/TVV ratio (p = 0.007) were observed over time, while no significant change was noted in TVV (p > 0.05). The RV/LV ratio increased significantly (p = 0.005), but no significant correlation was found between changes in PVV and RV/LV ratio (r = -0.020, p > 0.05). Interobserver reproducibility (ICC) showed excellent agreement (ICC for PVV = 0.91, for TVV = 0.89, for RV/LV ratio = 0.87).

Our findings suggest that PE is associated with selective reduction in small intrapulmonary vascular volume over time, consistent with vascular pruning. However, baseline clot burden alone, as measured by QI, does not adequately predict subsequent right ventricular remodeling or vascular changes. These results indicate that distal microvascular alterations and right ventricular adaptation are distinct components of post-embolic pathophysiology, and CTPA-derived quantitative metrics may offer valuable complementary information for patient risk stratification. Further studies with longer follow-up are necessary to confirm these findings and better understand the prognostic significance of vascular pruning in PE.