To investigate the clinical significance of pulmonary artery distensibility (PAD) monitored by electrocardiogram-gated computed tomography pulmonary angiography (CTPA) in the prognostic risk stratification of patients with acute pulmonary embolism (APE).

A total of 109 APE patients who underwent electrocardiogram-gated CTPA in our hospital from February 2021 to December 2025 were enrolled. According to the prognosis, 23 patients with poor prognosis were assigned to the observation group and 86 patients with good prognosis to the control group. Serum high-sensitivity cardiac troponin I (hs-cTnI), D-dimer, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were compared between the two groups. The simplified Pulmonary Embolism Severity Index (sPESI), simplified Wells score, and Pulmonary Embolism Rule-out Criteria (PERC) score were calculated. The right ventricle/left ventricle transverse diameter ratio (RV/LV), pulmonary artery obstruction index (PAOI), and PAD were measured by CTPA. The predictive value was assessed by receiver operating characteristic (ROC) curves. Multivariate logistic regression analysis was used to identify prognostic risk factors, and a nomogram model was constructed.

Compared with the control group, the observation group showed significantly higher serum hs-cTnI[96.50 (28.79, 269.32) pg/ml vs. 43.85 (24.22, 90.76) pg/ml], NT-proBNP [2 147.00 (422.05, 5 687.15) pg/ml vs. 140.60 (45.21, 614.20) pg/ml], sPESI [2.00(1.00, 3.00) points vs. 1.00(0.00, 1.00) points], and PERC score [2.00(2.00, 3.00) points vs. 1.00(1.00, 2.00) points], and lower systolic blood pressure [135.50 (119.75, 150.25) mmHg vs. 139.50 (124.50, 150.00) mmHg] (P<0.05). The observation group also had higher RV/LV [1.33 (1.08, 1.56) vs. 0.95 (0.90, 1.15)], a higher proportion of RV/LV>1.0 (89.66% vs. 49.65%), and higher PAOI [35.25% (31.03%, 40.73%) vs. 29.00% (25.93%, 34.23%)], while PAD was significantly lower [2.95 (2.22, 4.97)×10^-3/mmHg vs. 5.98(4.37, 7.31)×10^-3/mmHg] (P<0.05). ROC curve analysis showed that the area under the curve (AUC) of PAD for predicting poor short-term prognosis was 0.859 [95%CI: 0.803~0.904], with a sensitivity of 84.48% and a specificity of 80.14%. The AUC of RV/LV was 0.757 (95%CI: 0.691~0.815), with a sensitivity of 89.66% and a specificity of 54.61% at the cutoff value>1.0. The AUC of PAOI was 0.766 (95%CI: 0.700~0.823), with a sensitivity of 84.48% and a specificity of 70.21% at the cutoff value >30%. Multivariate logistic regression analysis revealed that NT-proBNP>125 pg/ml (OR=5.396, 95%CI: 1.822~15.978), RV/LV>1.0 (OR=7.562, 95%CI: 2.397~23.860), PAOI>30% (OR=13.784, 95%CI: 3.912~48.567), and PAD>4.28×10^-3/mmHg (OR=0.086, 95%CI: 0.028~0.270) were risk factors for the prognosis of APE (P<0.05). The AUC of the combined prediction was 0.94 (95%CI: 0.90~0.98), which was superior to that of any single indicator (P<0.05).

PAD measured by electrocardiogram-gated CTPA can reflect the mechanical changes of pulmonary vasculature in APE patients, and its predictive performance is superior to RV/LV and PAOI. The combination of PAD, RV/LV, PAOI, and NT-proBNP can improve the accuracy of risk stratification in APE patients, demonstrating clinical significance.