Abstract
OBJECTIVE: Residual chronic obstruction of Pulmonary Embolism (PE) can contribute to pulmonary hypertension and persistent cardiopulmonary limitations. This study comprehensively investigates the influence factors on the resolution of PE clots by CT pulmonary angiography (CTPA). METHODS: A retrospective analysis of 102 patients with acute PE diagnosed by CTPA was conducted based on a registered prospective PE cohort (NCT06073366). Follow-up CTPA studies (3 to 6 months post-diagnosis) were analyzed for the rate of improvement and the complete resolution rate of PE clots. Univariate analyses were performed using chi-square tests, and multivariate logistic regression was applied to adjust for confounding factors. RESULTS: A total of 2,958 vessels from 102 participants were analyzed, 219 were completely obstructed, and 1439 were partially obstructed. We did not identify any factors that had a significant effect on the rate of improvement. The complete resolution rate of PE clots was lower in completely obstructed vessels compared to partially obstructed vessels, and they had a 110% higher risk of residual thrombus (OR: 2.10, 95% CI: 1.46–2.98, p < 0.001). The rate of complete resolution of PE clot remained lower in accepting thrombolytic than in accepting anticoagulation (OR: 2.01, 95% CI: 1.14–3.77, p < 0.001). However, there was no significant difference in the effect of risk stratification of PE, location of clots (central clots only Vs central and peripheral clots Vs peripheral clots only), elderly, sex, obesity, and comorbid deep venous thrombosis on the complete resolution rate of PE clots. CONCLUSION: Patients with completely obstructed PE had a higher risk of residual thrombus than those with partially obstructed through medical therapy. The study highlights that after receiving medical therapy, patients with PE who have complete obstruction could require further exploration of treatment strategies for residual thrombus.