Residual perfusion defects after acute pulmonary embolism: Prevalence, determinants, and clinical impact

Residual perfusion defects are frequently observed on follow-up ventilation-perfusion (V/Q) scans after acute pulmonary embolism, yet their prognostic relevance remains uncertain. We assessed the prevalence, predictors, and clinical implications of residual perfusion defects after acute pulmonary embolism.

We conducted a retrospective cohort study of consecutive patients hospitalized with confirmed acute pulmonary embolism (2012-2024) who underwent baseline and follow-up V/Q scintigraphy. Patients were categorized by perfusion recovery or persistent residual perfusion defects. Clinical, laboratory, imaging, and outcome data were compared. Multivariable logistic regression identified independent predictors of residual perfusion defects.

Among 325 patients (median age 62 years; 47% male), residual perfusion defects persisted in 235 (72%) at a mean follow-up of 3 months. Residual perfusion defects were associated with older age, bilateral and higher-risk pulmonary embolism, and deep vein thrombosis. Patients with residual perfusion defects had higher inflammatory and thrombotic biomarkers and more pronounced right ventricular dysfunction with elevated pulmonary pressures. Independent predictors included prior venous thromboembolism (OR 7.61), intermediate-high/high-risk pulmonary embolism (OR 3.66), older age, and elevated C-reactive protein, whereas major provoking factors were protective. Dyspnea and mortality did not differ between groups. Notably, chronic thromboembolic pulmonary disease or pulmonary hypertension occurred exclusively in patients with residual perfusion defects.

Residual perfusion defects are common after acute pulmonary embolism and mark a more severe initial disease phenotype. While not associated with early clinical outcomes, their presence identifies patients at risk for chronic thromboembolic complications, supporting a targeted follow-up imaging strategy.