Pulmonary Vein Sign to Assess Chronic Thromboembolic Pulmonary Hypertension

Pulmonary vein sign (PVS) was found to be easy to detect and to have higher sensitivity and specificity in chronic thromboembolic pulmonary hypertension (CTEPH) compared with acute pulmonary embolism, according to a study published in the Journal of the American Heart Association.

Researchers conducted a blinded and retrospective computed tomography analysis of 200 participants (mean age, 56.3 ± 16.7 years; 51% women; proximal CTEPH, n=50; control groups: acute pulmonary embolism n=50; nonthromboembolic patients, n=50; and pulmonary arterial hypertension, n=50). Venous flow reduction was assessed by the presence of a filling defect of ≥2 cm in a pulmonary vein draining into the left atrium and left atrium attenuation >160 Hounsfield units.

PVS was found to occur most frequently in patients with CTEPH. PVS had a sensitivity of 78.0% and a specificity of 85.3% (95% CI, 64.0-88.5 and 78.6-90.6, respectively) vs 34.0% and 70.7% (95% CI, 21.2-48.8 and 62.7-77.8, respectively) in acute pulmonary embolism, 8.0% and 62% (95% CI, 2.2-19.2 and 53.7-69.8, respectively) in nonthromboembolic, and 2.0% and 60% (95% CI, 0.1-10.7 and 51.7-67.9, respectively) in pulmonary arterial hypertension.

Among patients with CTEPH, lobar and segmental arterial occlusive disease was most frequently associated with corresponding absent venous flow. In addition, PVS detection was highly reproducible (Kappa = 0.96; 95% CI, 0.90-1.01, P <.001).

“Our results show that in CTEPH, pulmonary venous flow is significantly compromised when there is proximal occlusion in the pulmonary arteries and that this can be readily visualized by computed tomography pulmonary angiogram (CTPA),” noted the researchers. “It is not surprising that the abnormal venous flow was more common in the lower lobe veins because clinicopathological studies have demonstrated that CTEPH is more predominant in the lower lobes.”

Study limitations include the use of a subjective evaluation method to assess pulmonary venous flow. However, there was high interobserver reproducibility (κ=0.96) between clinicians with different levels of experience for CTPA assessment. In addition, it was difficult to blind observers to the presence or absence of acute or chronic pulmonary embolism.

“Our study has shown that PVS on CTPA has higher sensitivity and specificity for CTEPH, compared with the other control groups (acute pulmonary embolism, pulmonary arterial hypertension, and nonthromboembolic),” concluded the researchers. “Furthermore, PVS is more prevalent in CTEPH compared with acute pulmonary embolism. Additionally, PVS is not a feature of pulmonary arterial hypertension. Therefore, asymmetric enhancement of pulmonary veins should prompt a search for CTEPH, particularly when there is evidence of pulmonary hypertension on CTPA.”

Disclosures: Some of the study authors reported affiliations with the pharmaceutical industry. Please see the original reference for a full list of disclosures.

Reference

Gopalan D, Nordgren-Rogberg A, Vi Le EP, et al. Abnormal pulmonary venous filling: An adjunct feature in the computed tomography pulmonary angiogram assessment of chronic thromboembolic pulmonary hypertension. J Am Heart Assoc. 2020;9(21):e018075.

This article originally appeared on The Cardiology Advisor