Vascular Pruning on CT and Interstitial Lung Abnormalities in the Framingham Heart Study

Area of Science:

• Pulmonary Medicine
• Radiology
• Cardiovascular Imaging

Background:

• Pulmonary vascular disease is linked to poor outcomes in interstitial lung disease (ILD).
• Noninvasive imaging can quantify pulmonary vessels, but the association between radiographic indicators of vasculopathy and early interstitial changes is unknown.

Purpose of the Study:

• To investigate if pulmonary vascular volumes, quantified by CT scans, are associated with interstitial lung abnormalities (ILA) in a general community sample.
• To explore the relationship between vascular volumes and ILA progression and restrictive spirometry patterns.

Main Methods:

• Utilized CT imaging from 2,386 Framingham Heart Study participants to calculate pulmonary vascular volumes, including small vessel fraction.
• Employed multivariable logistic regression to assess associations between vascular volumes and ILA, ILA progression, and restrictive spirometry.
• Conducted secondary analyses adjusting for diffusing capacity and emphysema, and a sensitivity analysis on participants with normal lung function.

Main Results:

• Lower pulmonary vascular volumes on CT were associated with increased odds of ILA, ILA progression, and restrictive spirometry patterns.
• Specifically, a one SD lower small vessel fraction correlated with 1.81-fold greater odds of ILA and 1.63-fold greater odds of restriction.
• These associations remained consistent after adjustments for diffusing capacity, emphysema, and in participants with normal lung function.

Conclusions:

• In a community-dwelling cohort without pre-existing lung disease, reduced pulmonary vascular volume (vascular pruning) on CT scans is associated with a higher likelihood of ILA, ILA progression, and restrictive spirometry.
• CT-derived vascular pruning may serve as an early indicator of pulmonary vasculopathy in the context of interstitial lung disease.