Low Forced Expiratory Volume in Chronic Thromboembolic Pulmonary Hypertension

Lower forced expiratory volume is significantly correlated with obstruction seen on computed tomography angiogram (CTA) in patients with chronic thromboembolic pulmonary hypertension CTEPH). This was among the findings of a recent study published in the journal BMC Pulmonary Medicine.

In the current study, investigators hypothesized that etiological factors might be related to (1) the finding that individuals with CTEPH have lower forced expiratory volume in 1 second (FEV₁) than healthy controls; and (2) the frequent clinical observation that individuals with CTEPH often show obstructive ventilatory impairment for unknown reasons.

Researchers therefore retrospectively analyzed CTEPH patients who had undergone a pulmonary function test and respiratory impedance test to evaluate their exertional dyspnea during admission for right heart catheterization between January 2000 and December 2019. Patients with a smoking history were excluded, in order to rule out the effect of smoking on obstructive impairment.

The study sample included 135 patients with CTEPH. The median FEV₁/FVC score was 76.0%. The researchers found that the FEV₁/FVC score had a negative correlation with the mean pulmonary artery pressure, pulmonary vascular resistance, and the CTA  obstruction score. Multivariate regression analysis showed that the CTA obstruction score was an independent factor of a lower FEV₁/FVC score.

The study authors concluded, “In CTEPH patients without a smoking history, the [FEV₁/FVC score] showed a significant correlation with the pulmonary arterial obstruction and the pulmonary hemodynamics.” They added, “A further investigation focusing on the obstructive impairment in CTEPH patients may shed new light on the CTEPH etiology.”

Reference

Yanagisawa A, Naito A, Jujo-Sanada T, et al. Vascular involvement in chronic thromboembolic pulmonary hypertension is associated with spirometry obstructive impairment. BMC Pulm Med. 2021;21(1):407. doi:10.1186/s12890-021-01779-x