Patients with interstitial lung disease (ILD) are at risk of developing pulmonary hypertension (PH). In this study, researchers found that the right ventricle to left ventricle diameter ratio (RV:LV) measured at CT pulmonary angiography (CTPA) could be a useful, noninvasive method to determine risk level in this patient population. The study included 92 consecutive patients (mean age, 65 ± 11 years; 64% were male) who underwent CTPA and right heart catheterization (RHC). Patient data including demographics, ILD subtype, echocardiography, and detailed CTPA measurements were gathered for each patient. Three techniques were used to measure RV:LV ratio at CTPA. Patients had FVC 57 ± 20% (predicted), gas transfer 22 ± 8% (predicted) and gas transfer co-efficient 51 ± 17% (predicted). At RHC, PH was confirmed in 78% of patients. In univariate analysis, an RV:LV ratio ≥ 1.0 was a strong independent predictor of mortality or transplantation (hazard ratio [HR] 3.26, 95% confidence interval [CI] 1.49–7.13, P=0.003), but invasive hemodynamic data was not. When adjusting for an ILD diagnosis of idiopathic pulmonary fibrosis and CT-derived ILD severity, RV:LV ratio was still a significant independent risk factor for mortality and transplantation (HR 3.19, CI: 1.44–7.10, P=0.004). The authors concluded that patients who are deemed high risk due to an increased RV:LV ratio should undergo closer follow-up, more aggressive treatment, and consideration for lung transplantation.
