Lung parenchymal and cardiac appearances on CTPA impact survival in chronic thromboembolic pulmonary hypertension: results from the ASPIRE Registry

Background Chronic thromboembolic pulmonary hypertension (CTEPH) is commonly evaluated using CT pulmonary angiography (CTPA). We evaluated the frequency and impact of parenchymal and cardiac abnormalities on survival in CTEPH. Methods Patients were identified from the ASPIRE (Assessing-the-Spectrum-of-Pulmonary-Hypertension-Identified-at-a-Referral-Centre) Registry. Kaplan-Meier analysis was used to assess survival. Results 290 patients (55% female, mean age 65±14 years) with CTEPH were included. Mosaic perfusion was noted in 83%, lung infarction in 73% and parenchymal lung disease in 28%. The severity of mosaic perfusion and lung infarction correlated with markers of disease severity (p<0.001). Whereas the presence of mosaic perfusion was associated with improved survival in all patients (p=0.03), it did not predict outcome in those undergoing pulmonary endarterectomy (PEA) (p=0.6) and those not undergoing PEA (p=0.22). The presence of lung infarction had no impact on mortality. The presence of co-existing lung disease was associated with a worse survival (p<0.008), in patients not undergoing PEA. Mosaic perfusion was less common in patients with parenchymal lung disease (65%) compared to those without parenchymal lung disease (90%), p<0.001. Increased right: left ventricular ratio and aortic diameter predicted worse outcome (p<0.002). Conclusion Lung parenchymal and cardiac changes on CTPA predict outcome in CTEPH. Co-existing parenchymal lung disease is not uncommon and when present may mask the presence of mosaic perfusion. This study highlights the importance of systematically evaluating the lung parenchyma and cardiac changes in patients with CTEPH.