Abstract 56: Differences Between Chronic Thromboembolic Disease And Chronic Thromboembolic Pulmonary Hypertension Patients At Time Of Presentation

Background: Approximately 1/3 of acute pulmonary embolism (PE) patients develop chronic thromboembolic disease (CTED), a condition in which a patient’s PE does not resolve after standard anticoagulation therapy. Chronic thromboembolic pulmonary hypertension (CTEPH) can occur in about 3-4% of acute PE patients. Though CTED and CTEPH share an underlying cause, few studies have compared symptom severity, patient history, and other clinical indicators for the two diseases. Moreover, CTED is sometimes considered to be an asymptomatic condition. The symptomatology in CTEPH is thought to be primarily determined by pulmonary hypertension, a characteristic that CTED patients do not share.

Methods: Data were collected at baseline diagnosis from 24 CTED and 65 CTEPH patients in the University of Michigan Pulmonary Hypertension Registry between 2016-2020. Demographic, 6-minute walk (6MW), echocardiography, past medical history, and brain natriuretic peptide (BNP) data were compared between groups.

Results: CTED patients were: 1) less symptomatic (better WHO functional class [FC], better predicted 6MW), 2) had more preserved oxygenation during 6MW, 3) had less RV dilation/dysfunction and RA dilation on echo, and 4) lower BNP, than CTEPH patients. Despite this, 54% of CTED patients demonstrated significantly impaired FC (III/IV) without evidence of significant RV dysfunction, exercise hypoxia or volume overload.

Conclusion: More than half of CTED patients in our study had significantly impaired FC. Further investigation into CTED symptomatology is warranted. CTEPH patients are more symptomatic and present with worse clinical metrics than CTED patients, which may be attributed to more advanced RV dysfunction and higher BNP level. These results may help distinguish CTED v. CTEPH diagnoses earlier, leading to earlier targeted treatment and better outcomes.