Chronic thromboembolic pulmonary hypertension is an uncommon complication of COVID-19: UK national surveillance and observational screening cohort studies

Introduction
Pulmonary embolism (PE) is a well-recognised complication of COVID-19 infection, and chronic thromboembolic pulmonary disease with and without pulmonary hypertension (CTEPD/CTEPH) are potential life-limiting consequences. At present the burden of CTEPD/CTEPH is unclear and optimal and cost-effective screening strategies yet to be established.

Methods
We evaluated the CTEPD/CTEPH referral rate to the UK national multidisciplinary team (MDT) during the 2017–2022 period to establish the national incidence of CTEPD/CTEPH potentially attributable to COVID-19-associated PE with historical comparator years. All individual cases of suspected CTEPH were reviewed by the MDT for evidence of associated COVID-19. In a separate multicentre cohort, the risk of developing CTEPH following hospitalisation with COVID-19 was calculated using simple clinical parameters at a median of 5 months post hospital discharge according to existing risk scores using symptoms, ECG and NT pro-BNP.

Results
By the second year of the pandemic, CTEPH diagnoses had returned to the pre-pandemic baseline (23.1 versus 27.8 cases per month, p=0.252). Of 334 confirmed CTEPD/CTEPH cases, 4 (1.2%) patients were identified to have CTEPH potentially associated with COVID-19 PE, and a further 3 (0.9%) CTEPD without PH. Of 1094 patients (mean age 58 years, 60.4% male) hospitalised with COVID-19 screened across the UK, 11 (1.0%) were at high risk of CTEPH at follow-up, none of whom had a diagnosis of CTEPH made at the national MDT.

Conclusion
A-priori risk of developing CTEPH following COVID-19-related hospitalisation is low. Simple risk scoring is a potentially effective way of screening patients for further investigation.