Chronic Dyspnea and Residual Pulmonary Vascular Sequelae After COVID-19 Pulmonary Embolism: A Retrospective Analysis

During the COVID-19 pandemic, Brazil was one of the most affected countries. Patients presented higher risk of acute venous thromboembolism (VTE), in particular, pulmonary embolism (PE). However, long-term implications of these events remain unknown. A retrospective analysis from the FENIX study was conducted, and patients with COVID-19-related VTE during hospitalization were included. Further analysis, up to 6 months after the acute event, was performed exclusively in patients with PE. Persistence of dyspnea and exercise intolerance was evaluated through imaging, rest, and exercise functional tests. Cumulative incidence of VTE during hospitalization among COVID-19 survivors followed at the outpatient clinic was 17.7% (n = 75/423) and of acute PE was 9.9% (n = 42/423). Patients with PE were mostly male (66%), 56 ± 16 years old, and mainly classified as intermediate-low risk (74%). Dyspnea (mMRC≥ 1) up to 6 months of PE was present in 56% (n = 19/34), with a borderline association with parenchymal lung sequelae on chest CT scan (p = 0.069). Symptomatic patients upon follow-up presented lower FEV1 and FVC, as well as increased peak VD/VT ratio and ventilatory inefficiency. No signs of pulmonary hypertension (PH) were identified on echocardiogram (ECHO) and cardiopulmonary exercise testing (CPET). Persistence of dyspnea among post-PE related to COVID-19 was high. However, no cases of PH were found; follow-up findings may be related to pulmonary parenchymal and microvascular injury. Also, we cannot exclude association with long-COVID, in which pathophysiological mechanisms are multifactorial, involving chronic inflammatory changes and multiorgan dysfunction, highlighting the need for comprehensive evaluation of exercise intolerance through invasive CPET.