Cardiopulmonary Exercise Testing in People With Dyspnea With a Recent Acute Pulmonary Embolism

Background: Cardiopulmonary exercise testing (CPET) may provide a helpful tool to assess underlying causes of dyspnea in patients with acute pulmonary embolism (PE). However, the response to exercise in the first weeks after diagnosis of an acute PE is currently unknown. Research Question: What are the cardiopulmonary responses to and safety of performing strenuous exercise within 2 to 4 weeks postacute PE? Study Design and Methods: A total of 100 patients with acute PE, without major comorbidities, experiencing dyspnea (Medical Research Council dyspnea scale = 2) and functional limitations (Post-Venous Thromboembolism Functional Status Scale grade = 2) 1 to 2 weeks after PE diagnosis, underwent CPET within 2 to 4 weeks after diagnosis. We evaluated the frequency of peak oxygen consumption < 80% predicted, a peak oxygen pulse < 80% predicted or oxygen pulse<inf>AT</inf>/oxygen pulse<inf>rest</inf> < 2.6, and a ventilatory equivalent for carbon dioxide = 34 at anaerobic threshold or dead space to tidal volume ratio > 30% at peak, and their association with markers of PE severity at diagnosis. Results: There were no adverse events related to the procedure. CPET disclosed peak oxygen consumption < 80% predicted in 23% of patients, oxygen pulse < 80% predicted or oxygen pulse<inf>AT</inf>/oxygen pulse<inf>rest</inf> < 2.6 in 75%, and ventilatory equivalent for carbon dioxide at anaerobic threshold = 34 or peak dead space to tidal volume ratio > 30% in 49%. In 1 of 7 patients, none of the previously reported signs were present (14%). Intermediate-high risk PE and central PE were associated with increased incidence of these abnormalities. Interpretation: There were no complications when performing strenuous exercise in the first weeks after a PE diagnosis in this study. Despite dyspnea, 1 of 7 patients had adequate cardiopulmonary reserve, suggesting that post-PE symptoms are multifactorial. Intermediate-high risk and central PE were associated with higher incidences of abnormal CPET outcomes. Clinical Trial Registration: Dutch Trial Register; No.: NTR NL9615; URL: https://onderzoekmetmensen.nl/en/trial/54292