PB0971 - Clinical and echocardiographic variables associated with residual perfusion defects after pulmonary embolism

Background: Residual perfusion defects (RPD) after pulmonary embolism (PE) are common, and the detection of RPD is clinically relevant even in the absence of pulmonary hypertension.

Aims: The aim of this study was to explore baseline characteristics and echocardiographic findings at follow-up associated with RPD after PE.

Methods: The study cohort is a part of the PE REHAB-trial (NCT03405480), an ongoing randomized controlled trial to assess the effect of pulmonary rehabilitation in patients with persistent dyspnea after PE. Patients aged 18-75 years with a history of PE, confirmed by computed tomography pulmonary angiography 6-72 months earlier and persistent dyspnea corresponding to modified Medical Research Council dyspnea scale ≥ 1 were included. Participants (n=169) completed a diagnostic work-up consisting of standard transthoracic echocardiography and ventilation/perfusion (V/Q) scintigraphy. V/Q scintigraphy were deemed either positive or negative, according to the European Association of Nuclear Medicine criteria. Clinical data at time of PE-diagnosis was obtained. Thrombotic burden at diagnosis was assessed using the Mean Bilateral Proximal Extension of the Clot (MBPEC)-score, where higher number indicates more proximal emboli. Clinical and echocardiographic characteristics were explored in univariate analyses using t-test or Mann-Whitney U-test. Multiple logistic regression was performed to assess the association between selected variables and the presence of residual perfusion defects.

Results: RPD were detected in 52/169 (31%) of PE-survivors with persistent dyspnea. Higher MBPEC-score at diagnosis and reduced pulmonary acceleration time at follow-up were associated with RPD; adjusted odds ratios 1.76 (95% CI: 1.16–2.67, p-value < 0.01) and 0.67 (95% CI: 0.55–0.82, p-value < 0.001) per 10 milliseconds, respectively. Pulmonary acceleration time had greater feasibility compared to other echocardiographic measurements of right ventricular function and pulmonary hypertension.

Conclusion(s): RPD are common after pulmonary embolism. Greater thrombotic burden at diagnosis and shortened pulmonary acceleration time at echocardiographic follow-up may help identify patients with RPD.