Clinical outcomes and factors associated with pulmonary infarction following acute pulmonary embolism: a retrospective observational study at a US academic centre

OBJECTIVE: Pulmonary infarction is a common clinical and radiographic finding in acute pulmonary embolism (PE), yet the clinical relevance and prognostic significance of pulmonary infarction remain unclear. The study aims to investigate the clinical features, radiographic characteristics, impact of reperfusion therapy and outcomes of patients with pulmonary infarction. DESIGN, SETTING AND PARTICIPANTS: A retrospective cohort study of 496 adult patients (≥18 years of age) diagnosed with PE who were evaluated by the PE response team at a tertiary academic referral centre in the USA. We collected baseline characteristics, laboratory, radiographic and outcome data. Statistical analysis was performed by Student’s t-test, Mann-Whitney U test, Fischer’s exact or χ(2) test where appropriate. Multivariate logistic regression was used to evaluate potential risk factors for pulmonary infarction. RESULTS: We identified 143 (29%) cases of pulmonary infarction in 496 patients with PE. Patients with infarction were significantly younger (52±15.9 vs 61±16.6 years, p<0.001) and with fewer comorbidities. Most infarctions occurred in the lower lobes (60%) and involved a single lobe (64%). The presence of right ventricular (RV) strain on CT imaging was significantly more common in patients with infarction (21% vs 14%, p=0.031). There was no significant difference in advanced reperfusion therapy, in-hospital mortality, length of stay and readmissions between groups. In multivariate analysis, age and evidence of RV strain on CT and haemoptysis increased the risk of infarction. CONCLUSIONS: Radiographic evidence of pulmonary infarction was demonstrated in nearly one-third of patients with acute PE. There was no difference in the rate of reperfusion therapies and the presence of infarction did not correlate with poorer outcomes.