Pulmonary perfusion defects or residual vascular obstruction and persistent symptoms after pulmonary embolism: a systematic review and meta-analysis

Introduction: Up to 50% of pulmonary embolism (PE) patients have perfusion defects or residual vascular obstruction during follow-up despite adequate anticoagulant treatment, and a similar percentage experience chronic functional limitations and/or dyspnoea post-PE. We aimed to evaluate the association between pulmonary perfusion defects or residual vascular obstruction and functional recovery after PE. Methods: We performed a systematic review and meta-analysis including studies assessing both the presence of perfusion defects or residual vascular obstruction and functional recovery ( i.e. persistent symptoms, quality of life, exercise endurance). An odds ratio was pooled for perfusion defects or residual vascular obstruction and persistent symptoms using a random-effect model. Results: 12 studies were included totalling 1888 PE patients; at a median of 6 months after PE (range 2–72 months), 34% had perfusion defects or residual vascular obstruction and 37% reported persistent symptoms. Among patients with perfusion defects or residual vascular obstruction, 48% (95% CI 37–60%, I 2 =82%) remained symptomatic during follow-up, compared to 34% (95% CI 20–51%, I 2 =96%) of patients without such defects. Presence of perfusion defects or residual vascular obstruction was associated with persistent symptoms (OR 2.15, 95% CI 1.66–2.78; I 2 =0%, τ = 0). Notably, there was no association between these defects and quality of life or cardiopulmonary exercise test parameters. Conclusion: While the odds of having persistent symptoms was higher in patients with perfusion defects or residual vascular obstruction after acute PE, a significant proportion of these patients reported no limitations. A possible causality between perfusion defects or residual vascular obstruction and residual functional limitation therefore remains to be proven.