Right ventricular function and thrombus load in patients with pulmonary embolism and diagnostic delay

It has been reported that the time between symptom onset and objective diagnosis of pulmonary embolism (PE) does not affect patients' prognosis with regard to re-thrombosis and mortality risk. However, this observation is contra-intuitive and poorly understood. We further elaborated on this paradox by evaluating thrombus load and right ventricular function in patients with and without diagnostic delay.

We performed a post hoc analysis of a previously published observational prospective outcome study in 113 consecutive PE patients. Qanadli-score and RV/LV ratio were scored in all patients, as was the duration from symptom onset to clinical presentation and diagnosis. Diagnostic delay was defined as a period of more than 7 days between symptom onset and clinical presentation. Further endpoints were mortality and hospital readmission in a 6-week follow-up period.

Twenty patients with and 93 patients without delay were studied, who had comparable baseline characteristics and co-morbidities. In linear analyses, Qanadli-score (R² of 0.021; P = 0.130) and RV/LV ratio (R² < 0.001; P = 0.991) were not associated with diagnostic delay. Likewise, longer delay was not predictive of 6-week mortality (odds ratio, 0.65; 95% CI, 0.08-5.57) or hospital readmission (odds ratio, 0.75; 95% CI, 0.15-3.65).

In our patient cohort, diagnostic delay was not associated with higher thrombus load or right ventricular dysfunction. This provides a possible explanation for the lack of prognostic relevance of diagnostic delay.