Are clinical parameters and biomarkers predictive of severity of acute pulmonary emboli on CTPA?

Aim: To explore the link between clinical presentation and biomarkers with CTPA findings. Methods: Retrospective case note analysis of consecutive cases presenting to a large teaching hospital. An independent radiologist reviewed CTPAs and clot burden quantified using an obstruction index. Results: One hundred and seventy cases were identified and notes retrieved in 137 cases. (i) Clinical presentation: correlation was seen between clot burden and systolic blood pressure (BP) (r = -0.299, P = 0.0006) and heart rate (r = 0.240, P = 0.0056). Median obstruction index was significantly higher in those with a presenting BP < 90 mmHg [41.25% (95% CI 30-50) vs. 15% (95% CI 12.5-25), (P = 0.0004)]. Clot burden was significantly higher in patients with temperature of > 37.5 degrees C [30% (95% CI 25.0-42.5) vs. 15% (95% CI 12.5-28.3), P = 0.02)] and (ii)Biomarkers: significant correlation between clot burden and D-dimer was seen (r = 0.36, P = 0.0001). Location of thrombus was associated with significant differences in D-dimer level. A subgroup of patients had cardiac biomarkers measured (n = 24). There was a statistically significant correlation between troponin I and clot burden (r = 0.412, P = 0.048) and RV/LV ratio (r = 0.699, P = 0.0013). Discussion: These findings suggest that clinical parameters and biomarkers have a role in predicting the radiological severity of PE. These data support the need for further studies of risk stratification in patients presenting with acute PE.