Intermediate-risk pulmonary embolism: Aiming to improve patient stratification

Background: Intermediate-risk pulmonary embolism (PE) patients present a therapeutic dilemma. While some are at risk for developing adverse events, possibly requiring escalation therapy, most will have a benign course. Our aim was to define predictors which will identify those patients who will not deteriorate despite the presence of RV involvement. Methods: We evaluated 179 consecutive intermediate-risk PE patients (47% males; mean age: 66 ± 16 years), allocating them to those who did and did not need escalation therapy and evaluating the predictors for deterioration. We then formulated a score to distinguish between those who would not require escalation therapy. Results: Twenty-six patients (15%) required escalation therapy which was associated with significantly more episodes of syncope (42% vs. 15%, p = 0.001), higher D-Dimer levels (10,810 ± 19,147 vs. 3816 ± 6255, p < 0.001), echocardiographic evidence of severe right ventricular (RV) dysfunction (42% vs. 19%, p < 0.01), or a higher RV/left ventricular (LV) diameter ratio on computed tomography (CT) (1.9 ± 0.6 vs. 1.46 ± 0.5, p < 0.001). On multivariate analysis the presence of syncope (HR 2.8 CI 1.1–7.1) and severe RV dysfunction on echocardiography (HR 3.5 CI 1.4–9.3) were found to be independent predictors for escalation therapy. A combined score of 1 was associated with only a 1.9% risk for escalation, while a maximum score of 4 was associated with a 57% risk for escalation therapy (P for trend<0.001). Conclusions: A small but significant number of intermediate-risk PE patients required escalation therapy. A combined score comprising clinical, imaging, and laboratory parameters might aid in further risk stratification, identifying those intermediate risk PE patients with a more benign clinical course.