D-dimer On Admission in Pulmonary Embolism as a Marker of Disease Severity and Prognosis

Introduction:
Pulmonary embolism (PE) can be lethal in the acute phase and lead to chronic disability. Thus, rapid diagnosis and prognostic stratification is critical. Although D-dimer plays a major role in the primary screening of PE, there is a paucity of data on the prognostic uses of initial D-dimer values, which might be especially important among intermediate risk PE patients where therapy should be individualized.

Methods:
The study comprised 259 consecutive intermediate risk PE patients (2008-2016). Patients were stratified according to D-dimer tertiles upon admission, and followed for 30 days. The primary endpoint was defined as a composite of 30-day mortality or the need for escalation therapy (hemodynamic support, mechanical ventilation and reperfusion therapy either by thrombolysis or surgical thrombectomy).

Results:
The mean age was 66±16 years and 55% were females. Mean D-dimer on admission was 4216±8570 mg/dl. Patients in the third D-dimer tertile compared to those in the first tertile were older (69±14 vs. 60±18 years, p=0.03) but otherwise there were no differences in their baseline characteristics. Third vs. lower D-dimer tertile was associated with more pronounced signs of right ventricular (RV) strain [troponin I levels (1.6±2.5 vs. 0.7±1.5 mcg/dl, p=0.02), RV/LV diameter ratio (1.5±0.5 vs. 1.2±0.5, p=0.01) and systolic pulmonary artery pressure (53±12 vs. 46±15 mmHg, p=0.02)], and accordingly, they were more likely to develop the primary endpoint (19 % vs. 7%, p=0.02), hemodynamic instability (15% vs. 1.5%, p=0.01) as well as the need for escalation therapy (19% vs. 5.6%, p=0.01), while they suffered from a higher bleeding rate (19% vs. 5.9%, p=0.01).

Discussion:
High D-dimer levels on admission were consistently associated with signs of RV strain as well as with a worse clinical course in patients hospitalized with intermediate risk PE. D-dimer might be a useful clinical aid to help tailor treatment in this population.