Pro-brain natriuretic peptide as a marker of successful thrombolysis in patients with submassive pulmonary thromboembolism

Introduction

Pulmonary embolism (PE) is frequently under-diagnosed and associated with high lethality despite progress in prophylaxis and treatment. Aggressive management may improve outcome in patients with high risk of right ventricle (RV) failure secondary to pulmonary hypertension. CT scan angiography, cardiac echo and biomarkers (pro-brain natriuretic peptide (proBNP) and troponin) have been used to identify these high-risk patients. We wanted to evaluate relationship between interventional treatment of acute PE with cardiac biomarkers changes.

Methods

Patients with PE < 24 hours confirmed by thoracic CT scan angiography, pulmonary circulation obstruction > 50% and echographic or CT evidence of RV dysfunction underwent invasive angiography and thrombolysis with r-tPA. Reperfusion was evaluated by Miller–Walsh's score and a second angiograph was performed 6 hours later to re-evaluate. Plasmatic proBNP and troponin were measured before and 6 hours after angiography.

Results

Thirteen patients, four men (31%), age 60.4 ± 19.2 years. ProBNP pre/post angiography in whole group = 3,672 ± 2,894/2,954 ± 2,648 (P = 0.055); in successful reperfusion group = 4,225 ± 3,050/3,233 ± 2,910 (pre/post) (P < 0.013) and in unsuccessful reperfusion group = 1,830 ± 1,320/2,024 ± 1,512 (pre/post) (P = not significant). Troponin pre/post angiography = 0.31 ± 0.27/0.23 ± 0.28 (P = not significant), without a significant lowering with regards to reperfusion. A significant lowering was seen in pulmonary arterial mean pressure before and after angiography in the whole group = 34.5 ± 8.9/23.4 ± 6.9 (P < 0.002), as in successfully reperfused patients (P < 0.005). No complications were derived from the procedure. Twenty-eight-day mortality was 8.3% (one patient from the reperfused group).

Conclusion

Biomarkers may help to define a high-risk PE group, susceptible to benefit from more aggressive management. ProBNP has a dynamic and sensitive correlation with pulmonary bed circulatory status, and with major variations in pulmonary hemodynamics, as we observed. Cardiopulmonary overload improves after successful direct thrombolysis. Angiographic reperfusion correlates directly with a significant lowering in proBNP levels and a significant improvement on pulmonary pressures. We think this aggressive approach may be recommended: if indirect evidence of reperfusion is present (for example, significant lowering on plasmatic proBNP levels), a control invasive angiography could be avoided. Also, these results could be extrapolated to intravenous thrombolysis.