Systemic thrombolysis in haemodynamically unstable pulmonary embolism: The earlier the better?

The temporal window for the administration of systemic thrombolysis (ST) in acute pulmonary embolism (PE) has not yet been clarified. We assessed the relationship between short-term cardiovascular (CV) mortality and time of ST administration.

Among 394 consecutive patients admitted between January 2010 and June 2017 with a confirmed PE, we retrospectively review the clinical and instrumental data of those labelled as high-risk PE (n = 76, 41 males, mean aged 64.7 ± 9.1 years old).

A receiving operating curve (ROC) analysis established the optimal temporal threshold for the administration of the ST, in respect to the 30-day CV mortality at 8.5 h from the symptom onset (Area under Curve 0.79 ± 0.6, 95% CI 0.73-0.86, p < 0.0001). Mantel-Cox analysis showed that there was a significant difference in the distribution of survival between patients treated within 8.5 h from the beginning of symptoms onset to those treated after 8.6 h [log rank (Mantel-Cox) chi-square 9.68 p = 0.002]. Cox-regression analysis demonstrated that the administration of ST after 8.6 h from the symptom's onset was an independent predictor of 30-day CV mortality in high-risk PE patients (HR 7.81, 95% CI 1.84-33.05, p = 0.005), independently from the occurrence of major bleeding events (HR 5.89, 95% CI 1.38-25.13, p = 0.01), previous CAD (HR 3.31, 95& CI 1.07-10.231. p = 0.03), RV/LV ratio after 2 h from the administration ST > 1 (HR (12.91, 95% CI 3.04-54.77, p = 0.001) and PAH at discharge (HR 3.86, 95% CI 2.22-4.68, p = 0.002).

ST administered within 8.5 h from symptoms onset may be associated with a reduced 30-day CV mortality in high-risk PE patients.