Relation of ultrasound morphologic characteristics of central pulmonary artery thromboemboli to their ex vivo lysibility.

Background: Ultrasound morphology of massive central pulmonary artery thromboemboli (TE) is an independent predictor of 30-day mortality. The aim of this study was to asses ex vivo lysibility of morphologically different TE.
Methods: Forty-five central pulmonary artery TE, collected at autopsies, were divided into hypoechoic (group A) and hyperechoic (group B) categories. TE were lysed with alteplase in a perfusing system simulating pulmonary circulation for 1 hour.
Results: The grey scale mean of thrombi in group B was higher compared with group A (64 +/- 7 vs. 38 +/- 7, respectively, P < .01). Spontaneous lysis in group A did not differ compared with group B (2.2% +/- 0.5% vs. 2.1% +/- 0.4%, P = .4). After incubation with alteplase, the weight of TE was reduced more in group A than in group B (16% +/- 2% vs. 11% +/- 2%, P < .001). The grey scale mean negatively correlated with the percentage of TE weight reduction (0.768) (P < .001).
Conclusion: Ultrasound morphology of TE from central pulmonary arteries correlates significantly with ex vivo lysibility. Hypoechoic TE are more susceptible to thrombolysis than hyperechoic TE.