Prognostic significance of free-floating right heart thromboemboli in acute pulmonary embolism: results from the Italian Pulmonary Embolism Registry.

The exact prevalence of mobile right heart thromboemboli (RHTh) in patients with pulmonary embolism (PE) is unknown, depending upon PE severity and the use of early echocardiography. Similarly, the mortality rate is variable, though RHTh detection appears to substantially increase the risk of death in patients with PE. The aim of this study was to assess the prevalence of RHTh in different risk categories in a wide series of patients with PE, and to analyse the effect of RHTh on in-hospital mortality. Among 1,716 patients enrolled in the Italian Pulmonary Embolism Registry, 1,275 (13.3% at high risk, 59.3% at intermediate risk and 27.4% at low risk) had echocardiography within 48 hours from hospital admission and entered the study. Overall, RHTh were detected in 57 patients (4.5%, at admission echocardiography in 88%): in 27/169 (16%) high-risk, in 29/756 (3.8%) intermediate-risk and 1/350 (0.3%) low-risk patients, respectively. At multivariate analysis, only advanced age (odds ratio [OR] 1.61, 95% confidence [CI] 1.27-2.03, p<0.0001), high-risk category (OR vs low-risk category 37.82, 95% CI 11.26-127.06, p<0.0001) and recurrent PE (OR 45.92, 95%CI 15.19-139.96, p<0.0001) showed a statistically significant effect on mortality. The presence of RHTh significantly increased the risk of dying (OR 3.89, 95%CI 1.98-7.67, p=0.0001) at univariate analysis, but this result was not mantained in the multivariate model (OR 1.64, 95%CI 0.75-3.60, p=0.216). In conclusion, though patients with RHTh had a more severe presentation of PE, this study did not detect an association between RHTh and prognosis.