Introduction: A series of clinical scores were develo-ped to assess the risk of complications in patients with acute pulmonary embolism (APE), in order to better select those with short-term reduced risk that can be treated as outpatients or rapidly discharged from the hospital, if circumstances are adequate. Still, most APE patients are admited to the hospital for initiation of treatment, independent of correlation to lower risk of complications.

Objective: To evaluate the parameters associated with prolonged hospitalization of APE patients, for optimi-zing the selection of patients to be treated as inpatients. Methods: We prospectively evaluated all consecutive adult patients diagnosed with APE admitted to our Cardiology Department from January 2014 to March 2019. Patients with in-hospital mortality were exclu-ded. We considered an extended length of hospital stay (LOS) a duration longer than the median time of hos-pitalization of our study group.

Results: The study cohort included 102 patients with a mean age of 67.4 ± 12.1 years. 63.7% were female. The median LOS was 10 (interquartile range 8-13) days. An extended LOS was considered to be longer than 10 days. Female patients had a RR of 2.46 (95%CI 1.35-4.47, p<0.01) of a longer LOS compared to male pati-ents. Clinical parameters such as heart rate (r=0.236, p=0.017) and shock index (r=0.277, p=0.005) were correlated to LOS. Higher leucocyte count (r=0.256, p=0.01) and lower hemoglobin levels (r=-0.199, p=0.046) were also associated with an extended hospi-talization, as was an increased diameter of the inferior vena cava (r=0.308, p=0.012). Patients with prior pro-longed immobilization had a higher risk of an exten-ded LOS (RR 1.74, 1.20-2.50, p=0.01). Patients with a new right bundle branch block (1.53; 95%CI 1.03-2.25, p=0.037), central APE (1.93; 95%CI 0.95-3.93, p=0.05) and a free floating right heart thrombus (1.8; 95%CI 1.24-2.63, p=0.016) had a higher risk for prolonged ho-spitalization. Increased troponin levels associated the highest risk of extended LOS (2.41; 95%CI 1.32-4.38, p<0.01). No significant correlation was found between PESI score and LOS.

Conclusions: The median duration of hospitalization of APE patients is still prolonged, which carries a sig-nificant economic burden. The highest risk of prolon-ged LOS was found for female patients with increased troponin levels and prior prolonged immobilization. Central APE and free foating right heart thrombus were also associated with longer LOS. We consider the development of a discharge criteria chart useful in gui-ding the physician while chosing the optimal duration of hospitalization using frequevent clinical and paracli-nical evaluations.