Identification of patients with low-risk pulmonary embolism suitable for outpatient treatment using the pulmonary embolism severity index (PESI)

There is increasing evidence that outpatient treatment of patients with low-risk stable pulmonary embolism (PE) is safe, effective and potentially reduces costs. It is not clear how many patients presenting to an Irish Emergency Department (ED) are potentially suitable for outpatient management. To identify how many patients presenting to our ED over a 1-year period who were diagnosed with acute PE are potentially suitable for outpatient treatment. A retrospective observational study was conducted over a 1-year period. Clinical notes for patients who had a positive computed tomographic pulmonary angiogram (CTPA) within 24 h of presentation to the ED were examined to risk stratify the patients according to the pulmonary embolism severity index (PESI). Forty-seven patients who presented to our ED were diagnosed with a PE. Clinical notes were missing for 3 cases, and 44 cases were analysed further. The mean age was 64.3 (+/- 16.8 SD) years and 24 (54.5 %, 95 % CI 40-68.3 %) were males. Six patients (13.6 %, 95 % CI 6.4-26.7 %) had a background of cancer. Fifteen cases (34.1 %, 95 % CI 21.9-48.7 %) were deemed to be low risk as they were categorised as PESI risk class I or II. Our study found that 61/420 (14.5 %, 95 % CI 11.5-18.2) of CTPAs done were positive for PE. This study suggests that a significant percentage of patients diagnosed with acute PE are low risk as per PESI and therefore potentially suitable for outpatient management.