Validity of the Pulmonary Embolism Rule-Out Criteria (PERC) for ruling out pulmonary embolism in low-risk patients at high altitudes

ABSTRACT

Abstract Objectives: to validate the diagnostic yield of the PERC score for ruling out pulmonary embolism in low-risk patients at high altitudes (>2500 meters above sea level [ASL]). Methods: a cross-sectional study with diagnostic test analysis in patients over the age of 18 with suspected pulmonary embolism on admission or during hospitalization, who underwent chest computed tomography angiography between August 2009 and January 2020 in a tertiary care hospital located on the Bogotá savannah. The yield of the PERC score was assessed, calculated with an SaO2<95% and an SaO2<90% in patients with different risk levels according to the Wells, Geneva and Pisa scores for pulmonary embolism. Results: one thousand eighty-seven were included in the final analysis, 42% with PE. Patients classified as low-risk using the Wells score had a PERC ACOR calculated with SaO2<95% of 0.56 (95%CI0.50-0.62) (p=0.049), and calculated with SaO2<90% of 0.60 (95%CI0.54-0.66) (p=0.002). The ACOR for subjects classified as low-risk using the Geneva score, with a PERC calculated with SaO2<95%, was 0.53 (95%CI0.45-0.60) (p=0.459) and for a PERC calculated with SaO2<90% it was 0.55 (95%CI0.47-0.62) (P=0.218). The ACOR for subjects with a less than 10% probability of PE according to the Pisa score classification, with a PERC calculated with SaO2<95%, was 0.54 (95%CI0.44-0.64)(p=0.422), and for a PERC calculated with SaO2<90% it was 0.56 (95%CI0.46-0.66)(p=0.236). Conclusions: the PERC score calculated with an oxygen saturation <90% has a similar diagnostic yield to the PERC score calculated with an oxygen saturation <95% for ruling out PE in patients classified as low-risk by the Wells score at high altitudes (>2,500 meters ASL). (Acta Med Colomb 2021; 46. DOI https//doi.org/10.36104/amc.2021.2010).