C22-17 Transthoracic Echocardiography in Biomarker-negative Pulmonary Embolism: A Multicenter Retrospective Cohort Analysis

Rationale Transthoracic echocardiography (TTE) is frequently obtained for hospitalized acute pulmonary embolism (PE) to assess right-ventricular function. Its value in lower-risk patients—those with negative cardiac biomarkers such as troponin and brain natriuretic peptide (BNP) is uncertain. We evaluated whether inpatient TTE in biomarker-negative PE is associated with healthcare utilization and short-term safety outcomes. Methods We conducted a retrospective cohort study of adults admitted with PE and negative cardiac biomarkers at Kaiser Permanente Southern California hospitals (10/1/2015-6/30/2025), identified by ICD-10 codes. Exclusions were age <18 years, pregnancy on the index date, lack of continuous membership in the prior year, prior PE or oral anticoagulation within 1 year, no CT pulmonary angiography or no cardiac biomarker testing within 24 hours of hospitalization, any abnormal biomarker in that window, or missing data. The exposure was receipt of TTE during hospitalization. Outcomes were length of stay (LOS), 30-day all-cause mortality, and a composite of in-hospital death or death/readmission within 30 days after discharge. Prespecified covariates included age, sex, race/ethnicity, body mass index, and simplified PESI. A propensity score for TTE was estimated by logistic regression; because TTE was more prevalent, we used optimal full matching with a 0.10-SD caliper on the logit and applied post-matching weights with robust (sandwich) standard errors in all outcome models. LOS was analyzed with weighted linear regression (reported as difference in days). Binary outcomes used weighted logistic regression, reported as odds ratios (OR) with 95% confidence intervals (CI). Two-sided p < 0.05 denoted statistical significance. Analyses were performed in SAS 9.4. The KPSC IRB approved the study with waiver of consent. Results We included 3,745 patients (TTE n = 2,163; no-TTE n = 1,582); 3,742 remained after matching (2,162 vs 1,580). Age was similar between groups; the proportion male was slightly lower with TTE (45.3% vs 49.1%; p = 0.022). In weighted analyses, TTE was associated with longer LOS by 0.59 days (95% CI, 0.47-0.71; p < 0.001). There was one in-hospital death in no-TTE and none in TTE; thus 30-day mortality from admission was numerically equivalent to post-discharge 30-day mortality. There was no statistically significant difference in 30-day mortality (no-TTE vs TTE: OR 1.79; 95% CI 0.84-3.70; p = 0.13) or in the composite outcome (OR 0.95; 95% CI 0.72-1.25; p = 0.70). Conclusion In biomarker-negative PE, inpatient TTE was associated with greater resource use (longer LOS) without improvement in short-term outcomes, including 30-day mortality, supporting more selective use.