Abstract Rationale Pulmonary embolism (PE) is the third most common cause of cardiovascular death and causes 60,000-100,000 deaths in the US annually. Attainment of therapeutic anticoagulation within 24 hours of PE diagnosis has been associated with reduced mortality. Low molecular weight heparin (LMWH) and unfractionated heparin (UFH) are recommended for patients at intermediate-high or high risk of death from PE, though no consensus exists on the optimal agent. Some guidelines favor LMWH due to shorter time to therapeutic levels and lower rates of bleeding and heparin-induced thrombocytopenia. Despite these potential benefits, UFH use remains high in acute PE. We hypothesized that LMWH would be underutilized compared with UFH among patients with acute PE referred to our Pulmonary Embolism Response Team (PERT). Methods This work was reviewed by the Johns Hopkins IRB and is exempt from informed consent. We reviewed medical records for all PERT activations between 08/30/2021-08/30/2022. The dataset includes baseline clinical characteristics, demographics, risk assessment, triage and treatment decisions, anticoagulation details, and clinical outcomes. The primary endpoint was proportion of subjects receiving UFH with therapeutic levels within 22-26 hours, defined by the first activated partial thromboplastin time within therapeutic range. BMI-adjusted Cockcroft Gault equation was utilized to estimate creatinine clearance (CrCl) at the time of anticoagulation initiation. The proportion of patients eligible for LMWH was estimated by tabulating non-high-risk patients on UFH with CrCl ≥ 30 mL/min. Results The population included 102 patients with confirmed PE. Median age was 63.5 years and 53.9% of subjects were female. UFH was the initial anticoagulant for 93 subjects (91.2%), while only 4 patients (3.9%) initially received LMWH. Among those receiving UFH, 88.2% were therapeutic within 22-26 hours and 62.4% were therapeutic within 4-8 hours. There were 9 deaths (8.8%) and 4 major bleeding events (3.9%) within 30 days of PE diagnosis; all were on UFH and all patients who died were therapeutic within 10-14 hours. Among those receiving UFH as initial therapy without high-risk disease, 94.3% would have been a candidate for LMWH by institutional guidelines. Conclusions Among patients evaluated for acute PE by an institutional PERT, the vast majority received initial anticoagulation with UFH despite being eligible to receive LMWH, and most were therapeutic within 22-26 hours. Further studies to evaluate potential benefits and risks related to initial anticoagulant choice in acute PE are warranted. This abstract is funded by: None
Claxton et al. (Fri,) studied this question.