No Echo, no problem? Predictors of right heart strain among patients with pulmonary embolism

Right heart strain (RHS) in pulmonary embolism (PE) is traditionally diagnosed with transthoracic echocardiography (TTE). Given limited access to TTE, clinicians use vital signs, laboratory markers, and computed tomography angiography (CTA) to estimate RHS. We investigate the association between these indicators and RHS on TTE among patients with PE.

We reviewed charts of adult patients with PE transferred to a quaternary center from 2019 to 2022, excluding patients given thrombolytics before transfer. We collected vital signs and laboratory values at the time of transfer request and arrival. All CTAs were reinterpreted by a study radiologist. We used a hybrid Classification and Regression Tree - logistic regression to identify predictors of RHS on TTE.

We included 185 patients, 139 (75 %) with RHS on TTE. Patients with serum lactate <2 mmol/L with diastolic blood pressure (DBP) >63 mmHg at initial consult were 77 % less likely to have RHS (OR 0.23, 95 % CI 0.12-0.6, p < 0.001); those under 26 years with heart rate (HR) >90 bpm and lactate 2-8.5 mmol/L were 93.6 % less likely to have RHS (OR 0.064, 95 % CI 0.006-0.67, p = 0.022). Patients with higher HR at initial consult had higher rates of RHS (OR 1.01, 95 % CI 1.00.2-1.05, p = 0.03). Those with signs of RHS on CTA were 2.43 times more likely to have RHS (95 % CI 1.22-5.9, p = 0.014).

HR, lactate, DBP, and CTA findings of RHS were predictive of RHS on TTE among patients with PE. Clinicians should consider a collection of variables when assessing RHS in patients with PE when TTE is not available.