Management of low-risk patients with pulmonary embolism differs based on CT scan findings

Key takeaways:

• Low-risk patients with and without concerning CT findings had comparable clinical outcomes.
• More patients with concerning CT findings received echocardiograms and bedside ultrasounds.

Patients presenting with low-risk pulmonary embolism are managed in different ways based on CT scan findings and not clinical risk factors, according to study results published in JAMA Network Open.

Colin Greineder

“I think most emergency physicians are going to find the results of this study very surprising,” Colin Greineder, MD, PhD, assistant professor of emergency medicine and pharmacology at University of Michigan Medical School, told Healio. “ER doctors have been taught and continue to teach new trainees that large, bilateral emboli and pulmonary embolisms (PEs) associated with right heart strain or pulmonary infarct on CT scan are life-threatening emergencies. One of our most important findings is that these PE characteristics were not associated with worse clinical outcomes (out to 30 days) in patients classified as low-risk by PE severity index (PESI) score.”

In a single center cohort study, Greineder and colleagues analyzed 817 adults (median age, 58 years; 51% women; 15.8% Black) diagnosed with acute PE in the ED between October 2016 and December 2019, of which 331 (40.5%) had low-risk PE, to see how concerning CT findings impact all-cause mortality and treatment.

In addition to mortality, researchers assessed hospitalization, ICU admission, length of stay, echocardiography and/or bedside ultrasonography and activation of the PE response team.

There were five different types of concerning CT findings, with varying prevalence according to risk groups. Compared with low-risk patients, patients classified as high-risk experienced more instances of right ventricle enlargement (difference, 4.4%; 95% CI, 2.2%-6.5%), septal abnormalities (difference, 5.1%; 95% CI, 2.1%-8.1%) and had significantly increased mean right ventricle–to–left ventricle ratios (mean difference, 0.12; 95% CI, 0.08-0.02).

On the other hand, more low-risk patients had pulmonary infarction (18.7% vs. 13%). Further, bilateral central embolus presence did not significantly differ between risk groups (difference, –1.7%; 95% CI, –8.8% to 5.4%).

Of the cohort of patients with low-risk pulmonary embolisms, 180 had no concerning CTPE findings, whereas 151 had at least one concerning finding.

Mortality in low-risk patients by day 30 was comparable between those with concerning CT findings and those with no concerning findings (0 vs. 4), according to the study. Among high-risk patients, 88 patients died by day 30.

ED discharge, stay duration, ICU

When assessing ED discharge rates among low-risk patients, fewer patients with concerning CTPE findings achieved this outcome compared with patients who had no concerning findings (3 [2%] vs. 14 [7.8%]; P = .01). The ED discharge rate of patients with concerning findings did not significantly differ from that of high-risk patients (2% vs. 0.8%).

Researchers found no significant difference between low-risk patients with concerning CT findings and without these findings when evaluating hospital stay duration (mean, 2.3 days vs. 2.6 days); however, there was a significant difference when assessing high-risk patients against low-risk with concerning CT findings (5.8 days vs. 2.3 days).

ICU admissions rates were similar among both low-risk groups, with two patients each who needed to be moved to the ICU. Notably, 80 high-risk patients required ICU admission.

Echocardiography, ultrasonography use

Additionally, use of echocardiography was higher among those with concerning CTPE findings (87 patients [57.6%] vs. 49 patients [27.2%]; P < .001). More low-risk patients with concerning CTPE findings also used point-of-care ultrasonography compared with low-risk patients who had no concerning findings (35 patients [23.2%] vs. 15 patients [8.3%]; P < .001).

When assessing high-risk patients against low-risk patients with concerning findings on CT, researchers found no differences in the usage rate of echocardiography (53.9% vs. 57.6%) and point-of-care ultrasounds (26.8% vs. 23.2%).

Lastly, patients with concerning CTPE findings in the low-risk group also interacted with the PE response team more than those who did not have any concerning findings (34 patients [22.5%] vs. 11 patients [6.1%]; P < .001). Again, high-risk patients and low-risk patients that had concerning CT findings did not differ from each other (28.4% vs. 22.5%).

“The take home message for providers is that the patient’s clinical risk factors and physiology should be guiding our decision-making,” Greineder told Healio. “We have a well-validated risk stratification tool which consolidates these into an easy-to-use score and that is what we should be paying attention to, rather than what is on the CT scan.”

In terms of future studies, Greineder said prospective, multicenter studies are needed to confirm what was found in this study.

“This is a single site, retrospective study, and our PE patients may differ from those treated at other sites,” Greineder told Healio. “We need to validate these findings with prospective, multi-center data. I think we will find the same trends at other hospitals and health systems, and then the really interesting question will be how we can get clinicians to change their attitudes and behavior when they’ve been taught something for so many years.”

Reference:

• ‘Concerning’ CT scans may cause unnecessary hospitalization for some pulmonary embolism patients. https://www.michiganmedicine.org/health-lab/concerning-ct-scans-may-cause-unnecessary-hospitalization-some-pulmonary-embolism-patients-0. Published June 15, 2023. Accessed June 15, 2023.