A new study highlights the critical role emergency providers play in identifying the incidence of pulmonary embolisms (PE) in patients who present with COVID-19.

Researchers have delineated some factors that either heighten or decrease the risk that a patient has or may develop a PE so that treatment can be optimized at an early stage.1

In the retrospective study, investigators from the Henry Ford Health System in Detroit analyzed the cases of 328 COVID-19-positive patients who underwent pulmonary CT angiography after presenting to health system hospitals between mid-March and mid-April. They found 22% of these patients had a PE.

Further, the researchers identified the risk of suffering a PE was nearly three times higher in patients with a body mass index (BMI) of 30 kg/m2 or above, a level considerably higher than what is considered an ideal BMI for adults (between 18.5 kg/m2 and 24.9 kg/m2).

Investigators also discovered elevated levels of D-dimer and C-reactive proteins, in conjunction with rising oxygen requirements, also may be indications that a PE is present. They noted this is the case even in patients who are on preventive blood thinners already.

Thomas Song, MD, senior author of the study and a radiologist at Henry Ford Hospital in Detroit, says these findings suggest the standard of care emergency providers practice in terms of their clinical assessment of patients who present with COVID-19 is fine. Still, this information identifies additional risk factors on which to concentrate. “It is a combination of things that people are already doing, but [also] really focusing on those lab values and oxygenation levels, along with obesity as an additional risk factor that we had not thought of before,” he says.

Song adds these data show patients who were on statins before presenting to the hospital were less likely to develop a PE. “That is protective,” he says of the statins. “We are bringing in other factors for the emergency clinicians [to consider] in deciding how to manage these patients, and to determine who is at high risk for PE.”

For instance, one decision clinicians need to make is which COVID-19 patients should undergo further evaluation to look for a potential PE. Investigators stress the appropriate test for this purpose is CT angiography. “A non-contrast chest CT won’t find [PE],” Song notes. “Even when you do a routine chest CT where you give contrast, that [test] may not find all the clots.” On the other hand, CT angiography is optimized to look at the pulmonary arteries themselves, and it is readily available, Song stresses. “It is a widely used test in most EDs,” he adds.

Closing in on a diagnosis of PE early likely provides benefits, Song suggests. With a delayed diagnosis, “the patient could deteriorate clinically from a cardiopulmonary standpoint, and then be at risk for an ICU [intensive care unit] admission and [require] ventilator support,” he explains.

In fact, Song observes the patients in the study all tended to end up in the same place, regardless of whether they were found to have a PE. “There was no difference in ICU-level care, ventilation requirements, or length of stay,” he shares. “You wonder if that is because we did find things early on. The patients [with PE] were treated, and their outcome was no different than [the patients] who did not have a PE.” While investigators did not look at this issue specifically, Song suggests early treatment of PE may have enabled the study participants to avoid complications that could have led to more deaths, longer lengths of stay, extra ICU admissions, and/or other adverse outcomes.

Song adds it is positive so many cases involving PE are identified in the emergency department (ED). Indeed, more than half of the PE diagnoses made as part of this study happened while patients still were in the ED. Seventy-two percent of these patients with PEs did not require ICU-level care.

It is a different situation in Europe, where research has shown most diagnoses of PE are made in the ICU, often after patients have been placed on ventilators for several days. “Here in the U.S., I think we are seeing it in the ICU, we are seeing it in the ED, and we are seeing it on the regular inpatient floors. But we are glad that the ED physicians are first line and will find out who is at risk for PE,” Song stresses.

In most cases, treatment for PE will involve anticoagulation or blood thinners, explains Song. However, he notes that in a tiny subset of massive PEs, clinicians will use thrombectomy, a surgical procedure used to remove blood clots from arteries or veins. Realizing there is an elevated risk of clotting in patients diagnosed with COVID-19, many clinicians are prescribing low doses of blood thinners to these patients to prevent the development of blood clots, including PEs. “It is something that should be considered,” Song suggests.

REFERENCE

  1. Poyiadji N, Cormier P, Patel PY, et al. Acute pulmonary embolism and COVID-19. Radiology 2020 May 14;201955. doi: 10.1148/radiol.2020201955. [Online ahead of print].