USPSTF advises against carotid artery stenosis screening

By Theresa Pablos, AuntMinnie staff writer

August 5, 2020 -- The U.S. Preventive Services Task Force (USPSTF) is poised to once again recommend against screening for asymptomatic carotid artery stenosis. The task force reaffirmed its D rating in a draft recommendation statement published on August 4.

The USPSTF last weighed in on the topic in 2014, concluding with moderate certainty that the harms of screening for carotid artery stenosis in the general population outweighed the benefits. In its new draft recommendation statement, the agency reaffirmed that position, stating there was not enough new evidence to change its previous recommendation against screening with either carotid duplex ultrasound, CT angiography, or MR angiography.

"The USPSTF found no new substantial evidence that could change its recommendation and therefore reaffirms its recommendation," the task force wrote.

In theory, screening the general population for stenosis could lead to early detection of narrowed blood vessels, thus enabling medical professionals to conduct potentially life-saving interventions, such as carotid endarterectomy (CEA) and carotid artery stenting (CAS). But the USPSTF concluded that the evidence it reviewed didn't readily support that hypothesis.

The task force has consistently found limited evidence in favor of asymptomatic carotid artery stenosis screening, especially when compared with other medical therapies, such as statins and antihypertensive agents. And the evidence has been particularly lacking since the USPSTF's last review in 2014.

USPSTF draft recommendation rationale for asymptomatic carotid artery stenosis
Detection	Ultrasonography has reasonable sensitivity and specificity for detecting clinically relevant carotid artery stenosis, but it also yields many false-positive results in the general population.
	Scanning the neck for carotid bruits has poor accuracy for clinically relevant carotid artery stenosis.
Benefits	Direct evidence does not indicate that screening for asymptomatic carotid artery stenosis can improve stroke, mortality, or other adverse health outcomes.
	Carotid endarterectomy (CEA) or carotid artery angioplasty and stenting (CAS) provides little or no benefit for improving stroke, myocardial infarction, mortality, or other adverse outcomes compared with current medical therapy.
Harms	While direct evidence does not show that screening for asymptomatic carotid artery stenosis can cause harm, there are known harms with confirmatory testing and interventions.
	Direct evidence supports that treating asymptomatic patients with CEA or CAS could cause harms, including stroke or death.
	Harms related to screening and treating asymptomatic carotid artery stenosis have small-to-moderate magnitude.

After searching the scientific literature, USPSTF investigators found no recent eligible studies that directly investigated the benefits or harms of asymptomatic carotid artery stenosis screening. The two studies that were conducted on the topic in the past six years were both prematurely terminated and produced mixed results.

When looking at the benefits and harms of CEA or CAS, the authors found an additional two national datasets and three surgical registries that met their inclusion criteria. Rates of 30-day postoperative stroke or death after CEA ranged from 1.4% to 3.5% depending on the registry or database. Similarly, 30-day stroke or death after CAS ranged from 2.6% to 5.1%.

Based on the evidence -- or lack thereof -- the investigators concluded there wasn't enough new information to change the D rating for asymptomatic carotid artery stenosis screening. However, they pointed out that two clinical trials are currently underway, which may shed light on the topic in the future.

"There were few new trials, all with methodologic concerns, examining the important question of the comparative effectiveness and harms of revascularization plus best medical treatment compared with best medical treatment alone," they wrote. "The ongoing CREST-2 and ECST-2 trials will be the largest trials to address this issue."

The draft recommendation is available for public comment through August 31. After the comment period has ended, the task force will publish its final recommendation.

COVID-19 pandemic driving increase in ultrasound use

By Theresa Pablos, AuntMinnie staff writer

August 3, 2020 -- The COVID-19 pandemic is driving an increase in the use of lung ultrasonography among physicians in Italy, according to the results of a small survey published in the Journal of Ultrasound in Medicine.

More physicians said they're using ultrasound equipment now than before the pandemic, and experienced physicians are performing more lung ultrasound scans than ever before. The findings support anecdotal evidence that COVID-19 has increased interest in ultrasound, including among clinicians with no prior ultrasound experience.

"Thanks to online resources, many operators could e-learn and apply the technique," wrote the authors, Dr. Allessandro Zanforlin and Dr. Francesco Tursi, who are both members of the Italian thoracic ultrasound academy behind the survey (July 16, 2020, Journal of Ultrasound in Medicine).

The informal, one-week-long survey was conducted by Italian ultrasound society Academia di Ecografia Thoracia after the group noticed its membership spiked from 1,700 members in February to 4,000 members in May. The academy promoted its survey on social media and received 123 responses.

Survey respondents worked in a variety of settings, including on COVID-19 floors (34%), in intensive care units (31%), and in the emergency department (20%). The majority said they used lung ultrasound to monitor pneumonia (63%) and screen for COVID-19 (60%).

A total of 14% of respondents started using lung ultrasound exclusively because of the COVID-19 pandemic. Among these respondents, 81% said they learned how to perform lung ultrasound scans by following video tutorials or participating in webinars. The remaining 19% of respondents gained experience through expert mentoring or local courses.

As the number of patients with COVID-19 surged at hospitals in Italy, so too did the number of lung ultrasound exams. Respondents said the number of daily chest scans increased from an average of three per day before the pandemic to seven per day during the outbreak. For so-called "expert operators" with at least five years of lung ultrasound experience, the number of exams rose from five per day to nine per day.

The majority of respondents also said their lung ultrasound exams had increased in quality (58%) and accuracy (66%) during the pandemic. These percentages were even higher for participants who took an online course or webinar, with 83% of these respondents saying their exams increased in both quality and accuracy.

One factor driving the increase in lung ultrasound exams could be the availability of additional equipment thanks to donations and emergency purchase approvals. More than half of respondents said they acquired new ultrasound equipment during the pandemic, namely portable wheeled systems (37%) or handheld/wireless systems (19%).

The survey adds to the evidence that ultrasound is becoming an invaluable tool for care teams, especially those in Italy, who are treating patients with the novel coronavirus. However, the increase in skilled operators and new equipment may mean the modality will remain prominent for lung imaging even after the pandemic is over.

"What we are learning from this pandemic is the importance of [lung ultrasound] in the diagnosis, evaluations, and monitoring of pneumonia, which, in the hands of many physicians ... could improve the quality of the treatment of respiratory patients," the authors concluded.