Carotid lumen size linked to death from all causes

By Theresa Pablos, AuntMinnie staff writer

August 21, 2020 -- Could ultrasound measurements of the carotid lumen diameter be a better measure than carotid intima-media thickness (CIMT) for predicting mortality from cardiovascular disease? Lumen diameter indeed could add new information, according to a study in the Journal of the American Heart Association.

Researchers from Germany found that lumen diameter measurements of the carotid artery derived from ultrasound scans predicted mortality from both cardiovascular disease and from all causes. And they believe that it provides more information than CIMT.

CIMT has been used as a noninvasive biomarker for cardiovascular disease risk stratification and the risk of future cardiovascular events, the authors report. Both the coronary and carotid arteries distend during the early stages of atherosclerosis, a phenomenon that can be detected and measured on ultrasound scans.

But recent research has raised doubts about the reliability of CIMT for predicting individual outcomes. The new evidence, published on August 4, demonstrates that lumen size might be a better predictor of death from both cardiovascular and noncardiovascular events, with larger lumens indicating higher risk.

"Our results suggest that [lumen diameter] may be superior to CIMT," wrote the authors, led by Dr. Felix Fritze from the University of Greifswald's medical school in Greifswald, Germany.

The team of German researchers compared the effectiveness of CIMT and lumen diameter using data from a prior study that conducted baseline screenings and 10- and 15-year follow-up exams on the population of a German village.

As part of the baseline assessment, individuals underwent carotid ultrasonography. The original research team also recorded relevant health information, including cholesterol levels, diabetes status, and mortality outcomes.

For the new analysis, Fritze and colleagues created various models to analyze data from 2,751 participants, including 506 who died during the original study. Their further cardiovascular mortality analysis used outcomes from all but 214 of the participants with unknown causes of death.

The researchers found that individuals with the largest CIMT measurements had the highest hazard ratio (HR) for all-cause mortality, at 1.73, compared with a hazard ratio for lumen diameter of 1.29 and the combination of CIMT and lumen diameter at 1.26.

The model using lumen diameter alone was significantly associated with death from all causes, deaths attributed to cardiovascular events, and deaths attributed to noncardiovascular events. On the other hand, the model using CIMT alone was significantly associated with all-cause mortality and noncardiovascular mortality -- but not cardiovascular mortality.

To help determine the likelihood of their models predicting future values, the authors conducted an Akaike information criterion (AIC) analysis. In this analysis, the lumen diameter model came out on top for both all-cause mortality and cardiovascular mortality. It also came in second for cardiovascular mortality, just behind a model that combined lumen size and CIMT values.

Furthermore, the lumen diameter model remained significant for all-cause mortality even after the researchers excluded people with chronic kidney disease, prior myocardial infarction, and type 2 diabetes. The same wasn't true for the CIMT model.

Lumen diameter vs. CIMT for predicting mortality
Model	Rank (AIC)
	All-cause mortality	Cardiovascular mortality	Noncardiovascular mortality
Lumen diameter	No. 1	No. 1	No. 2
Lumen diameter + CIMT	No. 2	No. 2	No. 1
CIMT	No. 3	No. 5	No. 3
None	No. 4	No. 4	No. 4
Lumen diameter ÷ CIMT	No. 5	No. 3	No. 5

The authors do not know why the model using lumen diameter performed much better than CIMT in their analysis. They hypothesized it could be because lumen size is related to CIMT but is also much easier to measure.

"The larger caliber of [lumen diameter] compared with CIMT may improve manual measurement accuracy and thus may be more applicable for an outpatient setting," they wrote.

It's important to note the study only included white participants from one part of Germany, so the results may not be applicable to a more diverse population. As a result, the authors called for follow-up research with more robust patient populations to verify their findings.

"To the best of our knowledge, this is the first study to compare the informative value of CIMT and [lumen diameter] with regard to all-cause, cardiovascular, and noncardiovascular mortality associations," they concluded. "We report that [lumen diameter] provides more information than CIMT."

US effective for working up masses found on DBT

By Kate Madden Yee, AuntMinnie.com staff writer

August 24, 2020 -- Ultrasound appears to be an effective and safe diagnostic workup modality when it comes to evaluating masses identified on screening digital breast tomosynthesis (DBT), according to research published in the European Journal of Radiology (EJR).

The findings suggest that, at least in the case of breast masses, it may not be necessary for women to undergo both digital mammography and ultrasound after screening DBT -- which has the benefit of reducing radiation exposure, wrote a group led by Dr. Jessica Porembka of the University of Texas Southwestern Medical Center in Dallas.

"DBT has been shown to be superior to conventional views in the diagnostic setting ... [and] women who already underwent screening DBT may be receiving unnecessary digital mammography prior to ultrasound imaging," the group wrote in an EJR article posted on August 5. "This potentially adds unnecessary complexity, cost, and radiation exposure, as well as prolonged diagnostic workup times without adding significant value."

Screening DBT reduces recalls compared with digital mammography alone, but still, sometimes follow-up is needed. Porembka and colleagues investigated whether in some of these cases --perhaps by type of lesion found on DBT -- women could undergo ultrasound alone rather than also having additional mammography.

The study included 266 noncalcified lesions in 247 women detected on screening DBT between January 2014 and December 2016. The lesions ranged from architectural distortions and asymmetries to focal asymmetries and masses. The investigators assessed the number and type of lesions that underwent diagnostic follow-up only with ultrasound.

The researchers found that ultrasound alone was used in 69% of workups of recalled masses, and that the odds of masses being worked up with ultrasound alone was eight times that of the odds of digital mammography and ultrasound being used. The authors also found that "ultrasound alone in the diagnostic evaluation of a mass seen on screening DBT had a higher yield of true lesions than masses worked up with digital mammography/ultrasound," confirming that "masses seen on screening DBT can be adequately evaluated with ultrasound alone."

However, ultrasound alone did less well with architectural distortions and focal asymmetries, with a detection rate of 44% and 25%, respectively, Porembka and colleagues cautioned.

"Our findings suggest that a combination of both [digital mammography and ultrasound] was preferred by radiologists in the work up of architectural distortions given the differential diagnosis of radial scar versus malignancy," the team noted. "For focal asymmetries, 68% were evaluated with digital mammography/ultrasound, while only 25% were evaluated with ultrasound alone, indicating that a combination of digital mammography/ultrasound is likely warranted in the work up of focal asymmetry on DBT."

In any case, the study results are good news for women undergoing diagnostic follow-up for masses found on screening DBT, according to the researchers.

"The implication of our findings is that we can save women unnecessary radiation and unnecessary cost of digital mammography by utilizing ultrasound alone in the evaluation of recalled masses," they concluded.