When Nudges Aren’t Enough: Study Ponders AS Referral System Changes

Adding automated prompts to transthoracic echocardiography (TTE) reports and electronic medical records (EMRs) in patients with moderate to severe aortic stenosis (AS) does not dramatically improve referral for specialized assessment or valve intervention, a Canadian study suggests.

Only about 60% of patients with severe AS and a little over 20% with moderate AS were referred by the ordering physician to a heart team for assessment, with the majority (80%) of unreferred patients who remained alive having no clinical documentation of conditions that would exclude them from consideration for AVR, such as significant frailty or a life-limiting comorbidity.

Unreferred patients with severe AS were far more likely to die than those who did get a referral (19.6% vs 2.3%; P < 0.001). Among unreferred patients who died, 45% had no compelling reason for not being referred.

“In a homogeneous, affluent, predominantly white population, our detection and treatment of aortic stenosis is abysmal. That's what this study says to me,” senior author David A. Wood, MD (Vancouver General Hospital/Dilawri Cardiovascular Institute, Canada), told TCTMD.  ”If you were to replicate this in a more heterogeneous population with marginalized populations, I would imagine it would be significantly worse.”

The study was published online February 10, 2026, ahead of print in Structural Heart, with lead author Sophie Offen, MBBS, PhD (Dilawri Cardiovascular Institute).

Other studies that have used similar prompts, like last year’s DETECT AS, have shown an increase in AVR and reductions in treatment disparities—including among elderly patients and women. Despite the gain in referrals, about 40% of symptomatic AS patients in that study didn’t get timely treatment.

Sammy Elmariah, MD (University of California, San Francisco), senior investigator of DETECT AS, said he believes the Canadian experience confirms his study’s findings that these passive alerts, when acted upon, can make a difference.

“There's a robust difference in mortality, for example, in the patients that are referred versus those that are not referred,” he noted.  ”In DETECT AS, we very clearly saw significant improvement in rates of referral that had beneficial impact on patient outcomes. I think what this study is pointing to that was also highlighted in DETECT AS is simply the fact that we need to do even better. This gets us partway there to the ideal of having all of these patients evaluated in a timely fashion, but unfortunately it doesn't get us fully over the finish line.”

Referred vs Nonreferred Patients

The study included 343 patients (mean age 77 years; 43% women) who underwent TTE and met echocardiographic criteria for the diagnosis of moderate (59%) or severe (41%) AS. No significant differences by age, sex, or other patient or echocardiographic characteristics were seen between referred and nonreferred patients with severe AS. Comorbidities also were similar between groups with the exception of chronic lung disease, which had a slightly higher rate of nonreferral. Characteristics in those with moderate AS also were mostly similar between those who were referred and not referred, with the only comorbidity difference being lower renal function in the nonreferred group.

In the nonreferred group with severe AS, 27.5% had NYHA class II symptoms and 47.5% (19/40) had class III symptoms. More than two-thirds of nonreferred patients reported worsening symptoms over the past 6 months and about 50% were being managed with a watchful-waiting strategy.

A look at referral patterns by provider found that a cardiologist or cardiothoracic surgeon was the ordering physician for the TTE in 55.4% of nonreferred severe AS patients and in 66.2% of moderate AS patients.

We will save lives and prevent morbidity by giving up some autonomy to a system that allows automatic prompts and ultimately automatic referrals. David A. Wood

Based on the study’s results, Wood  said his healthcare system has now decided on an automatic referral strategy based on echo results, “because we really don't see any other solution for preventing otherwise healthy patients in their seventies and eighties from being missed and then coming in when they're too sick to be effectively treated.”

To TCTMD, he stressed that this decision pathway is not meant to take away physician or patient autonomy.

“There are absolutely scenarios [where] due to comorbidities, projected lifespan, or personal preference, patients will not want to proceed with either transcatheter or surgical valve replacement,” Wood said. “We fully acknowledge that, but they should be given the opportunity to make an informed decision.

“The current system of doing ultrasounds and then following up with your referring clinician leads to a problem where 40 to 50% of people are not referred and have a much higher mortality than they need to have,” he continued. “We interviewed the clinicians in our health catchment area and heard loud and clear that anything we can do to automate and simplify the referral process for a Class I indication, like severe aortic stenosis, would be welcomed in 2026.”

Ultimately, Wood said, he believes individual physicians will need to accept the automated referrals to fix the broken system that is preventing so many AS patients from getting the care they need in a timely manner.

“We will save lives and prevent morbidity by giving up some autonomy to a system that allows automatic prompts and ultimately automatic referrals,” he added. “We need to rethink what the standard of care is, and if that means a loss of autonomy to more effectively treat and triage patients, that's what's needed.”

Elmariah noted that it may be easier to implement an automatic referral process in a healthcare system like Canada than in the US.

“Having said that, we too are in the midst of testing a system that is a little bit more automated [and] culturally a little bit more in tune with the US healthcare system and some of the concerns that providers have about automatic referral, but does seek to move the needle further beyond just these passive nudges.” he added.

“Specifically what we're doing here at UCSF is we have a pathway by which alerts are sent to providers and there is an automated or facilitated referral to the heart valve team, but there's an opt-out feature for providers so that if a provider specifically doesn't want a patient referred, they can decline the referral,” Elmariah continued. “If there is not action taken, either to accept or decline the referral, then we send that referral anyway after a 2-week period. So, what we're doing is setting a safety net to ensure that patients don't fall through the cracks.”  

Elmariah said the opt-out feature is important because the clinician sending their patient for the echocardiography is the one who knows them best. At the same time, there are opportunities for patient education via the prompts.

He noted the recent guidelines from the American Society of Echocardiography for standardized reporting of TTE requires the addition of very clear language in the EMR that states that a patient has significant aortic stenosis and suggesting that if medically appropriate, the patient should be referred for further evaluation.

“The reason that's important is that more and more patients in possession of results of their clinical testing,” Elmariah said. “So, if they see clear language like that as opposed to a bunch of numbers, quantitating the severity of aortic stenosis, they at least will become more aware that there actually is a problem that warrants further evaluation.”

For Wood and colleagues, the problem identified in the paper may just be the tip of the iceberg since they believe that the number of potential patients identified in the study would've been much higher if the echocardiograms had been reviewed by a core lab.