• Each year, about 73,000 people in the United States undergo a TAVR procedure to treat aortic stenosis.
  • Between 3% to 7% of people who have a TAVR experience a stroke within 30 days of the procedure.
  • Researchers from the University of Michigan report that hospitals without comprehensive stroke center status may be missing strokes occurring after a TAVR.

About 3% of people aged 75 or older in Europe and the United States have a condition called aortic stenosis.

This condition occurs when the aortic valve in the heart does not open completely, reducing blood flow from the heart to the rest of the body.

In some cases of aortic stenosis, the aortic valve needs to be fully replaced, which in the past generally required open heart surgery.

In 2011, the less invasive transcatheter aortic valve replacement (TAVR) technique was approved for use by the U.S. Food and Drug Administration.

Since its approval, almost 73,000 people in the United States undergo a TAVR each year.

Stroke is one of the known common risks associated with a TAVR procedure. Of people who undergo the procedure, 3% to 7% experience a stroke within 30 days of the procedure.

Now, researchers from the University of Michigan report that hospitals without the highest stroke care designation may be missing strokes that happen following a TAVR.

The researchers found that hospitals with comprehensive stroke centers reported the risk of stroke following a TAVR as 2.21 times higher than hospitals without comprehensive stroke centers.

The study was recently published in the journal JACC: Cardiovascular Interventions.

A stroke occurs when the brain’s blood supply is reduced or blocked. This decreases the amount of oxygen available to the brain, causing brain cells to start dying.

Each year, about 15 million people around the world have a stroke. Of that number, about 5 million are left permanently disabled and another 5 million lose their lives.

A stroke is a life-threatening emergency and requires immediate medical care. The quicker a person receives medical assistance can impact the long-term effects of the stroke.

Symptoms of a stroke include:

  • difficulty speaking or understanding speech
  • dizziness and/or difficulty walking
  • headache
  • vomiting
  • numbness or inability to move certain parts of the body, including the face, arms, and legs
  • vision issues

Risk factors for a stroke include:

  • age
  • family history
  • heart disease
  • obesity
  • high blood pressure
  • diabetes
  • smoking and/or alcohol use
  • illicit drug use

In the United States, hospitals can receive different levels of stroke care certifications through The Joint Commission, the American Heart Association, and the American Stroke Association.

The highest level of these is the comprehensive stroke center (CSC) certification. To receive this designation, a hospital must meet a set of standardized performance measures and submit monthly data.

There are currently almost 300 comprehensive stroke centers in the United States.

“A comprehensive stroke center provides the highest level of stroke care in the United States,” said Dr. Michael Grossman, an interventional cardiologist at the University of Michigan Health Frankel Cardiovascular Center, a professor of cardiology at U-M Medical School, and senior author of this study.

“This designation implies that stroke care is coordinated and expedited. It also implies that there are on-call neurologists available to quickly evaluate and appropriately direct (the) management of patients with acute stroke,” he told Medical News Today.

“An important part of this designation is the fact that staff are trained and powered to recognize stroke and seek appropriate evaluation immediately,” Grossman added. “There are systems of care in place designed to obtain imaging immediately and provide management including medical and potentially invasive procedures to abort the stroke. These treatments should be provided within minutes to hours.”

For this study, Grossman and his team evaluated data through the Michigan Structural Heart Consortium from more than 6,200 TAVRs performed at 22 hospitals in Michigan between 2016 and mid-2019.

The data came from both hospitals with certification and those without the certification.

“When we looked at the data and did chart reviews, we noticed that there were differences not only in the recognition and reporting of stroke but in who on the care teams were actually recognizing these events and alerting the physicians,” Grossman said. “This recognition would lead to (the) initiation of further evaluation and appropriate management.”

“In some institutions, these events were recognized in the postprocedure area, and in others, they were recognized only the next day, or possibly not at all,” he added. “Some of these neurologic findings can be relatively transient, subtle, and partially or fully recover within a few hours.”

Upon analysis, researchers found the risk of stroke within 30 days after a TAVR was 2.21 times higher in hospitals with a CSC than in hospitals without one.

Grossman said researchers were not surprised by these results based upon their experience and reviewing the significant differences in stroke rates across hospitals.

“Stroke rates in clinical trials have varied between 2% and 6%,” he explained. “Most of these trials mandated routine neurologic evaluation both before and after the TAVR procedure (and) at some also involved evaluation by neurologists.”

“We felt that centers where physicians and staff and systems of care are geared toward early recognition and rapid management of stroke would potentially find more strokes in these post-procedure patients,” Grossman added. “As it turned out, that is what we found after adjustment for potential confounding variables.”

Grossman said this study suggested that there is a difference in recognition and reporting of stroke across TAVR centers based upon stroke center status.

“It also suggests that there is at least a possibility that patients who have a stroke post-TAVR are not recognized and potentially not receiving optimal treatment,” he said. “In my opinion, pre and post-TAVR neurologic evaluation should be standard of care. This neurologic evaluation can be performed by trained nurses in the post-procedure area. The patient with suspected neurologic deficits can then be quickly evaluated by a neurologist and appropriately managed.”

Next research steps

After reviewing this study, Dr. Michael Broukhim, an interventional cardiologist at Providence Saint John’s Health Center in California, told Medical News Today these were interesting findings in that the observed stroke rates were higher in comprehensive stroke centers.

“But I think it could be explained by if you’re not looking for a stroke, then you won’t find a stroke,” he explained. “Meaning if you don’t have the appropriate expertise to detect the stroke, then you will not be able to necessarily know if your patient had a stroke or not.”

Broukhim said one of the most important parts of stroke recognition is training nursing staff to recognize the signs and symptoms of the condition.

“At comprehensive stroke centers, we have fantastic nurses who are able to immediately recognize a sign or symptom of stroke, and they notify the physicians who are taking care of the patients, and there’s an immediate action plan set in place,’ he said. “And at that point, whatever potential treatment or decision is made for each individual patient based on their risks, benefits, and their comorbidities.”

Medical News Today also spoke with Dr. Sanjiv Patel, an interventional cardiologist at MemorialCare Heart & Vascular Institute at Orange Coast Medical Center in California, about this study.

Patel also found these findings interesting and said in the next steps of this research, he would like to see more specific information on the patient populations in each hospital.

“What kind of patient population (was in) the center?,” he said. “What were the risks for complications from surgery — were (they) high risk (or) low risk? And are we comparing population to population appropriately, meaning (the) same level of risk?”

“Because if it is the same population in these non-stroke centers and stroke centers (and) the population across both the risk was similar, then you got to look into this more to see what was the reason for doing an MRI on these patients whether they had symptoms or not. If so, then obviously they need to see what happened,” Patel explained. “If you don’t have any information on patients accept this data, it’s an observation basically at this point in time.”