Symposium Research Suggests Severe Aortic Clot Associated with Stroke After TAVR.

This article was written by Jason Galo, MD, PGY-7 Interventional Cardiology Fellow.

Research presented by interventional cardiology fellow Jason Galo, MD, at the MedStar Health – Georgetown University Research & Education Symposium finds an association between severe aortic thrombus and stroke following TAVR. 

Aortic stenosis is a very common heart condition, and transcatheter aortic valve replacement (TAVR) is a minimally invasive treatment that can help. However, about 3% of people who get TAVR have a potentially life-threatening stroke after the procedure. 

Our research suggests that having a severe blood clot in the wall of the aorta before TAVR may be associated with having a stroke afterward. What’s more, we may be able to identify patients who are at risk using current imaging techniques. 

Aortic stenosis, the most common type of heart valve disease, affects 5% of people over age 65. The aortic valve controls blood flow from the heart into the aorta, the body’s largest blood vessel. Aortic stenosis narrows the valve, and blood can’t flow through properly. If left untreated, aortic stenosis can lead to abnormal heart rhythms, heart failure, and stroke.

MedStar Health clinician-researchers have been involved in every major clinical trial of TAVR since the first one in 2007. We treat approximately 550 patients per year with this minimally invasive procedure to replace a faulty aortic valve, making us one of the top centers in the country for this revolutionary treatment. Before TAVR, aortic stenosis treatments were limited to medication and open-heart surgery. 

A prior study of a small number of patients suggested that severe clots in the aorta might be behind stroke complications, so our team set out to use MedStar Health’s deep experience with TAVR to understand more. 

Using TAVR data to improve care.

Our researchers began by analyzing data we’ve collected over many years of performing TAVRs. This retrospective observational study compared 65 patients who had an MRI-confirmed stroke after TAVR with a random selection of 96 patients who did not.

Interventional cardiologists used a standardized scale to examine the pre-TAVR CT scans of included patients. They assigned scores to each patient’s aortic wall to judge how severe the clots were and considered factors such as patients’ ages, genders, and conditions like diabetes or high blood pressure. 

Multivariate regression analysis helped us identify which of these things was associated with having a clot and whether having a severe clot was significantly related to stroke.

We found that patients with a severe clot in their aortic wall before TAVR were six times more likely to have a stroke after the procedure than patients without the clot – no matter what other variables were at play. 

We also found that patients who had a stroke were sicker before surgery and more likely to have:

• Heart failure within two weeks before TAVR

• Severe calcification

• Lower levels of albumin – a sign of chronic inflammation

Our study has some limitations. It is not a gold-standard randomized trial, and it examines a relatively small group of patients at only MedStar Health. Yet our advanced statistical analysis means we can confidently suggest that severe aortic wall clot is associated with stroke following TAVR. 

Related reading: Valve Disease Treatment: A Team Approach is a Winning Strategy.

Protecting patients from stroke.

Now that we have more confidence about this relationship, we’re considering what it might mean and how to best protect patients from stroke.

More research is needed to know for sure whether aortic clots before TAVR are the cause of stroke after the procedure. We suspect that, during TAVR surgery, the movement of wires and equipment through the aorta against the blood flow could potentially dislodge clots. If this debris makes its way to the brain, it can clog the blood vessels and result in a stroke.

A net-like piece of equipment called a cerebral embolic protection device (CEPD) can be used to block two of the three arteries that supply blood to the brain. However, studies have shown these devices don’t significantly improve stroke rates, so they’re not often used. 

Our study provides enough evidence to consider careful image analysis of the aorta for all patients before TAVR. Every patient with a TAVR procedure gets a CT scan before the operation. We now know that examining the scan of the aorta for signs of severe clotting can help identify patients at risk for stroke. In patients with a severe clot in the wall of the aorta, a CEPD might help prevent stroke. 

Related reading: Research Identifies Gaps—and Opportunities—in Heart Disease Care Among Older Women.

Leaders in aortic stenosis treatment.

MedStar Health has been at the forefront of minimally invasive treatment for aortic stenosis since the first clinical trials of TAVR in 2007. Our years of experience with TAVR mean we’re --prepared to improve the event for patients.

MedStar Health Research Institute is at the center of how we advance care. This study and others like it can be a step toward helping us lower the rates of complications, making TAVR safer for everyone.