Reducing the Guesswork in Tricuspid Regurgitation Care
Using Hemodynamics to Find the Right Treatment
For people with tricuspid valve regurgitation, there are a number of viable strategies to treat their condition, including minimally invasive transcatheter valve replacement and valve repair. But with this increase in options comes an important question: How do we determine which strategy is the right choice for each patient?
The Role of Hemodynamics in Treatment Selection
Hemodynamics—the study of how blood circulates through the body—may help provide an answer. “Patients with valvular heart disease have very interesting hemodynamics,” notes Michael Brener, an interventional cardiologist at Columbia University Irving Medical Center whose research focuses on hemodynamics. “Between the two commercially available options that we have now—valve repair and replacement—we need to refine how we choose the treatment for each patient. We need to identify which patients would do better with a valve replacement, because that strategy isn’t a good fit for everybody.”
The tricuspid valve controls the flow of blood from the right atrium into the right ventricle, where it is passed along to the lungs through the pulmonary valve. In tricuspid regurgitation (TR), the valve doesn’t close correctly, allowing blood to flow back into the right atrium. This forces the heart to work harder to pump blood, leading to symptoms like fatigue, shortness of breath, and rapid heartbeat. Over time, severe tricuspid regurgitation causes right-side heart strain and can lead to heart failure.
Valve Repair vs. Valve Replacement: Key Differences
Tricuspid valve repair uses clip-like devices to hold the existing valve flaps together or rings to reshape the valve. This reduces regurgitation and restores a more natural blood flow and pressure.
In tricuspid valve replacement, an artificial valve device is implanted in the diseased valve and takes over its function, which dramatically reduces or eliminates regurgitation. But with this immediate and complete correction comes a potential concern: once the regurgitation is eliminated, can the heart handle the change in pressure?
“When you reduce regurgitation acutely, it means that suddenly the heart has to pump all of the blood in one direction. It doesn't normally do that; it's actually very easy to pump blood in the wrong direction. Think of it like a pump: it's just blood flowing down with gravity. So, it's going to take the path of least resistance. When you eliminate the path of least resistance (blood going backward), now blood has to pump forward into the pulmonary arteries, which may be under high resistance, relatively speaking.”
Using Pressure-Volume Analysis to Guide Decisions
Understanding the hemodynamics involved can help determine if that pressure would be too much for a person’s heart to tolerate. A test called a pressure volume analysis is used to measure the changes in ventricular pressure and volume during a cardiac cycle, or heartbeat.
“Using a pressure-volume analysis lets us determine which patients will have enough reserve (the difference between resting output and output under exertion) and sufficient right ventricular contractile function to be able to tolerate valve replacement. I think that will help us hone in on who is going to be a better replacement candidate. And if someone isn't a candidate for valve replacement, we might need to emphasize valve repair.”
Another factor to consider is ventricular-pulmonary artery (V-PA) coupling, which matches the contraction of the right ventricle to the resistance of the pulmonary arteries. When correctly coupled, blood is efficiently transferred in the right direction. But when uncoupled, the ventricle can’t overcome the afterload (the resistance from the pulmonary arteries). This leads to retrograde flow (blood flowing backward.)
Assessing V-PA coupling can potentially provide additional insight into what treatment strategy might be the better option. “We believe that patients who are appropriately coupled but still have significant regurgitation are good candidates for valve replacement; when uncoupled, repair may be the better choice. Assessing that in a very high fidelity way before intervention would allow you to tailor therapy more accurately.”
A Hemodynamic Path Forward
Hemodynamics offers a potential route for improving outcomes for tricuspid valve disease care, ensuring that patients are effectively matched with the right treatment. “I think understanding the underlying hemodynamics will be the key to effectively treating this underserved group of patients.”
Related