Leading expert in interventional cardiology, Dr. Jeffrey Popma, MD, explains the critical differences between surgical and transcatheter aortic valve replacement. He details the superior hemodynamic performance of newer TAVR valves, which can achieve mean gradients as low as 6-8 mmHg. Dr. Jeffrey Popma, MD, discusses the long-term durability of mechanical valves versus bioprosthetic options. He highlights how valve design impacts patient outcomes and functional status. The interview explores the evolving evidence from high-risk and intermediate-risk patient trials.
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Choosing the Best Aortic Valve Replacement: TAVR vs. Surgery for Aortic Stenosis
Jump To Section
- Types of Aortic Valves for Replacement
- Mechanical Valve Durability and Warfarin
- Bioprosthetic Valve Options for Elderly Patients
- TAVR Valve Design Differences and Performance
- Hemodynamic Performance Comparison: TAVR vs. Surgery
- Long-Term Outcomes and Ongoing Studies
- Full Transcript
Types of Aortic Valves for Replacement
Dr. Jeffrey Popma, MD, a leading interventional cardiologist, outlines the primary categories of aortic valves used in treatment. He explains that the medical community traditionally understood surgical options best. These include mechanical valves and bioprosthetic valves derived from animal tissue. The choice between them is a fundamental decision in aortic stenosis management. Dr. Anton Titov, MD, facilitates this deep dive into the technical aspects of valve selection.
Mechanical Valve Durability and Warfarin
Mechanical aortic valves are often the preferred choice for younger patients with severe aortic stenosis. Dr. Jeffrey Popma, MD, notes their exceptional durability, often lasting 20 to 30 years without degeneration. This long-term benefit comes with a requirement for lifelong anticoagulation therapy. Patients must take warfarin to prevent dangerous blood clots from forming on the valve. This trade-off between durability and medication is a key consideration in the shared decision-making process for aortic valve replacement.
Bioprosthetic Valve Options for Elderly Patients
For elderly patients, the clinical calculus shifts toward bioprosthetic or tissue valves. Dr. Jeffrey Popma, MD, describes these as either porcine (pig) or bovine (cow) aortic valves. Surgical bioprostheses come in two main designs: stented and stentless aortic valve systems. These valves avoid the need for long-term warfarin therapy, which is a significant advantage for older populations. However, they historically carried a risk of structural valve deterioration over a shorter timeframe compared to mechanical options.
TAVR Valve Design Differences and Performance
Transcatheter aortic valve replacement (TAVR or TAVI) introduced new design paradigms. Dr. Jeffrey Popma, MD, explains that TAVR valves utilize bovine or porcine pericardial tissue shaped into valves. Their design is fundamentally different from surgical valves, often featuring a lower profile. Some TAVR systems position the valve apparatus above the native annulus. These design innovations are not merely technical details. They directly lead to measurable differences in clinical outcomes and hemodynamic performance after implantation.
Hemodynamic Performance Comparison: TAVR vs. Surgery
The hemodynamic performance of an aortic valve is a critical metric of its success. Dr. Jeffrey Popma, MD, provides clear data, stating that severe aortic stenosis typically presents with a mean gradient of 40 mmHg. A successful surgical aortic valve replacement can reduce this gradient to approximately 12 mmHg. Remarkably, newer generation TAVR valves can achieve even lower residual gradients, often between 6 and 10 mmHg. This superior hemodynamic result means the heart doesn't have to work as hard to pump blood through the new valve. Echocardiographic data from trials now consistently shows better valve performance indices with TAVR.
Long-Term Outcomes and Ongoing Studies
A crucial unanswered question is whether superior hemodynamics translate into long-term patient benefit. Dr. Jeffrey Popma, MD, emphasizes that the medical community is still gathering long-term data on TAVR durability. Evidence from three-year outcomes in high-risk patients and two-year outcomes in intermediate-risk patients is promising. The starting performance platform of a valve likely influences its long-term fate. Dr. Popma anticipates that surgical techniques will also evolve to achieve similarly low gradients. This ongoing research will ultimately define the best choice for aortic valve replacement for each individual patient.
Full Transcript
Dr. Anton Titov, MD: What are different types of aortic valves that are used in transcatheter aortic valve replacement? It is called TAVR, or transcatheter aortic valve implantation, TAVI, as it is known in Europe.
Dr. Jeffrey Popma, MD: We as interventional cardiologists didn't really know all that much about surgical aortic valves. We certainly knew that mechanical valves were preferred in younger patients. Although patients were required to take warfarin, the valve durability was excellent. Patients would go for 20 to 30 years with the mechanical valve.
Dr. Anton Titov, MD: They will not have any degeneration occur. But when we get into patients who are a little bit elderly, we take the choice of either a porcine or bovine bioprosthesis aortic valve surgically. There are both stented and stentless aortic valve systems.
Dr. Jeffrey Popma, MD: On the transcatheter side, there are a number of devices with either bovine pericardial shape valves or porcine pericardial shape valves. We realized that there are a few design differences between TAVR and surgical aortic valves. They will lead to differences in outcomes.
The question right now is all about hemodynamic performance. For a typical patient with severe aortic stenosis, a mean gradient would be 40 millimeters of mercury. Sometimes we are going to call it severe. It is an index for how severely narrow the aortic valve is.
We do a surgical aortic valve replacement. We can reduce aortic valve gradient down to 12 millimeters of mercury.
Dr. Anton Titov, MD: It sounds great, right? You have gone from 40 to 12, and the patient will be very functional. But some of our newer transcatheter aortic valves perform very well.
Dr. Jeffrey Popma, MD: Because TAVI aortic valves have a lower profile in some valves, and because of the fact that the aortic valve apparatus is above the valve in others, we can now get in some patients gradients of 6, 8, or 10 millimeters of mercury. This is compared to the 12 or so on our surgical aortic valves.
In fact, now we look at the three-year outcomes for high-risk patients. We look at two-year outcomes in the intermediate risk patients. The echocardiographic indices of valve performance are better with the transcatheter aortic valves than they are with surgically replaced aortic valves.
We don't know whether or not that translates into a long-term benefit for the patients. Sometimes whatever starting platform you have is going to affect long-term outcome. We are still sorting it out in long-term studies of transcatheter aortic valve replacement.
But certainly we have learned that we can get very low residual gradients with our transcatheter aortic valves. Gradients are better than what we will find thus far with surgical aortic valves. Although I suspect that the surgeons are now coming up with other ways to get very low aortic valve gradients as well.
Dr. Anton Titov, MD: The hemodynamic performance is still one of those unmet needs. It differentiates the surgical and the different transcatheter aortic valves.