PAUL A. FRIEDMAN: Hi. My name is Paul Friedman. I'm Chair of the Department of Cardiovascular Medicine. And I'm fortunate to have with me today Dr. Malakh Shrestha, who is the Director of the Mayo Clinic Aortic Center of Excellence. And he directs our Aortic Surgery Unit for our Cardiovascular Surgical Department. Malakh, thank you so much for joining me today.

MALAKH L. SHRESTHA: Thank you very much for having me today, Paul.

PAUL A. FRIEDMAN: Today, I'd like to discuss aortic regurgitation, maybe a few brief comments about how it's diagnosed. But I'm really interested in the David procedure and how that's advanced the treatment, the surgical treatment for aortic insufficiency and diseases of the aorta. So just to review for our listeners, maybe make a few words about how patients present with aortic insufficiency and what the key findings and diagnostic tools are.

MALAKH L. SHRESTHA: Yeah. In contrast to the aortic stenosis, unfortunately with aortic insufficiency, patients can have a normal life till really cardiac insufficiency symptoms start in. So in most of the patients, they do come with some sort of shortness of breath. And then-- or in some of the patients, they have a routine cardiac check-up and the cardiologist or the physician picks up some murmur. So that's how they get diagnosed with aortic insufficiency.

But having said that, the third group would be-- which is we do talk about congenital heart problem. One of them is a bicuspid aortic valve, which is very common, because 1% to 2% of the human population has it. So we are talking of millions of people here. So a group of the bicuspid aortic valve patients develop aortic valve regurgitation. So there are two separate groups here.

PAUL A. FRIEDMAN: Right. And of course, there's a huge, long list of physical exam findings from Corrigan's pulse to Quincke's pulse, the bobbing uvula and the pounding pulses because of the big pulse pressure and the low diastolic pressure. But what's really intriguing is some of the new surgical treatment. So tell me about the David procedure.

MALAKH L. SHRESTHA: So classically, actually, if the valve had a problem, it would be replaced. So over the last 50 years, since the first aortic valve replacement was done, there are basically two types of valves, one with a mechanical valve and a tissue valve. Both have advantages and disadvantages.

With the tissue valve, it lasts maybe 10, 15 years. With a mechanical valve, the patient would be kept on a lifelong Coumadin, which is a big drawback, especially for younger patients.

But in aortic insufficiency, the third choice could be the aortic valve repair. So in 1992-- it's quite an old technique now. So Tirone David in Toronto, in fact, came up with this technique called the valve-sparing re-implantation technique where replaced the aortic root, but preserved the valve. So over the time, this procedure, because it was so-- became very famous, and we now call it the David procedure whereby the aortic valve is preserved and the dilated aortic root and the ascending aorta is replaced with a graft.

PAUL A. FRIEDMAN: So are there any patients who you'd say are particularly good candidates for the David procedure?

MALAKH L. SHRESTHA: Yes. Thank you for asking me this question. This is very important, because especially in younger patients, let's say Marfan disease patients or any other connective tissue disorder patients, they would have dilated aortic roots, but a normal aortic valve. And they are usually young, you know? 15, 20, 25.

For these people, putting in a mechanical valve is a tragedy because they would have 50, 60 years to look ahead with Coumadin. That is horrible. And a tissue valve is not an option because they would need to come every 10 years. So if you could offer the David procedure for these patients, they could have potentially 20, 30 years free from not only valve replacement, but also from Coumadin and redo operations.

So we've shown also that after 20 years also that the freedom from valve replacement is more than 85% in this group also. So this is great for Marfan's, but also for the bicuspid aortic valves. Also, a lot of surgeons have been just doing a valve replacement. And bicuspid aortic valve usually present in-- you know, between 30s and the 40s. So even they have 30 to 40 years to look forward to life expectancy. So also, this group is the second most important group.

PAUL A. FRIEDMAN: So it's really the younger cohort that people want. If they're older, above 70, 75, then maybe it's less important.

MALAKH L. SHRESTHA: Yeah, exactly, because this does take at least twice as long as to do a valve replacement and technically more difficult. I think after age of 70, the results have shown that there is no added advantage because even if you put a tissue valve, it gets quicker. And the patient, of course, because they don't survive 20 more years, then it's enough. Yeah.

PAUL A. FRIEDMAN: So when you're talking to a patient and you're reviewing the options, mechanical valve, tissue valve, David procedure, what do you see as the pros and cons of each choice?

MALAKH L. SHRESTHA: So with the mechanical valve, of course, the biggest drawback is that the patients need to be kept on lifelong Coumadin. So not everyone is so, you know, sure of taking their medicines at a regular interval, getting checked so that the INR level is at the perfect level.

So if someone forgets for two or three months, or sometimes I had patients who didn't want to take medicines and comes back with clots in their aortic valve. So that has always been the biggest problem because when we say the valve lasts forever, it only lasts forever outside the human body, not inside, right?

PAUL A. FRIEDMAN: [LAUGHS] Right.

MALAKH L. SHRESTHA: And with a tissue valve, although the tissue valves are getting better every year with new valves, prosthesis coming to the market, but they still on the general last maybe 15 years. And especially in younger age group, it doesn't last that much. So although the patients do not need to take Coumadin, they do not last long, so they may-- they will have to come back again, especially younger patients.

With the David procedure, the first one was done in '92. If the valve leaflets are still normal at the index operation, then Tirone has shown initiatives over the last 30 years with more than 300 patients that freedom from valve replacement after 15 years was more than 95%. Even my own results that we did in Hanover in Germany, which we published over the years, where we had about 800 patients now, the freedom from valve replacement after 20 years were more than that 85%. So this is a big advantage.

And because the valve is a living tissue, the rate of endocarditis is extremely low. It is less than 0.5%. So it's less than not even half a percent-- 1%. Whereas with the tissue valves or the mechanical valves, both because they are foreign materials inside the heart, there is 1% to 2% chances of endocarditis if the patients are not careful every year. So that's a big advantage. If the valve can be repaired, then I think that should be done, especially in younger patients.

PAUL A. FRIEDMAN: Now, is it a technically difficult procedure? How is it done? And how widely is it offered?

MALAKH L. SHRESTHA: So technically, it's a lot more difficult than replacing the valve. You have to preserve the valve, take out the whole and replace the whole root, re-implanting the coronary. So technically, it does take years to learn this technique.

And because at the end of the procedure the valve has to be perfect without any agitation, that's why a lot of surgeons are not really keen to do this unless they can do it perfectly. So that's why, although it's done all over the world, not in big numbers. There are only some centers of excellence in every country that do them.

PAUL A. FRIEDMAN: No, that makes sense. And I'm interested. In terms of follow-up for the cardiologist or general physician looking after the patient, maybe a few general comments about following up the patient who's had an aortic valve surgical therapy. And anything different about the David procedure than some of the other procedures we should be mindful of?

MALAKH L. SHRESTHA: I think with the-- more or less it's similar. But especially this is a lot more easier than, let's say, the mechanical valve patients or the tissue valve patients because patients do not need to take any Coumadin. I put my patients only on aspirin post-operatively. And before this is, because we have to replace the root, we do maybe one CT scan, depending on whether-- how much aorta we have replaced.

And then follow-up is only echocardiography, so this is a lot easier because the patients do not need to take Coumadin after this procedure unless they have any other concomitant problems, comorbidities. So this is very easy for the follow-up. So maybe once every year, it's enough.

PAUL A. FRIEDMAN: Clearly, a big advance in the surgical therapy for patients with aortic insufficiency. Dr. Shrestha, thank you so much for joining me today. Fascinating topic. Thank you.

MALAKH L. SHRESTHA: Thank you very much, Dr. Friedman.