As a heart specialist, Dr. Mohanakrishnan Sathyamoorthy – better known as “Dr. Mo”, helps patients manage valve and heart disease. This includes identifying patients who require heart valve replacement, seeing them through the process, and managing them long term.
Dr. Mo is a board certified Cardiologist practicing in Fort Worth, Texas, where he serves as the Vice Chief of the Medical Staff and Chief of the Cardiovascular Division at Baylor All Saints Medical Center. He is also the Medical Director of Cardiology at Baylor Heart and Vascular Hospital Fort Worth, and Adjunct Faculty at Vanderbilt University.
Mechanical vs. Tissue Valves
Regarding heart valve replacement options, Dr. Mo said there are distinct advantages to both mechanical valves and bioprosthetic, or tissue, valves. However, he pointed out that for many patients, especially those less than 60 years old, a mechanical valve offers a greater probability of having only one heart valve operation in the patient’s lifetime.1,2
“The real challenge with tissue valves over time is they tend to deteriorate,” Dr. Mo said. “The likelihood for reoperation with a tissue valve is much higher, so, … the younger a patient is, the more likely they’re going to have at least one re-do operation in their lifetime and perhaps more.”2,3
Avoiding an additional heart surgery in the future is an important factor for patients to consider when deciding on the type of valve they want.
“I think anyone that is contemplating open heart surgery is going to view that surgery as perhaps the greatest medical challenge they’ll have to overcome in their lifetime,” he said. “It’s a very intense operative experience, with a real intense commitment to post-operative recovery, rehabilitation and conditioning. So the amount of effort that a patient expends both physically and emotionally is quite great. I’m certain, at least through understanding of our patients over my practice history, the preference is always to try to have one operation if at all possible.”
One of the benefits typically attributed to tissue valves is that there may not be a necessity for blood thinner medication (e.g., warfarin), as opposed to a mechanical valve, which requires lifelong anticoagulation therapy.1 However, this is not necessarily always true, Dr. Mo said.
“What we’ve learned through studying patients over a long period of time is that many folks who undergo tissue valve replacements eventually require a blood thinning necessity for the use of warfarin,” he said. 4 “So, [a tissue valve not requiring blood thinners] is sometimes perceived as a benefit, but in fact, ends up perhaps not over their lifetime maintaining that potential benefit.”4
Other Heart Valve Surgery Options
While other types of heart valve procedures continue to evolve, Dr. Mo said many of these new approaches, such as Valve in Valve, or Transcatheter Aortic Valve Implantation (TAVR), lack long term data on their effectiveness.4,5,6
I think emerging concepts like Valve in Valve operative techniques are absolutely important to advancing the science and the practice of medicine,” he said. “However, as a practicing heart specialist, I always think of a precautionary tale and relate this back to evidence. Do we have evidence over a long period of time that these types of approaches will in fact deliver the expectation and the promise of that type of less invasive, or more minimally invasive second valve replacement operation? And the answer is we don’t have that data yet. And so, to a certain extent we’re relying on optimism and hope, without evidence – long term evidence.”5
“The second thing that I’m always concerned about is just a simple concept of plumbing. If you think about the size of the original valve that was deployed, and as that tissue valve deteriorates necessitating another valve that could be placed using one of these more minimally invasive techniques leading to a Valve in Valve operation, you have to fundamentally ask the question how much space is there left for that second valve, and if the space is not enough or the fit is tight, then what types of additional problems may arise from that? In other words, will the pressures in the heart rise more, and if they do, they can cause significant symptoms for patients. So we end up perhaps eliminating one problem and creating another.”1,5,6
Dr. Mo said in considering heart surgery it is always important for the patient to understand what the options and benefits are of a surgery or procedure, as well as potential drawbacks and pitfalls, in order to know what lies ahead.
“I think the hope, and the promise, and the expectation of the discussion of cardiac surgery for most patients is, this is my lifetime operation and I’m really hopeful that this won’t ever take place again. I think it’s very reasonable to expect any of our patients to feel great trepidation to go back and have more operative intervention. For all the common sense reasons, it’s a big deal and if it can be done successfully once, I think most patients would appreciate that.”
On-X Aortic Valve – Requiring Lower INR*
One of the concerns patients sometimes have when considering mechanical valves is the required use of lifelong blood thinner medication (i.e. warfarin).1,7 The trade off with warfarin, Dr. Mo said, is that as the level of the blood thinning requirement increases in order to reduce clot formation, patients are often exposed to higher bleeding risks.1
“Where we have found a great promise and benefit of the On-X mechanical valve in the aortic position is new literature evidence-based support for a lower blood thinning requirement; in fact, so low that, to my knowledge…, it’s the lowest blood thinning requirement for any clinical indication that exists in clinical medicine today.”1,7
Dr. Mo also stated that the On-X Aortic Valve actually requires lower anticoagulation therapy than what would be necessary to manage clots in the leg, for instance, or for prevention of strokes from an arrhythmia or atrial fibrillation.1
“To a physician, and as a former scientist, to me this is so unbelievably powerful and important to consider,” he said. “The greatest advantage [of the On-X Aortic Valve] really lies around the shape of the valve, its material characteristics – leading to a much lower necessity for blood thinning requirements using warfarin,” he said.1,7
Another extremely beneficial result of the On-X valve’s state-of-the-art material and unique design is that it produces lower gradient values.7 The gradient value measures the pressure difference from one side of the heart valve to the other, and is a defining factor in gauging a valve’s performance. The On-X Heart Valve provides optimal mean gradients compared with other mechanical or bioprosthetic aortic heart valves.8-12
With the On-X Valve, Dr. Mo believes patients have “the best of both worlds – a valve that essentially is very unlikely to require a second operation married with a valve that reduces bleeding risks associated with blood thinner.”7
* After 3 months standard therapy. See Instructions for Use for full details.7
- Nishimura R et al., Circulation. 2017;135:e1159-95.
- van Geldorp M et al., J Thorac Cardiovasc Surg. 2009;137:881-6.
- Wang M et al., Ann Thorac Surg 2017;pii: S0003-4975(17)30266-7.
- Briffa N and Chambers J Circulation. 2017;135:1101–3.
- Dvir D et al., JAMA. 2014;312(2):162-70.
- IMS US Sales Report, Q4, 2010 to Q3, 2016. Perimount models 2700, 2800, and 3300. Report run by CryoLife Marketing, 04/10/2017. Data on file.
- On-X Prosthetic Heart Valve Instructions for Use with INR 1.5 – 2.0
- St. Jude Medical Physician’s Manual Mechanical Heart Valve.
- CarboMedics Prosthetic Heart Valve Instructions for Use.
- Medtronic Open Pivot Heart Valve Instructions for Use.
- Edwards Life Sciences Carpentier-Edwards PERIMOUNT Magna Ease Pericardial Aortic Bioprosthesis Model 3300TFX Instructions for Use.
- Medtronic Mosaic Porcine Bioprosthesis with Cinch Advanced Implant System Instructions for Use.