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Good afternoon. My name is Paul Forfia. I'm an associate professor of medicine and a cardiologist. I'm director of the pulmonary hypertension and right heart failure program and pulmonary thromboendarterectomy program at Temple University Hospital in Philadelphia.
My talk today is entitled Mitral Valve Disease. That’s mitral valve regurgitation or stenosis and the development of pulmonary arteriopathy, when should mitral valve be repaired or replaced? When we go through this, it’s very important for the audience to understand that the first step in considering pulmonary arteriopathy in mitral valve disease and when to do a mitral valve repair or replacement is to first identify when mitral valve disease is clinically significant.
This is a point that cannot be overestimated. We cannot take this point for granted. Often times when patients have significant mitral stenosis or mitral regurgitation, the reason why they develop pulmonary arteriopathy is that their mitral valve disease is underestimated in its severity for months or for years that leads to injury of the pulmonary circulation. First thing is to properly assess the mitral valve disease.
The echo clip on the left shows a patient with significant mitral stenosis and the echo clip on the right shows a patient with significant mitral regurgitation. Again first point here is properly estimate your mitral valve disease to begin with. It’s important not to be misled by your echocardiographic findings and to think along first principle lines. The patient’s echo on the left, you'll see a patient who has an enlarged right ventricle. In fact, the right ventricle that's larger than the left ventricle. This can lead the reader to think that the primary problem is a right heart problem when in fact if you look at this echo in its completion you'll see this patient has severe mitral stenosis and the root cause of this patient’s symptoms, pulmonary hypertension and right-sided cardiac enlargement, is mitral valve disease.
The echo clip on the right shows the same patient with significant tricuspid regurgitation. Again, this can mislead the physician to thinking the primary problem is right-sided. Again, rooted in first principle, the primary lesion is mitral valve disease. Then lastly, if you look at the bottom, this patient’s PA systolic pressure by Doppler is 100 mm of mercury which is severe pulmonary hypertension by any standard. There is a temptation to conclude that the patient’s mitral valve disease cannot be the cause of pulmonary hypertension this severe.
This is an error.
A patient with severe mitral valve disease can have very severe pulmonary hypertension and again, thinking along first principle lines, the primary lesion is still mitral valve disease. We have to be a logical clinician and we have to integrate our clinical information with our Doppler echo findings or our other diagnostic testing findings. Remember that our first obligation is to resolve the source of the patient’s shortness of breath or dyspnea. Then we can characterize the pulmonary hypertension.
For example, if a patient has moderate MR or MS and is short of breath then the dyspnea should be thought to be related to the mitral valve dysfunction until proven otherwise and therefore that the pulmonary hypertension is likely related to the mitral valve disease. This is a logical and deductive way of clinical thinking. Now we'll switch our site to the lungs and the pulmonary arteriopathy.
Well, it’s been known for many decades that mitral valve disease can cause changes in the pulmonary circulation, whether it be mitral insufficiency or mitral stenosis. This is just one example of a paper published in 1951 showing that severe pulmonary vascular disease can occur in patients with a regurgitant mitral valve. The same thing occurs in mitral stenosis. Now, we’ve identified the mitral valve disease and now we're going to characterize the pulmonary hypertension.
There are a couple of ways you can do this. Of course, the confirmatory way to do this is by right heart cath but first let me just show you some basic echo information. The echo to the left shows a patient who has significant mitral valve disease. However, the right side of their heart is normal in size and function, and their Doppler pattern in the RV outflow track shows no evidence of what we call notching. This patient has no evidence of pulmonary arteriopathy with a structurally normal and functional right heart, with no evidence of notching of the RV outflow track Doppler profile.
Patient on the right, in contrast, has a large and dysfunctional right heart with deep mid-systolic notching on the RV outflow track Doppler profile and this would be very typical of a patient who has arteriopathy in association with their mitral valve disease. This slide just shows you a very traditional way of thinking about arteriopathy by hemodynamics, we can characterize arteriopathy by an elevated transpulmonary gradient and an elevated pulmonary vascular resistance and more recently we also talk about the diastolic pulmonary gradient which is an elevated difference between the pulmonary diastolic pressure and the wedge pressure.
Now, we'll actually show three patient examples by right heart catheterization. I’m just going to highlight patient one and patient three just for contrast. Patient one has a right atrial pressure of seven in the setting of severe pulmonary hypertension but note that their left heart filling pressure or their pulmonary artery occlusion pressure, otherwise known as their wedge pressure, is very high at 30. Their PVR is only 2.6 Woods units and they have systemic hypertension.
This patient has pulmonary hypertension in the setting of their mitral valve disease, but this is purely passive left atrial congestion. This patient does not have pulmonary arteriopathy. The patients all the way to the right, patient number three, quite different. A right atrial pressure of 22, a wedge pressure that’s not that high but look how elevated that pulmonary vascular resistance is at 11 Woods units with a low cardiac output.
Remember, both of these patients have severe mitral valve disease. One patient, the patient one, does not have arteriopathy. Patient three does have arteriopathy. Now, what’s interesting is that in either case, these patients still need their mitral valve surgically or interventional cardiology technique repaired or replaced. Now we fix the valve.
Our mitral valve repair replacement in the setting of pulmonary arteriopathy should preferably occur at a center where they have pulmonary hypertension expertise and experience in managing all forms of pulmonary hypertension. This is a very important point. If you have a patient with mitral valve disease and they have arteriopathy, that surgical repair should happen at a place where there’s on-site medical expertise in the management of pulmonary hypertension because the patient may retain their pulmonary hypertension in the ICU after the surgery, which may require special attention.
Mitral valve repair is preferred over a replacement when possible and remember to respect the arteriopathy and follow the patient closely in the postop setting. Repeat their echo, repeat their hemodynamics and follow them over those first several days in the unit. Of course we should be following these patients in clinic thereafter.
I put this slide up here just to show you that although we have clinical guidelines and ways to classify pulmonary hypertension, and this is just the title slide from the NICE document published in 2014, the guidelines and pulmonary hypertension really don’t apply to many of our patients who are going for heart surgery and who are treated in the ICU following heart surgery. We have a relative blind spot in our guidelines as we extrapolate our evidence into patients in the operating room or patients in the ICU.
With that in mind, we have to be good clinicians, we have to integrate our information, we have to think along pathophysiologic lines and we have to adhere to first principle basic physiology in medicine in order for these patients to have the best outcome.
To summarize a critical first step in the setting of mitral valve disease and pulmonary arteriopathy is to recognize and appreciate the presence of significant mitral valve disease. This is a key step that can’t be overlooked.
We think along first principle lines. Severe mitral valve disease causes dyspnea. This also causes pulmonary hypertension. The pulmonary hypertension is from the mitral valve disease and therefore you should fix the mitral valve disease. Pulmonary arteriopathy does occur in mitral valve disease, whether it be a stenotic or a regurgitant mitral valve. Pulmonary arteriopathy can be recognized non-invasively and confirmed by invasive hemodynamics. Lastly, fix the valve and watch for residual arteriopathy that may need specific treatment. Thank you very much.