Know When to Refer Your Patients to the PH Center

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Welcome to CME on ReachMD. This episode is part of our MinuteCME curriculum and is titled “Know When to Refer Your Patients to the PH Center”.

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Dr. Preston:
Let's talk about when to refer your patients to the PH center. Know when to refer your patients to the PH center.

So, first, if you suspect pulmonary hypertension, the PH center can offer hemodynamic evaluation. Because the right heart catheterization is still the only validated method to confirm and grade pulmonary hypertension, and it's best performed at the PH center. The recent studies have shown that even patients with mean PA pressure less than 20, or a mean PA pressure between 21 and 24 at rest may develop pulmonary hypertension, sometimes during exercise. And this is what we call exercise induced pulmonary hypertension. So, minimal elevations in PA pressures may be a trigger to think that this patient may develop or may have hypertension in the future. The use of exercise hemodynamic measurements in symptomatic patients with pulmonary perfusion defects and normal resting mean PA pressure can reveal the presence of abnormal cardiodynamic response to effort, especially in patients with chronic clots. So doing an exercise during the right heart catheterization in patients with chronic PEs, or with prior PEs, can uncover the defects that are significant during exercise. And that's what we call exercise induced pulmonary hypertension. On the other hand, exercise in patients with pulmonary hypertension that looks like a type one PH, and they have a normal wedge, may uncover abnormalities in the left heart and increases in wedge with exercise. So just the presence of diastolic left heart disease, that may account for the increased pressures on the right side. So, in other words, group two pulmonary hypertension. So that's why a center can perform these more complex studies during the right heart catheterization. And that's why we recommend the right heart cath be done at a PH center.

So, let's see, the diagnosis of PAH. We have to confirm it by the right heart cath. We can calculate resistances after we do all the direct measurements. It can give us a guidance to what type of therapy we should implement. It excludes other diagnosis of PH, other etiologies of PH, such as left heart disease. And it measures the right ventricular function by measuring the right atrial pressure, and by measuring the cardiac output. On the right-hand side, this table gives you the variables that we are typically measuring during the right heart catheterization. The last point is very important for patients in whom we suspect idiopathic PAH or drugs and toxins in this PH or familial PH. The vasodilator challenge is a crucial step at the end of a right heart cath to identify those folks who may benefit from calcium channel blocker treatment only. So they won't need the more expensive, more advanced therapies. The lower part suggests that hemodynamic values used in the ESC, ERS guidelines. The functional class in the hemodynamic parameters, together, can give you a good assessment of how severe the pulmonary hypertension is.

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