Transcript
Announcer:
Welcome to Clinician’s Roundtable on ReachMD. On this episode, we’ll hear from Dr. Jean Elwing, who’s a Professor of Medicine and the Director of the Pulmonary Hypertension Program in the Division of Pulmonary, Critical Care, and Sleep Medicine at the University of Cincinnati. She’ll be discussing how we can better recognize pulmonary hypertension in patients with interstitial lung disease. Here’s Dr. Elwing now.
Dr. Elwing:
It is so challenging to detect pulmonary hypertension in the setting of interstitial lung disease because there is so much overlap of symptoms in both conditions. Dyspnea, fatigue, exercise intolerance, and increasing oxygen requirements are things we see in progressive ILD, but they also occur in pulmonary hypertension. Pulmonary hypertension can be developing in parallel to pulmonary fibrosis, and in some patients, both are contributing to the clinical deterioration.
Another big challenge we face is there's not one single non-invasive test we can reliably use to prove or disprove the presence of pulmonary hypertension in this population. Echocardiograms are extremely useful, but they can be clinically challenging. They oftentimes are technically difficult in patients with lung disease, and we cannot solely rely on an estimated pulmonary pressure.
One study that's been very helpful is the PHINDER study, and it really illustrates this challenge. In the preliminary prospective data, clinician gestalt did not do very well. It alone had limited accuracy for the identification of pulmonary hypertension. Importantly, even some patients who they thought had a low likelihood of having pulmonary hypertension ended up going on to have proven pulmonary hypertension by right heart catheterization.
So for me, the most important concept is disproportionality. Is the shortness of breath, the oxygen requirement, or the decreased exercise capacity out of proportion to the interstitial lung disease? So when a patient's symptoms, functional limitation, oxygen requirement, or exercise capacity is changing and is not consistent with the pattern of the interstitial lung disease, we need to look for pulmonary hypertension. So ask yourself, “Is the ILD alone enough to explain what is happening to the patient?” And we have to also be aware that we could have progression of both conditions at the same time.
There are some clues we should pay attention to. It's usually not just one thing; it's the pattern. It's the trajectory of several findings over time. One of the biggest clues is worsening shortness of breath or declining exercise tolerance that's out of proportion to what's happening with the interstitial lung disease. Increasing oxygen requirements or worsening exertional desaturations also should get our attention. On our pulmonary function tests, we can find some more clues. If there's a decreasing diffusing capacity out of proportion to what's happening with the lung function, that should raise suspicion. Also, when we do our six-minute walk test, is the exercise tolerance changing or the oxygen requirement increasing? And we need to be very suspicious if that's happening in the setting of a stable CT chest. CT imaging should be used for more than just looking at the lung parenchyma; we need to look at the pulmonary artery size and the ratio of that pulmonary artery to the aorta, and also look at the right heart. Is the right heart enlarging? And then we can also, of course, look at our echocardiogram, which is our classic tool we use to look for pulmonary hypertension. We want to know more than the estimated pulmonary pressure; we also want to look at right atrial size, right ventricular size, and RV function. In terms of labs, we can look at our NT-proBNP or our BNP.
So we need to put all the pieces together to try to drive us towards the correct diagnosis of interstitial lung disease or interstitial lung disease with pulmonary hypertension.
Announcer:
That was Dr. Jean Elwing discussing how we can recognize pulmonary hypertension in patients with interstitial lung disease. To access this and other episodes in our series, visit Clinician’s Roundtable on ReachMD.com, where you can Be Part of the Knowledge. Thanks for listening!
