Echocardiography and Pulmonary Hypertension

Question If a patient is symptomatic of pulmonary hypertension (PH) but their echocardiogram is normal, should you still do a cardiac catheter?

Response from Michael A. Mathier, MDAssistant Professor of Medicine; Director, Cardiovascular Fellowship, University of Pittsburgh, Pittsburgh, Pennsylvania; Director, Pulmonary Hypertension Program, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania

To state the question in a different way, "What is the sensitivity of echocardiography for the diagnosis of PH"? Or, more colloquially, "What is the chance that a patient with a normal echocardiogram has PH?"
The simple answers are: the sensitivity of echocardiography for the diagnosis of PH appears to be very good; and the chance of a patient with a normal echocardiogram having PH appears to be very small.
Echocardiographic estimates of pulmonary artery (PA) pressures are almost always made based on a measure of the tricuspid regurgitation jet velocity, which appears to be measurable in the overwhelming majority of, though not all, patients.[1] Therefore, if a "normal" echocardiogram does not include a measurable tricuspid regurgitation velocity, one must be cautious in relying on it to exclude PH.
A number of studies have examined the sensitivity of echocardiography for the diagnosis of PH, using cardiac catheterization as a gold standard. These studies have found sensitivities ranging from 79% to 100%.[2,3] Furthermore, most studies have found excellent correlations between PA pressure estimated by echocardiography and that measured by catheterization.[4] It bears remembering, however, that an important determinant of the diagnostic value of echocardiography for PH is the pretest probability of PH for the patient or the population under study. When this is factored in, one arrives at the negative predictive value, or the likelihood that a normal echocardiogram in a given population truly indicates an absence of PH. For example, in a population with advanced liver disease (which we expect to have a fairly high prevalence of PH), the negative predictive value of a normal echocardiogram is 92%, meaning that 8% of patients with advanced liver disease who have a normal echocardiogram will nonetheless be found to have PH.[5] It is important to remember that this represents a high-risk population, and the negative predictive value would be expected to be quite a bit higher in a general population.
Of course, the decision to pursue cardiac catheterization in the face of a normal echocardiogram needs to be made on a case-by-case basis. If a patient has a high prior probability of PH, based on risk factors and symptoms, a normal echo may not dissuade the clinician from proceeding with catheterization. Right heart catheterization is a very low-risk procedure and may be warranted in some cases, even when echocardiography is not suggestive of PH.

http://www.medscape.com/viewarticle/559904