Contrast Enhanced PA Pressure Measurements

Pulmonary hypertension (PH) is an abnormal increase of the pressure inside the lung circulation. This condition can be caused by many different diseases. If PH persists for a long period of time, irreversible damage to the lung circulation and to the heart may ensue. A definitive diagnosis of PH requires direct measurement of the pressure within the lung circulation with a procedure called right heart catheterization (RHC). While overall safe, RHC is an invasive procedure and is associated with a small risk of complications (\~1.1%) and, very rarely, death (0.055%), even when performed in experienced laboratories. Therefore, alternative diagnostic approaches are often employed such as an ultrasound technique called Doppler echocardiography which is non-invasive, relatively inexpensive and widely available technique. It is suitable not only as a screening tool but also for serial monitoring of disease progression in PH. However, the accuracy of Doppler echocardiography in measuring pressure in the lung circulation appears to be modest in patients with suspected PH. To improve the performance of Doppler echocardiography it is common practice to inject a small amount of agitated saline or an echocardiographic contrast medium (usually composed of microbubbles of fat containing a minuscule amount of a gas) into a vein. However, the accuracy of using agitated saline or a contrast agent in the measurement of pressures inside the lung circulation has not been established. The proposed study will assess the accuracy of Doppler echocardiographic measurements of pressures in the pulmonary circulation by simultaneously comparing the pressures collected during a RHC. The investigators will enroll 100 consecutive patients undergoing RHC in the Catheterization Laboratory of Northwestern Memorial Hospital. The investigators will measure pulmonary pressures by RHC and by Doppler echocardiography at baseline and following the injection of agitated saline as well as Optison®, an FDA-approved contrast agent commonly used in the echo laboratory. The investigators will then determine the accuracy of the Doppler echocardiography measurement without and with the use of agitated saline or Optison® with the measurements obtained during the RHC which is the gold standard. The results of this study will allow determination whether the use of echo contrast improves the accuracy of Doppler echocardiography and whether contrast-enhanced Doppler measurements are a clinically useful alternative to RHC measurements.