US Echocardiography Transthoracic Resting Transthoracic Doppler echocardiography is a noninvasive test that is a useful part of the initial evaluation of suspected PH [22]. A recent meta-analysis by Ni et al [23] showed that, overall, it has good sensitivity and fair specificity (85% and 74%, respectively) for detecting moderate to severe PH. However, it does not perform as well in detecting mild PH, particularly cases of PH secondary to lung diseases. Transthoracic Doppler echocardiography uses continuous wave Doppler to measure the peak tricuspid regurgitation velocity, which is used in combination with various echocardiographic signs suggestive of PH to assign a low, intermediate, or high echocardiographic probability of PH [24-26]. Echocardiographic signs suggestive of PH fall into 3 categories: right ventricular (RV) findings, PA findings, and inferior vena cava (IVC)/right atrial (RA) findings. RV findings include RV/left ventricular (LV) basal diameter ratio >1 and flattening of the interventricular septum. PA findings include PA diameter >25 mm, early diastolic Transthoracic Doppler echocardiography is also useful in the assessment of multiple right heart parameters that are influenced by PH, including RA and RV size, RV systolic function, RV strain, tricuspid annular plane systolic excursion, and biventricular index. A biventricular index (RV end-diastolic area to LV end-diastolic area) >0.93 is associated with an increased risk of death in patients with PH [22,27]. The presence of pericardial effusion as well as valvular morphology and function are also easily assessed by echocardiography. An echocardiographic bubble study using agitated saline can be performed during the examination to assess for intracardiac shunts [11]. Studies have shown that real-time 3-D echocardiography evaluates RV volumes and the ejection fraction more accurately than conventional 2-D echocardiography [28].
Suspected Pulmonary Hypertension. US Echocardiography Transthoracic Resting Transthoracic Doppler echocardiography is a noninvasive test that is a useful part of the initial evaluation of suspected PH [22]. A recent meta-analysis by Ni et al [23] showed that, overall, it has good sensitivity and fair specificity (85% and 74%, respectively) for detecting moderate to severe PH. However, it does not perform as well in detecting mild PH, particularly cases of PH secondary to lung diseases. Transthoracic Doppler echocardiography uses continuous wave Doppler to measure the peak tricuspid regurgitation velocity, which is used in combination with various echocardiographic signs suggestive of PH to assign a low, intermediate, or high echocardiographic probability of PH [24-26]. Echocardiographic signs suggestive of PH fall into 3 categories: right ventricular (RV) findings, PA findings, and inferior vena cava (IVC)/right atrial (RA) findings. RV findings include RV/left ventricular (LV) basal diameter ratio >1 and flattening of the interventricular septum. PA findings include PA diameter >25 mm, early diastolic Transthoracic Doppler echocardiography is also useful in the assessment of multiple right heart parameters that are influenced by PH, including RA and RV size, RV systolic function, RV strain, tricuspid annular plane systolic excursion, and biventricular index. A biventricular index (RV end-diastolic area to LV end-diastolic area) >0.93 is associated with an increased risk of death in patients with PH [22,27]. The presence of pericardial effusion as well as valvular morphology and function are also easily assessed by echocardiography. An echocardiographic bubble study using agitated saline can be performed during the examination to assess for intracardiac shunts [11]. Studies have shown that real-time 3-D echocardiography evaluates RV volumes and the ejection fraction more accurately than conventional 2-D echocardiography [28].